Download pptx - 2013 tms gvu tensiometer

TMS – Seminar 2013

Tensiometry for the 21st Century: Principles,

Innovations Field and Applications

Georg von Unold

Sole Distributor : Team Medical & Scientific Sdn. Bhd. Tel : 03-5122 5108

Email : [email protected]


• Water in soils, as well as on the surface will always move from areas of higher potential to areas of lower potential.

Some Background on tensiometers


Content

Some background on tensiometers How do tensiometers work Assembly of tensiometers Types of tensiometer

T4 T4e T8 TS1 T5 T5x

Refill kits (T4, T8) Data collection


Soil specific Relation Potential to Water Content

10.04.2023 TMS – Seminar 2013

Tensiometer range

10.04.2023 TMS – Seminar 2013

Sensors & applications


Assembly of a tensiometer

Reference air pressure

High grade ceramic cupFilled with degassed water.

Pressure sensor

Sensor body incl electronics (T8)

ShaftRefilling tube

Temperature sensor (T8)


How do tensiometers work?

• Soil water and Tensiometer water have contact through a porous ceramic A wetted porous ceramic creates an ideal pore/water interface. The ceramic is permeable for water, but not for air up to 15 bars tension. So we can measure tension.

• The soil water tension is directly conducted to the pressure transducer which offers a continuous signal.

• The atmospheric reference pressure is provided through a membrane on the cable, a distinctive patented method.


The T4/T4e Tensiometer

The T4/T4e Precision tensiometer is made for outdoor monitoring projects

These tensiometers work from +100 kPa (water pressure) to -85 kPa (suction / soil water tension).

If the soil gets drier than -85 kPa, the Tensiometer runs dry and must be refilled as soon as the soil is sufficiently moist again.

The T4 is available in 2 versions: the standard T4 without refilling tubes, and the T4e with refilling tubes for refilling the Tensiometer with a syringe.

Types of tensiometer


The T4/T4e Tensiometer

Measures +100 kPa ... -85 kPaBridge Signal: +100 mV ... -85mV


ApplicationsField measurementsWater balance, leaching, transport studiesEcological impact studies , model calibrationAgricultural or forest studiesIn-situ retention curvesData logger applicationsSpot readings with the INFIELD7b

BenefitsReliable outdoor tensiometerSolid constructionInstallation in any orientationYear-round operation deeper than 30 cm

Limits Will not work in dry or frozen soils


T4 Tensiometer refilling

To assure rapid and reliable measurement of the soil water tension, the cup must be filled, bubble-free, with degassed water. After dry periods or periods with wet and dry cycles, the T4 or T4e must be refilled.

The following items are required for all refilling methods: Syringe with valve (one supplied with each order) Degassed, de-ionized or distilled water Measuring device for checking the pressure signal



The T4-e Tensiometer refilling

The T4e is equipped with 2 stainless-steel capillary tubes which lead through the cable gland and the shaft. Each one has an opening that ends inside the ceramic cup.

The main advantage of the T4e is:it allows easy refilling of the T4e while it remains installed in the ground.

Tube 1 ends at the very tip of the cup, tube 2 ends next to the pressure transducer opening. Outside, both tubes are connected with a short rubber tube.

Any air bubbles will ascend and accumulate either in the ceramic’s tip around tube 1 (upwards installation angle) or next to opening 2 (downwards installation angle). Accordingly the air is removed either through tube 1 or 2



The T8 Tensiometer

The T8 is ideally suited for long term monitoring projects. These tensiometers work from +100 kPa (water pressure) to -85

kPa (suction / soil water tension). If the soil gets drier than -85 kPa, the Tensiometer runs dry and

must be refilled as soon as the soil is sufficiently moist again (syringe refill unit)

The electronics are integrated in the body of the T8. The housing is made of fiberglass reinforced plastic. The electronics are completely sealed and thus well protected against moisture.

The T8 version 2005 has an internal microprocessor and offers water tension and temperature as analog output signals plus the refilling status as a digital signal.

To change the signal range settings or use the serial interface of the T8, use the tensioLINK® USB converter and Windows tensioVIEW® software



The T8 Tensiometer

Measures +100 kPa ... -85 kPaSignals: configurable Interfaces: tensioLINK, SDI12


Applications

Field measurementsWater balance, leaching, transportstudies, model calibrationAgricultural or forest studiesIn-situ retention curvesData logger applicationsSpot readings with the INFIELD7b

BenefitsIntegrated amplifierIntegrated soil temperature sensorIntegrated fill level indicatorIntegrated external refilling: Solid construction

LimitsWill not work in dry or frozen soils


T8 Tensiometer refilling

To assure a rapid and reliable measurement of the soil water tension, the cup must be filled, bubble-free, with degassed water. After dry periods or periods with wet and dry cycles, the T8 must be refilled.

