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1. M 2 L Ext Output x 3 Filter cee stage Pressure sensor USB port Flow control Vacuum pump Figure 1 Operating principle of the ELPI a DEKATI Dekati Ltd 2011 ELPI User Manual 1 w The ELPI unit can be used either as a standalone instrument or with an external computer Automatic zeroing function in the ELPI unit enables long term standalone operation Through the ELPl vi software the unit can be controlled remotely with TCP IP or connection 6 analog inputs and 3 analog outputs from to ELPI unit can be used for transferring information between measurement systems The ELPI internal software ELPInux and the ELPI vi software can both be used to save the measurement results More information on the function of the ELPI impactor can be found in J Keskinen K Pietarinen and M Lehtim ki 1992 Electrical Low Pressure Impactor J Aerosol Sci Vol 23 No 4 pp 353 360 KS DEKATI Dekati Ltd 2011 ELPI User Manual 2 w 2 SPECIFICATIONS Measurement Nominal air flow Particle size range Number of channels Sampling rate 10 l min 0 006 10 um 14 electrically detected preseparator stage 10Hz Operation conditions instrument Ambient temperature Ambient humidity Sample conditions 10 35 C 0 90 RH non condensing Gas temperature lt 60 C Dimensions Weight 15 kg without impact
2. ceccceceeccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 27 6 3 Yearly service 27 6 4 ELPI standard service 28 a DEK ATI Dekati Ltd 2011 ELPl User Manual vi b di 7 ELPI INTERNAL SOFTWARE 7 1 Distribution charts 7 2 Navigation 7 2 1 Men 1 3 P 7 2 2 Menu rr c EE apos m 7 2 4 Changing or setting the value essssseessese 7 2 5 Advanced Paramelels ease sen tep Aog bise nuca uA qusti ei aeu euER 7 2 6 MEE uelle mcm 7 2 7 Append Data to FG e Teese JMSB AN CINONY ooo ue tite Ren EB egies ld a P Ea 7 2 9 Import Device Parameters eeseeeeeeeeseeee 7 2 10 Import Impactor ParameterS c eceeeeeeeeeeeeeeeeneeeeeeeees DAR EDON Er 7 2 12 Device Neoe 7 2 13 Zeroing of the electrometer currents 7 2 14 Setting the controller parameters ssesssssss 7 2 15 Auxiliary analog channel settings sssssss 7 2 16 Impactor NUMBER 2m en oer eren beu x enne Eos en bud uni 7 2 17 Setting the filter stage on off eeeessseessssssss 7 2 18 Setting the Auto Zeroing interval ssssssssss CAE LE oou rm 7 2 20 Setting the distribution moment ssssesssssss 7 2 21 Setting the distribution type usce sni tener paene tio rnb pan 7 2 22 Setting the fine particle loss corre
3. vector formed from the midpoint values Di of each stage dD dlog Dp Ci 1 Xi Di Di 1 dlog Dp Area distribution Area distribution gives the total surface area of all particles in each size range It is formed by multiplying the current distribution by the conversion vector and by a vector formed from the surface areas of spheres having diameter equal to midpoint values Di of each stage dA dlog Dp Ci 1 Xi Di rr Di7 1 dlog Dp Volume distribution Volume distribution gives the total volume of all particles in each size range It is formed by multiplying the current distribution by the conversion vector and by a vector formed from the volumes of spheres having diameter equal to midpoint values Di of each stage dV dlog Dp Ci 1 Xi Di s vr Di 1 dlog Dp a DEKATI Dekati Ltd 2011 ELPI User Manual 75 w 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Dia 0 006 0 017 0 03 0 06 0 108 0 17 0 26 0 4 0 64 1 1 6 2 5 4 4 6 8 an 585 69 1233 40 4571 91 12232 4 29672 2 36239 5 68540 1 80523 3 80747 2 44362 2 23538 5 8385 29 585 69 1233 40 Conversion vector from current to number 422 4522 337 9666 118 3627 59 9285 39 0460 23 3455 13 0898 6 6202 3 8080 1 9749 1 1360 0 4600 0 3086 0 2026 distribution dN dlogDp from above Number distribution 247426 416848 541143 733069 1158580 846029 897176 533080 307485 87610 26739 3857
4. IP address of the ELPI unit For details on different options for the Ethernet connection please see chapter 9 Ethernet connection a DEK ATI Dekati Ltd 2011 ELPI User Manual 56 w Parameterslmpactor xxxxx xml file consists of following parameters Calculation group consists of parameters that affect the concentration calculation Dilution factor of the sample Estimated density of the sample Cut points for the impactor stages Downstream pressures of the impactor stages Residence times of the impactor stages Not in use should always be 1 Not in use should always be 1 Not in use should always be 1 Charger efficiency curve parameters Flow rate from the data sheet HW Control parameters consist of PID parameters for external accessories Impactor calibration temperature Header parameters are mostly user defined informative parameters that are saved to the data file header These parameters can either be changed in the parameter file or in the ELPI VI software all caren Date when the impactor was last cleaned Collection substrate type Greased Al foils 0 Al foils 1 Bare stage 2 Nucle bore 3 Filter 4 Other 5 ELPI impactor serial number Not in use a DEKATI Dekati Ltd 2011 ELPI User Manual 57 w 9 ETHERNET CONNECTION When the ELPl is used with ELPlvi via Ethernet connection the IPconfig parameters in the ParametersDevice file that need to be changed depending on the setup
5. 1404 621 dN dlogDp And we get the number distribution Terms Number distribution Number distribution is formed by multiplying the current distribution with the conversion vector dN Ci 1 Xi Di 1 dlog Dp Aerosol distributions are normally given in the 1 dlog Dp mode It is formed by dividing the stages measured value by the logarithmic width of the stage In 1 dlog Dp mode the area of the histogram gives the value in each size range dN dlog Dp dN 1 dlog Dp Diameter distribution Diameter distribution gives the total diameter of all particles in each size range It is formed by multiplying the current distribution by the conversion vector and by a Mass distribution Mass distribution gives the total mass of all particles in each size range It is formed by multiplying the current distribution by the conversion vector and by a vector formed from the masses of spheres having diameter equal to midpoint values Di of each stage Note that mass distribution is scaled to unit mg m dV dlog Dp Ci 1 Xi Di Tt Di Density 1 dlog Dp 10 A 2 1 Using different density values in the ELPI calculation By default the ELPI and the ELPI VI software use density value of one 1 for the particles in the calculation of particle concentrations and size distributions This is a good estimate in most applications and the results can be considered reliable If it is kn
6. O ring set for ELPI impactor Dekati Fine Particle Sampler Dekati diluter Sampling cyclone a DEK ATI Dekati Ltd 2011 ELPI User Manual b di 77 C ELPI SUPPORT Dekati Itd encourages you to comment on the products we make Please fill out the following forms and send them to Dekati Itd Mail to Dekati Itd Osuusmyllynkatu 13 FIN 33700 Tampere Finland Fax to Dekati Itd 358 3 3578140 email support 2dekati fi DEKATI Dekati Ltd 2011 ELPI User Manual 78 w Documentation comment form Dekati Itd encourages you to comment on the documentation supplied with our products This information helps us provide quality products to meet your needs ELPl vi version and revision number ELPl vi Help file version number ELPI User manual version number Please comment on the completeness clarity and organization of the manual and help files If you find errors in the manual or in the help files please record the page numbers and describe the errors Thank you for your help Name Title Company Address phone fax email K CN DEKATI Dekati Ltd 2011 ELPI User Manual 79 w ELPI Technical support form If you find any troubles or errors concerning the ELPI unit or ELPl vi Measurement program please provide us the following information Used external computer Processor Clock Speed RAM Hard disk Operating System Version number Video board driver
7. Saving to File off Append Data To File Off USB Memory Mounted Import Impactor Parameters Export Open Modify If the mounting of the USB drive is successful the texts Import and Export change their colors from grey to white This means that reading from and saving to the USB drive is possible The data is always saved to the USB stick when saving is on no data is saved to the internal computer 7 2 9 Import Device Parameters When Import Device Parameters text is selected all files named ParametersDevice xxxxx xml will be read from the USB drive into ELPInux This operation can t be done if the USB drive has not been mounted the text is grey 7 2 10 Import Impactor Parameters When Import Impactor Parameters text is selected all files named Parameterslmpactor xxxxx xml will be read from the USB drive into ELPInux This operation can t be done if the USB drive has not been mounted the text is grey 7 2 11 Export When Export text is selected all parameter files will be saved to he USB drive This operation cannot be done if the USB drive has not been mounted the text is grey a DEKATI Dekati Ltd 2011 ELPI User Manual 41 w Control menu When the Control option is selected in the main menu a submenu is opened Current fA 11 53 18 Trap Flush Start Electrometer Calibration Pressure PID P Pressure PID Pressure PID D Low Pressure Set Point OpenModify 7 2 12 Device controls
8. are connected together with an ethernet cable between them then you have to set fixed ip addresses See previous chapter to both of them a DEK ATI Dekati Ltd 2011 ELPI User Manual 58 w Also Netmasks have to be configured same For example set address 10 16 0 26 to ELPl and 10 16 0 27 to the PC and set netmask 255 255 255 0 to both devices Setting the fixed IP address for the PC depends on the operation system but can usually be found at Contol Panel gt Network Connections Network and Sharing Center gt LAN properties Local Area Connection gt Properties gt TCP IP gt Properties r Internet Protocol Version 4 TCP IPv4 Properties i General You can get IP settings assigned automatically if your network supports this capability Otherwise you need to ask your network administrator for the appropriate IP settings Obtain an IP address automatically Use the following IP address IP address Subnet mask Default gateway Obtain DNS server address automatically Use the following DNS server addresses Preferred DNS server Alternate DNS server F Validate settings upon exit Advanced K CN DEKATI Dekati Ltd 2011 ELPI User Manual 59 w A PHYSICAL OPERATION A 1 Particle collection and properties A 1 1 Impactor In the ELPI a cascade impactor is used to collect particles size selectively An impactor is a simple device having two co linear
9. 0 5060 0 8000 1 2649 2 0000 3 3166 5 4699 Stokes Dp um 0 006 0 017 0 030 0 0600 0 108 0 170 0 260 0 400 0 640 1 000 1 600 2 500 4 400 6 8 10 Cc 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Di 0 0100 9 0154 0 0294 0 0574 0 0997 0 1591 0 2500 0 3994 0 6391 1 0182 1 6181 2 6926 4 4508 At this point we have to decide if aerodynamic or stokes particle size is used Let s assume that it is aerodynamic Impactor 4 7 1 11 12 1 14 onana 2 3 5 6 8 9 10 3 5 Aero Dpa dynamic um 0006 0 017 0 03 0 06 0 108 0 17 0 26 O4 0 64 1 16 25 44 68 10 Cc 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 Di 0 0136 0 0226 0 0424 0 0805 0 1355 0 2102 0 3225 0 5060 0 8000 1 2649 2 0000 3 3166 5 4699 Stokes Dp um 0 006 0 017 0 030 0 0600 0 108 0 170 0 260 0 400 0 640 1 000 1 600 2 500 4 400 6 8 10 Cc 37 1057 19 6398 11 2747 5 8383 3 4773 2 4547 1 8844 1 5432 1 3282 1 2073 1 1287 1 0821 1 0465 1 0300 Di 0 0100 9 0154 0 0294 0 0574 0 0997 0 1591 0 2500 0 3994 0 6391 1 0182 1 6181 2 6926 4 4508 Di um 0 0136 0 0226 0 0424 0 0805 0 1355 0 2102 0 3225 0 5060 0 8000 1 2649 2 0000 3 3166 5 4699 Then we calculate a dlogDp multiplier vector Dp dlogDp log cU n Impactor E 4 7 1 11 12 1 14 1 properties 1 2 3 5 6 8 9 0 3 5 Aero Dpa 0 006 0
10. 017 0 03 0 06 10 108 0 17 0 26 0 4 064 1 16 25 44 68 10 dynamic um Cc 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Di 0 0136 0 0226 0 04240 0805 0 1355 0 2102 0 32250 5060 0 8000 1 2649 2 0000 3 3166 5 4699 8 2462 Stokes Dp um 0 006 0 017 0 03 0 06 0 108 0 17 026 0 4 0 64 1 16 25 44 68 10 Ce _137 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Di 0 0136 0 0226 0 04240 0805 0 1355 0 2102 0 32250 5060 0 8000 1 2649 2 0000 3 3166 5 4699 8 2462 Di um 0 0136 0 0226 0 04240 0805 0 1355 0 2102 0 32250 5060 0 8000 1 2649 2 0000 3 3166 5 4699 8 2462 dlogDp 0 4523 0 2467 0 3010 0 2553 0 1970 0 1845 0 1871 0 20410 1938 0 2041 0 1938 0 2455 0 1891 0 1675 Where Di values are either stokes or aerodynamic values depending on the selection K N DEKATI Dekati Ltd 2011 ELPI User Manual NV 72 Finally we calculate the conversion vector X from current to number Now we need the charger efficiency function Charger efficiency function is a three part power fit and it is a result of calibration values P n and constants e and Q where P Charger penetration n average charge per particle e elementary charge 1 602 10 C Q Calibration flow rate 10lpm P n values are originated from artic
11. EVEN TO MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE EITHER EXPRESS OR IMPLIED ARE MADE WITH RESPECT TO THE SOFTWARE NO STATUTORY WARRANTY SHALL APPLY EITHER DEKATI LTD DOES NOT WARRANT GUARANTEE OR MAKE ANY REPRESENTATIONS REGARDING THE USE OH THE RESULTS OF THE USE OF THE SOFTWARE OR THE DOCUMENTATION AND DOES NOT WARRANT THAT THE OPERATION OF THE SOFTWARE WILL BE UNINTERRUPTED OR K N DEKATI Dekati Ltd 2011 ELPI User Manual iii w ERROR FREE OR THAT THE SOFTWARE WILL MEET THE NEEDS FOR WHICH IT HAS BEEN ACQUIRED IN NO EVENT SHALL DEKATI LTD AND ITS DIRECTORS AGENTS AND EMPLOYEES OR ITS SUPPLIERS BE LIABLE FOR DIRECT INDIRECT INCIDENTAL EXEMPLARY OR CONSEQUENTIAL DAMAGES EXPENSES LOST ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE OR THE DOCUMENTATION LICENSEE ACKNOWLEDGES THAT THE LICENSE FEE REFLECTS THIS ALLOCATION OF RISK DEKATI LTD EXPRESSLY DISCLAIMS ANY WARRANTIES NOT STATED HEREIN IF DEKATI LTD FURNISHES LICENSEE WITH ADVICE OR OTHER ASSISTANCE WHICH CONCERNS THE SOFTWARE OR ANY PORTION THEREOF SUPPLIED HEREUNDER OR ANY SYSTEM OR EQUIPMENT ON WHICH ANY SUCH SOFTWARE MAY BE INSTALLED AND WHICH IS NOT REQUIRED PURSUANT TO THIS AGREEMENT THE FURNISHING OF SUCH ADVICE OR ASSISTANCE WILL NOT SUBJECT DEKATI LTD TO ANY LIABILITY WHETHER IN CONTRACT WARRANTY TORT INCLUDING NEGLIGENCE OR OTHERWISE GENERAL WARNING DEKATI LTD PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF
12. Manual viii w 1 INSTRUMENT DESCRIPTION The ELPI Electrical Low Pressure Impactor is a real time particle spectrometer for measuring airborne particle size distribution in real time The operating principle is based on well known ELPI technology The particles are first charged to a known charge level in a corona charger After charging the particles are size classified in a low pressure cascade impactor according to their aerodynamic diameter The impactor stages are electrically insulated and sensitive electrometers are connected to each impactor stage The charged particles collected in a specific impactor stage produce an electrical current which is recorded by the respective electrometer channel This current is proportional to the number concentration of particles on each stage The ELPI measures particles in 14 size fractions in the range from 6 nm to 10 um The 13 impactor stages operating in the range of 17nm 10 um collect the sample in a way that the collected sample can be chemically analyzed The final stage measuring in the range of 6 17nm is a back up filter stage l Clean flush air for zeroing T Sensor n PUp lt q D Charger Display and controls 7 HV source T kapani 140 13 amp Egiectrometers 324 Internal PC impactor 11 Connection to PC 10 gt Optional 9 3 L 2h AID a _ 6 t Ext Input x 6 5 1
