Dielectric MGD 2002 Helium Detector User Manual
Contents
1. Certificate Optional 17 PARTS LISTS A STANDARD PACKAGE Upon initial receipt of the MGD 2002 multi gas detector the following components come included as standard items Numbers in parenthasesis indicate the quantity included 1 MGD 2002 Multi gas Detector PN 79766 2 Silica gel drying adapter PN 84972 3 Probe Assembly PN 83325 4 7 2V Nickle Metal Hydride Battery PN 82492 5 Carrying Strap PN 84923 6 12VDC auto plug in adapter PN 84677 7 100 24VAC Universal AC charger PN 84673 W North American power cord 8 Eurpoean power cord PN 84674 9 Boot Housing PN 84210 10 Extension Rods 2 PN 83325 11 Instruction Booklet IB 417 PN 84671 12 Warranty Card Serialized PN 84973 13 Needle Probe PN 84165 14 Moisture Cartridge 2 PN 83220 15 Carrying Case PN 84672 18 B REPLACABLE PARTS If for any reason a field replaceable unit FRU is required the following list of items is provided to ease the ordering process Note Only user replaceable items are listed If for any reason an item is needed that is not on this list the device Should be sent back to Dielectric Communications for repair and recalibration 1 Moisture Cartridge PN 83220 2 Spare Battery PN 82492 3 Boot Housing PN 84210 4 12VDC auto plug in adapter PN 84677 5 100 24VAC Universal AC charger PN 84673 6 Eurpoean power cord PN 84674 7 Extension Rods 2 PN 83325 8 Needle Probe PN 84165 C Accessories Options the fo2. effect Methane s number is so small it acts like a negative tracer gas Thus it has a warming thermoconductivy or TC What makes methane so trouble some is that it s very small and can thus pass through most filters with out detection or elimination Even in today s high tech environment the only way to eliminate methane is to burn it off Unfortunately in a hand held device burning off stray gasses is not an option Other gasses such as Propane C H Pentane C H and Ethane C H Carbon Dioxide CO Carbon Monoxide CO Nitrous Oxide N 0 and Ozone 0 and most other CFCs also have a negative TC TC but are easily eliminated by the second filter in the wand section Unfortunately the crushed activated charcoal has a limited useful life when used in an environment of high organic compounds such as those mentioned It s for this reason we at Dielectric strongly suggest return ing the MGD 2002 at a minimum of once a year to recalibrate During factory recalibration the silica gel filters are cleared and the other two filters are replaced Refer to page 17 for all the value added benefits that are included in a factory recalibration 9 Key By Key Operation The MGD 2002 features high tech membrane switches with a large multi function liquid crystal display and a patented filter system Each key of the membrane switch features a raised embosed edge that is designed to be felt when wearing protective gloves The
3. relative abundance in 6 the atmosphere is so small it has a very small impact on the overall TC of air Note that as the numbers increase the TC of the gasses increase with Hydrogen H and Helium He being the most thermally conductive It s this distinction between the TC of CDA as compared to the TC of hydrogen or helium that we are interested in Our MGD 2002 is designed with two ranges The low range detects gas between 25 and 20 000 parts per milion PPM in increments of 25 ppm Mathematically 20 000 ppm is a concentration of 2 The high range is between 2 and 100 Calibration of the MGD is accomplished via the microprocessor Initially when the sample air contains no zero tracer gas it will draw in 100 CDA The micro processor is then told that the reading it s getting is to be refered to as Zero Using a known controlled volume of CDA 2 tracer gas Scientific grade is injected into a closed loop The accuracy of the gas is 2 00 and the detector should read 2 00 This setting is then stored in memory The last calibration point is to draw in 100 scientific grade tracer gas and the reading stored in memory Since the TC of the tracer gas is constant the readings observed are directly proportional to the concentration received Another way to state this is that two points make a straight line and the more points given the more accurate the straight line will be After the calibration process any c
4. 6 0380 Krypton Kr 0000114 1414 1140 6865131EH7 838000 Hydrogen H2 0000053 053 530 3491684EH7 2019 Nitrous Oxide N20 0000031 031 310 18668MEH7 440100 Xenon Xe 0000009 009 8 5239179EM6 1512900 Ozone 03 0000000 003 25 150551EH6 479982 Sum 100 000021 1 000 000 21 1000000212 6 022046E 23 Table 1 bonded with another of it s own kind If the elemental gas does not have a subscript that gas has a full outer electron shell and will not react or bond with any other element These few elements are known as Nobel gasses All the gasses listed in Table 1 as well as those that are not all possess an intrinsic property called Thermal Conductivity For brevity we will refer to thermal conductivity as TC and it has a unit of measure of W m k One way to explain TC is it s ability to absorb heat or wisk away heat from a heat source An easy way to think about this is to remember how hot you feel when you sweat Air helps to cool your body temperature Table 2 on page 7 shows the IC for clean dry air CDA as well as it s nine most abundant components For example CDA has a TC constant of 0 026 since it s mostly comprised of nitrogen 78 1 that has a TC of 0 026 The next most abundant gas is oxygen 20 9 with a TC of 0 027 which is remarkably close to nitrogen and thus stays very close to 0 026 The third highest concentration in CDA is Argon 0 9 with a TC of 0 018 but since it s
