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METER HYPROP 2 Manual

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HYPROP 2

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  • Page 1 HYPROP 2...

  • Page 2: Table Of Contents

    18263-03 10.2024 TABLE OF CONTENTS 1. Introduction ....................1 1.1 HYPROP Complete Set ................1 1.2 HYPROP Extension Set ................2 1.3 HYPROP Starter Set ................... 2 2. Operation ....................3 2.1 Installation ....................3 2.2 Hyprop Measurement Process ..............5 2.3 Soil Sample Preparation ................
  • Page 3 2.6.5 Optimal Measurement Curve ............59 2.6.6 Suboptimal Measurement Curve ........... 60 2.6.7 Finishing a Measurement ............... 61 2.7 Postprocessing ..................65 2.7.1 Extension of the Measurement Range ........... 65 2.7.2 Determining Dry Soil Weight ............65 2.7.3 Disassembling and Cleaning ............66 2.8 Data Evaluation and Export ..............
  • Page 4 APPENDIX A. Determining Air Entry Value .......89 APPENDIX B. Example Measurement Results ....91 APPENDIX C. WP4C Use After HYPROP ......99 APPENDIX D. Measuring Units ........104 References ....................105 Index ....................... 107...

  • Page 6: Introduction

    METER Group GmbH offers a warranty for material and production defects for this device in accordance with locally applicable legal provisions for a maximum of 12 months. The warranty does not cover damage caused by misuse, unauthorized servicing or circumstances beyond our control.

  • Page 7: Hyprop Extension Set

    • 2 Reservoir syringes • 1 Tensiometer shaft auger • 1 Tube for vacuum syringe and refilling adapter • 1 Auger guide • 1 METER Soil sampling ring with lids • Deionized water • 1 HYPROP USB adapter • 1 Power device Prior to use, verify the HYPROP and accessories arrived in good condition.

  • Page 8: Operation

    PRECAUTION METER sensors are built to the highest standards, but misuse, improper protection, or improper installation may damage the sensor and possibly void the manufacturer’s warranty. Before integrating HYPROP 2 into a system, make sure to follow the recommended installation instructions and have the proper protections in place to safeguard sensors from damage.
  • Page 9 OPERATION Table 1 Installation (continued) Installation (continued) Custom Setup Screen If there is a problem executing the file HYPROP.exe please download and install Microsoft NET Framework 4.8.0 manually and be sure to have the current version of the Windows installer.

  • Page 10: Hyprop Measurement Process

    USB port. The HYPROP LED should flash white three times and then turn off (Section 3.2.1). Multiple LABROS Balances and HYPROPs can be used simultaneously by connecting them to a powered USB hub. METER recommends a maximum of 20 balances and HYPROPs per computer. Connecting...
  • Page 11 OPERATION HYPROP Measurement Process Take multiple soil samples in the field Section 2.3 IMPORTANT: Soil prep and device prep processes have intermittent downtime. To reduce wait time, work on steps of one process while waiting on steps from another process to finish. See parallel process steps below. Prepare devices: Prepare the soil sample tensiometer shafts and water degassing...

  • Page 12: Soil Sample Preparation

    METER recommends using METER soil sample rings because the highly polished stainless steel surface minimizes friction and soil disturbance. The soil remains intact and air pockets are reduced.
  • Page 13 Make sure there are no large stones or roots at the selected location. Place the soil sample ring with the cutting edge down on the ground. Place the METER hammering adapter (available for 100 mL and 250 mL) on the sample ring (Figure 3).
  • Page 14 Adapter Soil Sample Ring Figure 4 Pound METER hammering adapter with PE hammer to drive soil sample ring into ground Remove the hammering adapter. Use a spade to dig the sample ring out of the hole, including the undisturbed soil sample.

  • Page 15: Disturbed Soil Sample

    (i.e., more than the quantity that the sample ring holds needs to be collected in order to completely fill the sample ring, even when soil has been packed to fill the sample ring). The tools needed to collect a disturbed soil sample are listed below: • METER soil sample ring • fork • knife...