13. O rings e contacting metal and insulator surfaces are clean and intact e the vacuum gasket under the ELPI impactor is properly positioned and the NW16 gasket at the ELPI outlet in the NW16 flange connections is properly positioned e that teflon tape has been applied on the ELPI vacuum connections to seal them K N DEKATI Dekati Ltd 2011 ELPI User Manual 20 w 4 5 Electrometer zeroing Zeroing is needed to adjust the measured current for the electrometers bias current Different bias currents are caused for example by different operation conditions like ambient temperature Flush pump Zeroing has to be performed before ELPI is used for measuring If the measurement period is long zeroing should be checked regularly especially if ambient temperature conditions change during measurement Zeroing can either be performed manually or the zeroing period of the ELPI can be preprogrammed to a certain time interval more detailed instructions for this can be found in the ELPI internal software section of this manual The flush pump can be used to check the offset currents The flush pump is located inside the ELPI unit and it pumps clean HEPA filtered air through the instrument This way electrometer readings at zero concentrations can be checked When the flush pump is switched ON the airflow comes out of the ELPI inlet The ELPI inlet should be open at all times when the flush pump is switched
14. ON to prevent any damage to the flush pump The flush pump can also be used to keep the ELPI clean between the measurements when the flush is ON there is no sample collected into the ELPI impactor The flush pump can be switched on from the ELPI unit display using the push buttons or from the ELPl vi software Zeroing Before zeroing the ELPI should reach its stable operation temperature and the measured currents must be properly stabilized It is therefore necessary to switch on the unit at least half an hour before the zeroing and measurement Before starting the zeroing procedure the charger is adjusted to normal measurement settings impactor low pressure is adjusted to 40 mbar and the flush pump is switched on to let a flow of clean and filtered air go through the instrument At this point it is often useful to look at the current values in different impactor stages This can be done e g by looking at the ELPI display the default graph when the ELPI is turned on shows the current values on each impactor stage as a function of time In the beginning the current values may drift up or down After they have stabilized the zeroing can be started Note that the current measurement always has some noise The zeroing can be started when the drift of the electrometers has stopped After successful zeroing the current values noise levels with flush pump ON or with filtered inlet air should not exceed 10 fA Ze
15. RELIABILITY SUITABLE FOR USE IN THE DIAGNOSIS AND TREATMENT OF HUMANS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN RELIABILITY OF OPERATION OF THE SOFTWARE CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY COMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS OR DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISSUSES OR ERRORS ON THE PART OF THE USER OR APPLICATION DESIGNER ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ELECTRONIC MONITORING DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS If any provisions of this agreement is partially or wholly held invalid the offering clause will be modified so as to be enforceable and shall be fully
16. all these particles cannot be predicted by single equations Large molecules gt Rigid bodies Kinetic gas theory Fluid mechanics Diffusion charging wo Field charging Rayleigh scattering 4 Fraunhofer scattering 0 001 0 01 0 1 1 10 100 Particle Size uum Jum ELP I Definition of the particle size is not self evident Optical and morphological properties of aerosol particles can have large variations For this reason different measurement methods can give different results for same aerosol In impactors size fractionation is based on a quantity called the aerodynamic diameter It is defined as a diameter of a unit density py spherical particle having the same settling velocity Vrs as the actual particle Another widely used definition is the Stokes diameter D s which is the diameter of a spherical particle having the same bulk density and settling velocity as the actual particle K N DEKATI Dekati Ltd 2011 ELPI User Manual 62 w Real particle Stokes Diameter Aerodynamic Diameter Q Vis 0 22 cm s 0 22 cm s 0 22 cm s D app 3 bum 4 3yum 8 6 um Pp 4 g cm 4 g cm 1 g cm A 1 3 Particle impaction and stopping distance Particle flow path through the jet plate nozzle and in the sharply curving gas stream between the jet and the collection plates depends on the inertial forces acting on the particle and friction between the particle and the f
17. connector 4 3 Collection substrates The collection substrates are used on the collection plates for two reasons the use of the collection substrates enable gravimetric or chemical analysis after the measurement and the use of collection substrates makes the maintenance much easier The collection substrates should be 25 mm in diameter smooth and poreless and can be made for example from household aluminum foil Other substrate materials are also available e g polycarbonate foils are suitable for different types of chemical analysis The maximum thickness for the substrates is 0 1 mm K CN DEKATI Dekati Ltd 2011 ELPI User Manual 18 w The most commonly used grease in impactor measurements is Apiezon L because of its purity and low evaporation properties Dekati Ltd provides Apiezon L for substrate greasing but other types of greases may also be used as long as the grease has low evaporation characteristics even in low pressures min 40 mbar abs a thin and smooth layer of used grease can be applied on the substrate and the grease has low enough viscosity so that the air flow inside the impactor does not blow the grease out of the impactor collection substrates For high temperature applications above 150 C Dekati provides Apiezon H grease 4 3 1 Inserting the collection substrates 1 Disassemble the impactor and separate the stages as explained in Section 4 1 2 Remove the substrate holder rings from the impaction plates Yo
18. plates of which the other has a small nozzle in it The plate with nozzles in it is called the jet plate and the second one the collection plate Aerosol passes through the nozzles of the jet plate with high speed and makes a sharp turn to flow between the plates Particles larger than a certain size characteristic to the dimensions of the impactor can t make the sharp turn and impact on the second plate Nozzle Diameter Dj Jet velocity U Jetto plate distance Collection substrates Impactor operating principle Cascade impactors consist of several successive impactor stages with decreasing cut diameters The highest stage stage 15 in the Dekati impactor has a cut KN DEK ATI Dekati Ltd 2011 ELPI User Manual 60 w diameter of about 10 um and the lowest impactor stage stage 2 about 17 nm see exact values in the impactor data sheet The lowest stages of the Dekati impactor operate in reduced pressure and so it is also called a low pressure impactor The cut diameter for an impactor is defined as the size of particles collected with 50 efficiency Ideally the collection efficiency would be a step function so that all particles bigger than certain cut point were collected on the impactor stage whereas all particles smaller than certain size continued with the flow to lower stages However due to bounce and blow off some of the bigger particles will go to lower stages than they should and due to diffusion some of the sma
19. the ELPI external pump please see the pump manual Remove the ELPI impactor charger assembly from the ELPI unit Remove the ELPI vacuum pump connector and possible inlet connectors Place the ELPI impactor and charger assembly and accessories in the separate compartments inside the black transport box Place the black box into a cardboard box or similar Secure the packing with e g Styrofoam to make sure that the black box does not move inside the larger box The ELPI instrument should always be handled with care to prevent any damage to the instrument DEKATI Dekati Ltd 2011 ELPI User Manual 9 w 4 SETTING UP THE INSTRUMENT 4 1 Disassembling and assembling the impactor 4 1 1 Disassembling the impactor To release the impactor from the ELPI housing take off the charger trap and flush pump connectors Press the release button at the bottom of the impactor and pull the impactor from the housing K N DEKATI Dekati Ltd 2011 ELPI User Manual 10 w Lift the locking handle to the upright position and slide the charger with the pre selector stage out from the impactor assembly Turn the locking ring at the bottom of the ELPI impactor clockwise and lift the impactor cover KS DEKATI Dekati Ltd 2011 ELPI User Manual 11 w IL The collection plate and PEEK insulator of the stage 15 attached with the charger are placed on top of the impactor as
20. the channel geometric midpoint Di Area is the total area of the particles channel geometric midpoint Di is used for the calculations Volume is the total volume of the particles channel geometric midpoint Di is used for the calculations Number 1 cm3 10 04 10 Charger U 4700 Charger 1uA Trap U 10 Pressure 40 mbar Press 2 1025 mbar Temp 35 C Total 38437 87 1icm3 Saved 0 lines File FileName Menu 1 3 Clear Chart Distribution 2 7 Change View Figure 4 Multi view with the number distribution selected If Current or RawCurrent has been selected all measurement channels are displayed in time history chart With the other moments only the total sum of all measurement channels is displayed The calculation of the moments is based on the measured raw currents or on the calculated corrected currents which take the effect of fine particle losses in the impactor taken into The currents used in the calculation can be selected in the Display menu see details in Section 7 2 17 a DEK ATI Dekati Ltd 2011 ELPI User Manual 32 w Change View When the Change View button is pressed the chart type shown on the display is changed in the following order Multi view Distribution view Time history view Multi view etc Multi view is combination of both the Distribution and time history view Distribution view displays the distribution of the selected moment The moment can be selected through the Distribut
21. the impactor is an absolute filter stage 3 4 2 Charger Corona charger is used for particle charging before size classification in the impactor Charger s ability to give a known charge to particles depends on the amount of ions it produces The ion flow is controlled by the charger corona current In ELPI it is set to 1 uA Charger corona current is the most important parameter for proper operation of the charger the charger is current controlled meaning that the voltage may change a little 1 kV from its set up value 3 5 kV This is normal and usually there s no need of concern as long as the current remains constant Because a small amount of particles is collected on the charger walls via diffusion and electrical forces an insulating layer may be formed on the inner surface of the charger walls This layer increases the resistance within the charger hence more voltage is required to achieve the 1 uA current Therefore a rise in the charger voltage may indicate a need to clean the charger 3 4 3 Trap voltage Trap voltage is a static DC field inside the charger after the corona discharge area Trap field causes causing an electric field that removes charged molecule groups Trap acts as a zero grade mobility analyzer or like a small electrostatic precipitator In the ELPI the trap voltage is 9 V 0 5 V 3 4 4 Flush pump Flush pump is used to feed clean HEPA filtered air into the charger and from there into the imp
22. 0 0 063 0 109 0 173 0 267 0 407 0 655 1 021 1 655 2 520 4 085 6 560 9 990 Pressure kPa 4 000 10 000 21 900 38 510 68 190 89 170 97 290 99 730 100 520 101 030 101 200 101 260 101 310 101 330 ResTime 0 010 0 017 0 030 0 053 0 069 0 076 0 078 0 078 0 100 0 100 0 110 0 120 0 140 0 000 FilterStage FALSE Unit number Impactor serial number from Setup Impactor window Flow rate Calibrated instrument flow rate from the parameter file D50Values um Calibrated impactor D50 values from the parameter file Pressure kPa Pressure calibration values from the parameter file ResTime Residence times in each impactor stage from the parameter file FilterStage Filter stage status TRUE or FALSE 7 3 3 Charger data Charger data is read from the parameter file Correct values can be found in the ELPI gata sheet If wrong setup values are used during the measurement the data can be recalculated with correct setup values using the ELPI VI Data File Filter program Charger Data UnitNo A ChargerSetup 10 lpm ChargerI mA 1 0000 Chargeru kV 3 0000 TrapU V 0 0000 Efficiency Dp mult exp 0 0240 5 9410 1 6370 10 0000 1 8190 1 3200 1 8190 1 3200 Unit number Not implemented Charger setup Charger setup information from the parameter file Chargerl mA Charger current from the parameter file ChargerU kV Charger high voltage from the parameter file TrapU V Trap voltage from parameter file Efficiency Dp mult exp Charg
23. 0000 3 3166 5 4699 8 2462 Stokes Dp um 0 006 0 017 0 03 0 06 0 108 0 17 026 0 4 064 1 16 25 44 68 10 Cc 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Di 0 0136 0 0226 0 04240 0805 0 1355 0 2102 0 32250 5060 0 8000 1 2649 2 0000 3 3166 5 4699 8 2462 Di um 0 0136 0 0226 0 0424 0 0805 0 1355 0 2102 0 3225 0 5060 0 8000 1 2649 2 0000 3 3166 5 4699 8 2462 dlogDp 0 4523 0 2467 0 30100 2553 0 1970 0 1845 0 1871 0 2041 0 1938 0 2041 0 1938 0 2455 0 1891 0 1675 X fAcc 0 0052 0 0120 0 0281 0 0654 0 1300 0 2321 0 40830 7400 1 3549 2 4806 4 5417 8 8553 17 1412 29 47 We are able to form all conversion vectors Number dN dlogDp 1 cm3 1 X 1 dlogDp Dilution Diameter dD dlogDp um cm 1 X Di 1 dlogDp Dilution Area dA dlogDp um cm3 1 X Di TT 1 dlogDp Dilution Volume dV dlogDp um cm 1 X Di TT 1 6 1 dlogDp Dilution Mass dM dlogDp mg m 1 X DP TT 1 6 1 dlogDp Dilution Density 0 001 Number N 1 cm3 1 X Dilution Diameter D um cm 1 X Di Dilution Area A um cm 1 X Di TT Dilution Volume V um cm 1 X DP TT 1 6 Dilution Mass M mg m 1 X Di TT 1 6 Dilution Density 0 001 Conversion 4 7 1 11 12 1 14 Vectors 2 3 5 6 8 9 0 3 Number dN dlogDp 422 4522 337 9666 118 3627 59 9285 39 0460 23 3455 13 0898 6 6202 3 8080 1 9749 1 1360 0 4600 0 3086 0 2026 1 cm Diameter dD dlogDp 5 7481 7 6324 5
