MODEL 4500 SERIES VIBRATING WIRE PIEZOMETER
| INSTALLATION |
11
7:
FIGURE 7:
Typical Soft Soils Installation
The piezometer should be connected to a readout box and monitored during the
installation process. If pressures reach or exceed the calibrated range, the
installation should be stopped and the pressure allowed to dissipate.
The drill rod can be left in place or it can be removed. If it is to be removed, a
special five-foot section of EW (or AW) rod with reaction wings and a left-hand
thread are attached directly to the piezometer tip. This section is detached from
the rest of the drill string by rotating the string clockwise. The reaction wings
prevent the EW rod from turning. A LH/RH adapter is available from
GEOKON
.
This adapter is retrieved along with the drill string.
4.5
MODEL 4500H AND MODEL 4500HH TRANSDUCER
When connecting the Model 4500H transducer to external fittings, the fitting
should be tightened into the 1/4-18 NPT female port by placing a wrench on the
flats provided on the transducer housing. Avoid tightening onto a closed system;
the process of tightening the fittings could overrange and permanently damage
the transducer. If in doubt, attach the gauge leads to a readout box and take
readings while tightening. For an easier and more positive connection to the
transducer, PTFE (plumber’s) tape on the threads is recommended. The
maximum pressure for the 4500H is 3 MPa.
The
GEOKON
Model 4500HH is designed for high-pressure environments. This
model uses a 7/16-20, 60-degree, female, medium pressure fitting. The
maximum pressure for the 4500HH is 75 MPa.
CAUTION!
All high-pressure sensors are potentially dangerous. Care must be
taken not to overrange them beyond their calibrated range. Sensors are tested
to 150% of their range to provide a factor of safety.
4.6
SPLICING AND JUNCTION BOXES
Because the vibrating wire output signal is a frequency rather than a current or
voltage, variations in cable resistance have little effect on gauge readings.
Therefore, splicing of cables has no effect, and in some cases may in fact be
