Table of Contents
Advertisement
rings, which tend to trap air and reduce the cell stiffness. The oil is de-aired
,
using a Nold DeAerator
which materially improves the fluid stiffness and the
performance of the cell. The pressure transducer normally employed is the
Model 4500H, which is available in several different pressure ranges
GEOKON
(see Appendix A). The cable is attached to the transducer in a sealed, waterproof
manner. For earth pressure cells located inside a soil mass, the cable may be
armored and provided with strain relief at the cell to reduce the likelihood of
pullout.
Located inside the vibrating wire pressure transducer housing is a thermistor for
the measurement of temperature at the cell location. In addition, a tripolar
plasma surge arrestor inside the transducer housing protects the vibrating wire
pluck and read coils from electrical transients such as may be induced by direct
or indirect lightning strikes.
Alternative pressure transducers with voltage (0-100 mV, 0-5 VDC, 0-10 VDC) or
current (4 - 20 mA) output are also available for dynamic readout capability.
Consult the factory for additional information.
1.3 EARTH PRESSURE CELL CONSTRUCTION
1.3.1 MODEL 4800 EARTH PRESSURE CELLS
Model 4800 Earth Pressure Cells may be rectangular or circular in shape. The
standard size for the rectangular Model 4800 is 150 mm × 250 mm (6" × 10"),
for the circular it is 230 mm (9") in diameter. Standard thickness for both styles is
6 mm (aspect ratio ≈ 40). For laboratory tests, smaller, thinner cells can be
manufactured. Contact the factory for additional information.
6"
150 mm
10"
250 mm
Top View
Side View
FIGURE 4: Model 4800 Rectangular Earth Pressure Cell
9"
230 mm
Top View
Side View
FIGURE 5: Model 4800 Circular Earth Pressure Cell
MODEL 4800 SERIES VW EARTH PRESSURE CELLS | INTRODUCTION | 3
Pressure Cell
Transducer Housing
(4 conductor, 22 AWG)
Pressure Cell
Transducer Housing
(4 conductor, 22 AWG)
4:
Instrument Cable
5:
Instrument Cable
Advertisement
Table of Contents