24. 0217 4 8241 5 2907 4 9081 4 2213 3 3496 3 0464 2 4981 2 2720 1 5255 1 6879 1 6706 um cm3 Area dA dlogDp 0 2457 0 5415 0 6693 1 2200 2 2522 3 2417 4 2768 5 3243 7 6565 9 9271 14 2754 15 8952 29 0054 43 2800 um2 cm Volume dV dlogDp 0 0006 0 0020 0 0047 0 0164 0 0509 0 1136 0 2299 0 4490 1 0209 2 0928 4 7585 8 7864 26 4429 59 4826 um3 cm3 Mass dM dlogDp 0 0000 0 0000 0 0000 0 0000 0 0001 0 0001 0 0002 0 0004 0 0010 0 0021 0 0048 0 0088 0 0264 0 0595 mg m en 191 0741 83 3670 35 6307 15 2981 7 6930 4 3078 2 4489 1 3513 0 7381 0 4031 0 2202 0 1129 0 0583 0 0339 um 2 5998 1 8827 1 5117 1 2315 1 0424 0 9057 0 7898 0 6837 0 5905 0 5099 0 4404 0 3745 0 3191 0 2798 umet 0 1111 0 1336 0 2015 0 3114 0 4437 0 5982 0 8001 1 0868 1 4840 2 0263 2 7669 3 9025 5 4837 7 2490 REA 0 0003 0 0005 0 0014 0 0042 0 0100 0 0210 0 0430 0 0916 0 1979 0 4272 0 9223 2 1572 4 9992 9 9628 iced 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0001 0 0002 0 0004 0 0009 0 0022 0 0050 0 0100 K S DEKATI Dekati Ltd 2011 ELPI User Manual NV 74 Now when we multiply the current values vector with these conversion vectors we get the selected distribution For example consider the following values
25. 0245 1 0166 We calculate also geometric mean of each channel which is called Di Di equals Di of channel n Di VDP Dp Impactor repaos 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Aero Dpa dynamic um 0 006 0 017 0 03 0 06 0 108 0 17 0 26 0 4 0 64 1 1 6 2 5 4 4 6 8 10 Cca 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Dia 0 0136 0 0226 0 0424 0 0805 0 1355 0 2102 0 3225 0 5060 0 8000 1 2649 2 0000 3 3166 5 4699 Next we must find the same values for particle Stokes diameters Iteration must be used to find out the stokes diameter Dp Dp Ss Density Cc C a a DEKATI Dekati Ltd 2011 ELPI User Manual w 71 Where Cc is again 2 76 Dp 6 32 2 01 g 0109576 Now we have the following values for the impactor stages Impactor properties 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Aero Dpa 0 006 0 017 0 03 0 06 10 108 0 17 0 26 0 4 0 64 1 16 25 44 68 10 dynamic um Cc 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Di 0 0136 0 0226 0 0424 0 0805 0 1355 0 2102 0 3225
26. Charger Trap and Flush can have either the value On or Off The charger and the flush pump can be set On also in the chart view when the Menu 2 3 has been selected When measurements are made the charger and the trap should always be on 7 2 13 Zeroing of the electrometer currents The zeroing of the electrometer currents starts when Start Electrometer Calibration has been selected The status text Start is changed to Running for the duration of the zeroing process The zeroing parameters can be set in the parameter file During the zeroing operation the system does not respond to any commands given by the user 7 2 14 Setting the controller parameters The parameters of the PID controller of the impactor low pressure are set by choosing Pressure PID P I or D A new window is opened where the values can be set These values should not be changed The impactor low pressure set point can be set by choosing Low Pressure Set Point A new window is opened where the value can be set K N DEKATI Dekati Ltd 2011 ELPI User Manual 42 w Setup menu Selecting the Setup option in the main menu will open the submenu below Path main setup Aux Channel Setup Impactor Number 321 Filter Stage No Auto Zero Interval 0 hour s IP Address 192 168 0 85 Open Modify 7 2 15 Auxiliary analog channel settings With Aux Channel Setup the measurement result for the analog auxiliary channels 1 2 and 3 are defined There a
27. Current fA 2000 4000 6000 Time s Electrometer offset Small negative current can be measured due to electrometer offset in case the noise levels of the electrometers cause most part of the signal See 4 5 for instructions on how to zero the ELPI electrometers Measuring charged particles If the ELPI charger is turned off a reading of negative currents indicate that the particles have a negative charge state In most cases the original charge of the particles does not affect the ELPI results when the charger is ON If the original charge of the particles is negative the ELPI charger produces a sufficient amount of positive ions to first neutralize and then charge the particles normally therefore no neutralizer is needed If the original charge of the particles is positive in some cases there might be a need to neutralize the particles before they enter the ELPI If the particles originally have a charge level of more than 30 50 of the charge produced by the ELPI charger use of a neutralizer is recommended This means that if the current reading with charger OFF is more than 30 50 of the current reading with charger ON a neutralizer should be used If the charger is switched ON the ELPI can be used to measure the original charge of the particles Note that if particle number concentration is wanted the ELPI charger must be switched ON K N DEKATI Dekati Ltd 2011 ELPI U
28. E LETTERS ON lowercase letters OFF CbTLsfpavzfff C Charger high voltage status b Charger switching mode T Trap voltage status L Trap high low s Trap switching mode K N DEKATI Dekati Ltd 2011 ELPI User Manual 52 w 4 5 f Flush pump status p External pump control status a Data OK v Concentrator virtual impactor pump Z Zeroing i not in use j not in use k not inuse Raw measured current values Channels 1 14 MISC indicates that the next 13 values contain miscellaneous measurement channels see the Data format chapter 6 MISC Channel values Charger current Charger voltage Trap voltage Impactor low pressure 6 AUX Channel values Sample air temperature Electronics temperature and Concentrator air flow 7 CAL indicates that next 14 values are calculated values The type of calculated data can be seen in the Data Format section of the data file 8 9 10 11 12 13 Calculated concentration values for each stage Stages 1 14 CON indicates that next value is Concentration value The type of calculated data can be seen in the Data Format section of the data file Total concentration value from the stages 1 to 14 COM indicates that next field is user comment User comment typed in during the measurement in the instrument control section of the main window PM10 PM2 5 PM1 PN10 PN2 5 and PN1 values a DEK ATI Dek
29. ELPI USER MANUAL ver 1 12 Copyright Dekati Ltd 2011 Dekati Ltd Osuusmyllynkatu 13 FIN 33700 Tampere Finland o e Tel 358 3357 8100 99 o 49 Fax 4358 3357 8140 cp e Q o o a www dekati com 3 oo support dekati fi DEKATI v wy Excellence in Particle Measurements DE N 2d l Dek ati Lt d 2011 E ELPI User Man ual Dekati Ltd Software license agreement IMPORTANT READ CAREFULLY BEFORE OPENING SOFTWARE PACKET ONLY ADDRESSEE OR A REPRESENTATIVE OF ADDRESSEE MENTIONED ON THE PACK SLIP IS ALLOWED TO OPEN THE SOFTWARE PACKET BY OPENING THE SEALED PACKET CONTAINING THE SOFTWARE ADDRESSEE LICENSEE IS AGREEING TO BE BOUND BY THE TERMS MENTIONED HEREUNDER ANY TERMS OR PURCHASE CONDITIONS OF LICENSEE ARE DENIED AND DO NOT APPLY TO THIS AGREEMENT THE TERMS HEREUNDER FORM THE SOFTWARE LICENSE AGREEMENT CONDITIONS BETWEEN LICENSEE AND DEKATI LTD AS LICENSOR IF LICENSEE DOES NOT AGREE TO ALL OF THE TERMS OF THIS AGREEMENT LICENSEE MUST PROMPTLY RETURN THE SOFTWARE PACKET AND THE ACCOMPANYING ITEMS INCLUDING ALL WRITTEN MATERIALS AND THEIR CONTAINERS TO DEKATI LTD FOR A FULL REFUND ELPI VI SOFTWARE LICENSE GRANT OF LICENSE This License Agreement permits LICENSEE to use one copy of the enclosed software program the SOFTWARE on a single computer The SOFTWARE is in use on a computer when it is loaded into temporary memory i e RAM or installed into permanent memory e g CD ROM or ot
30. Other adapters Hardware IRQ DMA Base I O Address COMport ELPl vi version ELPI unit number Problem description Error messages if any log file messages Steps to reproduce problem Thank you for your help Name Title Company Address phone fax email a DEKATI Dekati Ltd 2011 ELPI4 User Manual 80 w ELPI comment form Please give us some comments on the ELPI This information helps us provide quality products to meet your needs ELPI unit ELPl vi Measurement program ELPl vi version and revision number ELPI unit number Please comment on the ELPI unit Mechanics user interface Suggestions for the ELPl vi Measurement program Thank you for your help Name Title Company Address phone fax email K CN DEKATI Dekati Ltd 2011 ELPI User Manual 81 w a DEKATI SS
31. The service is done by the local distributor or Dekati Ltd Standard service includes e Arrival inspection including reference test and general operation check in instrument s arrival condition e Cleaning e Calibration of electrometers e Calibration of pressure sensors e Calibration of temperature sensors e Calibration of trap and corona voltage and corona current e mpactor pressure calibration e Flush pump filter change e Final check of operation e Reports arrival inspection service and final check DEKATI Dekati Ltd 2011 ELPI4 User Manual 28 w T ELPI INTERNAL SOFTWARE ELPINUX ELPI can be used as a stand alone unit or with the ELPI VI software installed on a separate computer This chapter describes the use of ELPI internal software ELPInux For using the ELPI unit with the ELPI VI software see the ELPI software manual The data collection and saving can be independently controlled from both the unit and the software both also include the data calculation so changing a setup value in the software does not change the result in the ELPInux and vice versa The calibration parameter file of the ELPI and the impactor has been uploaded to the ELPI unit at Dekati Ltd before shipment The calibration parameter files include the cutpoints of the impactor stages and the charger calibration curves for detailed information see chapter 8 If multiple impactors are used in the same ELPI
32. actor This way it is possible to check the offset levels of the electrometers or to stop collecting the sample from the measurement point The amount of the flush air is larger than the impactor nominal flow rate so there is an air flow out of the ELPI inlet while the flush pump is used The ELPI inlet must not be closed when the flush pump is switched ON The HEPA filter that is used to clean the flush air is located inside the ELPI housing and should be changed every few years ELPI calibration service that is made at Dekati Ltd includes the change of the HEPA flush filter 3 4 5 Electrometers 14 electrometers are used to measure the current signals from the 13 impactor stages and the filter stage The electrometers are placed inside the ELPI electrometer box and each of them can measure current signals in the range of 0 500 000fA Zeroing is needed to adjust the offset levels of the electrometers A very small offset error may lead to an unreliable measurement result therefore the offset currents should always be checked before and after the measurement 3 4 6 Pressure and temperature sensors There are two pressure sensors and a temperature sensor in the ELPI unit The first pressure sensor is located in the ELPI charger and indicates the a DEK ATI Dekati Ltd 2011 ELPI User Manual 8 w sample pressure please note that when the flush is on pressure sensor reading is not accurate Second pressure sens
33. actor need regular cleaning The impactor should be kept clean to avoid any changes in the impactor cut points and to avoid the bouncing effect If the charger voltage rises above 4 5 kV it is usually indication that the charger should be cleaned The ELPI service program is divided to four parts Daily service Weekly Monthly service Yearly service ELPI calibration service Time interval of the services depends on how frequently the ELPI unit is used for measurements and how high concentrations are measured The daily weekly and yearly first service procedures are done by the user of the instrument ELPI full calibration service is conducted at Dekati Ltd or by official Dekati distributor The recommended time interval for ELPI calibration service is 2 3 years 6 1 Daily service Daily service includes changing the collection substrates and cleaning of the charger and impactor by wiping the surfaces When wiping the surfaces of the impactor and charger use a damp tissue with a suitable solvent The tissue should not release any fibres on the surfaces Also the leakage check and electrometer zeroing should be done before each measurement or when the impactor has been removed from the ELPI unit 6 1 1 Cleaning procedure 1 Disassemble the impactor as described in section 4 1 1 Remove the used collection substrates 2 Remove the pre separator stage and the inlet part of the charger see section 4 2 3 W
34. asurement accuracy of ELPI the effect of measuring conditions such as temperature and gas composition must also be taken into account The accuracy of the whole particle measurement depends both on the accuracy of the instrument and on the sampling system Very often the inaccuracy of the measurement is more due to the sampling system than the instrument itself For example storage effects in sampling systems deposition and re entrainment of particles from sampling lines can affect the results Also varying dilution ratio and or dilution gas properties may alter the size distribution Long and twisted sampling lines may lead to significant particle losses due to gravitation inertial and turbulent impaction thermophoresis diffusion and vapour condensation All these things have to be taken into consideration when evaluating the accuracy of the whole measurement a DEK ATI Dekati Ltd 2011 ELPI User Manual 69 w A 2 Example of ELPI calculation This section contains an example of ELPI calculation from current values to selected distribution Note that this calculation does not consider small particle correction Only the calculation from current values to aerosol size distribution is presented Few things have to be known before it is possible to calculate selected distribution from current values Impactor Aerodynamic D50 values see impactor data sheet Flowrate see impactor data sheet Charger Efficiency curve PneQ se
35. ati Ltd 2011 ELPI User Manual 53 w 8 PARAMETER FILE DESCRIPTION There are two parameter files in the ELPI unit Parameter files include all the necessary parameters for data calculation and saving including the cutpoints of the impactor stages and the charger calibration curves If multiple impactors are used in the same ELPI unit correct parameter files should be selected before the measurement The The parameter file has been uploaded to the ELPI unit already before shipment If a new parameter file needs to be uploaded to the unit import function should be used see section 7 2 9 for details The parameters are divided in to ten groups Calculation HW Control Headerlnfo ELPI IF Zeroing Monitor HAL DeviceManager ZeroOffset IPConfig Parameter Group HeaderInfo Group Name CleanedDate Name lt Type gt STRING lt Type gt lt Value gt dd mm yyyy hh mm lt Value gt lt Parameter gt Some of the values are user defined some are calibration values that should be checked from the data sheet and some of the values are constants that should not be changed In the following parameter description the user changeable parameters are marked with color parameters that can be changed through ELPI VI software with and calibration values and values that should not be changed with IB color the parameters that are not in use for the moment are marked with blue color Some of the parameters are Boolean para