  • Page 16: Saturate Soil Sample

    The next preparation step is to saturate the soil samples. The following sections explain how to properly saturate both sample types. NOTE: If the soil sample was measured with a METER KSAT before use in the HYPROP, the sample will already be saturated. Proceed directly to Section 2.5.
  • Page 17 OPERATION Examine the noncutting side of the sample ring for irregularities such as big stones, pebbles, woody debris, roots, and intensive smell. Estimate the possible lack of volume in mL attributed to the space taken up by irregularities identified in step 3. NOTE: Errors in soil volumes have a strong effect on the determined water contents in HYPROP, as in any other determination method for volumetric water contents.
  • Page 18 HYPROP 2 Cutting edge Noncutting edge Large filter paper Figure 9 Large filter paper Hold the filter paper and LABROS saturation plate together and turn the sample ring over so that the noncutting side is facing down. Remove the cover on the cutting side of the sample ring.
  • Page 19 OPERATION Figure 10 Cut protruding soil on cutting side of sample ring 10. Repeat step 3 through step 5 for cutting side. 11. Place one of the small filter papers on the cutting side of the sample ring (Figure 11). Top saturation plate Small filter paper Cutting edge Noncutting edge Large filter paper...
  • Page 20 HYPROP 2 12. Place the sample ring in a tray (Figure 12). Figure 12 Saturate plate in tray 13. Fill the tray with about 3 cm of room-temperature tap water. 14. Tilt the LABROS saturation plate carefully to every side to remove air bubbles.

  • Page 21: Device Preparation: Tensiometer Shafts, Hyprop Sensor Unit, And Labros Balance

    • Do not use any device if the electrical wire is damaged. • Always release the vacuum before opening any connection or removing a device. METER group is not liable for equipment if it is not manufactured by the METER group. After following...
  • Page 22 End fitting with valve Manometer Figure 13 METER Refill Unit PROCEDURE STEPS Connect vacuum mount and beaker mount. Connect vacuum mount and vacuum pump. Connect the end fitting with valve to the beaker mount. Fill the beakers with distilled water and place them in the beaker mount.

  • Page 23: Using Syringes

    16. Open the valve slowly to ventilate the system. 17. The devices can now be removed. NOTE: More than one beaker mount and HYPROP sensor unit can be connected to the refill unit. METER recommends connecting five beaker mounts and five HYPROPs maximum.
  • Page 24 HYPROP 2 Figure 15 Fill reservoir syringe Cover the reservoir syringe tightly with a finger. Pull the plunger out and hold it Figure 16. The vacuum in the syringe degasses the water. This can be seen by air bubbles appearing. Figure 16 Degassing water in reservoir syringe Shake and turn the reservoir syringe to collect the air bubbles appearing at the inner surface of the syringe Figure 17.
  • Page 25 OPERATION Repeat this procedure until no more air bubbles appear. Push the tube piece on the tip of the syringe (Figure 17). Figure 17 Collecting air bubbles 10. Push the plunger of the syringe until a meniscus builds up on the tube piece (Figure 18). Figure 18 Build a meniscus 11.
  • Page 26 HYPROP 2 Figure 19 Insert tensiometer shaft 12. Fill the vacuum syringe with 5 mL deionized water. Turn the syringe upside down and remove residual air (Figure 20). Figure 20 Fill the vacuum syringe 13. Degas the water in the vacuum syringe (similar to the process using the reservoir syringe).
  • Page 27 OPERATION 14. Push the tube piece over the tip of the syringe. 15. Push the plunger of the syringe until a meniscus builds up on the tube piece. 16. Connect the two syringes and the tensiometer shaft (Figure 21). The two O-rings seal the tubes against the tensiometer shaft. Figure 21 Connect the syringes 17.
  • Page 28 HYPROP 2 Figure 22 Let the plunger stoppers snap 18. Hold the plunger and syringe, press in the plunger stoppers and let the plunger slowly move forward (Figure 23). Figure 23 Release the plunger 19. Remove the syringe then turn it upside down and remove residual air (Figure 24).
  • Page 29 OPERATION Figure 24 Remove air 20. Again, push the vacuum syringe bubble free onto the tensiometer shaft. Degas the water in the second tensiometer shaft, performing the same steps until no more air bubbles are shown. 21. Fill the holes of the HYPROP sensor unit with deionized water using the droplet syringe (Figure 25).
  • Page 30 HYPROP 2 CAUTION Do not stick the syringe tip into the holes of the sensor unit. You may damage the pressure sensor. 22. Place the refilling adapter on top of the sensor unit and attach it. 23. Fill the refilling adapter bubble free with 23 mL deionized water using the droplet syringe (Figure 27).
  • Page 31 OPERATION 24. Fill the vacuum syringe with 15 to 20 ml deionized water. 25. Degas the water in the syringe as explained above. 26. Push the blue tube piece onto the vacuum syringe and fill the tube (Figure 28). Figure 28 Fill the vacuum syringe 27.
  • Page 32 HYPROP 2 METER Figure 29 Degas the water in the sensor unit CAUTION Be extremely cautious. Do not let the plunger of the syringe shoot down as the pressure shock will damage the pressure sensor.
  • Page 33 OPERATION Figure 30 Remove air bubbles PRECAUTION Never bump the sensor unit on a hard surface. The impact will cause pressure shocks that damage the pressure sensors (Figure 31). Figure 31 Caution: do not bump on hard surface...
  • Page 34 HYPROP 2 30. To relieve the pressure, hold the plunger and the syringe. Next press in the plunger stoppers and let the plunger slowly move forward (Figure 32). METER Figure 32 Release the plunger CAUTION Be extremely cautious. Do not let the plunger of the syringe shoot down as the pressure shock will damage the...
  • Page 35 OPERATION 31. Remove the syringe from the tube, turn it upside down, and remove residual air (Figure 33). Figure 33 Remove air 32. Repeat step 29 through step 31until no air bubbles are visible. 33. Push the vacuum syringe filled with degassed water into the tube on the refilling adapter. 34.

