Vibrating Wire Piezometer
Geosense® VWP-3000 Series of Vibrating Wire Piezometers use the well-proven method of converting fluid pressures on a sensitive diaphragm into a frequency signal.
Frequency signals are particularly suitable for the demanding environment of Civil Engineering applications, since the signals are capable of long transmission distances without degradation, tolerant of wet wiring conditions and resistant to external electrical noise.
Working principle
The VW Piezometer operates on the principle that a tensioned wire, when plucked, vibrates at its resonant frequency. Around the wire is a magnetic coil which when pulsed by a vibrating readout or data logger interface plucks the wire and measures the resultant resonant frequency of vibration. A change in distance between the anchor and the diaphragm is related to pressure differentials and can be converted to a kPa reading.
Temperature information can be used if logging regularly to determine swift temperature changes during which pressure readings may be exaggerated
Features
- Reliable long-term performance
- Rugged, suitable for demanding environments
- High accuracy
- Insensitive to long cable lengths
- All non-drive-in models can have threaded adaptors to customer specifications
Applications
- Pore pressure measurement in soils and rocks
- Fluid pressures in hydro-fracture and pump tests
Specifications
VWP-3000 Vibrating Wire Piezometers may be read by the VW-2106 or any vibrating wire readout device and may be readily connected with data loggers with vibrating wire interface modules.
Vibrating wire piezometers output a frequency signal and are therefore insensitive to resistance changes in connecting cables caused by contact resistance or leakage to ground.
Cable may be readily and simply extended on site without special precautions. Gauges may be read up to 1000 metres away from their installed location.
VWP-3000 *
Standard construction to measure groundwater elevations and pore pressures.
VWP-3100 *
Heavy duty body for direct burial in fills and dam embankments.
VWP-3200 *
Low pressure version to measure groundwater elevations and pore pressures.
VWP-3300 *
A low pressure vented version to compensate for barometric pressure changes
VWP-3400
Heavy duty Drive-in Type 1 featuring inclined ports to minimise smearing affects.
VWP-3500
Slim line Drive-in Type 2 featuring large surface area porous filter.
* Available with High or Low air entry filter
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Specifications |
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Type |
Description |
Pressure Range kPa |
Over Range |
Resolution |
Accuracy |
Non-Linearity |
Temp Range |
Thermal Effect |
Diameter X Length |
Weight |
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VWP-3000 |
Standard LAE |
345, 518, 690, 1034, 2068, 3447, 5171, 6895 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
20x140 mm |
210 g |
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VWP-3001 |
Standard HAE |
345, 518, 690, 1034, 2068, 3447, 5171, 6895 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
20x140 mm |
210 g |
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VWP-3100 |
Heavy Duty LAE |
345, 518, 690, 1034, 2068, 3447, 5171, 6895 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
25x151 mm |
450 g |
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VWP-3101 |
Heavy Duty HAE |
345, 518, 690, 1034, 2068, 3447, 5171, 6895 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
25x151 mm |
450 g |
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VWP-3200 |
Low Pressure LAE |
70, 173 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
25x151 mm |
600 g |
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VWP-3201 |
Low Pressure HAE |
70, 173 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
25x151 mm |
600 g |
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VWP-3300 |
Low Pressure Vented LAE |
70, 173 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
25x151 mm |
600 g |
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VWP-3301 |
Low Pressure Vented HAE |
70, 173 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
25x151 mm |
600 g |
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VWP-3400 |
Drive In Type 1 |
345, 518, 690, 1034, 2068, 3447, 5171, 6895 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
35x218 mm |
1335 g |
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VWP-3500 |
Drive in Type 2 |
345, 518, 690, 1034, 2068, 3447, 5171, 6895 kPa |
2 X Rated Pressure |
0.025% FS |
±0.1% FS |
<0.5% FS |
-20 to +80 oC |
<0.05 % FS/ oC |
33 x 470 mm |
2100 g |
Description
| Materials | Stainless Steel |
| Excitation | Pluck or Swept Frequency |
| Over Voltage Protection | 90 V gas plasma arrester |
| Thermistor | 3k Ohms @ 25oC |
| Range | 2200-3500 Hz |
| Nominal Zero Value | 3130 Hz |
| Thermal Effect | 0.05% FS / oC |
Ordering Information
- Type
- Cable length
- Pressure Range
