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Pore Pressure Transducer (PPT) Calibration Procedure By Javier Ubilla Rensselaer Polytechnic Institute
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The main components of the PPT are the Head which contains the Diaphragm with 4 strain gauges attached in full bridge configuration. This Diaphragm is protected with a Porous Stone. The sensor is connected to the Data Acquisition System (DAQ) through a Transition Cable and then a Thin Cable. In order to facilitate the saturation of the PPT, especially in tests where viscous fluid is used, at RPI the Porous Stone of the sensor is replaced with filter paper.
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Estimate the maximum expected pore pressure to be measured during the test and select the appropriate range for the PPT (10, 50, 100 or 200 PSI). Also, according to the location of the sensor determine to use a PPT with a thick cable (Model GE Druck PDCR 81) or with a thin cable (Model GE Druck PDCR 81-3478). For more information about this miniature http://www.gesensing.com/druckproducts/ pressure transducer visit
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Connect the PPT to the National Instruments Data Acquisition System (DAQ), using the Modulus SCXI-1520 and the Accessory SCXI-1314.
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Input an Initial Calibration Factor (ICF) of 1.0 and NULL the sensor. After the NULL is completed monitor the sensor, check that the sensor reading is stable and with a low level of noise. Blow in the sensor and make sure that the sensor responds to the increase in pressure. Insert the transition cable in the appropriate rubber plug as shown in the figure. Two rubber plugs are available which will perfectly fit the PPT with thick or thin cable.
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Insert the head of the PPT in the triaxial chamber and seal the chamber with the rubber plug as shown in the picture.
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Turn on the GE Druck Portable Pressure Calibrator model DPI 610/615. This calibration device is being used to produce a stable pressure inside the sealed triaxial chamber. The calibration device has a screen which displays the pressure inside the chamber
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The main components of the PPT are the Head which contains the Diaphragm with 4 strain gauges attached in full bridge configuration. This Diaphragm is protected with a Porous Stone. The sensor is connected to the Data Acquisition System (DAQ) through a Transition Cable and then a Thin Cable. In order to facilitate the saturation of the PPT, especially in tests where viscous fluid is used, at RPI the Porous Stone of the sensor is replaced with filter paper.
-
Estimate the maximum expected pore pressure to be measured during the test and select the appropriate range for the PPT (10, 50, 100 or 200 PSI). Also, according to the location of the sensor determine to use a PPT with a thick cable (Model GE Druck PDCR 81) or with a thin cable (Model GE Druck PDCR 81-3478). For more information about this miniature http://www.gesensing.com/druckproducts/ pressure transducer visit
-
-
Connect the PPT to the National Instruments Data Acquisition System (DAQ), using the Modulus SCXI-1520 and the Accessory SCXI-1314.
-
Input an Initial Calibration Factor (ICF) of 1.0 and NULL the sensor. After the NULL is completed monitor the sensor, check that the sensor reading is stable and with a low level of noise. Blow in the sensor and make sure that the sensor responds to the increase in pressure. Insert the transition cable in the appropriate rubber plug as shown in the figure. Two rubber plugs are available which will perfectly fit the PPT with thick or thin cable.
-
-
Insert the head of the PPT in the triaxial chamber and seal the chamber with the rubber plug as shown in the picture.
-
Turn on the GE Druck Portable Pressure Calibrator model DPI 610/615. This calibration device is being used to produce a stable pressure inside the sealed triaxial chamber. The calibration device has a screen which displays the pressure inside the chamber