  • Page 36: Offset Recalibration

    Recalibration before mounting the tensiometer shafts, the software automatically verifies if the offset values for both pressure transducers are within the range set by METER development (+/–0.5 hPa). The software provides recommendations when offset recalibration is needed. Contact METER Customer Support if there is any problem setting the zero point.
  • Page 37 OPERATION Select Show Devices (Figure 35). The device should be listed on the left side of the software screen. Figure 35 Show devices Carefully remove the refilling adapter so that the water remains on the HYPROP sensor unit. Select Offset Recalibration Wizard and choose the device you want to process by using the drop down menu to select HYPROP Device (Figure 36).
  • Page 38 HYPROP 2 Figure 36 Offset Recalibration Figure 37 Offset Recalibration - connected device...

  • Page 39: Installing Tensiometer Shafts Into Sensor Unit

    Value is out of range! Please be sure to follow If all steps are processed correctly and the value all steps described in this Wizard as well as is still out of range, please contact METER support the manual. for a device checkup.
  • Page 40 HYPROP 2 Figure 38 Refilling - connected device Prepare a syringe filled with distilled, degassed water. Wear gloves and unscrew the tensiometer shafts one at a time from the refilling unit. IMPORTANT: Be careful not to tilt the tensiometer shaft or to lose any water. Never touch the ceramic tips with bare fingers as grease or soap reduces the hydrophilic characteristics of it.
  • Page 41 OPERATION Figure 39 Water lens Screw in the tensiometer shafts one at a time, in the matching marked hole (i.e., the longer shaft screws into the hole marked long and the short shaft into the hole marked short) (Figure 40). Be careful not to enclose any air while screwing in the shafts. IMPORTANT: Always keep the ceramic tip wet during this process.
  • Page 42 HYPROP 2 Figure 40 Screwing in tensiometer shafts Screw the tensiometer shaft carefully until the O-ring in the sensor unit starts sealing and the pressure increases rapidly. Monitor this by observing the pressure values visualized in the Refilling Wizard. 10. Screw in with small turns until the tensiometer shaft is tight.
  • Page 43 OPERATION Figure 41 Pressure range IMPORTANT: Read step 11 andstep 12 before completeing these steps as the process of function check goes by very fast. 11. Moisten the ceramic tip and let the pressure go down to 0 hPa. 12. Next ensure the unit is correctly prepared to take a measurement by performing the following test: Keeping a syringe filled with degassed water on hand, dry the ceramic tip with a paper towel.
  • Page 44 HYPROP 2 Figure 42 Testing refilling 13. Repeat all steps for the second tensiometer shaft. Always remember to keep both ceramic tips moistened. 14. When both tensiometer shafts are screwed in successfully, disconnect the HYPROP sensor unit from the USB adapter and close the Refilling Wizard.
  • Page 45 OPERATION 16. Place the silicone disk on the sensor unit and remove any air between the surface and the disk (Figure 44). Figure 44 Silicone disk 17. Turn the assembled HYPROP upside-down and place it in a beaker filled with distilled water. Be sure that both ceramic tips are dipped in the water (Figure 45).

