Casagrande type porous filter used in piezometric measurements.

Technology suitable for measurements in medium-low permeability soils or where rapid reaction pressure measurements are required.

The reading can be carried out either via the classic phreatimeter or with a pressure transducer.

Tecnopenta has designed and markets a modified version of these cells which allows the communication between cell and sensor to be sealed and at the same time makes the pressure transducer recoverable without extracting the pipe.

This model is particularly suited to measurement in confined aquifers.

Both the classic version and the modified version are available.

The modified Casagrande I1-P20 TN cell consists of a porous element connected with a rigid pipe to the ground level. This porous element I1-P20TN differs from the classic two-tube model in that they have been replaced by a single tube of larger diameter which allows the insertion inside of a pressure transducer equipped with a conical steel tip which fits onto a appropriate conical seat obtained on the upper part of the Casagrande Cell.

The transducer descends to the porous cell through PVC pipes screwed together.

The rigid PVC pipes with a diameter of 42 mm and a length of 2.5 m are joined
between them by means of M/F thread (waterproof).

The connection between the porous filter and the pressure transducer occurs by mechanical thrust of the conical final part of the sensor inside the housing present in the upper part of the filter.

The seal is ensured by two successive O-rings. The mechanical thrust occurs by means of ballasts (variable number depending on the length of the cable and the pressure to be counteracted) which are made to slide on the cable from the surface and which insert the transducer into its housing by pushing its rear part.