Smart Gas Pressure Sensors
Contents
1. Smart Gas Pressure Sensors Differential Gas Pressure Product No 3141 Number of pressure ports 2 e 200 kPa Resolution 0 1 kPa e 30 psi Resolution 0 02 psi Differential Gas Pressure Product No 3139 Number of pressure ports 2 e 10 kPa Resolution 0 01 kPa e 1 5 psi Resolution 0 001 psi Absolute Gas Barometric Pressure or Altitude Product No 3210 Number of pressure ports 1 e OQ to 110 kPa Absolute Resolution 0 1 kPa e 85 to 110 kPa Absolute Resolution 0 1 kPa e 0 to 33 inHg Resolution 0 01 inHg e Altitude 500 to 12 000 m Resolution 4 m Absolute Gas Pressure Product No 3142 99 Number of pressure ports 1 N DATA HARVEST e 0 to 700 kPa Absolute Resolution 0 3 kPa AN e 0 to 100 psi Resolution 0 1 psi X M Data Harvest Group Ltd 1 Eden Court Leighton Buzzard Beds LU7 4FY Tel 01525 373666 Fax 01525 851638 e mail sales data harvest co uk www data harvest co uk DRILIO No 4 Data Harvest Freely photocopiable for use within the purchasers establishment SMA NAI Gas Pressure Sensors POHU CIO e E a E 2 The Differential Gas Pressure S QNSOSS cccccceecceccecceececcecceecuecueceecuecuecuecueeaesaesaeeaecueseeeeens 3 Absolute Gas Pressure Barometric Pressure or Altitude Sensor 4 Absolute Gas PreSSure ccccccccccccceccecceccecceececaecaecuecuecuecaecaecaecaeeaesaeeaeeceesuecuesueseeseeaeeseeseeaneeas 5 CONE 92. that flexes as the pressure changes The sensor s electronics has temperature compensation to minimise the effect of ambient temperature changes on data There are 4 Gas Pressure Sensors with ranges designed specifically to suit experimental conditions 1 The Smart Q Differential Gas Pressure Sensor Product No 3141 has two ports and gives an output relative to the difference of pressure between the two ports It can be used to measure differential pressure in either KPascals or pounds per square inch If the second port is left open to the atmosphere then pressure is measured relative to atmospheric pressure 2 The Smart Q Differential Gas Pressure Sensor Product No 3139 is similar to 3141 but with a much more sensitive range This makes it suitable for investigations that require measurement of small pressure changes with high resolution e g as in many Biology investigations It can be used to measure differential pressure in either KPascals or pounds per square inch 3 The Smart Q Absolute Gas Pressure Barometric Pressure or Altitude Sensor Product No 3210 can be used to measure either absolute pressure in kKPascals or inches of mercury or altitude in meters above sea level 4 The Smart Q Absolute Gas Pressure Sensor Product No 3142 is similar to 3210 but has a wider pressure range equivalent to 7 atm It can be used to measure absolute pressure in either KPascals or pounds per square inch Sa mart Gas Pressure Sens
3. 4 mm O D x 2 5 mm I D Absolute Pressure 4 x large pipette tips Sensor 4 x small pipette tips Product No 3140 1 x straight push fit connector 1x Tee piece push fit connector 2 x 3 way valves stop cocks and 1x 20 ml Syringe Small air space 3 way valve to push air bubbles out with top up syringe lt Tubing filled with water Rate of plant transpiration Only use these Sensors to measure non corrosive non ionic media such as air or dry gases These Sensors are not suitable for use with flammable gases The vapour pressure of liquids can be monitored but do not allow liquid to enter the Sensor Protect from the weather keep the Sensor dry The container used with the Pressure Sensor must be suitable for the task and able to sustain the pressure The type of container selected will depend on the investigation A non flexible airtight container like a syringe could be used for quantitative investigations e g pressure vs volume Gas contained in a system under pressure will try to find a way out The longer the investigation lasts the more dominant the effect of any leaks will become try to complete the investigation as quickly as it allows Units of Measurement Pressure can be measured using a wide range of units The standard SI unit of pressure is the pascal Pa InHg USA and mBar UK are used for weather measurements only The conversion from kPa to mBar is simply to multiply by 10 Equiva