36. ction 7 2 23 Setting the backlight level of the display 7 3 Data File Format 7 3 1 aco MOMENT 7 3 2 Imipaclor data sostiene donec nepos badge nep ad ose nue DECORE doce 7 3 4 Data format auucsesttispeueeteqesens epeteettesusentd pee sttepare va tepesepetepxumM dus 7 3 5 pri 8 PARAMETER FILE DESCRIPTION 9 ETHERNET CONNECTION 9 1 Acquiring IP address via DHCP on an Ethernet interface 9 2 Using fixed IP address 9 3 Connecting the ELPI unit and PC A PHYSICAL OPERATION A 1 Particle collection and properties A 1 1 A 1 2 A 1 3 A 1 4 A 1 5 A 1 6 A 1 7 K S DEKATI SS WAC UO E E AE Particle Size and Shapes suiestesusueevass tienen eva prn sk Ute e suse EE Particle impaction and stopping distance Particle losses in impactor Correction algorithm Impactor WAVY Et Particle charging Laaeaccsu denies sodas eda adu nde sadi denda esae sie Dien Gas to particle CONVERSION uoce unen ce Rente ib dex na a d Dekati Ltd 2011 ELPI User Manual vii A 1 8 Negative current values sssseseeenn 66 A 1 9 Measurement accuracy of ELPI secere 69 A 2 Example of ELPI calculation 70 A 2 1 Using different density values in the ELPI calculation 76 B ELPI ACCESSORIES 77 C ELPI SUPPORT 78 a DEKATI Dekati Ltd 2011 ELPl User
37. data file consists of four separate information fields Measurement info Impactor data Charger data and data format 7 3 4 Header Header gives general information about the measurement and is mostly user definable Measurement info The Measurement info part of the data file contains information that was put in the Setup Measurement window before the measurement and time of the measurement ELPI DATA FILE Date 26 10 2010 Time 15 05 06 Location Dekati ltd Description ELPI manual Operator run ENI Cleaned 26 10 2010 15 04 Sampled greased al foils a DEKATI Dekati Ltd 2011 ELPI User Manual 49 w Date and time when saving is started Location Description Operator and Last cleaning time cannot be set in ELPInux They are stored into the parameter file from where they are read to the data file Alternatively they can be set in the ELPl vi software 7 3 2 Impactor data Impactor data values are used in the calculation of concentrations and corrected currents Correct values can be found in the Impactor Data Sheet delivered with the instrument If wrong setup values have been used during the measurement the data should be recalculated with correct setup values using the ELPI VI Data File Filter program see more information from the ELPI VI software manual These values are uploaded to each ELPI unit before shipment Impactor Data UnitNo FlowRate lpm 10 000 D50values um 0 006 0 017 0 03
38. de negative values or Aux Channel 3 Include negative values can have value Yes or No Aux Channel 1 Limit to 5 V or Aux Channel 1 Limit to 5 V or Aux Channel 1 Limit to 5 V can have the value Fullscale or Limited The following table shows an example how the output of the auxiliary channel changes if the total current can have values from O to 100 000 fA or from 100 000 fA to 100 000 fA The voltage output has always a positive value The output moment maximum value can be set in the parameter file see chapter 8 Table 1 Possible combinations of the analog output channels Unsigned Signed Analog Total current Analog Total current output example output example Fullscale OV OfA OV 100 000 fA 5V 50 00 fA 5V 0 fA 10 V 100 000 fA 10 V 100 000 fA Limited OV 0 fA OV 100 000 fA 2 5V 50 000 fA 2 5 V 0 fA 5V 100 000 fA 5V 100 000 fA 44 K N DEKATI Dekati Ltd 2011 ELPI User Manual w 7 2 16 Impactor Number When Impactor Number is selected a new window showing all installed impactor options opens Current fA 12 01 30 Aux Channel Setup 2345 Filter Stage 3333 current Auto Zero Interval old IP Address Open Modify All parameter files located in the default directory are listed and the character string between and xml parameter file name should be e g Parameters_1234 xml is shown in the new window The impactor number Unit number should be the same in the parameter file as the nu
39. e it is important to conduct the leakage test after each time the impactor is assembled ELPI is equipped with an internal pressure sensor reading of the pressure sensor can be found from the ELPI display Pressure indicates the pressure after the impactor To perform the ELPI leakage check 1 2 Connect the pump to the ELPI outlet as in a normal measurement Turn on the pump You should see the internal pressure sensor reading change on the ELPI display Read the pressure reading and adjust the pressure adjustment valve to get a reading of 40 mbar Close tightly the inlet of the charger using e g a leakage check tool provided with the ELPI unit or an eraser After a while the pressure should reach the end pressure of the pump check this from pump specifications Close the pressure adjustment valve in the ELPI unit front panel The pressure should not rise more than 20 mbar per minute If the leakage is less than this you can continue with the instructions given in section 4 5 If you fail to get the values above check that that the impactor is properly positioned in its support If a leakage still exists check that the impactor is properly assembled see Section 4 1 that the charger is properly assembled see section 4 2 O rings of the impactor insulators are properly positioned O rings of the impactor insulators are clean A small amount of vacuum grease can be applied on the
40. e ELPI data sheet Particles Density Is Aerodynamic or Stokes diameter wanted ELPI Current values Dilution factor Used symbols Dpa Particle aerodynamic diameter Dps Particle stokes diameter Dia Geometric mean of a channel Aerodynamic diameter Dis Geometric mean of a channel Stokes diameter CCa Cunningham s slip correction vector for aerodynamic particle size COs Cunningham s slip correction vector for stokes particle size a DEK ATI Dekati Ltd 2011 ELPI User Manual 70 w If we assume that the following startup values are used Impactor properties 1 2 3 4 5 6 7 8 9 10 141 12 13 14 15 Aerodynamic Dpa um 0 006 0 017 0 03 0 06 0 108 0 17 0 26 0 4 0 64 1 1 6 25 44 68 10 1 819 Mult3 1 819 1 8201 Exp3 1 3201 10 Density 1 Dilution 1 Then Cunningham s slip correction factor is calculated using equation 2 d yk D Cea 1 6 324 2 01 e 99 P for each D50 value 76 pressure in 76 Dp cmHg Now we have the Cunningham s slip correction factor for each D50 value Beers 112 3 4 5 6 7 8 9 40 tt 12 13 14 15 properties Aero clie 0 006 0 017 0 03 0 06 0 108 0 17 26 04 064 1 16 25 44 68 10 ynamic pm Cca 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1
41. e ELPI unit is used with the ELPl vi software zero button can be used for zeroing the instrument See details from the ELPI vi manual Zero levels can be reduced by connecting two screws included in the shipment to the holes on the top plate and top part of impactor E JJ a DEK ATI Dekati Ltd 2011 ELPI User Manual 22 w 5 MAKING AMEASUREMENT 5 1 Instrument setup Quick start up instructions for an ELPI measurement are given in this chapter For more detailed instructions on the different procedures see respective chapters 1 Check that the impactor and charger are clean If cleaning is needed follow the instructions given in chapter 6 Assemble the impactor and the charger use suitable collection substrates in the impactor 2 Place the charger impactor assembly to the ELPI housing Press the assembly firmly into its place so that the release button at the bottom of ELPI unit is locked Connect the charger and trap BNC connectors and the hose for the flush pump 3 Connect the power supply to line voltage Connect the vacuum pump to the ELPI outlet with the vacuum hose 5 Switch on the ELPI power from the front panel by pressing the ON button for few seconds 6 Select the correct impactor serial number in the setup window if you have multiple impactors see section 7 2 15 7 Perform the leakage test see section 4 3 8 Use a metering valve in the ELPI unit front panel
42. e channel presents the concentration See more details in Appendix A In dW format the distribution displays the measured concentration value for each size class 7 2 22 Setting the fine particle loss correction The use of fine particle correction is set by choosing Correction The parameter toggles from False to True Should always be ON 7 2 23 Setting the backlight level of the display The backlight level of the display can be set with the Backlight option This opens a new window Current fA 12 10 42 Distribution Moment Level2 Level3 Correction Level4 Leveld Distribution Type Open Modify The level can be set into the appropriate level Level is the lowest level and Level 5 is the brightest level K N DEKATI Dekati Ltd 2011 ELPI User Manual 48 w Log The log files saved during the operation of the system can be viewed by choosing Log and pressing Open Modify This opens a new window showing the log file types By choosing one of them the list of log files of this type is shown The newest log file is without number Current fA 15 18 10 hwcontrol log 01 08 2010 14 01 18 hal log 01 06 2010 14 01 00 elpi_if log 01 06 2010 14 00 40 dataprocessing1 log 01 06 2010 13 59 48 dataprocessing log 01 06 2010 13 59 48 datamanager log 01 06 2010 13 59 24 Select Log 7 3 Data File Format ELPI saves data in a dat ASCII file that consists of two parts Header and Data The Header part of the
43. e charger impactor assembly to the ELPI housing and connect the charger and trap BNC connectors and the hose for the flush air KS DEKATI Dekati Ltd 2011 ELPI User Manual w Zero levels can be reduced by connecting two screws included in the shipment to the holes on the top plate and top part of impactor r n 4 2 Disassembling and assembling the charger Open the charger locking ring by turning it anti clockwise K N DEKATI Dekati Ltd 2011 ELPI User Manual 16 w Remove the pre selector stage from the charger assembly The two parts are kept together by an o ring Remove the centre part of the charger from the inlet part by pushing the connector upwards Be careful not to break the needle Continue disassembling by removing the trap cone The trap is held in its place by a screw thread Pliers can be used to help the disassembling Careful handling is required the trap part should not be scratched or damaged KS DEKATI Dekati Ltd 2011 ELPI User Manual 17 w Remove the trap and HV BNC connectors The needle is kept in its place by the connectors after they are removed slide the needle carefully out of the charger assembly The tip of the needle can easily get broken so it should be handled carefully Remove the trap connection ring and the needle Take off the charger inlet connector from the inlet part Remove o rings from the charger inlet part centre part and inlet
44. e fine particles The more fine particles are detected at the lowest stages the more losses are assumed in the upper stages Thus the correction algorithm corrects the raw values more if a large number of particles is detected at the lowest stages of ELPI Corrected current values If you are looking at the corrected current values in the ELPI data it is possible to have negative values especially in the upper stages of ELPI This can happen if the average particle size is very small and a low near zero concentration of coarse mode particles 22 5 um is present These negative values are caused by the operation of the correction algorithm correction for the fine particle losses If no large particles are present all the current measured in the upper stages is K S DEKATI Dekati Ltd 2011 ELPI User Manual 66 w corrected in some cases over corrected resulting in negative values However negative values in other types of distributions e g number or mass distributions are saved as zero in the data file Raw current values The raw current values are the measured current values and they are not corrected in any way The negative values in these are not due to the correction algorithm Induced current In most cases the raw negative current values are caused by sudden changes in sample particle concentration a charge going through a conducting loop or plate is known to induce a current into a conductor As the charge approach
45. enforced and the remainder of this Agreement will continue in full force and effect THIS AGREEMENT IS GOVERNED BY THE LAWS OF FINLAND LICENSEE AGREES THAT THE COURT IN HELSINKI HAS THE EXCLUSIVE VENUE OF COMPETENT JURISDICTION WITH REGARD TO ANY DISPUTE THAT MAY ARISE FROM THIS AGREEMENT a DEK ATI Dekati Ltd 2011 ELPl User Manual iv b di Precautions Both the ELPI and the external PC must be connected to the mains supply with an earth connector Do not switch on the ELPI while the high voltage connectors of the charger are disconnected Do not touch the electrometer connections before making the ground contact Static electricity may cause severe damage to the electrometer amplifiers Do not direct explosive gases through the ELPI charger When the flush pump is used e g while zeroing the airflow through the device is altered and some flush air comes out from the sample inlet We recommend you to take necessary precautions to avoid accidental start up of the main pump or any external unit connected to the outputs during the power up sequence of the ELPI DEKATI Dekati Ltd 2011 ELPI User Manual V w TABLE OF CONTENTS Chapter Page 1 INSTRUMENT DESCRIPTION 1 2 SPECIFICATIONS 3 3 UNPACKING AND PACKING 5 3 1 Required external accessories 6 3 2 Recommended accessories 6 3 3 ELPI housing and connectors 6 3 4 ELPI components 7 3 4 1 DRUM Me H 7 dus AANA seserinis s
46. ennae aiaa aeai aaa cedente petendo 8 343 Wap VOolBtjOu ssena eer re eran eee eee 8 Cee Fe SM SCS 6610 31 cece rete eee ee ere er er ener re re ne ae 8 2b BIS CIO CLOT Sie ctietetieaenincatocetneatbeetoensbentucutniolvesenentucayniutoeaybnetts 8 3 4 6 Pressure and temperature SENSOMS ceeeeeeeeeeeeeeeeeeeeeeeeees 8 3 4 7 Pressure adjustment ValVe cccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 9 3 4 8 Analog input and output connectors sssssssssssss 9 3 5 Packing the ELPI for shipment 9 4 SETTING UP THE INSTRUMENT 10 4 1 Disassembling and assembling the impactor 10 4 1 1 Disassembling the impactor ssesseeeeesee 10 4 1 2 lmpactor assemiblifigi eene b E en exe doses de xvn vei 12 4 2 Disassembling and assembling the charger 16 4 3 Collection substrates 18 4 3 1 Inserting the collection Substrates ccccceeeeeeeeeeeeeeeeeeeees 19 4 39 2 Greasing the collection substrates sssuuuss 19 4 4 Leakage check 20 4 5 Electrometer zeroing 21 5 MAKING A MEASUREMENT 23 5 1 Instrument setup 23 5 2 Gravimetric measurements 23 5 3 Chemical analysis 24 5 4 Blank samples 25 6 MAINTENANCE AND SERVICE 26 6 1 Daily service 26 6 1 1 Cleaning procedure cicer careret enean ccn nete pneum 26 6 2 Weekly Monthly service 27 6 2 1 Cleaning the impactor sete ceteccconeice ce celenett aeencoaiea ieee eeteaatiale 27 6 2 2 Cleaning the charger 0
47. er efficiency function from the parameter file a DEK ATI Dekati Ltd 2011 ELPI User Manual 50 w 7 3 4 Data format Data format field tells what type of data has been saved in the data file This has been selected in the Main gt data gt advanced gt distribution moment before the measurement If other types of distributions are needed after the measurement these can be calculated with the ELPlpluscalc software or the ELPI VI Data File Filter program Data Format VersionNo 1 0 rev 100 DelimiterChar RawData Current fA CalculatedMoment Number 1 cm CalculatedType dW dlogDp Density g cm 3 1 00 StokesDp FALSE CalculatedDi um 0 011 0 023 0 043 0 083 0 137 0 215 0 330 0 516 0 818 1 300 2 042 3 208 5 177 8 095 Correction TRUE Dilution 1 00 DataOrder Date Time yyyy mm dd hh mm ss RAW Status Channell Channel2 Channel3 Channel4 Channelb5 Channel6 Channel7 Channel8 Channel9 Channell10 Channell11 Channell12 Channell13 Channell4 MISC Charger I Charger U Trap U Impactor low pressure Aux channell Aux channel2 Aux channel3 Aux channel4 Aux channel5 Aux channel6 Sample air temperature Electronics temperature Consentrator air flow CAL Filterstage ZeroStage Stagel Stage2 Stage3 Stage4 Stage5 Stage6 Stage 7 Stage8 Stage9 StagelO Stagell Stagel12 CON Concentration value COM User comment PM10 PM2 5 PM1 PN10 PN2 5 PN1 Version No ELPI VI software version number used in the measu
