Low-Pressure VW Piezometers
Durham Geo’s Low-Pressure VW Piezometers are specially designed to monitor small changes in pore-water pressure. Low-Pressure VW Piezometers can also be used, in conjuction with a barometer, to monitor water levels in open wells and wiers.
The VW piezometer converts water pressure to a frequency signal via a diaphragm, a tensioned steel wire, and an electromagnetic coil. The piezometer is designed so that a change in pressure on the diaphragm causes a change in tension of the wire. When excited by the electromagnetic coil, the wire vibrates at its natural frequency. The vibration of the wire in the proximity of the coil generates a frequency signal that is transmitted to the readout device. The readout device processes the signal, applies calibration factors, and displays a reading in the required engineering unit.
Advantages of Vibrating Wire Piezometers
High Resolution: VW piezometers provide a resolution of 0.025% of full scale.
High Accuracy: Slope Indicator’s automated, precision calibration system ensures that all VW piezometers meet or exceed their accuracy specifications.
Groutable: The VW piezometer can be directly grouted-in with a bentonite-cement grout. More information about the direct grout-in method can be found in the VW piezometer manual and in a technical note.
Rapid Response: VW piezometers offer rapid response to changes in pore water pressure, whether they are grouted in, pushed into cohesive soils, or embedded in a sand filter zone.
Reliable Signal Transmission: With properly shielded cable, signals from the VW piezometer can be transmitted long distances.
Temperature Measurement: All VW piezometers are equipped with a temperature sensor.
For more information
Please download the datasheet and manual for the VW Piezometer. These documents can be viewed and printed with Adobe Acrobat Reader. For more information about fully-grouted piezometers, please visit our Papers and References page.
Low-Pressure VW Piezometers Specifications
|LOW-PRESSURE VW PIEZOMETERS|
|0.7 bar (10 psi) Piezometer||52611610|
|1.8 bar (25 psi) Piezometer||52611625|
VW Piezometer Specifications
|VW PIEZOMETER SPECIFICATIONS|
|Sensor Type||Pluck-type vibrating wire sensor with built-in thermistor|
|Range||Standard ranges are listed at left. Custom calibration ranges are available|
|Accuracy||±0.1% FS for 0.7 – 7 bar sensors, ±0.3% FS for 17 and 35 bar sensors|
|Maximum Pressure||1.5 x rated range|
|Filter||50-micron, sintered stainless steel. A ceramic 1-bar high-air entry filter can be ordered for standard and heavy-duty piezometers by specifying part number 60101240 in addition to the piezometer part number|
|Temperature Coefficient||< 0.04% FS per °C|
|Size||Standard: 19 x 195 mm (0.75 x 7.75″)
Low-Pressure: 29 x 191 mm (1.125 x 7.5″).
Heavy-Duty: 29 x 191 mm (1.125 x 7.5″).
Push-In: 35 x 270 mm (1.385 x 10.5″)
|Weight||Standard: 0.16 kg (0.3 lb).
Low-pressure: 0.45 kg (1 lb).
Heavy-Duty: 0.8 kg (1.75 lb).
Push-in: 1.2 kg (2.75 lb).
|SIGNAL CABLE SPECIFICATIONS|
|Signal Cable||50613824||Shielded cable with four 22-gauge tinned-copper conductors and polyvinyl chloride (PVC) jacket|
|Armored Signal Cable||50613586||Shield cable with four 22-gauge tinned-copperconductors, inner polyurethane jacket, steel braid armor, and outer high-density, polyethylene jacket. For heavy duty piezometer only|
|READOUT & TERMINAL BOXES|
|VW Data Recorder||52613500|
|Jumper Cable for Terminal Box||52613557|
|Terminal Box for 6 sensors||57711606|
|Terminal Box for 12 Sensors||57711600|
|Terminal Box for 24 Sensors||97711624|
|VW MiniLogger for 1 Sensor||52613310|
|Campbell Scientific Data Loggers|