  • Page 46: Hyprop Sensor Unit And Soil Sample

    HYPROP 2 2.5.6 HYPROP SENSOR UNIT AND SOIL SAMPLE To assemble the HYPROP sensor unit and soil sample you will need the following equipment: • Hand auger for tensiometer shafts • Drilling adapter • Syringe with water • Paper towel...
  • Page 47 OPERATION Drill the long hole in three steps and the small hole in two steps to avoid compressing the soil. The material of the holes does not have to be weighed or stored as this volume is automatically mentioned as a subtracted volume in the evaluation. NOTE: Before removing the drilling adapter, remember which one is the hole for the long shaft and which hole is for the short shaft.

  • Page 48: Labros Balance

    HYPROP 2 Turn the whole setup around and place it out of the tray. For more stability the clips can be fixed at the saturation plate. 10. Remove the saturation plate, fix the soil sampling ring with the clips, and put a lid on top of the sample with the nonwoven cloth to avoid evaporation before the measurement starts.
  • Page 49 OPERATION Be sure nothing is placed on the balance and that there are no magnet cables in use (see Section 2.6.1 for connecting magnet cables). Tare the balance. Press the Function button until S.A. CAL appears. Press the buttons Function and Zero/Tare at the same time and release them at the same time.

  • Page 50: Hyprop Measurement Modes

    • One balance for each sensor unit • Balance connected to the computer via USB hub • USB adapter used for connecting separate devices for preparation steps NOTE: The USB hub is not included with any HYPROP kit. METER recommends a powered USB hub.
  • Page 51 OPERATION Preparation Measurement USB hub Max. 10 sensor units cable per USB hub sensor unit sensor LABROS units Balances HYPROP USB-adapter Figure 50 Multi-balance mode 2.6.1.1 STARTING A MEASUREMENT After preparing the sample and the devices properly, use the following steps to perform the HYPROP measurement using the multi-balance mode.
  • Page 52 HYPROP 2 NOTE: This method is tested for a maximum of 20 balances and HYPROP sensor units (maximum 10 HYPROP sensor units per USB hub). LABROS SoilView software automatically displays all connected balances and sensor units on the left side of the software screen (Figure 52). If not, check if the balances are turned on and all connected HYPROP sensor units have individual device IDs (Section 3.2.2).
  • Page 53 OPERATION 2.6.1.2 MEASUREMENT WIZARD OPTION Open the Wizard by clicking on the Measurement Wizard icon (Figure 54). Figure 54 Measurement Wizard icon Select the HYPROP sensor unit that contains the soil sample to be measured. Enter the sample name as well as the storage location. The balance will be automatically detected.
  • Page 54 HYPROP 2 Figure 55 Select Apply in Start Measurement Wizard Remove the lid and the nonwoven cloth and clean. Dry the soil sampling ring carefully with a paper towel. Repeat step 1 through step 5 Section 2.6.1.1 for all HYPROP sensor units to be measured.

  • Page 55: Measuring With Single-Balance Mode

    OPERATION Figure 56 Start manager Select Start to start the measurement. Remove the lid and the nonwoven cloth and clean. Dry the soil sampling ring carefully with a paper towel. Repeat step 1 through step 5 Section 2.6.1.1 for all HYPROP sensor units to be measured. Using the manager there is also the possibility to configure all measurements and start them all at the same time, using the button Start All (Figure 57).
  • Page 56 HYPROP 2 NOTE: This method is tested for a maximum of 20 HYPROP sensor units. Connect all HYPROP sensor units to be measured to the HYPROP connection cables and click on Show devices in the left upper corner of the software screen.
  • Page 57 OPERATION 2.6.2.2 USING THE MEASUREMENT WIZARD Open the Measurement Wizard by clicking on the Measurement Wizard icon (Figure 60). Figure 60 Measurement Wizard icon Select the HYPROP sensor unit with the soil sample to be measured. Enter the sample name as well as the storage location. The balance will be automatically detected.
  • Page 58 HYPROP 2 Figure 61 Select Apply in Start Measurement Wizard Remove the lid and the nonwoven cloth and clean and dry the soil sampling ring carefully with a paper towel. Repeat steps in Section 2.6.2.1 for all HYPROP sensor units to be measured.

  • Page 59: Weighing The Sample

    OPERATION Tension values will be recorded automatically in a defined frequency (default: 10 min) until the measurement is stopped. Weight values must be taken manually. See Section 2.6.3 for weighing the sample. See Section 2.6.7 for information on how and when to stop a measurement 2.6.2.3 USING THE MANAGER Enter sample name and storage location in the line showing the HYPROP sensor unit with the soil sample to be measured.