4. 6 meee erences EE E eee eee E eee ne eee ee eee 5 PAO CS sea E EE EEEE ese euned tmeivectaaries E neces 5 Practical IMO ANON sneictececeaavsvancisetioneican ues aisancneacdaastssiea ETENE ae Aa Paara Eoria Ataia aiei 6 Units of Measurement 20 0 e eee ee cecceccecceceeceeceeeeceeaecueceececaeceecueaecaeceeseeaececeeaeeaecueaesnesueseeneseeaeeaeeaes 6 Best sensor FECOMMENCALIONS 22 cee eececcecceceeceececeecueceececueceeaecaecuecesaececueseeaecueaeseeceeaeeaesueaneaes 7 PAI SS I AION wicrcstrarttid antncetenadeeameay an ccnseebancseu ates sacnchescse sence ccuates taehyindadeinutinacelsneawintencinnianisaigmiceduetes 8 Boyle s Law Pressure VS Volume cccseeccceeeseeeeeeeceeeeeeeeeeeeeeeeeseaaeeeeeesaaeeeeeeesaeeeeeeeaas 8 Rate of Reaction between marble chips and hydrochloric ACIC ccccccsseeeeeeeeeeeeneees 10 WAV OUI AUN E T E E EE AA E E E E E E E A E E E EE 11 Introduction Pressure is defined as force per unit area and can be measured using a wide range of units The standard SI unit of pressure is the pascal Pa Alternative measures are inches of mercury and pounds per square inch The Smart Q Gas Pressure Sensors are equipped with a micro controller that greatly improves the accuracy precision and consistency of readings They are supplied calibrated and the stored calibration is automatically loaded when the Pressure Sensor is connected The sensing element in the Smart Q Gas Pressure Sensors is a diaphragm
5. as Abs Pressure with a maximum value of 300 and the number to add as 101 3 Finish Click to the left of the graph area to display Abs Pressure Typical results Abs Pressure kPa 300 0 0 0 0 00000 0 05000 0 10000 0 15000 0 20000 28 June 2006 16 25 51 1MVolume 1 mis Graph Type set to line graph shown with automatic Best Fit Tools applied SMA ee Gas Pressure Sensors Rate of Reaction between marble chips and hydrochloric acid The rate of a chemical reaction can be affected by concentration of reacting chemicals temperature particle size and catalysts The progress of the reaction between calcium carbonate and hydrochloric acid can be monitored by the evolution of carbon dioxide CaCO 2HCI gt CaCl H2O COs The carbon dioxide produced will cause a pressure increase in a sealed container ee 0 5 mol dm HCI tC 4 Se on Syringe with needle FRSA Y through the rubber gt q Pressure bung needs to be a i O Sensor tight fit c Conical flask Marble chips or powder e Assemble the apparatus as shown The quantity of marble chips will depend upon the size of the flask i e in a 250 ml flask use 5 g of large marble chips e The two chemicals need to be kept separate until you are ready to start logging Place the rubber bung in the flask without the syringe attached to release any pressure Draw up 10 cm of 0 5 mo
6. d atmosphere e g O2 photosynthesis of an aquatic plant approx 10 kPa movement S R S Rate of Respiration e g Germinating seeds approx 10 kPa movement S gt Yeast Fermentation e g Carbon dioxide production approx 10 kPa movement Rate of Transpiration e g Plant on a windy or sunny day approx 10 kPa movement S S Chest expansion e g With Breathing Rate belt Product No 3190 approx 3 kPa movement Bursting a Balloon e g Abs 100 140 kPa Diff 0 40 kPa S S Depth gauge lower the end of pvc tube into water VEVETA e g 15 cm depth 1 5 kPa approx Changes in air pressure e g Weather studies approx 95 to 105 kPa S S Altitude investigations Se Si art Gas Pressure Sensors Investigations Boyle s Law Pressure vs Volume Pressure kPa Yolurne mls 5 4 Connect a short piece approx 2 cm of PVC tubing to the nozzle of a 20 ml syringe Move the syringe piston to the required volume mark e g 20 mls before connecting to the Pressure Sensor Push the tubing onto the Pressure Sensor port marked P1 Start the EASYSENSE software and select Snapshot from the Home page Select Pre Log Function from the Tools menu Select Preset function with General from the first drop down list and then Asks for Value from the second list Next Type in Volume as the name enter the units to be used e g mls and alter the maximum value to 20 Finish From the O
7. e areas can have pressure above or below the average Energy from water vapour condensing in colder air and from convection currents can increase these effects as they move through the atmosphere changing our weather To show the pattern of pressure changes all the places on the map that have equal air pressure are joined by lines called isobars Isobars have their pressure marked in millibars mB or inches of mercury in of Hg The conversion from kPA to mBar is simply to multiply by 10 Conversion 1 kPascal 10 millibar 0 14504 psi 1 000 millibars 1 bar 100 000 Newtons acting on a square meter 1 millibar 0 02953 inches of mercury 1 hectoPascal 1 millibar Note The value for Barometric pressure reported by airports and weather stations is usually given for the pressure at sea level i e pressure after it has been adjusted to its equivalent at sea level The value obtained by this Sensor will be the pressure at its current location This Sensor can also display values for Altitude No matter what weather systems are doing the airs pressure decreases with height The Altitude scale has been calibrated to measure height rather than pressure The conversion of pressure to altitude assumes 1 atmosphere 101 325 kPa of pressure at sea level so the Sensor will give a relative rather than an absolute value of altitude Note To give an exact height the barometric pressure at sea level for that location would be required this may
