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4 Measuring flux

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The value of ErrQ can vary in the range from 0 up to 1.

Values of ErrQ close to zero (ErrQ < 0.5) means that the regression is not good

and that the linear curve computed does not fit the curve.
Values of ErrQ close to one (ErrQ > 0.9) means that the regression is quite good

and the linear curve fits the flux curve very well.
Since the points are homogeneously distributed in the time domain the ErrQ

quality factor is a univocal indicator of the regression quality. Please note that

when the slope of the regression is zero the ErrQ also has to be zero.

Obtained a, the slope of the flux curve expressed in ppm/sec, an additional
calculation will be necessary, taking account of the accumulation chamber shape

and of the environmental parameters, to transform the slope into a flux

evaluation. This matter is described in detail in the chapter 4.

The complete theory of the accumulation chamber method will be not discussed
in this handbook and can be found in the papers listed in the Appendix.

4.2

The measurement

Start the measurement on FluxManager as explained in the previous chapter.

Having pressed the

Start

button, the plot of the concentration of the target gas

is shown in the display.
Once the measurement is started, the user can place the accumulation chamber

in the desired point, checking the perfect sealing of the chamber with the soil.

The chamber was placed onto the soil

If there is a soil gas emission, a few seconds after placing the chamber on the
soil the concentration starts increasing.

Touching the display, the software computes the linear regression within the

selected interval.

Содержание Portable diffuse flux meter

Страница 1: ...Portable diffuse flux meter Release 9 1 January 2019...

Страница 2: ...WEST Systems WEST Systems...

Страница 3: ...writing to support westsystems com and providing information about part number serial number and description of the issue Instructions on packaging and shipping will be e mailed back to the Customer...

Страница 4: ...y costs custom problems etc Check that the Company your shipping agent chooses lands in Galileo Galilei Airport in Pisa If not ask your shipping agent to change the Company or send the items by DHL or...

Страница 5: ...e measurement 28 4 3 Quantifying the flux 32 Components 37 5 1 Accumulation chamber 37 5 2 Pump 42 5 3 Fluxmeter battery 44 5 4 Fluxmeter battery charger 45 5 5 Backpack 47 5 6 Tubes 47 5 7 Filters 49...

Страница 6: ...C Volatile Organic Compounds detector 83 11 1 Specifications 84 11 2 Measuring principle 85 11 3 Warm up 85 11 4 VOC fluxes measurement 85 11 5 Calibration check 86 11 6 Calibration 88 11 7 VOC correc...

Страница 7: ...Hydrogen Sulfide is a poisonous gas air concentration higher than a few ppm can be lethal the short term exposure limit STEL recommended by NIOSH is 10 ppm Diffuse carbon dioxide fluxes are normally...

Страница 8: ...vity perform a full charge of the batteries at least every 3 months 2 3 Filters and tubes Connect the chamber to the fluxmeter using the provided black blue twin tubes In some cases the colour of the...

Страница 9: ...rument will turn off automatically after one hour if not under the control of FluxManager software Once powered the fluxmeter runs the initialization process which takes about 20 seconds During the in...

Страница 10: ...re and in case the value is below 50 C it will ask the user if he wish to continue The user can continue being aware of the previous considerations Normally the sensor after a cold startup requires ab...

Страница 11: ...device comes from West Systems with the app pre installed In case you acquired the mobile device separately install the app by opening Google Play Store from the device and looking for Fluxmanager2 C...

Страница 12: ...3 FluxManager Software WEST Systems PAGE 12 www westsystems com WEST Systems...

Страница 13: ...scan operation is completed you can repeat it by pressing the Scan button On the contrary if all the expected instruments are on the list the user can proceed with pressing the Connect button It is n...

Страница 14: ...remains active for all the sensors regardless of whether or not the sensor is in fogeround or background or has the track disabled Initially only current reading and the elapsed time are displayed Tou...

Страница 15: ...ove the left and right cursors to the desired position To move the cursors you have to touch the screen close to the limit you want to move and drag it to the correct position The software will move t...

Страница 16: ...ing time Once the sampling is completed press the Stop button to end the acquisition The chamber and the pump will continue to run for a number of seconds usually 30 seconds but it can be overwritten...

Страница 17: ...site name Note the name of the site is used to display the recorded points on the map Only the points related to the most recent site name will be displayed Hence changing the name of the site in the...

Страница 18: ...the field is automatically filled with the value recorded by the probe average value of the 1 Hz sampling during the measurement If this value is not available or if the user prefers to use its own se...