  • Page 60: Configure Hyprop Profile

    HYPROP 2 Disconnect the HYPROP sensor unit to be weighed. The software automatically identifies the sample that will be weighed. A software window appears showing the steps to proceed (Figure 64). When the reading is done, quickly reconnect the HYPROP sensor unit to the HYPROP USB adapter.
  • Page 61 OPERATION Figure 65 Example HYPROP profile one balance per HYPROP...
  • Page 62 HYPROP 2 Figure 66 Example HYPROP profile one balance for multiple HYPROPs To generate a new customized measurement profile, follow the steps below: Press the New Profile button. Enter all necessary values. Press the Save Profile button to enter a profile name and store it.
  • Page 63 OPERATION Figure 67 Generating a customized profile Table 6 lists all parameters that can be defined for the measurement profile. Table 6 Measurement Parameter Descriptions Measurement Parameter Description One balance per HYPROP mode Type of measurement mode One balance for more HYPROPs mode Measurement interval [hh:mm] Time between tension and weight measurements.

  • Page 64: Optimal Measurement Curve

    HYPROP 2 2.6.5 OPTIMAL MEASUREMENT CURVE Every optimal measurement can be divided into four different phases: Tension value curve increases without Phase 1: regular measurement range flattening until it reaches the boiling point of the water. Ideally, when the system is filled completely...

  • Page 65: Suboptimal Measurement Curve

    OPERATION air entry point of the tensiometer shaft tension Phase 2 Phase 1 Phase 3 Phase 4 regular measurement range boiling cavitation air entry delay 2,000 1,000 actual atmospheric air pressure time Figure 68 Measurement phases for one tensiometer shaft Please refer to APPENDIX C for example measuring curves for various soils.

  • Page 66: Finishing A Measurement

    HYPROP 2 tension Phase 4 Phase 1 Phase 3 regular measurement range cavitation phase air entry 2,000 air entry 1,000 actual atmospheric air pressure time tension top tension bottom Figure 69 Suboptimal measurement curve 2.6.7 FINISHING A MEASUREMENT The varying options of tensiometer shaft air entry values for additional measurement points will affect when to stop a measurement.
  • Page 67 OPERATION OPTION 1: USING BOTH AIR ENTRY POINTS upper tensiometer shaft lower tensiometer shaft time of measurement stop interpolation of air entry point of upper tensiometer interpolation of air entry point of lower tensiometer time Figure 70 Stop measurement using both air entry points In Figure 70, both tensiometers have reached the air entry point of the ceramic.
  • Page 68 HYPROP 2 OPTION 2: USING ONE AIR ENTRY POINT upper tensiometer shaft lower tensiometer shaft time of measurement stop interpolation of air entry point of upper tensiometer interpolation of air entry point of lower tensiometer time Figure 71 Stop measurement using one air entry point...
  • Page 69 OPERATION OPTION 3: STOP WITHOUT USING AIR ENTRY POINTS upper tensiometer shaft lower tensiometer shaft time of measurement stop interpolation of air entry point of upper tensiometer time Figure 72 Stop measurement without using air entry points Figure 72 shows the air entry point of the lower tensiometer has not been reached so the data point of the lower tensiometer is missing to generate the arithmetic mean with the air entry point of the upper tensiometer.

  • Page 70: Postprocessing

    WP4C. Also the WP4C product and support page for more information on using the WP4C (meter.ly/WP4C) 2.7.2 DETERMINING DRY SOIL WEIGHT The LABROS SoilView-Analysis software uses the dry soil weight to calculate initial water content and volumetric water content during evaporation.

  • Page 71: Disassembling And Cleaning

    OPERATION Determining dry soil weight steps: Disconnect the HYPROP sensor unit from the balance or the tensioLink and place the whole system in a pan. Open the clips and carefully remove the soil sample with the sampling ring from the HYPROP sensor unit.
  • Page 72 HYPROP 2 Figure 74 Clean the sensor unit positioned upside down with running water Avoiding the ceramic tips of the tensiometer shafts, carefully dry the sensor unit with a cloth. Unscrew the tensiometer shafts. Hold the sensor unit upside down and use a washing bottle with distilled water to wash the surface of the sensor unit.

  • Page 73: Data Evaluation And Export

    Calculates retention and conductivity data, and option to add externally Evaluation measured data Fitting Fits hydraulic functions and parameters Export Exporting for data, graphs, function, and parameters For more details about how to use LABROS SoilView-Analysis software, please read the LABROS SoilView-Analysis for HYPROP manual (meter.ly/hyprop-support).