48. es the conductor it induces an image charge which is of opposite polarity If an electric current is measured from the conductor a changing signal is recorded as the charge passes through the conductor As the ELPI single impactor stage is basically such a conductor and as in the upper stages a majority of current is only passing through the stage and not depositing a similar phenomenon is seen O charged particle q liis conducting plane current Radius R electrometer In ELPI readout this can be seen as two current peaks one negative and one positive A positive image current peak arises as the positively charged particles enter the stage and a negative current peak is formed as the particles leave the stage Total current over these two peaks is zero If the aerosol flow is constant there is the same amount of small particles entering and leaving the stage and no current peak is produced However when the aerosol concentration changes very rapidly the image current produced by leaving and entering particles may not be cancelled out and a current peak is formed a DEKATI Dekati Ltd 2011 ELPI User Manual 67 w Figure A Ideal response of a stage to the small charged particles going through the stage M Marjam ki TUT report 8 95 Current Time 16000 14000 12000 10000 8000 6000 4000 2000 Figure B A measurement of real induced currents M Marjam ki TUT report 8 95
49. fully cleaned Greasing of the collection substrates and assembling of the impactor is preferably done in a clean room When disassembling and moving the impactor contamination is prevented by using a clean transport case In a laboratory samples are stored in a dry dark and cool place Samples are handled in a clean room The collection substrate must be chosen in consideration of the analysis method Collection substrates can be manufactured from different materials and are available for example in aluminum PTFE Teflon glass fibre and polycarbonate a DEK ATI Dekati Ltd 2011 ELPI User Manual 24 w Polycarbonate substrates are well suited for different chemical analysis these substrates are also available from Dekati Ltd 5 4 Blank samples Whenever conducting gravimetric measurements or chemical analysis use of blank samples is recommended Blank samples are handled exactly the same way as the real measurement samples but the measurement is made using a HEPA filter at the instrument inlet so no sample is collected on the collection foils With blank samples the effect of substrate handling can be taken into account a DEKATI Dekati Ltd 2011 ELPI User Manual 25 w 6 MAINTENANCE AND SERVICE Particles are collected inside the ELPI impactor when measurements are conducted There are also particle losses inside the charger and particles are collected on the charger surfaces Therefore both the charger and the imp
50. harge from the stage by triboelectric effects As the amount of collected particles increases the impacting particles can start to cause re entrainment of the collected particles The gas flow pattern changes affecting the cut diameter and finally the stage can even be clogged The acceptable amount of collected particle mass depends on the particle size distribution and particle properties and needs to be found out by experience As a rule of thumb 1 mg of particles per one impactor stage is absolute maximum However this value depends on the type of particles and can be even smaller A 1 6 Particle charging Before the particles are collected in the impactor they must be charged to make electrical detection possible ELPI s charger uses corona discharge to produce gas ions that can transmit their charge to the particles passing the charger Corona discharge produces a high number of ions and it is controlled by adjusting the corona current to a predefined value As a result of the charging process particles will have a known positive charge state that is stable during different operation conditions and high enough to ensure good detection limit Most aerosol particles are charged by nature In processes where particles may have very high charge states it is recommended that they are neutralised before entering ELPI The neutralisation is most critical if the particles have positive polarity Positively charged particles will have higher
51. her storage device If the anticipated number of users of the SOFTWARE could exceed the number of users permitted by applicable licenses LICENSEE must have a reasonable mechanism or process in place to ensure that the number of persons using the SOFTWARE does not exceed the number permitted by the applicable licenses All rights not expressly granted to LICENSEE in this Agreement are reserved to DEKATI LTD COPYRIGHT The SOFTWARE is owned by DEKATI LTD or its suppliers and is protected by the applicable copyright laws and international treaty provisions Therefore LICENSEE must treat SOFTWARE like any other copyrighted material LICENSEE may however either a make one copy of the SOFTWARE solely for backup or archival purposes or b transfer the SOFTWARE to a single hard disk provided LICENSEE keeps the original solely for backup or archival purposes The SOFTWARE must be held in confidence and protected from disclosure to third parties by the LICENSEE because it contains trade secret information of DEKATI LTD LICENSEE may not copy the written materials accompanying the SOFTWARE OTHER RESTRICTIONS LICENSEE may not reverse engineer decompile or disassemble the software LICENSEE may transfer the SOFTWARE to a third party provided that after each transfer LICENSEE must not retain any copies of the SOFTWARE including all upgrades that LICENSEE may have received not retain any of the written materials accompanying the SOFTWARE LICENSEE must inc
52. high density values are selected when the filter stage is used and Stokes is selected as the diameter type the impactor cutpoints are recalculated with this given density value With gt 1 density values the cutpoint decrease from the calibrated values given in the data sheet If the density is increased enough the lower cutpoint of impactor stage 1 i e upper cutpoint of filter stage can be lower than 6nm i e the lower cutpoint of the filter stage This however cannot be true based on the operating principle of the ELPI If high density values are used when filter stage is installed in the instrument and Stokes diameter is selected the new impactor cutpoints are first calculated If in this situation the lower cutpoint of the impactor stage 1 is smaller than 6nm an error message appears in the software The results cannot be calculated with these values because of the characteristics of the physical operation of the instrument a DEK ATI Dekati Ltd 2011 ELPI User Manual 76 w B ELPI ACCESSORIES ELPI accessories Please contact Dekati Itd for more information ELPI Spare Impactor and Charger unit Insulator ring set for ELPI impactor DEKATI impactor collection plate set Impactor collection plate set 14pcs Vacuum hose 1 5 m pressure valve NW16 flange connectors ELPI power supply Corona needle ELPI filter stage block Substrate positioning tool Leakage test tool ELPI inlet connector with o ring
53. iciency curves This algorithm is called correction algorithm and it is implemented in the ELPInux and the ELPI VI software The fine particle correction algorithm corrects both for diffusion and space charger losses The correction method is described in more detail in Virtanen A Marjam ki M Ristim ki J Keskinen J 2001 Fine particle losses in electrical low pressure impactor Journal of Aerosol Science vol 32 pp 389 401 K N DEKATI Dekati Ltd 2011 ELPI User Manual 64 w In ELPInux and ELPI VI software it is possible to save both Raw Uncorrected and Corrected particle size distributions When true particle concentrations are wanted the correction should always be used A 1 5 Impactor loading If an impactor measurement continues a long time or sampling is made from a high particle concentration the high amount of collected particles can have a negative effect on the impactor performance Properties of the collection plate or collection foil if used surface change when it is covered with collected particles This may lead to an increase in the bounce effect even if the stages were greased Particles impacting the collection plate bounce off from the surface and back to the gas flow and are collected onto the next stages or pass through the impactor without being collected at all As the particles bounce from the collection surface they can give their charge or part of it to the stage Particles can also gain c
54. ing file Postfix of the saving file File save path Append data to the previous file Zeroing parameters define the electrometer calibration sequence Waiting time before zeroing s Averaging time of zeroing s Interval between auto zeroing h Monitoring parameters Saving to file On Alarm trap voltage low Alarm trap voltage high Alarm charger voltage low Alarm charger voltage high Alarm charger current low Alarm charger current high a DEKATI Dekati Ltd 2011 ELPI User Manual 55 b di Alarm impactor low pressure low Alarm impactor low pressure high HAL parameters Aux channel limited to 5 V Negative values possible Conv factor of thermocouple mV C Imp low pressure sensor offset Imp low pressure sensor gain Ambient pressure sensor offset Ambient pressure sensor gain Not in use Not in use Sampling rate ms Sample temp sensor offset Extra temp sensor offset Device Manager Aux channel on at startup Not in use Flush pump on at startup Vacuum pump on at startup Trap on at startup Charger on at startup Charger current at startup Charger voltage at startup Trap voltage at startup Not in use Set point of impactor low pressure Level of display lighting Max value of total moment aux ch t fA Max value of total moment aux ch t fA Not in use ZeroOffset parameters ElectrometerZeroOffset x Zero offset of channel fA IpConfig
55. io used in the data calculation Does not affect raw data Selected in the Datafile Advanced Parameters window before starting the saving of data Data order The order of the data in the data rows below 7 3 5 Data ELPI data file consist of data rows that are saved at the interval defined in the Datafile Advanced Parameters window before starting the saving of data If the Saving Interval is set for example to the value 10 the time gap between samples is 1 second Each data row describes the particle size distribution during the time of the sample Each sample row looks as described below 2000 08 21 13 23 26 RAW CbTLsfpavZijk 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 1 123e 01 MISC 1 000e 00 5 000e 03 4 000e6 02 1 000e 01 0 000e 00 0 000e 00 0 000e 00 0 0 00e 00 0 000e00 0 0006 00 2 106e 00 0 000e 00 0 000e 00 CAL 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 4 567e 08 CON 2 042e 09 COM User comment 4 567e 01 4 567e 01 4 567e 01 4 567e 08 4 567e 08 4 567e 08 Data rows have the following parts ie Date and time Date and time of the measured sample 2 RAW indicates that this is raw data raw current values read from the ELPI unit 3 Status string is a letter code display for ELPI unit control states UPPERCAS
56. ion button The time history view displays the time history of the selected moment If Current or RawCurrent has been selected the currents of all channels will be displayed If other moment Number Diameter Area Volume or Mass has been selected the total sum of all measurement channels is displayed Current fA 10 09 59 Menu 1 3 Clear Chart Distribution 1 7 Change View Figure 5 Current distribution view a DEK ATI Dekati Ltd 2011 ELPI User Manual 33 w Current fA 10 14 02 E E E 5 E Ej MEN I 0 0E 00 Jn 10 05 18 Menu 1 3 10 14 51 3 6E 0 22 tt 0 0E400 DOES 10 06 05 10 07 50 10 09 36 Menu 1 3 Clear Chart Distribution 2 7 Change View Figure 7 Time history view of total number of particles 7 2 2 Menu 2 3 When the Menu button is pressed once the functions of the push buttons change Charger button controls the charger and trap voltage ON and OFF Flush is used to control the flush pump that feeds HEPA filtered air through the charger and impactor unit The saving of the data to the USB can be started and stopped by pressing the Saving button The USB memory should first be mounted see section Data File DEKATI Dekati Ltd 2011 ELPI User Manual 34 w For details and changing the save parameters please see section 7 3 Data file description 7 2 3 Menu 3 3 When the Menu button is pressed second time the display is changed to a menu display In this display
57. ipe all parts using a suitable solvent Choose the most suitable solvent considering the type of particles you are measuring Salt particles dissolve best in water whereas hydrocarbon particles dissolve better in a DEK ATI Dekati Ltd 2011 ELPI User Manual 26 w hydrocarbon based solvents It is recommended to wipe the parts last with isopropanol to ease the drying 4 Let the parts dry before assembling Assemble he impactor and the charger 6 2 Weekly Monthly service Weekly service includes the changing the collection substrates and cleaning of the charger and impactor in an ultrasonic bath 6 2 1 Bm O qe 6 2 2 Cleaning the impactor Disassemble the impactor as described in section 4 1 1 Remove the used collection substrates Take off the o rings from the insulators Place the parts except o rings to an ultrasonic bath with a suitable solvent wash the insulators separately Choose the most suitable solvent considering the type of particles you are measuring Salt particles dissolve best in water whereas hydrocarbon particles dissolve better in hydrocarbon based solvents Let the parts dry properly before assembling It is recommended to use isopropanol as the last solvent because it eases the drying Cleaning the charger First disassemble the charger as described in section 4 2 All the parts except for the BNC connectors and o rings can be washed in an ultrasonic bath with a suitable so
58. ld always be in the correct numbered order number 1 at the bottom of the impactor and number 14 at the top of the impactor The collection plates are identical and their order does not affect the electrical detection but if chemical or other analysis is made of the collected samples the collection plates should also be in correct numerical order collection plate number 2 under the jetplate 2 etc The filter stage does not have a collection plate so therefore the numbering of the collection plates starts from number 2 To start assembling the impactor place the two o rings on both sides of the insulators Place the first insulator on the impactor base see figure below All of the insulators are identical and symmetrical so the order or orientation of the insulators does not matter Place stage number 1 filter stage on the insulator Place an insulator on the filter stage and collection plate of stage number 2 on top of it Place jet plate 2 Then continue with placing first the insulator then collection plate 3 jet plate 3 etc Finally place the last stage no 14 and then the last insulator and collection plate no 15 KS DEKATI Dekati Ltd 2011 ELP User Manual 14 w Put the impactor cover on the impactor assembly and turn the locking disc anti clock wise Hold the handle in upright position and place the charger assembly with the pre separator stage on top of the impactor assembly Press down the handle Place th
