Filter monitoring is a core task of differential pressure gauges – the differential pressure increases as soon as the filter becomes clogged. The measuring instruments thus signal when the filter needs to be cleaned or replaced. The efficiency of such a solution can be illustrated by the example of WIKA pressure gauges of the DELTA-line series in water treatment. In the water industry, reverse osmosis is a widely used process to separate water from unwanted substances. The corresponding filter systems work with semi-permeable membranes. For filter monitoring, an international solution provider for the treatment of drinking, industrial and wastewater uses WIKA model DPGS40 differential pressure gauges in its plants in Germany. The instrument measures the pressure on both sides of the membrane.

Timely intervention at the filter

In addition to the on-site display of the differential pressure, the pressure gauge has an integrated microswitch. This sends a warning signal to the control centre when a defined limit value is reached. This enables the operator to arrange for timely cleaning or replacement of the filter. Due to its mechanical measuring principle, the filter monitoring also functions reliably in the event of a power failure.

Continuous monitoring

Prompt intervention at the filter is necessary for two reasons. Firstly: It prevents possible contamination of the water. Secondly: The operator saves energy with the help of continuous filter monitoring. The more fouled a filter is, the harder the pump has to work for the desired media flow.

Integrated working pressure indication

The customer chose the DELTA-line pressure gauge for filter monitoring for yet another reason – because of the integrated working pressure indication. This information is important to the plant manager because it allows him to draw conclusions about the respective pump performance. To obtain this information without the two-in-one solution, he would otherwise have had to set up an additional measuring location.

Further measuring requirements

In addition to filter monitoring, the differential pressure gauges of the DELTA-line series are suitable for tasks in level and flow measurement. In different versions, they cover a wide range of applications. DPGx instruments are available with analogue signal output and up to two microswitches. All have ATEX approval. There is also a variant with SIL certification and DNV-GL approval for marine applications.


Greg Rusznyak

WIKA Instruments (Pty) Ltd
Tel. +27 11 621 0000

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