VIBRATING WIRE PIEZOMETERS

Piezometers are designed to measure fluid pressures, such as ground water elevations and pore pressures, when buried in embankments, fills, inside boreholes, wells and riser pipes. Vibrating Wire (VW) Piezometers contain a high tensile steel wire with a fixed anchor at one end and are attached to a diaphragm in contact with water pressure at the other end. The wire is electrically plucked, with the resonant frequency of the vibration proportional to the tension in the wire. This frequency induces and alternating current in a coil which is detected by a readout unit, and can then be converted to a pressure. The frequency output is immune to external electrical noise.

KEY FEATURES
  • Measure water changes as small as 0.5 mm (0.02 in)

  • Immune from cable effects, including length, splicing, noise and moisture

  • Bulit-in ionized gas dischage device protection against transient damage

  • Excellent reliability in typical geotechnical conditions

  • Stainless steel porous filter to prevent soil particles from coming in contact with the diaphragm

  • Built in thermistor permits temperature measurement and temperature compensation

  • Integral lightning protection

  • Cable lengths can be changed without affecting calibration

  • Temperature ranges from -20C to +80C (-4F to 176F)