  • Page 74: System

    HYPROP 2 3. SYSTEM This section describes the specification, components, and theory of the HYPROP 2 system. 3.1 SPECIFICATIONS MEASUREMENT SPECIFICATIONS Measuring Range Pressure transducer +3.0 hPa to –1000 hPa (–2400 hPa with boiling delay) Temperature sensor –20 to 70 °C...

  • Page 75: Physical Specifications

    SYSTEM PHYSICAL SPECIFICATIONS Sensor Unit Material Dimensions Height 63 mm, Ø 80 mm Tensiometer Shaft Ceramic Al2O3 sinter, air entry point > 200 kPa; Ø 5 mm Shaft material Acrylic glass; Ø 5 mm Total length Short shaft: 31 mm; Long shaft: 56 mm Polyurethane Tubing Outer diameter 6 mm...

  • Page 76: Components

    HYPROP 2 Reproducibility 0.01 g Linearity 0.01 g Adjustment Internally COMPLIANCE EM ISO/IEC 17050:2010 (CE Mark) 3.2 COMPONENTS The HYPROP measurement system consists of the following components: • the HYPROP sensor unit set • the sample preparation set • the HYPROP refill unit set •...

  • Page 77: Led Indicator

    SYSTEM Sample ring Silicone gasket O-ring (black) for dirt protection Ceramic Tensio shafts Shaft O-ring (red) For sealing the tensio shafts to the pressure sensor Sensor unit Balance Figure 76 HYPROP system and LABROS Balance 3.2.1 LED INDICATOR The status of the instrument is indicated by the LED ring indicator on the measurement head.

  • Page 78: Change Device Identification (Id)

    HYPROP 2 MULTI-BALANCE MODE White flashing HYPROP detected by the computer via LABROS Balance. three times HYPROP detected by LABROS SoilView software and can be White constant configured for measurement. White flashing HYPROP is ready for measurement. Blue pulsing Measurement is in progress.
  • Page 79 SYSTEM Figure 77 Check device ID For changing the device ID select the sensor unit with a right mouse click. Select Change Device ID (Figure 78). Figure 78 Change Device ID Change the device ID and save the change by selecting Apply. There is also the opportunity to change a device name. To do so, select the option Rename in the dropdown menu (Figure 78).

  • Page 80: Tube Connections

    HYPROP 2 3.2.3 TUBE CONNECTIONS To avoid any leakage in the connections, always cut the tube straight across and not angled (Figure 79). Figure 79 Cutting the tube To connect the tube to the fitting, push it until it latches (Figure 80). Figure 80 Connecting the tube To remove the tube press the blue ring and pull (Figure 81).

  • Page 81: Additional Functions Of Labros Soilview Software

    SYSTEM 3.2.4 ADDITIONAL FUNCTIONS OF LABROS SOILVIEW SOFTWARE The Main menu toolbar (Figure 82) contains main actions in the software. Table 7 describes the Main menu options. Figure 82 Main menu toolbar Table 7 Main menu options Main Menu Options Descriptions File Close the application Open the Refilling Wizard, the Measurement Wizard, or the Extras Update Wizard...

  • Page 82: Theory

    HYPROP 2 Figure 83 Open measurements to continue Select the measurement to be continued. Press Save. Select whether the measurement should be continued or overwritten. NOTE: When continuing a measurement, the same device has to be used because the weight of the device is a critical parameter for the evaluation.

  • Page 83: Measuring Method

    2011, 2013a, b; Schindler et al., 2012). Systematic differences could not be found. 3.3.1 MEASURING METHOD HYPROP 2 measures the relationship between water content and water potential in the soil matrix. Water content is defined as the amount of water in a known amount of soil. This can be measured on either a mass basis (gravimetric water content) or a volumetric basis (volumetric water content).
  • Page 84 HYPROP 2 Figure 84 Typical retention curve of sand...

  • Page 85: Generating Data Points

    This pressure is measured by an extremely sensitive pressure transducer in the HYPROP 2 housing. As the soil sample dries, more water is pulled out of the tensiometer shafts until the pressure reaches cavitation and an air bubble is formed in the water column.
  • Page 86 HYPROP 2 the sample based on the sample mass minus all tare components (sensor unit, sample ring, dry mass of the soil). The dry mass of the soil can be determined after the measurement by drying the sample in an oven at 105°C (Section 2.7.2).