59. le Marjam ki M Keskinen J Chen D H and Pui D Y H 1999 Performance Evaluation of the Electrical Low Pressure Impactor ELPI Journal of Aerosol Science 31 2 2000 pp 249 261 Giving us the efficiency function Charger efficiency Di lt 0 095 um X Di 4 48Di 7 0 095um Di 1 196 4 480 Dp M 9087 94 1 2930 Dp 1 3805 t3529Dp4 1308 1 Dp um The charger efficiency curve is calibrated using flowrate of 10lpm so we must reduce the efficiency curve to a real flow For example stage 1 Dis 0 0291 less than 0 095 Flow rate 9 71 Charger efficiency as above 9 71 Fowrate L 4 Ag 0 0291 997 Ed X 4 48 Di Calibratio nflow Note that Stokes Di is used because the charging process is dependent on the particles stokes diameter That s why it is always necessary to estimate the particle density and calculate the particle stokes diameter a DEKATI Dekati Ltd 2011 ELPI User Manual 73 w Impactor x 1 2 4 7 1 11 12 1 14 1 Sidperties 3 5 6 8 9 0 3 5 Aero Dp 0 006 0 017 0 03 0 06 0 108 0 17 0 26 0 4 0 64 1 16 25 44 68 10 dynamic um Cc 37 1057 13 4843 7 9175 4 3070 2 7393 2 0539 1 6631 1 4205 1 2603 1 1663 1 1039 1 0665 1 0378 1 0245 1 0166 Di 0 0136 0 0226 0 04240 0805 0 1355 0 2102 0 32250 5060 0 8000 1 2649 2
60. ller particles will stay on upper stages than they should Thus the true collection efficiency of an impactor stage is an S shaped function Collection efficiency Ideal curve Bounce Interception diffusion 9 z 0 01 0 1 1 10 100 Dp um The figure above gives an example of a collection efficiency curve of an impactor stage The bounce can be reduced in ELPI impactor by greasing the collection substrates or by using the sintered collection plates diffusional losses on the upper stages of ELPI have been determined and are taken into account in ELPI calculation The calibration of the ELPI impactor stages and determination of the collection efficiency curves are described in more detail in Marjam ki M Keskinen J Chen D R and Pui D Y H 2000 Performance Evaluation of the Electrical Low Pressure Impactor ELPI Journal of Aerosol Science 31 2 pp 249 261 In ELPI the particles are charged in a corona charger before they enter the impactor These charged particles are then size classified in a 14 stage impactor and the weak electrical current that arises as the particles are collected on the collection plates is measured from each stage This way real time data is gained using the impactor technique a DEK ATI Dekati Ltd 2011 ELPI User Manual 61 w A 1 2 Particle Size and Shape Particle size distribution represents a region of five orders of magnitudes Therefore their behaviour of
61. lowing gas If the inertial forces are stronger than the frictional forces particle is diverted from the gas stream If the deviation is large enough particle impacts to the collection plate and is collected Stopping distance is a useful quantity to estimate how the particles behave when the gas flow changes its direction It gives the maximum distance S that a particle with some initial velocity V can travel in still gas Sea Vt Here tstands for relaxation time Table below gives stopping distances for selected particles assuming that they have initial velocity of 10 m s Particle Relaxation Stopping Time to travel 95 diameter time s distance of Stopping distance S 10 nm 6 8 x 10 68 nm 2 0 x 10 100 nm 8 8 x 10 880 nm 2 6 x 107 1 um 3 6 x 10 36 um 1 1 x 10 10 um 3 1 x10 2 3 mm 8 5 x 10 a DEK ATI Dekati Ltd 2011 ELPI User Manual 63 b di To collect the smallest particles the gas velocity has to be high Lowering the operation pressure also helps to collect small particles as thinner gas has a weaker effect on particle motion If we calculate the ratio of the stopping distance of a particle to a radius of the jet plate nozzle we get a quantity called Stokes number Stk Stk S r If the Stokes number is close to the zero particles follow the gas streamlines perfectly On higher Stokes numbers particles deviate from the gas flow and on some specific value of Stokes number they impact o
62. lude all applicable copyright notices on any transfer OPERATING SYSTEM OPTIONS CD ROM MEDIA If the SOFTWARE is distributed with multiple version on a CD ROM for compatibility with different operating systems LICENSEE s license grant extends to using only the applicable versions for LICENSEE s operating system LICENSEE is however granted the limited right to use more than one version of the SOFTWARE solely for the purpose of creating executables for multiple operating systems LIMITED WARRANTY LIMITED WARRANTY DEKATI LTD warrants for LICENSEE s benefit alone that a the SOFTWARE will perform substantially in accordance with the accompanying written materials for a period of ninety 90 days from the date of shipment and b the medium on which the SOFTWARE is recorded will be free from defects in materials and workmanship under normal use and service for a period of ninety 90 days from the date of receipt CUSTOMER REMEDIES DEKATI LTD s entire liability and LICENSEE s sole and exclusive remedy shall be at Dekati Ltd s option either a return of the software fee paid or b repair or replacement of the SOFTWARE that does not meet Limited Warranty of the SOFTWARE Any replacement SOFTWARE will be warranted for the remainder of the original warranty period or thirty 30 days whichever is longer NO OTHER WARRANTIES EXCEPT AS EXPRESSLY SET FORTH ABOVE THE SOFTWARE AND THE DOCUMENTATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND
63. lvent Choose the most suitable solvent considering the type of particles you are measuring Salt particles dissolve best in water whereas hydrocarbon particles dissolve better in hydrocarbon based solvents Let the parts dry properly before assembling It is recommended to use isopropanol as the last solvent because it eases the drying Every time the charger has been disassembled and is being assembled again electrical contacts need to be measured The contact should be measured between the needle and the HV connector between trap and the trap cone 6 3 Yearly service Check the impactor flow rate with e g laminar flow element The measured value should correspond to the impactor flow rate value on the data sheet Inlet pressure a DEKATI Dekati Ltd 2011 ELPI User Manual 27 w of the impactor should be 1013 3 mbar and the low pressure under the first stage 40 mbar when the flow rate is measured If the impactor flow rate is smaller than the value on the data sheet it is usually a sign that the impactor cleaning has not been efficient enough and the jets on the impactor jet plates have been clogged Try using different solvent with the ultrasonic cleaner Pressurised air can also be used for cleaning the jets 6 4 ELPI standard service In order to ensure proper operation of ELPI a more thorough service should be done every other year or three years The need for the service depends on how frequently ELPI is used
64. mber string in the file name The impactor number is also engraved on the impactor jet plates The engraving and the impactor number in the parameter file should be the same to ensure proper operation of the ELPI When the proper impactor number has been selected all parameters in that file will be loaded into the system memory and they will be used in the computations If the current option is selected the parameters of the current configuration will be used If the old option is selected the parameters of the previous configuration will be used a DEK ATI Dekati Ltd 2011 ELPI User Manual 45 w 7 2 17 Setting the filter stage on off When FilterStage is selected the value toggles from On to Off or vice versa The parameter can be set in the parameter file This should always be ON 7 2 18 Setting the Auto Zeroing interval When AutoZero is selected the auto zeroing period in hours of the impactor currents can be set During the AutoZero procedure the ELPI unit will turn on the flush pump and calibrate the electrometers automatically The AutoZero Interval defines the time between the Autozero procedures Current fA 12 02 36 Aux Channel Setup gt gt Impactor Number Filter Stage Decrement Accept IP Address Open Modify 7 2 19 IP Address When Ethernet connection is used for the data saving and unit control the IP Address of the unit can be seen from here The IP address can be changed th
65. meters with options O for NO OFF and 1 for YES ON ParametersDevice xxxxx xml file consists of following parameters Calculation group consists of parameters that affect the concentration calculation Stokes 1 or 0 Aerodynamical diameter Correction for fine particle losses On 1 or Off 0 Saved moment Corrected Current 0 Number 1 Diameter 2 Area 3 Volume 4 Mass 5 Raw Current 6 Biecvometereaioraion Electrometer calibration factor for each electrometer HW Control parameters consist of PID parameters for external accessories ConcentratorPID Not in use DEKATI Dekati Ltd 2011 ELPI User Manual 54 w Not in use Not in use Not in use Not in use Not in use Not in use Not in use not in use Not in use Not in use Header parameters are mostly user defined informative parameters that are saved to the data file header These parameters can either be changed in the parameter file or in the ELPI VI software Location of the measurement Description of the measurement Operator of the measurement Version of the internal software Should be set to comma if excel calculation sheet is used FileRecordRawData Save Raw data ELPI IF parameters are related to the data communication setting of the ELPI unit Write to serial port Write to tcp port Saving interval samples Moment saved to file Logarithmic data saved TCP Port Add PM and PN values to stored data Prefix of the sav
66. n the collection plate This critical Stokes number is approximately same for all the stages and is called the Stkso value For an impactor with round nozzles the Stkso value is about 0 22 A 1 4 Particle losses in impactor Correction algorithm As a result of the small differences in the bombardment of gas molecules from different directions particles have a small wiggling velocity component In still air it is most clearly seen and is called Brownian motion of the particles Diffusion is a well known result of Brownian motion in presence of concentration gradient In impactors diffusion causes particles that are smaller than the cut diameter of an impactor stage to be collected to some extent As the concentration of particles in the gas in the vicinity of the collection plate approaches zero diffusion creates a net flow of particles towards the collection plate This phenomenon is characteristic to all instruments using impactor technique not just the ELPI In gravimetric impactors this phenomenon has negligible effect on the result since the mass of these small particles is often insignificant compared to the actual impacted mass However when the particles are detected by their electrical charge the effect can be significant due to the better sensitivity of the charge measurement To overcome these losses an algorithm is used to correct the ELPI reading as the losses have been measured together with the stage collection eff
67. ns to previous menu but no change will be made Current fA 10 26 51 Numb Distribution Type udi ui Diameter Stokes Aerod Area Volume Correction Mass Saving Interval RawCurrent Dilution Ratio Particle Density Sampling Changing a parameter when there are several possible values If the possible options of the menu item are of number type a new window will be opened when the Open Modify button is pressed The new window shows the current value of the parameter and the possible control actions The moving of the cursor is made with Up and Down buttons and the selection of the menu item is made with Open Modify button By choosing Increment and by pressing Open Modify once the value of the parameter is increased with a step set forehand in the program By choosing Decrement and by pressing Open Modify once the value of the parameter is decreased with a step set forehand If the Open Modify button is pressed continuously the value of the parameter is running upwards downwards with constant step and speed The run is stopped by releasing the Open Modify button K N DEKATI Dekati Ltd 2011 ELPI User Manual 36 w n Current fA 11 35 49 Path main data advanced Distribution Moment Stokes Aerod Decrement Accept Correction Saving Interval Dilution Ratio Particle Density Sampling Open Modify When the value of the parameter is set into its right value it can be accepted by moving the c
68. od Correction Off Saving Interval 0 samples Dilution Ratio 1 000 Particle Density 1 000 Sampling Greased Al Foils Open Modify a DEK ATI Dekati Ltd 2011 ELPI User Manual 38 w The options of Distribution Moment are Current Number Diameter Area Volume Mass and RawCurrent Current fA 10 26 51 T Number Distribution Type Diameter Stokes Aerod Area Volume Correction Mass Saving Interval RawCurrent Dilution Ratio Particle Density Sampling The Raw currents of each stage are saved always when saving is on see details of the data format in section 7 3 The calculated moments are based on the raw or fine particle corrected currents depending on the value set to the Correction parameter The correction should always be on The options of Distribution type are DW and dlog Dp The options of Stokes Aerod are Aerodynamic and Stokes The options of Correction are On and Off The default value of the Saving Interval is the value set in the parameter file 1 is 1second The default value of the Dilution Ratio is the value set in the parameter file If dilution with a fixed dilution ratio is used the DR will be taken into account in the ELPI calculations when the parameter is set to show the dilution ratio The default value of the Density is the value set in the parameter file The type of the collecting plate can be set with the Sampling parameter A new window is opened showing a menu of the p
69. on L grease in solvent by adding the grease to the solvent little by little until the liquid is nearly opaque grease solvent ratio about 1 30 1 20 Consult your chemical material supplier for the proper handling of hazardous chemicals Grease one substrate using for example a fine brush Keep the edge of the substrate clean the part that remains under the substrate holder ring If the foils are not weighed or analysed after the measurement it is usually easier to grease the foils after they have been placed on the collection plates Another option is to use the Dekati collection substrate spray and stencil for greasing 15 substrates at the same time See Figure below More details on the substrate spray can be found in the substrate spray manual Wait a couple of minutes so that the solvent has evaporated Check that a thin and smooth layer of grease is left on the substrate If the layer is not good add some amount of grease in the solvent and repeat the procedure Grease the remaining substrates K N DEKATI Dekati Ltd 2011 ELPI User Manual 19 w 4 4 Leakage check Because the last stages of the ELPI operate in low pressure it is important that the impactor does not leak Leakage in the instrument changes the sample air flow impactor operation pressures and the particle cut off diameters of the impactor stages These alterations will cause errors in determining the aerosol size distribution and concentration Therefor