5. IB 417 RevA Part No 84671 e e lt e Dielectric Yechnologies A Radiodetection Company Dielectric Technologies RR 2 Box 756 Bridgton Commerce Center Bridgton ME 04009 877 247 3797 207 647 9495 Service Information Should a question comment or problem arise the information below is provided as a guide The number to call is 207 647 9495 or toll free at 877 247 3797 with the appropriate extension given below When returning a unit for factory service or calibration call the customer service department at ext 116 for a material return authorization number MRA The device should be boxed securely and contain information as to the person to contact with telephone number billing information and return shipping information If the device is being sent to the factory for service a written statement of the problem or symptoms should then be included The MRA number must be on the outside of the package or indicated on the shipping label Dielectric Technologies RR 2 Box 756 Bridgton Commerce Center Bridgton ME 04009 Table of Contents P COM NO r ususi SPE CINCO L sxicaxemendvacsanssacviceas AEO WV ANOS u suu DT D I Lu unun um yana Operations cu b Theory of Operation c Key by kev d Liquid Crystal Display LCD e LED Status T om u uu u l baa sassa bsa Maintenance a Clea
6. are two possible modes of operation for this device either automatic A or manual M thus this field will show and A or an M SOUND STATUS By default the MDG 2002 has the speaker disabled to conserve battery power Thus the speaker symbol will initially have an X through it Pressing the speaker button once will remove the X and enable the audio out circuitry PROBE LENGTH This icon is only used in the manual M mode When the sample button is pressed the microprocessor takes a reading based on how many lengths of probe that are being used This icon shows how many lengths and the timing is based on the lengths used as well as lengths displayed 13 MAINTENANCE CLEANING amp INSPECTION Instrument Clean away any debris or moisture accumulation with a clean soft moist NOT WET cloth Dirt or sand can scratch the lexan protective lense cover over the LCD thus ensure the cloth used is clean and soft Check exhaust ports on the top right side of the unit small brass fitting for any obstructions Collection Boot Clean with compressed air or with soap and water to remove mud and debris Dry thoroughly when done Small Probe Tip Clean with compressed air or with soap and water to remove mud and debris Dry thoroughly when done Extensions Clean with compressed air or with soap and water to remove mud and debris Dry thoroughly when done Filter Check the filters in handle before every use If the cartridge is
7. bration periodicity includes items such as the environment is the device going to be used in a harsh environment or in a clean room How frequently is this device going to be used once a month every six months or daily Is the highest accuracy strictly required or is the end user just identifying the area with the highest concentration of hydro gen or helium We at Dielectric recommend that if you frequently use this device or the accuracy is strictly required the calibration should be a minimum of once per year If however the device is used infrequently or the accu racy is not as critical factory recalibration can be delayed to as much as every two years Sending the unit back for calibration is not limited to the yearly or biannual calibration cycle chosen For example the user may suspect inaccurate operation that may be the result of the filters or plumbing being compromised with an oil residue oil vapors water dirt petro leum vapors or some other foreign material including grass and in sects During the factory re calibration the following value added steps and procedures will be accomplished 1 Inspection 2 Light cleaning As required 3 Silica gel filter dried As required 4 Carbon filter replaced 5 Intake and exhaust filter replaced 6 Air volume checked and adjusted 7 Temperature sensors checked and adjusted 8 Software updates installed As available 9 Calibration procedure completed 10 ISO Calibration