  • Page 87: Additional Notes

    This value is specific for a porous hydrophilic structure and depends on the contact angle and the pore size. The air entry point of the METER tensiometer shafts is about 8.8 bars so it does not limit the measuring range.
  • Page 88 HYPROP 2 OSMOTIC EFFECT The ceramic has a pore size of r = 0.3 μm and therefore cannot block ions. Thus, an influence of osmosis on the measurements is negligible. If the tensiometer shaft is dipped into a saturated NaCl solution the readout will show 1 kPa for a short moment, then it will drop to...

  • Page 89: Service

    4.1 CALIBRATION Each HYPROP device is pressure calibrated after manufacturing. In case of errors, LABROS SoilView will give a warning message to send the HYPROP back for an inspection by METER (See Section 2.5.4). Contact Customer Support with questions.
  • Page 90 HYPROP 2 Figure 86 Flattening measurement curve Changing the O-ring use fine-pointed tweezers: Pierce the O-ring with tweezer to pull it out (Figure 87).

  • Page 91: Storage

    Possible Solutions Fill the tensiometer shaft with deionized water by either The tensiometer shaft is dry using syringes (Section 2.5.3) or the METER Refill Unit (Section 2.5.2). Repeat the refilling process. If this does not help, try to Air bubbles can be seen in the...
  • Page 92 (Section 3.2.2). The pressure sensors have been destroyed. The sensor unit The software monitors tension values must be checked and repaired. Please contact Customer of 4000 hPa Support for sending the device to METER for repair.

  • Page 93: Customer Support

    NOTE: For products purchased through a distributor, please contact the distributor directly for assistance. 4.5 TERMS AND CONDITIONS By using METER instruments and documentation, you agree to abide by the METER Group, Inc. Terms and Conditions. Please refer to metergroup.com/terms-conditions...

  • Page 94: Appendix A. Determining Air Entry Value

    (Schindler et al., 2010). The default air entry value of 8.8 bar is the statistical mean of ceramic tips used in the 2010 series of METER HYPROP tensiometers. This value changes with time and use. Verify the value using the procedure described below.
  • Page 95 APPENDICES Figure 88 Determining air entry point Clean the ceramic tip carefully with a brush under running water. Place the tensiometer shafts for testing 24 h in a beaker filled with distilled water to saturate the ceramic tip. After saturation, completely empty the tensiometer shafts. Screw them in the refilling adapters and place them in the water filled container.

  • Page 96: Appendix B. Example Measurement Results

    HYPROP 2 APPENDIX B. EXAMPLE MEASUREMENT RESULTS Sandy loam (Ls3) example: Figure 89 Example measurement sandy loam This measurement process is typical for clay soils with wide pore size distribution. The water tensions rise continuously for almost two days, but at a moderate slope. This reflects a large pore fraction in clay of almost 10%.
  • Page 97 APPENDICES Retention curve sandy loam example: Figure 90 Example retention curve sandy loam The relatively uniform decrease of the water content with increasing pF values and the drop of the relatively flat conductivity data is characteristic of clays having a wide pore size distribution.
  • Page 98 HYPROP 2 Example Measurement of Clayey silt (Ut3) Figure 91 Example measurement clayey silt This measurement process is typical of a very fine grained substrate. The tensions rise spontaneously, steeply, and continuously right after the start of measurement. This reflects a very small proportion of coarse pores.
  • Page 99 APPENDICES Figure 92 Example retention curve clayey silt The drop of water content that initially is flat and then gets steeper with increasing pF values is characteristic for very fine grained and clayey substrates. The hydraulic conductivity at pF 2 is very high, but then the curve is even steeper than in the case of a clay soil. The description of the data with models is not a problem, however in dry areas the uncertainty increases.
  • Page 100 HYPROP 2 Example Measurement Slightly loamy sand (Sl2) Figure 93 Example measurement slightly loamy sand The measurement process is typical for sand with low fine pores. The tensions rise spontaneously immediately after the start of measurement until they reach a level that corresponds to the air entry point.
  • Page 101 APPENDICES Figure 94 Example retention curve slightly loamy sand The pronounced air entry point and the steep drop of the retention curve after reaching the air entry point is characteristic for sand. The hydraulic conductivity can be determined only from pF 2.0 and then drops steeply. Suitable models for data description are the Fayer-Simmons model, or the bimodal model to describe the subsequent drop of the retention values towards dehydration.
  • Page 102 HYPROP 2 Example Measurement Pure fine and middle sand (Ss) Figure 95 Example measurement pure fine and middle sand The measurement process is typical for sand with a small particle size distribution and without fine pores. The tensions rise spontaneously immediately after the start of measurement until they reach a level that corresponds to the air entry point.
  • Page 103 APPENDICES Figure 96 Example retention curve pure fine and middle sand The very sharply defined bubble point and the extremely steep drop in the retention curve after reaching the air entry point is characteristic of pure sand with a uniform grain size. The hydraulic conductivity can be determined only within a very narrow tension interval and drops very steeply.