Страница 19: ...emote locations The most common locations where to save the backup copy are 3 SD card In this case the data is still lost in case of loss or theft of the smartphone but is safe in case of damage of th...

Страница 20: ...he cable is plugged you should be able to select on the device the MTP mode Once the smartphone is connected open the file explorer on the PC and navigate inside the Android device internal memory You...

Страница 21: ...oogle Map servers For this reason the visualization is active only if the Android device has an Internet connection available Moreover the Google Play Services component must be updated on the Android...

Страница 22: ...r each sensor This setting affects only the on field visualization the sensor with chart disabled are sampled and recorded in the same way as the others one reading per second The entire recording is...

Страница 23: ...ssing By placing the left and right cursors on the chart the app shows the value of the linear regression within the selected interval and the related R2 coefficient The regression line is also drawn...

Страница 24: ...mber fan remain ON in order to clean the fluxmeter tubes and sensors cell with atmospheric air During the cleaning time the chamber must be raised from the soil Usually 20 30 seconds are enough for cl...

Страница 25: ...software WEST Systems PAGE 25 25 www westsystems com WEST Systems WEST Systems The menu About show the firmware and software version of the connected devices Please provide this information when reque...

Страница 26: ...t and the FluxManager software To better understand the this chapter a basic theory is explained The theorical flux curve is shown in the figure below The plot represent the variation of the concentra...

Страница 27: ...ore than 5 The two vertical lines delimit the interval where to compute the flux To have a good evaluation of the flux the correct interval of the flux curve has to be selected Never compute the flux...

Страница 28: ...ccount of the accumulation chamber shape and of the environmental parameters to transform the slope into a flux evaluation This matter is described in detail in the chapter 4 The complete theory of th...

Страница 29: ...mulation shapes The perfect curve The shape of the curve is quite perfect and the computation of the flux is done with a very good accuracy R2 regression quality factor very close to 1 Air contaminati...

Страница 30: ...measure in air one meter above the soil surface and afterwards repeat the flux measurement You can use the measurement choosing the second part of the curve for regression computation Selecting the s...

Страница 31: ...s no flux 14 The pump is not working 15 The tubes are not connected correctly Very high flux The first part of the curve is not linear The problem is due to the combined effect of the high flux and th...

Страница 32: ...trument measures the barometric pressure and the air temperature inside the chamber Choosing the flux measurement unit The first measurements made 20 years ago with the accumulation chamber was expres...

Страница 33: ...ation chamber factor in the A c K field This operation can be critical In any case on the saved files you ll find the results of flux evaluation expressed in both units the raw ppm sec and the moles s...

Страница 34: ...4 Measuring flux WEST Systems PAGE 34 www westsystems com WEST Systems Accumulation chamber A factors Volume 0 00277 m3 Area 0 0308 m2...

Страница 35: ...4 Measuring flux WEST Systems WEST Systems PAGE 35 35 www westsystems com WEST Systems Accumulation chamber B factors Volume 0 006186 m3 Area 0 0317 m2...

Страница 36: ...4 Measuring flux WEST Systems PAGE 36 www westsystems com WEST Systems Accumulation chamber C factors Volume 0 006878 m3 Area 0 0712 m2...

Страница 37: ...ase area 0 0308 m2 Internal height 98 mm Mass 1 35 Kg with battery Net volume 0 006186 m3 Base area 0 0317 m2 Internal height 198 mm Mass 1 55 Kg with battery Net volume 0 006878 m3 Base area 0 0712 m...

Страница 38: ...ve demonstrated that if soil is disturbed for example levelling the ground or digging a hole in order to place the chamber the flux condition varies in an unpredictable way and takes a long time to st...

Страница 39: ...minal voltage 8 4 V Max charge voltage 10 5 V In case of emergency for example if you are out in the field with low battery and no possibility to recharge the internal battery can be replaced by a com...

Страница 40: ...The sensor is placed inside the chamber on the ceiling The sensor is NOT protected against water or accidental impacts Please be careful when placing the chamber on the ground Pressure sensor The bar...

Страница 41: ...hamber and the surrounding air outside the chamber avoiding the pressurization of the chamber that would alter the gas flow from the soil Make sure it is not obstructed by dust clean it if necessary S...

Страница 42: ...50 mA 12 Volts Manufacturer KNF Order model NMP 830 KNDC Pneumatic fittings diameter 4 mm In order to avoid unwanted variation of pumping flow due to power supply the pump is supplied with a stabilize...

Страница 43: ...5 Components WEST Systems WEST Systems PAGE 43 43 www westsystems com WEST Systems 21 Reassemble the head...