70. or 22 kg with impactor Dimensions H400 x W420 x D220 mm Dimensions of impactor 65 x 300 mm Inlet G3 8 thread G3 8 NW16 and G3 8 hose connection connectors included in the shipment Outlet G3 8 thread G3 8 NW16 connector included in the Electrical specifications shipment Electric power Charger voltage 100 250 V 50 60 Hz 200W does not include pump or other accessories External power supply is included in the shipment 3 5 kV 0 5 kV Charger current 1 pA Pump specifications Pressure under the 1st stage 40 mbar Pump for 10lpm ELPI Computer specifications minimum 16 m3 h at 40 mbar abs recommended 25 m3 h at 40 mbar Pentium processor a MS Windows XP Vista or 7 Connection to ELPI RS 232 serial USB RS 232 adapter provided with the ELPI instrument Ethernet Analog channels 3 analog outputs 0 10V 6 analog inputs 0 10V K S DEKATI Dekati Ltd 2011 ELPI User Manual 3 NV Nominal impactor specifications D5096 Di Number min Number max Mass min Mass max um um 1 cm 1 cm ug m mg m asl tof 14 68 82 X 010 2 4E 04 30 10000 9 064 08 X A 1 GS5E 0 03 100 8 04 051 2 64Ev0 01 50 6 017 021 5 21E 06 4 006 008 20 73E 06 0 005 See exact values from the impactor data sheet a DEK ATI Dekati Ltd 2011 ELPI User Manual 4
71. or is located after the ELPI impactor This pressure should be set to 40 mbar with the front panel pressure adjustment valve when measuring with the ELPI unit The temperature sensor indicates the temperature of the electronics There are also two thermocouple connectors behind the ELPI unit The thermocouples can be used to measure for example sample temperature The sample temperature should not exceed 60 C 3 4 7 Pressure adjustment valve The pressure adjustment valve is used to adjust the 40 mbar below the first stage Turn clockwise to close and anti clockwise to open 3 4 8 Analog input and output connectors There are six analog input and three analog output connectors in the ELPl unit The analog input connectors accept voltage signal from 0 10 V The analog output connectors can have value total current total number total diameter total area total volume total mass PN10 PN2 5 PN1 PM10 PM2 5 or PM1 Total concentration means the total sum of all the stages PN 10 2 5 1 means the particle number concentration below 10 um 2 5 um 1 um respectively PM 10 2 5 1 means the particle mass concentration below 10 um 2 5 um 1 um respectively 3 5 Packing the ELPI for shipment If it is needed to transport the ELPI unit to another location the following instructions should be followed in packing the ELPI instrument to avoid damage to the instruments during shipping For packing instructions of
72. ossible plate types a DEKATI Dekati Ltd 2011 ELPI User Manual 39 w Current fA 11 37 33 Path main data advanced Distribution Moment Greased Al Foils Al Foils Bare Stage Stokes Aerod Nucle Bore Filter Other Distribution Type Correction Saving Interval Dilution Ratio Particle Density Sampling Open Modify The selection is made with the Up and Down and Open Modify buttons This selection does not affect the measured data but is saved in the data file header 7 2 6 Saving to File The data saving can be started with the Saving to File The saving can be started also in the graph view when the Menu 2 8 has been selected The saving will be stopped when the value is set to Off Current fA 10 21 06 Path imainidata Saving to File Off Append Data To File Off USB Memory Not Mounted Open Modify 7 2 7 Append Data to File Saving to a previous save file can be set with the Append Data to File option If the value is On a new header is written to the existing data file and the data is appended to the file If this option is Off a new save file is generated always when the saving starts DEKATI Dekati Ltd 2011 ELPI User Manual 40 w 7 2 8 USB memory With the USB memory option the USB memory stick can be Mounted or Dismounted for reading of the parameter files to the unit or for writing of the parameter files and data Current fA 13 12 14 Advanced Parameters gt gt
73. own however that the particle density is something else than 1g cm this density value can be used in the ELPI calculation In this case there are two options Aerodynamic and Stokes If Aerodynamic is selected the charging efficiency is calculated with the corresponding Stokes diameter impactor cutpoints and midpoints are calculated with Aerodynamic diameter corresponding to density 1 dlogDp vector is calculated with Aerodynamic diameter If Stokes is selected charging efficiency impactor cutpoints and midpoint and dlogDp vectors are all calculated with the Stokes diameter corresponding to the given density value Particle charging depends on the particle Stokes diameter which is why charging efficiency is always calculated with the Stokes diameter Also it should be kept in mind that impactors always classify particles according to their Aerodynamic diameter Filter stage extends the ELPI measurement range down to 6nm The filter stage is a back up filter put under the other impactor stages The filter stage lower cutpoint 6nm is fixed and is not changed even if Stokes diameter and different density values are selected This is because of the different operation of the filter stage from the other impactor stages and the fact that particles smaller than 6nm don t get through the ELPI charger Therefore it is not justified to decrease the lower cutpoint just by using differet density values in the calculation If
74. r chart Clear Chart button clears the time history chart The maximum number of samples shown in the time history chart is 1024 with 1 s sampling interval the maximum length of time axis is about 17 minutes When the data buffer is full the oldest samples are removed from the display and the time chart is updated so that the newest values are shown on the right Time stamp used is the system time seen in the upper right corner of the display Distribution Distribution button changes the moment shown in the distribution chart and in the time history chart Seven different moments are available with the following distribution charts K N DEKATI Dekati Ltd 2011 ELPI User Manual 31 w Current 1 7 Number 2 7 Diameter 3 7 Area 4 7 Volume 5 7 Mass 6 7 RawCurrent 7 7 Current 1 7 etc Current is the corrected current which takes into account the fine particle losses according to the fine particle correction algorithm The fine particle correction algorithm is explained in detail in Virtanen A Marjam ki M Ristimaki J Keskinen J 2001 Fine particle losses in electrical low pressure impactor Journal of Aerosol Science vol 32 pp 389 401 RawCurrent shows the measured current without the fine particles correction algorithm Number shows the number distribution and the total number concentration Diameter is the total diameter of the particles the diameter used for calculation is
75. re two options for each channel that can be set The whole range of the D A converter is 10 V Fullscale 0 10V which can be reduced to half range of 5 V Limited 0 5V It is also possible to set the zero level in the middle of the converters output if negative values are also recorded Current and raw Current can have negative values Aux Channel Setup selection opens a submenu Current fA 11 59 25 Path main setup auxchannel Aux Channel 1 Output Aux Channel 1 Include negative values Aux Channel 1 Limit To 5 Fullscale Aux Channel 2 Output Off Aux Channel 2 Include negative values No Aux Channel 2 Limit To 5 Fullscale Aux Channel 3 Output Off Aux Channel 3 Include negative values No Aux Channel 3 Limit To 5V Fullscale Open Modify a DEK ATI Dekati Ltd 2011 ELPI User Manual 43 w When Aux Channel 1 Output or Aux Channel 2 Output or Aux Channel 3 Output is selected the output value can be selected from the list Current fA Aux Channel 1 Include negative va Aux Channel 1 Limit To 5V Aux Channel 2 Output Aux Channel 2 Include negative va Aux Channel 2 Limit To 5 Aux Channel 3 Output Aux Channel 3 Include negative va Aux Channel 3 Limit To 5 11 58 05 Total Current Total Number Total Diameter Total Area Total Volume Total Mass Total Raw Current PNumber 1 PNumber 2 5 PNumber 10 PMass 1 PMass 2 5 Open Modify Aux Channel 1 Include negative values or Aux Channel 2 Inclu
76. rement Delimiter Char Data delimiter character comma space tabulator or semicolon Set in the parameter filelf the ElpiPlusCalc calculation sheet is used should be set to comma RawData Format of raw data Always Current CalculatedMoment Type of calculated values saved in the data file current number diameter area volume or mass Selected in the Datafile Advanced Parameters window before starting the saving of data CalculatedType Type of calculated data saved in the data file dW or dlogDp Selected in the Datafile Advanced Parameters window before starting the saving of data Density Particle density used in the data calculation Does not affect raw data Selected in the Datafile Advanced Parameters window before starting the saving of data a DEK ATI Dekati Ltd 2011 ELPI User Manual 51 w StokesDp Indicates whether Stokes diameter TRUE or Aerodynamic diameter FALSE has been used in the data calculation Selected in the Datafile Advanced Parameters window before starting the saving of data Calculated Di Impactor channels midpoints in stokes diameter Correction Indicates whether correction algorithm for small particle losses has been used in the saved data calculation TRUE or FALSE Should always be TRUE if true particle concentration is wanted Does not affect raw data Selected in the Datafile Advanced Parameters window before starting the saving of data Dilution Dilution rat
77. roing process 1 Start the flush pump Press the Menu button in the ELPI display and select Flush ON Alternatively the Flush can be started also from the ELPl vi software 2 Before starting the actual zeroing wait until the current values are stable There is always some noise in the electrometer readings but there should be no drift in the signal before the zeroing in started The current values can a DEKATI Dekati Ltd 2011 ELPI User Manual 21 w be checked from the first screen All currents display of the ELPI unit or from the ELPl vi software Data display Common window 3 Press the Menu button in the ELPI display twice to go to the Main menu window Choose Control Choose Start Electrometer calibration When the electrometer calibration is chosen the system does not respond to any commands before the calibration is done Alternatively the zeroing can be started from the ELPI VI software with the Zero button Zeroing can take few minutes 4 After the zeroing is finished check that the zero levels are within acceptable limits 10 fA with Flush ON The zero levels should always be checked from the raw current values 5 If the zeroing has not been successful ie the zero levels are not within acceptable limits leave the flush on for a longer period of time to stabilize the current signals and perform the zeroing again If it is still unsuccessful clean the impactor as described in Chapter 6 6 If th
78. rough the parameter file See chapter 8 Parameter file description for details K N DEKATI Dekati Ltd 2011 ELPI User Manual 46 w Display The parameters of the displayed data are set in the Display menu Current fA 12 08 32 Path main display Distribution Moment Distribution Type DW Correction False Backlight Level1 Open Modify 7 2 20 Setting the distribution moment ELPI always saves both the measured current values and the calculated distribution in the data file The format of the calculated data is defined in Distribution Moment menu Current Number Diameter Area Volume or Mass concentration can be selected as the shown concentration type Current fA 12 07 43 Path imain display Distribution Moment pisses Number Distribution Type Diameter Correction Area Volume Backlight M s RawCurrent Open Modify This option can be also set directly in the chart display mode a DEKATI Dekati Ltd 2011 ELPI User Manual 47 w 7 2 21 Setting the distribution type When Distribution Type is selected the value changes from DW to dlog Dp or vice versa e dW dlogDp format is commonly used in displaying size distribution data If dW dlogDp is selected the heights of all the channels are divided by the logarithmic width of the channel As the particle diameter is given in the logarithmic scale the distribution is corrected for unequal channel widths With dlogDp selected area of th
79. s are taken into account in the ELPI calculation in the charging efficiency curve and therefore need not be worried about in a standard ELPI measurement When gravimetric measurements are made with the ELPI impactor however these losses always need to be taken into account in the final results Therefore the gravimetric impactor measurements are only made when the charger and trap has been switched OFF In this setup no ELPI real time data is received from the instrument The software shows the natural charge of the sample Note If electrical detection charger and trap ON is also conducted during the collection of the mass sample particles are collected in the charger by electrical mechanism Measured masses need to be corrected for these losses 5 3 Chemical analysis The 14 upper stages 13 impactor stages and the pre separator stage of the ELPI impactor collect the sample on collection substrates so that the samples can be chemically analyzed When the sample has been collected each size fraction can be individually chemically or physically analyzed The sample on the filter stage can not be used for chemical analysis When making a chemical or physical analysis proper sample handling must be used to reduce the risk of contamination The contamination risk must be reduced by careful preparation and work procedures Before placing the collection substrate on the collection plates the collection plates must be care
80. sembly To disassemble the impactor remove first this collection plate and insulator Remove the rest of the stages collection plates and insulators 4 1 2 Impactor assembling Assembling the impactor is done in reverse order to disassembling Each of the impactor stages has three parts jet plate PEEK insulator with o rings and collection plate KS DEKATI Dekati Ltd 2011 ELPI User Manual 12 w PEEK insulator ring with two o rings Jet plate i Collection plate with c E d substrate holder ring Figure 2 Construction of one impactor stage The PEEK insulators have o rings on both sides and the collection plate has a substrate holder ring to keep the collection substrates on their places The design of the filter stage is a bit different it has only one part with insulators on each side The filter stage consists of many layers of fine mesh that traps the particles below 17 nm nominal This part should not be disassembled nor does it need any servicing Figure 3 Filter stage Before assembling the impactor greased collection substrates should be inserted on the collection plates to ease the cleaning of the impactor after the measurement and to prevent bouncing of the particles during the measurement please see section 4 2 Collection substrates for details KS DEKATI Dekati Ltd 2011 ELPI User Manual 13 w All the jet plates and the collection plates are numbered The jet plates shou