8. e of pressure Maggots ina l I metal cage Filter paper wick a Potassium hydroxide solution Investigating the uptake of oxygen by maggots The maximum pressure that these sensors can tolerate without permanent damage is Product No 3141 maximum pressure between ports P1 to P2 400 kPa or 58 psi Product No 3139 maximum pressure between ports P1 to P2 75 kPa or 10 psi SMA ee Gas Pressure Sensors Absolute Gas Pressure Barometric Pressure or Altitude Sensor Product No 3210 Qto110 kPa e 85to 110 kPa e Oto 33 inHg e Altitude 500 to 12 000 m This Pressure Sensor is used to measure absolute pressure the actual gas pressure at the port with respect to zero The pressure is measured against a built in internal vacuum reference The Sensor then produces an output voltage that varies with absolute pressure If the port is left open to the atmosphere the Sensor will display the value for atmospheric pressure pressure caused by the downward force of the Earth s gravity pressing the air down on the Earth The average pressure exerted at sea level by the atmosphere in Britain is 101 825 kPa 1 atmosphere Some equivalent values for 1 atmosphere atm are 101 825 kPa 760 mm of Hg 29 92 in of Hg at 0 C 14 70 psi 1013 millibar This Sensor can be used to measure Barometric Pressure for weather studies As the Earth spins some of the Earths atmosphere swirls into eddies Thes
9. early identified as life expired and we will dispose of them for you 11
10. l dm hydrochloric acid into the syringe and fix to the pvc tube e Start the EASYSENSE software and select EasyLog from the Home page e Click on the Start icon to begin logging and add the hydrochloric acid from the syringe to the flask Note Keep gentle pressure on the bung and the plunger of the syringe to prevent them from lifting e Use Gradient to find the rate of reaction from the slope of the graph Graph shown with the min and max limits reduced by using Sensor Settings Options SMA ee Gas Pressure Sensors Warranty All Data Harvest Sensors are warranted to be free from defects in materials and workmanship for a period of 12 months from the date of purchase provided they have been used in accordance with any instructions under normal laboratory conditions This warranty does not apply if the Sensor has been damaged by accident or misuse In the event of a fault developing within the 12 month period the Sensor must be returned to Data Harvest for repair or replacement at no expense to the user other than postal charges Note Data Harvest products are designed for educational use and are not intended for use in industrial medical or commercial applications WEEE Waste Electrical and Electronic Equipment Legislation Data Harvest Group Ltd is fully compliant with WEEE legislation and is pleased to provide a disposal service for any of our products when their life expires Simply return them to us cl
11. lent values for 1 atmosphere atm are 101 325 kPa 760 mm Hg 29 92 in of Hg at 0 C 14 70 psi 1013 millibar Conversion 1kPascal 10 millibar 0 14504 psi 1 Pascal 1 Newton per square meter 1 N m Smart Gas Pressure Sensors Best sensor recommendations The best sensor will depend on the way an investigation is conducted The recommendations and values quoted are based on our experience in using these Sensors vv Vv Best v Next Best Y Tolerable x Not recommended results will likely be outside of this Sensor s range or the resolution is not good enough Absolute No 3210 No 3140 0 110kPa Res 0 1 kPa Absolute No 3142 Differential No 3141 200 kPa Res 0 1 kPa Differential ati No 3139 Investigation 10 kPa Res 0 01 kPa 0 700 kPa Res 0 3 kPa VVVv A pre or post log function can be used to add atmospheric value to the result VVVv A pre or post log function can be used to add atmospheric value to the result Boyle s law Pressure vs volume e g 20 ml syringe approx 200 kPa movement Abs 100 200 300 kPa Diff 0 200 200 kPa AAA Gay Lussac s law Pressure vs absolute temperature e g approx 10 30 kPa movement S S 3 S Rates of chemical reaction SIN e g 5 20 kPa movement depends on quantity of chemicals If small quantities of chemical are used Production of gases in an enclose
12. not be 101 325 kPa For example the Sensor may display that the altitude at sea level is 100 m instead of zero due to atmospheric pressure being 1001 mBar not 1013 If the altitude for the starting level is known values can be adjusted using the Pre or Post log Functions in the EASYSENSE software The maximum pressure that this sensor can tolerate without permanent damage is 400 kPa or 118 inHg Sa mart Gas Pressure Sensors Absolute Gas Pressure Product No 3142 e 0to 700 kPa e Oto 100 psi This Smart Q Gas Pressure Sensor will measure absolute pressure the actual air pressure at the port with respect to zero The pressure is measured against a built in internal vacuum reference The Sensor then produces an output voltage that varies with absolute pressure An absolute pressure reading of 150 kPa may be described as a gauge pressure of 150 101 3 48 7 kPa gauge that is 48 7 kPa above atmospheric pressure The maximum pressure that this Sensor can tolerate without permanent damage is 700 kPa or 100 psi Connecting e Push one end of the sensor cable supplied with the EASYSENSE unit into the hooded socket on the Gas Pressure sensor with the locating arrow on the cable facing upwards e Connect the other end of the sensor cable to an input socket on the EASYSENSE unit e The EASYSENSE unit will detect that the Gas Pressure sensor is connected and display values using the currently selected range Range
