Heavy-Duty VW Piezometers

Heavy-Duty VW Piezometers

Durham Geo’s Heavy-Duty VW Piezometers are a variant of the standard borehole piezometer. The Heavy-Duty VW Piezometers feature a thick-walled stainless steel body and are supplied with double-jacket armored cable.

Operation

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.

Heavy-Duty VW Piezometer Specifications

HEAVY-DUTY VW PIEZOMETERS
3.5 bar (50 psi) Piezometer 52610520
7 bar (100 psi) Piezometer 52610530
10 bar (150 psi) Piezometer 52610560
17 bar (250 psi) Piezometer 52610540
35 bar (500 psi) Piezometer 52610550
Signal Cable, Armored 50613586

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
Resolution 0.025%FS
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
Materials Stainless steel
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
DATA LOGGERS
VW MiniLogger for 1 Sensor 52613310
4-Channel V-Logger 52615140
Campbell Scientific Data Loggers