  • Page 104: Appendix C. Wp4C Use After Hyprop

    HYPROP 2 APPENDIX C. WP4C USE AFTER HYPROP Procedure of sample for WP4C measurements after a HYPROP measurement. Perform the HYPROP measurement until the second tensiometer shows the air entry. An example of this is indicated within the red-marked area in Figure 98. Stopping substantially earlier may have the opposite effect.
  • Page 105 APPENDICES If this happens, stop the HYPROP measurement after cavitation of the top tensiometer. Or, a second option for clay samples is to use pieces of a drinking straw around the tensiometer shafts that can slide off when removing the sample. Figure 99 Remove the sample ring NOTE: For sandy soil samples, leave the sample on the HYPROP and collect the WP4C samples while removing the soil sample in layers.
  • Page 106 HYPROP 2 Figure 100 Document sample cup tare weight Take two WP4C samples from the top of the soil core. Use a spoon or other suitable instrument to get enough soil material to fill the first two WP4C cups half full (Figure 101).
  • Page 107 Place the first of the six WP4C samples into the WP4C and determine the water potential as described in the WP4C manual (meter.ly/wp4c-support). Immediately after finishing the WP4C measurement, remove the sample and place it on a precision scale (accuracy of +/–0.001 g) to determine the gross weight (WP4C + cup) of the moist sample.
  • Page 108 HYPROP 2 Dry all six samples in the drying oven at 105 °C for 24 h after measuring in the WP4C. Remove the samples from the oven and let them cool down in a desiccator. If not noted before, determine the gross weight (sample, cups, drying pan combined) and tare weights.

  • Page 109: Appendix D. Measuring Units

    APPENDICES APPENDIX D. MEASURING UNITS Units for soil water and matrix potential. Table A.1 Units for Soil Water and Matrix Potential kPa=J/kg –10 –1 –0.001 –0.01 –0.15 99.9993 Field capacity –62 –6.2 –0.006 –0.06 –0.89 99.998 –100 –10 –0.01 –0.1 –1.45 00.9926 Standard ca.

  • Page 110: References

    HYPROP 2 REFERENCES Brooks, R. H. and Corey, A. T. (1964): Hydraulic properties of porous media. Hydrology Paper 3. Colorado State University, Fort Collins, Colorado. Fredlund, D. G., & Xing, A. (1994): Equations for the soil-water characteristic curve. Canadian geotechnical journal, 31(4), 521–532.
  • Page 111 Schindler, U., Doerner, J. and Müller, L. (2015): Simplified method for quantifying the hydraulic properties of shrinking soils. Journal of Plant Nutrition and Soil Science 178 (1): 136–145. METER (2022): LABROS SoilView-Analysis for HYPROP Manual. METER Group AG Mettlacher Straße 8, 81379 München, Germany, 2022. URL www.metergroup. com/hyprop-2/#support Van Genuchten, M.

  • Page 112: Index

    INDEX INDEX air entry point 82 fax number 88 determinging air entry value 89 finishing a measurement options 62–65 phase 4 59–60 maintenance 84. See also  cleaning measurements 69–71 continue stoppped or completed 76 boiling delay 59 measurement range 65. See  specifications multi-balance measurement mode 45 calibration...
  • Page 113 HYPROP 2 specifications 69–72 communication 69 measurement 69 physical 70 tensiometer 16, 39, 41, 42 filling 16 installation 34 terms and conditions 88–106 theory 77–83 generating data points 80 measuring method 78 troubleshooting 86...
  • Page 114 METER Group, Inc. 2365 NE Hopkins Court Pullman, WA 99163 T: +1.509.332.2756 F: +1.509.332.5158 E: info@metergroup.com W: metergroup.com METER Group Gmbh Mettlacher Straße 8, 81379 München T: +49 89 1266520 F: +49 89 12665220 E: info.europe@metergroup.com W: metergroup.com © 2018–2024 All Rights Reserved.

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