8. compartment Our revolutionary new procedure allows the user to quickly assess the daily life span of the filter by simple visual cues A new dry cartridge will be vividly bright blue in color and is shown in figure 1 on page 9 The moisture car tridge will turn pink as it removes moisture from the air Figure 1 on page 9 The filter cartridge is still within it s useful life but will de grade further to a clear white color if continually used in high humidity environment or if water is present The useful life of these filters depends the relative humidity RH of the working environment For example on an average dry day the RH is roughly 20 in this case the filter should last between 4 6 hours If the relative humidity climbs to 50 RH the single cartridge might last only 2 3 hours If the humidity climbs to between 50 90 RH the filter may only last one hour 8 What makes our filters so revolutionary is that even on the most humid of days these filters can be replaced within seconds or cleared and reused within minutes Please refer to page 15 for instructions on how to clear these filters Spent Cartridge Dry Cartridge Figure 1 METHANE vs ACCURACY There are certain gasses that the MGD 2002 cannot eliminate and methane CH is the most abundant and troublesome of them all Just like humidity methane has a warming effect Referring back to table 2 on page 7 the higher the TC number the greater the cooling
9. defect and not later than ten 10 days after the last day of this warranty and 11 the Manufacturer shall have the option of requiring the return of the defective material transportation prepaid to establish the claim The Manufacturer shall not in any event be liable for the Purchaser s manufacturing costs loss of profits good will or any other special consequential incidental or other damages resulting from such defects THERE ARE NO OTHER WARRANTIES EXPRESSED OR IMPLIED WHICH EXTEND BEYOND THE WARRANTY SET FORTH HEREIN Dielectric Technologies Bridgton Commerce Center Bridgton ME 04009 877 247 3797 207 647 9495
10. llowing is a list of items that are recommnended for use with the MGD 2002 Multi gas detector that do not come as a standard item Items without part numbers are still in the design phase and have not yet been assigned N A 1 Head Phones PN 882 0007 2 Overhead Wire Boot PN N A 3 Non metallic Probe Assembly PN N A 4 Downloadable Software Revisions PN N A 19 WARRANTY The Manufacturer warrants that all goods supplied hereunder whether or not of its own manufacture will be of the kind described herein or in any specification and drawing approved by the Manufacturer and of merchantable quality and free from defects in material or workmanship under normal use and prescribed maintenance for a period of one 1 year with the exception of air dryers utilizing water sealed compressors as well as the compressors themselves which shall be for two 1 years Neither this warranty nor any other expressed or implied shall apply to goods delivered hereunder which have been damaged or subjected to alteration or negligence after delivery The Manufacturer s only obliga tion for breach of this warranty shall be the repair without charge or the furnishing F 0 B Bridgton Maine of a similar part to replace any part which within one 1 year with the exception as noted above from date of shipment is proven to have been defective provided that i the Purchaser shall have notified the Manufacturer within ten 10 days of the discovery of such
11. mperative that the user of this device observe all safety guidelines listed below to prevent personal injury property damage or damage to this detector e Do not operate the device if it has been damaged Refer to qualified factory service personnel referenced in the front of the manual Do not disassemble the device as it will void your warranty Only qualified factory service personnel should perform repairs Do not draw water into the helium detector Water vapor in the air is normal and the silica filter is designed to eliminate this amount of moisture However water will not only adversely affect this units operation but may cause severe damage Water found inside the unit will also void your warranty Use precautions when operating the detector in rain snow or adverse conditions Although the detector is water resistant it is not waterproof Do not allow water to accumulate on the faceplate as it could migrate into the electronics Do not use the probe tip to dig in the soil or in any manner other than directed in this manual Although this device has been designed to operate with a battery voltage as low as 6V do not operate the detector when the battery indicator displays 1 4 battery or less False readings will occur when operated under this condition Refer to page 16 for replacing the battery or recharging the battery Disclaimer The Occupational Safety and Health Administration OSHA states that the lower explo