Страница 44: ...tee operation during a whole working day To replace the battery unplug the battery connector from fluxmeter internal panel and remove the knob as indicated in the picture Charge the battery after each...

Страница 45: ...use please think about disconnecting the charger from the mains This will reduce the risk of hazards reduce the products environmental impact and save electricity costs The charger must be kept away f...

Страница 46: ...manufacturers recommend that trickle charge does not exceed 24 hours If in doubt contact the battery manufacturer for details If the safety timer runs out before dV is detected the charger will go di...

Страница 47: ...Manufacturer SMC Order code RS 686 2680 Chamber twin tube for connecting the chamber to the fluxmeter Internal diameter 4 mm External diameter 6 mm Material Polyurethan Color Black Blue or White Blue...

Страница 48: ...5 Components WEST Systems PAGE 48 www westsystems com WEST Systems Fluxmeter inlet port Fluxmeter outlet port PTFE membrane filter 50 mm...

Страница 49: ...rofibre filter cartridge filter Filtration efficiency 93 at 0 01 m Order code Balston 9922 05 DQ The PTFE membrane filters are permeable to gases and water vapour and are impermeable to liquid water a...

Страница 50: ...er calibration For fluxes between 300 and 700 moles m2 day the injected flux is controlled by means of a mechanical flow reducer and measured using a bubble flowmeter Accuracy 3 before and after the f...

Страница 51: ...ement error versus the imposed flux of carbon dioxide expressed in grams per square meter per day at different pumping flow rates In order to avoid unwanted variation of pumping flow due to power supp...

Страница 52: ...g device rotation speed The following plot shows the measured flux vs the mixing device rotation speed Battery status vs RPM The following plot shows the mixing device RPM Rotation per minute vs power...

Страница 53: ...ger files The selected folder will be proposed the next time you start the software Select the folder and press OK If there are valid files the application will start to parse the data To estimate the...

Страница 54: ...of chamber e g A B C that you inserted in the FluxManager software Check that the information about the chamber type A in the illustration is correct the displayed type is the one obtained from the f...

Страница 55: ...mperature in the measures that are missing this parameter replace the default values 1013 mBar and 20 C and press OK If the Apply to all analysis box is checked the parameters in the measures that alr...

Страница 56: ...com WEST Systems WEST Systems Selecting an item in the list or pressing one of the navigate buttons the flux curves are displayed Like in FluxManager are displayed the graphs of the sensors with TRAC...

Страница 57: ...lt of the regression computed on the field Moving the regression left and right limit will cause the immediate update of the fields Graph Displays the concentration vs time plot The red points are use...

Страница 58: ...existing interval will be overwritten We recommend saving the original FluxManager files in a folder and working with FluxRevision on a copy of the data 7 1 Report file The report file is a table wher...

Страница 59: ...TAB character so the file can be easily opened with a spreadsheet editor e g Microsoft Excel The LONGITUDE and LATITUDE fields are populated with the original data collected by the smartphone integra...

Страница 60: ...he FluxManager app as explained on chapter 3 Obviously it is important that the injected mixture does not contain carbon dioxide The method for injecting standard gas mixtures is explained in detail i...

Страница 61: ...ar bag or equivalent for the zero mixture and one for the span mixture We suggest to label them in order not to switch them Calibration Preliminary operations install the LI COR application on the lap...

Страница 62: ...Set the sampling frequency to 1 Hz The application shows the current concentration reading as well as the cell temperature and pressure Note the heater must be ON 8 Check the temperature of the cell...

Страница 63: ...ect the bag at the inlet port of the fluxmeter The CO2 concentration should rise 13 Fill the Span gas concentration ppm field with the actual CO2 concentration of your mixture e g if the CO2 content i...

Страница 64: ...llows increasing the pathlength in the gas The IN and OUT gas fittings can be used with rilsan 6x4 mm tubes or silicon 5x3 2 tubes Please respect inlet and outlet ports Always make sure that a filter...

Страница 65: ...0 C 45 C Selectivity to methane Flux Measurement range from 1 to 900 000 millimoles m2 per day Range Unit Precision 0 1000 mmoles m per day 25 1000 150 000 mmoles m per day 10 150 000 900 000 mmoles m...

Страница 66: ...westsystems com WEST Systems The following plot ppm vs seconds shows a stability test while injecting atmospheric air for about 1 000 seconds The plot ppm vs seconds shows an accumulation curve while...

