Two Bar And Higher Filters; Model 3400Dp - Geokon 3400 Series Instruction Manual

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3.2.2 Two Bar and Higher Filters

The proper procedure for de-airing and saturating these filters is somewhat complex;
therefore, it is recommended that saturation be done at the factory by Geokon. If
saturation must be done in the field, carefully follow the instructions below:
1) Place the assembled piezometer, filter down, in a vacuum chamber that has an inlet
port at the bottom for de-aired water.
2) Close off the water inlet and evacuate the chamber. The transducer should be
monitored while the chamber is being evacuated.
3) When maximum vacuum has been achieved, allow de-aired water to enter the
chamber until it reaches an elevation a few inches above the piezometer filter.
4) Close off the inlet port.
5) Release the vacuum.
6) Observe the transducer output. It may take up to 24 hours for the filter to completely
saturate and the pressure to rise to zero.
7) After saturation, the transducer should be kept in a container of de-aired water until
installation. If de-aired at the factory a special cap is applied to the piezometer to
maintain saturation.

3.3 Model 3400DP

The 3400DP Drive Point Piezometer is de-aired in the same way as the 3400 models by first
unscrewing the point of the piezometer assembly and then following the instruction for the 3400.