The following items are required for all refilling methods: Syringe with valve (one supplied with each order) Degassed, de-ionized or distilled water Measuring device for checking the pressure signal

The refilling procedure is similar as for the T4e



TS1 Tensiometer

The TS1 has a self refilling multipurpose tensiometer with an internal computer controlled pump for long term monitoring projects

These tensiometers work from +100 kPa (water pressure) to -85 kPa (suction / soil water tension).

The TS1 combines the principles of a pressure transducer Tensiometer to measure the soil water tension and a pore water sampler that extracts soil solution through a porous ceramic: inside the TS1 a bidirectional miniature pump is integrated between pressure transducer and ceramic cup. A microcontroller controls the functions of pump and sensors. To refill the cup a negative pressure, lower than the water tension in the surrounding soil is established to draw water into the ceramic cup. Excess water is released through an exhaust back into the soil.



TS1 design


TS1 Tensiometer

Measures 100 kPa ..-85 kPaSignals: configurableInterfaces: tensioLINK, SDI12

LimitsDoes not measure when soil is dry or frozen


Applications

Field measurements of pF/wcEcological impact studiesAgricultural studiesModel calibrationLong time monitoring studiesWater balance and transport studies

Benefits

Automatic self-refilling and deaeratingContinuous fill level controllingOptional pore water samplingAutomatic emptying before frostIntegrated soil temperature probeAuto logging functiontensioLINK and RS485 interfaceLow maintenance

http://www.ums-muc.de/typo3temp/pics/441ba807fa.jpg


T5 Tensiometer

These Tensiometers work from +100 kPa (water pressure/level) to -85 kPa (suction/soil water tension)

The T5x, with extended range goes to a lower tension of at least -200kPa.

The T5 Miniature Tensiometer is especially designed for point measurements, e. g. in soil columns, pots or laboratory lysimeters, or when the measurement of a minimal span is desired.

With an active surface of only 0,5 cm2 and a diameter of 5 mm the ceramic tip has all advantages of small dimensions: little soil disturbance, point pick-up and fast response.


T5 Tensiometer

Measures +100 kPa ...-85 kPaBridge Signal +100 mV ... -85 mVLimits


ApplicationsPoint measurement of water potentialMiniature lysimeter studiesLab determination of pF/wc and K/Psi

BenefitsAccurate zero-tension readingFast response: With sufficient filling the T5 responds within 5 seconds to an applied air pressure change of 0 to 85 kPaMost standard T5 reach a range of at least 150 kPa when delivered.

LimitsNot for dry soils, not frost resistantIn the field applications require impact protection


T5x Tensiometer with extended range The special version T5x is tested to reach a measuring range of -160 kPa

when delivered. To achieve this, the T5x requires an absolutely bubble free filling.

The T5x often goes to -250 kPa before running empty, and sometimes even to -450 kPa, but this is an exception and cannot be guaranteed.

The T5x is identical with the T5 but has a different ceramic. The extended measuring range is made possible by an effect called boiling retardation, the special ceramic with smaller pores and, as a necessary condition, an absolutely gas free filling.


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The T5/T5x Tensiometer refilling

To assure a rapid and reliable measurement of the soil water tension, the cup must be filled, bubble-free, with degassed water. After drying cycles the T5 must be refilled with the T5-set.



T5/T5x Tensiometer refilling

It is easy to refill the T5 without any vacuum pump with the T5-Set with several syringes.

Checking the refilling status, the refilling procedure itself and the response after refilling with the handheld unit INFIELD



T5/T5x Tensiometer refilling

Refilling the cup with degassed water


Refilling the body with degassed water


Refill kits

Refill kits for T4/T4e and T8

• The following requirements are obligatory: Deionized water Degased water INFIELD 7 Handheld to control the refiling process

• For laboratory refilling we recommend our BKT456 Refill kit

• For field applications we recommend the BKTex or a simple syringe kit


Reading and Data Logging

Infield 7 The INFIELD7, is a multi-functional handheld

read-out unit for Tensiometers and other soil probes.

The following probe types can be connected:UMS Tensiometers T1, T3, T4, T5, T8 and TS1SIS smart gypsum blockWatermark and Soilmoisture gypsum blockFD Thetaprobe ML2xFD EchoprobeTemperature probes

•

Advantages Memory for 250 readings Vertical water column compensation for Tensiometers T8 and TS1 configuration Download readings to PC with accessory USB-connector cable Firmware capable for upgrades


Logger & tensioLink - application


tensioView


tensioLink

10.04.2023 TMS – Seminar 2013

Thank you!