Страница 67: ...nsor needs to apply different settings on the laser diode This adaptations produce a gap of a few seconds during which a valid concentration value is not available 9 2 Computing flux The sensor presen...

Страница 68: ...you cross that threshold during the accumulation curve please apply the interpolation on the second part of the curve Do not include the ten seconds gap into the linear regression in order to prevent...

Страница 69: ...nto the detector we suggest filling a gas sampling bag e g Tedlar bag from the cylinder and then let the pump of the fluxmeter flow the gas inside the detectors In this way it s possible to recreate a...

Страница 70: ...e 30 C to 50 C Air pressure 800 hPa to 1200 hPa Air RH 15 90 non condensing Expected sensor life 24 months Chemical cell order code WEST H2S BH Detector order code WEST TOX 05 H2S BH Factory calibrati...

Страница 71: ...these cross sensitivity are reported Test ppm Reading ppm SO2 Sulfur Dioxide 20 2 NO Nytrogen monoxide 50 1 5 NO2 Nytrogen dioxide 10 3 Cl2 Chlorine 10 2 5 H2 Hydrogen 400 1 C2H4 Ethylene 400 0 4 CO...

Страница 72: ...ion check fails error 5 it is recommended to calibrate the detector Follow the procedure below 1 Switch on the fluxmeter and start a measurement with FluxManager in order to get the pump flowing 2 Let...

Страница 73: ...on the H2S detector to start the calibration 6 Warning as soon so the calibration starts the calibration parameters stored in the H2S detector will be reset to fabric default By clicking continue the...

Страница 74: ...s finally stable select the interval by tapping on the screen The average and standard deviation of the selected period is shown on the display A lower standard deviation indicates a good signal stabi...

Страница 75: ...f the span gas mixtures is 25 ppm 11 When the signal is finally stable select the interval by tapping on the screen The average and standard deviation of the selected period is shown on the display A...

Страница 76: ...l screen the app shows the average values that were selected for the zero and span gas mixtures Input the H2S concentration in ppm of the span calibration mixures 25 in the example Press the CALIBRATE...

Страница 77: ...10 WS TOX H2S Hydrogen sulfide detector PAGE 77 www westsystems com WEST Systems WEST Systems 10 2 Replacing the sensor head...

Страница 78: ...ST Systems WEST Systems WEST Systems Now install the new sensor head WS H2S BH Head and re assemble the detector Please check the O Ring status and check the sealing of the sensor head on line adapter...

Страница 79: ...is electronically stabilized Accuracy 3 For fluxes between 0 06 moles m2 day and 0 6 moles m2 day the injected flux is controlled by means of a mechanical flow reducer and measured using a bubble flo...

Страница 80: ...sing the accumulation chamber B that s more accurate for the hydrogen sulfide measurement Room temperature Between 20 2 and 21 4 C Air relative humidity 52 54 Barometric pressure between 1013 1 and 10...

Страница 81: ...cal hydrogen sulfide flux curve the slope is 0 028 ppm sec and the flux is 0 019 moles sm day In the plot below the base line of the hydrogen sulfide detector output is reported The initial drift is d...

Страница 82: ...ector PAGE 82 www westsystems com WEST Systems WEST Systems WEST Systems In the plot below the stability of the hydrogen sulfide detector output is reported The injected gas mixture at 1 liter per min...

Страница 83: ...communication lines to the sensor The cable pinout is shown in the following table Pin Signal 1 Gnd Legend 2 Gnd Gnd Ground reference for power supply and RS485 3 VDC VDC 10 28 Volts Power supply inp...

Страница 84: ...nge from 40 to 55 C Temperature relative humidity and pressure sensors are installed inside the measurement cell The sensitive element is installed in contact with the gas sample Temperature Measureme...

Страница 85: ...started 1 Switch on the fluxmeter Wait for the initialization to complete 2 Start the FluxManager app connect and press the Start button In this way the pump is turned on and start flowing atmospheric...

Страница 86: ...rrect functioning of the chamber and to assess the correct accumulation In almost any type of soil it is possible to detect a CO2 flux If the CO2 curve does not show a linear or exponential increment...

Страница 87: ...een as explained on chapter 3 Obviously it is important that the injected mixture does not contain traces of VOC Step 2 Verification of the span Fill the second Tedlar bag with a standard mixture cont...

Страница 88: ...n If the calibration check has returned a negative outcome error 5 it is recommended to recalibrate the sensor Apply the following procedure 1 Switch on the fluxmeter and start a measurement with Flux...