12. ncentration Air or what we term as Air is actually made up of a wide range of gasses Some of those gasses are pure elements some are naturally occuring simple compounds while others are complex man made compounds Table 1 on the next page shows a list of the twelve most abundant gasses that comprise what we term as AIR The table has been arranged in decreasing concentration order yet also provides other useful information such as chemical name chemical symbol percent in normal air concentration in parts per million parts per billion and atomic weights The naturally occuring elemental gasses are Nitrogen N Oxygen 0 Argon Ar Neon Ne Helium He Krypton Kr Hydrogen H and Xenon Xe Note that the subscript of 2 in the atomic symbol shows that the gaseous form of the element normally occurs when it is 9 EN us 6 022045E 23 atoms mole Avogadros Number 224141 Liters mole mole volume Mole Parts per Parts per Parts per Atomic Weight Gas Present Symbol Percent Million Billion mole grams per mole Nitrogen N2 78 082700 780 827 780 827 000 4 702175E 23 280135 Oxygen 02 20945700 209457 209457000 1 261359E 23 31 9988 Aron Ar 0934000 9340 9340000 5 624590E 21 39 9480 Carbon Dioxide CO2 0 035000 350 350 000 2407716E 20 440100 Neon Ne 0 001718 148 17 180 1 034587EH9 204797 Helium He 0 000524 5 24 5240 3155552EM8 4 0026 Methane CH4 0000170 170 1700 1 023748EM18 1
13. ning and Inspection b Filter Replacement C Clearing the Silica Gel Filter d Battery Replacement e Battery Recharging IO bi lli ceed pes epr E 22 sees TIUS Parts list a Standard Packacge b Replaceable Parts ACC665507166 sese u i cus ORE INED E HEN WW Hi Il Tc T Page 4 Page 10 Page 12 Page 13 Page 14 Page 14 Page 15 Page 16 Page 16 Page 18 Page 18 Page 19 PREPARATION UPON DELIVERY 1 Immediately inspect the MGD 2002 for any physical damage that may have been caused during shipping NOTE The Manufacturer s warranty does not cover damage caused in transit You must notify your carrier immediately for any damage claims 2 Turn the device over and open the battery compartment door Remove the battery to expose the device information placard Write the unit serial number on the warranty information card 3 Connect the battery plug to the main logic board Close the battery compartment door and secure with the quarter turn fastener 4 Plug the Universal power supply into a convenient AC wall outlet First then plug the other end into the device Second NOTE Charge battery for 2 hours before operating the Multi gas detector for the first time 5 Complete the warran
14. oncentration sampled will fall on the line TESTING THE THEORY We at the manfacturing facility have the capacity to mix any concentration of gas Table 2 at or below 2 00 We then arbitrarily choose a value to mix The MGD is then allowed to siphon this test mixture and the display should read the amount within 25ppm To test the higher numbers a tank of premixed scientific grade 15 00 tracer gas is used The MGD should display the correct value within 0 2 HUMIDITY vs ACCURACY As stated earlier water vapor or H 0 is a normal component of air The unit of measure of humidity is known as RH or percent relative humidity An average value of humidity on a normal dry day is 20 whereas on a very humid day can reach into the nineties or 100 when raining misting The MGD can correctly function with RH levels as high as 50 any value above 50 results in what is seen as negative gas Another way to state this is when the humidity goes up the accuracy goes down Humidity and accuracy are inverses of each other This doesn t mean that the MGD 2002 cannot be used when the humidity goes above 20 The wand section contains three independant filters one removes water vapor one removes chloroflourocarbons and the last removes large particulates MOISTURE FILTER Dielectrics revolutionary Patent Pending replacement filter car tridge system removes almost 100 of the moisture from the sample air before entering the sensing
15. pink or whitish in color replace the cartridge following the steps provided below The filter section can be cleaned with soap and water as long as the silica filter is in place and the knurled cap section is tightened firmly NOTE DO NOT ALLOW WATER TO ENTER THE CHARCOAL FILTER FILTER REPLACEMENT In order to replace the silica gel filter firmly grip the filter handle with one hand and turn the knurled cap assembly counter clockwise until they separate Once the cap assembly is removed turn the handle over so the filter will slide out using only gravity If the filter does not slide out voluntarily while holding the handle upside down lightly tap the side of the handle against any solid object available The filter will Slide out 14 With the spent filter cartridge removed ensure there is no foreign material in the handle section If the path is clear replace a new BLUE silica gel filter Replace the cap assembly using minimal force turning clock wise CLEARING THE SILICA GEL FILTER To restore these cartridges to a dry deep blue useful condition as Shown on PAGE 9 back flush the hand held probe with Compressed Dry Air or Dry Nitrogen Use the Needle probe connected to the front end of the probe handle and the Back Flushing Air Chuck assembly connected to the hose Figure 5 below The needle probe must be installed in order to defeat the one way check valve and allow air to flow back through the filter Figure 6 below shows