13. ors The Differential Gas Pressure Sensors Product No 3141 e 200 kPa e 30 psi Product No 3139 e 10kPa e 1 5 psi The Smart Q Differential Gas Pressure Sensors have two ports available to allow for the application of pressure to either side of the diaphragm These sensors measure the difference between the pressures applied to these ports P1 P2 Differential Pressure a Pi f po unlabelled If both ports are left open to the atmosphere the effect of atmospheric pressure will equal each other out and the difference between the ports will be zero If only one port is used and the unused port is left open to the atmosphere the Sensor will measure pressures above or below atmospheric pressure i e gauge pressure If the Sensor shows a reading of 25 kPa gauge that is 25 kPa above atmospheric pressure Since atmospheric pressure is approx 101 3 kPa the equivalent atmospheric pressure reading would be 25 101 3 126 3 kPa absolute ol lt Differential Pressure Sensor Product No 3139 ADO TONED Investigations that would traditionally use a manometer can utilise the Differential Sensors One port is connected to the living chamber that X 3 way Valve holds the organisms The other port is connected to a non living chamber which acts as a thermo barometer COs given off by the respiring organisms is absorbed by the potassium hydroxide resulting ina Empty metal cage chang
14. ptions icon select X Axis and select Channel OK If necessary click below the graph area so that Volume is displayed on the x axis Click on the Start icon to begin Click in the graph area to record the pressure and then enter a value of 20 into the dialogue box Push the syringe plunger in to decrease the volume by a regular amount e g every 1 ml click in the graph area to record the pressure and enter the volume value Repeat the above until either the value reaches near the top of the sensors range or it becomes too difficult to push Pressure kPa 176 170 440 0 250 160 325 15 0 41 7 140 522 130 629 120 120 0 765 11 0 925 10 0 110 8 3 0 136 9 8 0 11 1 18 0 0 0 6 0 8 0 12 0 14 0 28 June 2006 16 25 51 Volume mls Graph shown with the min and max limits reduced by using Sensor Settings Options with Graph Type set to x point style SMA ee Gas Pressure Sensors e Select Post log function from the Tools menu Select Formula and a x c from the drop down menu Next Select Volume as the channel Next Rename as 1 Volume 1 mls as the units the number of decimal places as 5 with a maximum value of 0 2 a 1 and c 0 Finish Click below the graph area to display 1 Volume e Ifthe Differential Pressure sensor was used select Post log function from the Tools menu Select Pre set function General and then Add a constant from the drop down menus Next Select Pressure as the channel Next Rename
15. s To alter the currently selected range e Connect the Gas Pressure sensor to the EASYSENSE unit Set Sensor Range Sensor 3 e Start the EASYSENSE program and select one of the logging modes from the Home page e g EasyLog Select Sensor Smee Pange Config from the Settings menu z e Select the Gas Pressure sensor from the list and click on the 110 kPa Change Range button ASE 85 110 kPa e The current range will be highlighted Select the required range and click on OK change in range to be detected The range setting will be retained until changed by the user With some EASYSENSE units it is possible to change the range from the unit Please refer to the EASYSENSE unit s user manual Sa mart Gas Pressure Sensors Practical information The sensor element has automatic internal temperature compensation from 0 C to 50 C Maximum Operating Temperature 40 C to 85 C Maximum Storage Temperature 55 C to 125 C Humidity O to 100 RH The external diameters of the ports on the Pressure Sensors are tapered from 4 0 to 4 3 mm Branch with leaves Use with PVC or Silicon tubing 3 0 to 3 5 mm internal diameter A Gas Pressure Accessory Pack Product No 3138 is available which contains a selection of tubing Tubing Clamp gt elements and valves which allow gas tight connections to the Gas Pressure sensor They are e 1x1 m PVC tube 3 mm bore x 1 mm wall thickness e 1x1mofnylon pneumatic tube
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