Страница 89: ...ap on the VOC detector to start the calibration 6 Warning as soon so the calibration starts the calibration parameters stored in the VOC detector will be reset to fabric default By clicking continue t...

Страница 90: ...l is finally stable select the interval by tapping on the screen The average and standard deviation of the selected period is shown on the display A lower standard deviation indicates a good signal st...

Страница 91: ...ation of the span gas mixtures is 25 ppm 11 When the signal is finally stable select the interval by tapping on the screen The average and standard deviation of the selected period is shown on the dis...

Страница 92: ...final screen the app shows the average values that were selected for the zero and span gas mixtures Input the concentration in ppm of the span calibration mixtures 25 in the example Press the CALIBRA...

Страница 93: ...onse factor RF expresses the ratio between the PID response to the particular compound and the PID response to the calibration gas isobutylene If the RF is 1 the PID response to a certain concentratio...

Страница 94: ...propane 1 10 04 2 Bromo 2 chloroethane 1 10 57 3 Bromo 2 methylpentane 1 10 09 2 Bromoacetone 9 73 1 Chemical name IE eV RF Bromoacetylene 10 31 4 Bromobenzene 8 98 0 32 Bromobutane 1 10 13 1 6 Bromob...

Страница 95: ...1 Citronellol acetate 9 1 5 Citronellol formate 9 1 5 Citronellyl isobutyrate 9 0 9 Coumarin 9 0 4 Creosote 9 1 Cresol m 8 36 2 2 Chemical name IE eV RF Cresol o 8 14 1 1 Cresol p 8 31 1 1 Cresyl ace...

Страница 96: ...rbonate 10 52 60 Dimethyl disulfide 8 46 0 2 Dimethyl ether 10 03 1 3 Dimethyl phosphite 10 53 8 Dimethyl phthalate 9 64 1 Dimethyl sulfoxide 9 10 20 Chemical name IE eV RF Dimethylacetamide N N 8 81...

Страница 97: ...Eugenol 9 0 4 Eugenol methyl ether 9 0 4 Fenchol 9 0 4 Ferrocene 6 88 0 8 Fluorobenzene 9 2 0 74 Fluorobenzoic acid 4 9 91 2 Formamide 10 20 2 Furan 8 88 0 4 Furfural 9 21 0 8 Furfuryl alcohol 9 9 2...

Страница 98: ...Fuel Jp 8 9 0 7 Kerosene 8 0 8 Ketene 9 62 3 Chemical name IE eV RF Linalool oxide 9 0 6 Linalyl acetate 9 1 1 Maleic anhydride 9 9 2 Mandelic acid 0 8 Menthol 9 0 5 Menthone 9 0 4 Mercaptoacetic acid...

Страница 99: ...pentyl alcohol 9 72 2 Nitric oxide 9 27 8 Nitroaniline 4 8 56 0 8 Nitrobenzene 9 92 1 7 Nitrogen trichloride 10 1 1 Nitrogen dioxide 9 58 10 N Methylolacrylamide 10 3 2 Nonane 9 72 1 4 Nonanol mixed i...

Страница 100: ...ert butyl bromide 9 92 0 99 Chemical name IE eV RF Tert butyl formate 10 52 8 Tetrabromoethane 1 1 2 2 10 2 Tetracarbonylnickel 8 28 1 Tetrachloroethylene 9 33 0 4 Tetrachloronaphthalene 1 2 3 4 1 Tet...

Страница 101: ...ne 9 9 1 Trioxane 10 3 2 Turpentine 8 5 0 6 Turpentine oil 8 0 6 TVOC 10 1 Undecane 9 56 1 1 Vanillin 9 1 Vinyl acetate 9 19 1 5 Vinyl bromide 9 8 1 5 Vinyl chloride 9 99 2 1 Vinyl ethyl ether 8 98 1...

Страница 102: ...oni M Guidi B Raco and L Marini Appl Geochem 13 543 552 1998 Diffuse CO2 efflux from Iwojima volcano Izu Ogasawara arc Japan Notsu K Sugiyama K Hosoe M Uemura A Shimoike Y Tsunomori F Sumino H Yamamot...

Страница 103: ...ence on Waste Management and the Environment 469 478 2002 Precursory diffuse carbon dioxide degassing related to a 5 1 magnitude earthquake in El Salvador Central America J M L Salazar N M P rez P A H...

Страница 104: ...04 www westsystems com Soil CO 2 and Temperature Monitoring Station Handbook Release 00 November 2011 WEST Systems WEST Systems www westsystems com Portable soil flux meter handbook Release 9 1 Januar...

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