16. pow ered but clears all the internal logic circuitry The device goes through its zeroing routine to deter mine a new baseline This button is preferred to turning the device off and back on in that it main tains power to the sensing elements thus main taining sensor stability Only press this button in a zero tracer gas environment MODE this button controls what is being dis played on the LCD By default the unit is in auto matic mode and will constantly show what the sens ing elements have detected in both concentration as well as time If the unit is placed in the manual mode the device will continue to draw in samples as normal However when the sample button is pressed the LCD no longer shows time but will only show what the sensors are detecting at that one particular moment of time The sample button tells the microprocessor to take one reading Upon pressing this button the microprocessor looks at the probe length selected and calculates how long it should take for the sample to get to the detector takes the sample then dis plays the result This is a one shot button meaning that for every Sample needed the sample button must be re pressed 11 Liquid Crystal Display LCD The LCD is a near real time display of the tracer gas the unit has detected The refresh rate is slightly greater than ten times every second Figure 2 Figure 3 Figure 4 Figure 2 on the left shows the liquid crys
17. simply plug the auto adapter into the cigarette lighter jack first and then the output jack into the device Second Again the internal software will detect the presence of the charger and will turn off the detection capa bility while the unit is in charge The Nickel Metal Hydride NiMh battery is equipped with a tempera ture sensing element to ensure the battery will not over heat and ex plode during the charge cycle Should the ambient temperature be too hot the sensor may cause the recharge circuitry to shut off prema turely As such it s highly recommended that this unit be charged away from any heat sources Although NiMh batteries are some of the best rechargeable batteries on the market today there are still some inherent draw backs with their use One such issue is that even if the device is unused for an extended period of time these batteries lose 40 of their charge during the first month and 20 every month after that Thus it s highly recommended that the unit be recharged before use 16 Calibration The MGD 2002 is a precision measuring device that requires factory calibration in order to ensure continued and sustained optimum oper ating performance Periodicity between calibration cycles is dependant on the environment in which the device is to be used the end users criteria for the equipment and the amount of time the equipment is used throughout the year For example decision criteria for choosing a cali
18. sive limit for hydrogen H gas is under 5 Any concentration above this level whether intentionally mixed or accidentally trapped in a confined space is highly explosive and unstable Since the MGD 2002 is capable of detecting both Hydrogen H and Helium He gas without any operator intervention we recommend that if you do use Hydrogen H gas mix the remaining 96 with Helium He gas for 100 usability and added safety MODEL MGD 2002 MULTI GAS DETECTOR OPERATIONS OVERVIEW The MGD 2002 Detector is a portable leak locating and pinpointing device that detects both Hydrogen H and Helium He when used as a tracer gas in a multitude of pressurized systems The characteristic of being lighter than air allows both Hydrogen H and Helium He to penetrate small leaks rapidly and permeate through the densest soils and pavements quickly The leak can therefore be pinpointed easily with this detector Our helium detector products are used today in many industries and applications including Military RF systems High Voltage AC power systems High definition television Chemical manufacturing Cellular and Analog telecommunication and industries utilizing above and below ground storage tanks THEORY OF OPERATION The MGD 2002 Multi Gas Detector is a 16 Bit microprocessor controlled precision instrument that operates on the principle of changing thermal conductivity to locate a specific tracer gas as well as quantify its local co
