Vibrating wire piezometer
The vibrating wire piezometer is widely used for measuring pore water pressure in soil and rocks and for measuring groundwater level.
The extremely sturdy, long-lasting sensor consists of a cylindrical stainless steel casing hosting a vibrating wire vented or non-vented pressure transducer, a fluid chamber and a sintered or stainless steel wire filter.
The pressure exercised by the water on the transducer distorts the metal diaphragm on which one end of the vibrating wire is fixed. This latter oscillates at a frequency proportional to the pressure to which it is subjected. Distortion of the length of the vibrating wire is measured in terms of variations in oscillation (Hz), using dedicated reading units, The transducer’s frequency output signal is not affected by the leght of the measuring wire or by electrical interference from external sources. In addition, it is particularly resistant to the presence of moisture on the reading terminals.
To measure temperature variations, the pressure transducer has an integrated 3 KΩ NTC thermistor for the correction of thermic drift.
- Full scale: from 69 kPa to 2068 kPa;
- Overpressure: 2x F.S.;
- Precision: +/- 0.1% F.S.;
- Resolution: 0,025% F.S.;
- Non linearity: <0,5% F.S.;
- Operating range: from -20 to 80° C;
- Output signal: Hz;
- Range: from 2200 to 3500 Hz;
- Zero nominal value: 3130 Hz;
- Thermistor: 3 KΩ at 25°C;
- Thermic drift: 0,05% F.S./°C;
- Material: stainless steel;
- Protection against overvoltage: 90V with gas surge-arrestor.
- Dimensions (69-173 kPa): 30×150 mm
- Dimensions (all other ranges): 24×150 mm