81. ser Manual 68 w A 1 9 Measurement accuracy of ELPI The measurement accuracy of ELPI depends on the size and type of particles that are measured In ELPI the particles are measured by the charge they carry so the accuracy of the concentration measurement is the accuracy of the current measurement Sensitivity is better with large particles since the amount of charge carried with one big particle is significantly bigger than with one small particle Noise levels and measurement accuracy may be affected by sudden temperature changes or e g vibration of the instrument and should therefore be checked before and after each measurement Figure 1 presents the accuracy of ELPI measurement when considering both number and mass concentrations for 10 lpm ELPI As can be seen the sensitivity with number concentration is better with larger particles whereas with mass the sensitivity is better with the smallest particles due to the fact that the mass of the larger particles is so much bigger a small error in number concentration can lead to bigger deviations in mass results 1000 00 4 100 000 e Number Mass 100 00 10 000 gt eo E E 2 10 00 1000 Fa 3 ES E 2 100 0100 4 D o vi o 0 10 0 010 0 01 0 001 0 0 0 1 1 0 10 0 Particle diameter um Measurement accuracy of 10lpm ELPI When considering the me
82. t 40 mbar absolute pressure Recommended 21 m h at 40 mbar absolute pressure 3 2 Recommended accessories ELPI can be used as a stand alone instrument but it can also be used with ELPI VI software If ELPI VI software is used a computer is needed External computer Pentium or above with Windows XP or Windows 2000 or Windows 7 Serial port or USB port for connection with the ELPI Also Ethernet connection available 3 3 ELPl housing and connectors Flush air connector Charger HV connector Trap voltage connector Electrometer needles Display Control buttons Vacuum connection for impactor USB port for data acquisition Pressure adjustment valve K N DEKATI Dekati Ltd 2011 ELPI User Manual 6 w Analog input connectors Pump control Ethernet connection Ons o Oc 0o m Analog output connectors Power supply connector Serial port Pump vacuum connection Sample inlet Charger Impactor Impactor release button 3 4 ELPl components 3 4 1 Impactor ELPI impactor is used for particle size fractionating It is a 14 stage cascade low pressure impactor with a size range from 6 nm to 10 um Electrical detection KS DEKATI Dekati Ltd 2011 ELPI User Manual 7 w is applied to 14 stages while the first stage of the impactor is a pre separator stage All stages are electrically insulated from each other using PEEK insulators The last stage of
83. than expected charge state after the ELPI charger and they will also have high loss rate in the charger The charger also removes larger particles and it is not recommended to use ELPI for gravimetric measurement and real time detection AT the same time a DEKATI Dekati Ltd 2011 ELPI User Manual 65 w Aerosol flow Corona voltage Trap voltag 9 T 400 50V ELPI charger A 1 7 Gas to particle conversion Some radical gases like SO can interact with the high energy plasma zone created by the corona discharge Ultra fine particles may be formed during this interaction which causes measurement artefacts in the ELPI If gas to particle conversion is suspected a test measurement with pre filtering of particles is suggested A 1 8 Negative current values The primary quantity that ELPI measures is current Due to e g diffusion of fine particles in the upper stages these measured current values have to be corrected for these losses before calculating the particle number concentration from the current values These values are designated in ELPI as Raw and Corrected values respectively See A 1 4 A correction algorithm is used to correct the raw measured values for the fine particle losses and it is concentration dependent The correction algorithm transfers part of the measured current signal from the upper stages to the lower ones since part of the signal in the upper stages is caused by diffusion of th
84. the four possible control actions shown at the bottom of the display are Back Open Modify Up Down The controls are selected with the push buttons below the display With the Back button it is possible to return one level backwards in the menu tree When the Back button is pressed in the Main Menu view the display returns to the chart view Menu 1 3 Current fA 10 10 32 Control gt gt Setup gt gt Display gt gt Log gt gt Figure 4 Main Menu view Use the Up and Down buttons to move the cursor and Open Modify button to select the item The menu options are shown at the left part of the display If there are submenus a gt gt prompt is shown after the menu item In the above figure all items of the Main Menu have submenus the Data file menu has been selected with a cursor 7 2 4 Changing or setting the value If the possible options of the menu item are of ettertype there are two possibilities a DEK ATI Dekati Ltd 2011 ELPI User Manual 35 w 1 If there are only two alternatives On Off Yes No True False the value will be changed immediately after pressing the Open Modify button 2 f there are several alternatives a new window will be opened showing a menu of the possible choices The cursor can be moved in the menu with the Up and Down buttons The selection is made by pressing the Open Modify button which returns the control to the upper menu level Pressing the Back button retur
85. to adjust the impactor low pressure to 40 mbar 9 Turnon the charger 10 Perform the electrometer zeroing with flush on see section 4 5 11 Connect the ELPI inlet to the desired sample line Pay attention to the sampling conditions 12 Start saving the data from Menu 2 3 For details on saving and changing the save parameters see chapter 7 and ELPI VI User manual 5 2 Gravimetric measurements ELPI instrument can be used to make gravimetric impactor measurements as well as gaining real time data of the sample concentration The gravimetric analysis can only be performed from the impactor stages the filter stage can not be gravimetrically analyzed Gravimetric measurements are made by following procedures outlined below 1 Grease the collection substrates a DEKATI Dekati Ltd 2011 ELPI User Manual 23 b di 2 Weigh the substrates using a microbalance recommended sensitivity 10 micrograms or better Place substrates on the impaction plates Assemble the impactor Switch on the pump and set the impactor outlet pressure to 40 mbar Collect the sample and record the sampling time Switch off the pump Disassemble the impactor Remove the collection substrates Weigh the collection substrates Calculate the mass collected on the substrates Calculate distribution Ta B DEW So qe Particle losses always occur in the ELPI charger when the charger has been switched on These losse
86. u can use the substrate positioning tool for this or simply fingers if contamination of the collection substrates is not a matter of concern Take the substrate positioning tool and Squeeze the tool gently and pull grab the collection plate so that the up while pushing the collection substrate holder ring fits in the big holes plate down gently of the tool When using the substrate positioning tool do not squeeze it too hard when trying to remove the substrate holder rings Squeezing it harder makes it even more difficult to remove the substrate holder ring If you are unable to remove the substrate holder ring try re positioning the tool around the substrate holder ring 3 Place the collection substrate carefully on the impaction collection plate Make sure that the foil is in the centre of the collection plate KS DEKATI Dekati Ltd 2011 ELPI User Manual 19 w 4 Place the substrate holder ring in its place Take the substrate holder ring into the tip of the substrate positioning tool and push it down until it clicks in its place Check that the collection substrate is smoothly in its place To remove the collection substrate after the measurement use again the substrate positioning tool 4 3 2 Greasing the collection substrates The collection substrates can be greased for example with Apiezon L grease high purity minimal evaporation dissolved in carbon tetrachloride toluene or acetone Dissolve Apiez
87. unit select the correct impactor number from the ELPInux software See 7 2 15 There are four push buttons in the ELPI unit front panel the rightmost one is used to turn the unit ON and OFF but it is also used for other functions the current function is seen at the bottom of screen On OFF button i Figure 1 Four push buttons below the ELPI screen K N DEKATI Dekati Ltd 2011 ELPI User Manual 29 w 7 1 Distribution charts When the system starts a multi view is displayed on the screen showing the current distribution chart the time history chart and the data values Current fA 10 02 38 Charger U 4700 Charger I 1uA Trap U 10 v Pressure 40 mbar Press 2 1025 mbar Temp 35 C Total 32949 55 fA Saved 0 lines File FileName Menu 1 3 Clear Chart Distribution 1 7 Change View Figure 2 Distribution time history data view alarms shown on the top of the screen with red The upper left corner of the display shows the selected distribution Current Number Diameter Area Volume Mass RawCurrent Current shows the corrected currents RawCurrent shows currents without the correction Time history chart shows the currents from all stages or the total concentration change over time The maximum number of samples shown on the screen is 1024 samples The alarms are shown above the distribution chart the status of the charger voltage Charger the status of the impactor low pressure Press
88. ure and the status of the trap voltage Trap Red text appears on the screen see picture above if the measured value of the variable is outside limits If there are no alarms no text is displayed Also some important parameters describing the status of the ELPI unit are shown on the right hand side of the screen Charger Charger voltage V Trap Trap voltage V Pressure Impactor low pressure mbar Press 2 Sample pressure mbar Temp Thermocouple temperature C a DEK ATI Dekati Ltd 2011 ELPI User Manual 30 w Total Total sum of all channels unit depending on selected moment Saved Number of saved lines if the saving is on File Name of the save file ELPI yyyymmdd hhmmss dat The system time is shown in the upper right corner of the display The time can be changed through the ELPI VI software please see the software manual for details 7 2 Navigation Below the time history chart are four navigation options which can be operated with the four push buttons below the display Figure 3 Four push buttons with Menu button circled on the left With the Menu button three different views Menu 1 3 Menu 2 3 and Menu 3 3 can be selected Each of these views has different functions for the other three push buttons 7 2 1 Menu 1 3 Figure 4 on the next page shows the Menu 1 3 view displayed at the startup of the system The current chart with the corrected currents and the selected distribution Clea
89. ursor to the Accept position and pressing Open Modify The control is then returned to the upper menu level If the Back button is pressed in this phase the control returns to the upper level and the value of the parameter is not changed Main Menu When the Menu 2 3 button is pressed in the chart display mode the following menu will be displayed Current fA 10 10 32 Path main Control Setup gt gt Display gt gt Log gt gt The gt gt prompt means that there are submenus When the Open Modify button is pressed the submenus will be opened a DEK ATI Dekati Ltd 2011 ELPI User Manual 37 w Data File The save parameters of the save data file are set in the Data File menu When the Data File gt gt is selected the following menu is displayed Current fA 13 12 14 Path imainidata USB stick mounted Advanced Parameters gt gt Saving to File Off Append Data To File Off USB Memory Mounted Import Device Parameters Import Impactor Parameters Export Open Modify There are six choices and the Advance Parameters contains a submenu The actions of these choices are explained in the following sections 7 2 5 Advanced Parameters When Advanced Parameters gt gt is selected the parameters of the data to be stored can be set The following menu is displayed Current fA 11 28 40 Path main data advanced Distribution Moment Current Distribution Type DW Stokes Aer
90. used Notepad should be used for editing the XML files 9 1 Acquiring IP address via DHCP on an Ethernet interface If the IP address is acquired via DHCP the address can change when the ELPI unit is turned off and again on UseDHCP 1 OverridelpAddress 1 OverridelpSettings 1 In this case the other parameters have no effect Import ParametersDevice xml file from USB memory to ELPI by first mounting the USB memory and then choosing Import Device Parameters Please note that all XML files named ParametersDevice xxxxx xml are uploaded to ELPI Select the correct Device file from menu and boot ELPI twice First boot will write etc network interfaces and second boot will enable using the new setup 9 2 Using fixed IP address If fixed IP address is used the settings should be as follows IpAddress 10 16 0 26 the address you want to set Gateway 10 16 0 1 same as in other local devices Netmask 255 255 255 0 same as in other local devices OverridelpAddress 1 OverridelpSettings 1 UseDHCP 0 Import ParametersDevice xml file from USB memory to ELPI by first mounting the USB memory and then choosing Import Device Parameters Please note that all XML files named ParametersDevice_xxxxx xml are uploaded to ELPI Select the correct Device file from menu and boot ELPI twice First boot will write etc network interfaces and second boot will enable using the new setup 9 3 Connecting the ELPI unit and PC If PC and ELPI
91. w 3 UNPACKING AND PACKING When opening the ELPI shipment for the first time check that all the items listed below are in the package The ELPI package contains ELPI unit including ELPl impactor and charger assembly ELPI carry case ELPI Manual ELPI VI Software Manual ELPI Data sheet Power supply Accessory box Aluminium foils 300pcs CF 300 Apiezon L grease incl mixing jar AG 10 2m of sample hose IPR 212 Impactor collection plate tool N1303 Tweezers for handling of the impactor foils IPR 403 2 pcs of 3 8 NW16 connectors IPR 110 1 2 3 8 connector for ELPI outlet RAO14 34 38 Tube connector RA030 12 38 Spare charger needle RS 232 Serial cable IPR 509 USB Serial adapter ELA 443 Impactor leakage test tool Teflon tape for vacuum connections ELPI flash drive including ELPI and ELPI VIT Manuals ELPI VI Software ELPIPluscalc data processing spread sheet ELPI Data sheet Vacuum hose including 2pcs of NW16 clamps and gaskets DEKATI Dekati Ltd 2011 ELPI User Manual 5 w If any of the items is missing from the shipment please contact your local ELPI distributor or Dekati Ltd When packing the ELPI unit for shipment the black transportation box should be used See Chapter 3 5 for details 3 1 Required external accessories The following item is needed but not included in the shipment Vacuum pump Minimum for 10 lpm ELPI 16 m h a

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