19. switches themselves require 12 in oz of pressure for the contacts to close and will make a noticable click that is both felt and heard thus ensuring the user with complete controls of the device when wearing gloves The following is a description of each key on the MGD CONTROL BUTTON DESCRIPTION 1 0 ON OFF The ON OFF button supplies power to the instrument Once the unit is turned on it will initialize then conduct a 30 second power on self test POST The instrument will turn off automatically when left unattended for a pe riod of longer than 15 minutes The light button is simply used to turn on and off the LCD backlight By default the LCD back light is turned off to conserve battery life With one push of this button the backlight will illuminate and will remain on until this button is pressed again or the unit is turned off The sound button is simply used to turn on and off the audio output of the internal speaker thus allowing the operator the ability to listen for the detection of the tracer gas and not have to watch the display By default the audio out put of this device is turned off 10 SAMPLE The Probe button is only used in the manual mode and tells the microprosessor how many physi cal lengths of probe are attached to the unit This is done to mathematically calculate how long it will take to get a sample from the boot to the sensing elements The Reset button allows the unit to remain
20. tal display upon pressing the On Off button This screen will remain displayed while the proces sor conducts a power on self test which will last for approximately 60 seconds Figure 3 on the left is displayed upon successful completion of the power on self test or when the unit has just been reset This display is showing the user that the unit is attempting to locate a zero point of reference Figure 4 on the left is the dis play upon successful completion of the initial zeroing routine This screen will remain in effect until the sensor elements sense the presence of a tracer gas The real time graph is updated once per second and shows 60 seconds of history 12 LCD STATUS ICONS There are five small icons shown at the bottom of the LCD screen The icon as well as it s function is displayed below listed in the order in which they are displayed on the LCD from left to right NOTE A function that has been turned off will have an X through it s icon ICON Dg NE EN 1151 moe edo BATTERY STATUS This icon gives the user a visual indicator of the rela tive life span remaining on the battery When the bat tery drops below 1 4 a warning beep will sound The unit will automatically shut off when an empty battery is shown RECHARGE STATUS This icon is either displayed or crossed out If the unit is recharging the icon will change to a lightening bolt and back to a plug when complete MODE There
21. the chuck valve attached to a Dielectric air dryer directing clean dry air CDA back through the silica This process will take approximately 10 minutes per silica gel filter to turn them back to a Deep Blue color gt m O BATTERY REPLACEMENT Turn the device over and remove the battery compartment cover us ing a flat tip screwdriver The fastener requires only minimal pressure and 1 4 turn counter clockwise Remove the battery and pull up on the three pin connector This connector is keyed to ensure one way instal lation Before installing the new battery ensure the power connector is at tached to the circuit board Once the battery jack is connected lay the battery in it s berth then replace the battery compartment cover Again the screw requires minimal pressure and only 1 4 turn clockwise BATTERY RECHARGING The MGD 2002 comes equipped with the jacks and adapters neces sary to recharge your unit either back at the office or while working in the field Refer to page 18 for a list of items that comes standard with this device To charge this device using the universal power supply simply plug in the universal AC power supply to any standard wall outlet first and then plug in the DC output plug to the device Second The internal software will detect the presence of the charger and will turn off the detection capability while the unit is in charge To charge this device using the standard 12VDC auto adapter
22. ty information card supplied with the instrument and return it for your warranty registration 6 Check the silica gel filter Ensure the color is blue Refer to page 14 for filter changing instructions or page 15 for filter clearing instructions 7 Before turning the device on connect either the needle probe or one of the extension rods to the probe assembly Then connect the probe assembly to the detector The probe assembly has check valves that keep the ambient air from deteriorating the effectivenesss of the silica gel filter Dimensions Weight Specifications LxWxD MGD 2002 only Shipping Temperature Range Humidity Range Sensitivity Selectivity Resolution Response Time Audio Out LCD Processor Battery Min Max Increment Low range High Range Type Speed ROM Voltage Type Weight Run Time Charging Cycles Charging Volts 33 7cm x 12 3cm x 8 3cm 13 3in x 4 9in x 3 3in 1400 grams 3 1 lbs 6800 grams 15 0 lbs 10c to 45c 14F to 113F 20 RH to 50 RH 25 PPM 1 000 000PPM 100 25 PPM Hydrogen H Helium He 25 PPM 0 2 2 Seconds approx Pulse Width Modulation 128 Bit X 64 Bit Dot Matrix With long life backlight Infineon 16 Bit 20 MHZ 512 KBytes 7 2 VDC Nickel Metal Hydride 383 0 grams 6 8 Hours Continuous 300 500 9 5 14 VDC 2A User Safety Warnings IMPORTANT It s i
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