Cleaning of submersible pressure transmitters or level probes

If Scarce of the submersible pressure transmitter or level probe is selected to measure the filling levels, this can indicate that the probe can be used under environmental requirements which may cause failure of common level sensors.
The most adverse conditions such as for example soiled media, abrasive ingredients and sludge when found in wastewater treatment plants, brackish and wastewater tanks as well as digester towers, impose special requirements on the design of a submersible pressure transmitter. One of the main requirements on a submersible pressure transmitter is to obtain the lowest possible susceptibility to contamination or build-up of the pressure sensor by optimizing its design. That is why the typical design of a pressure transmitter with narrow pressure ports isn’t used within level probes since it would tend to clog such applications.
The design of the submersible pressure transmitter and its pressurised sensor diaphragm is optimised in order to achieve very low susceptibility to contamination. However, continuous operation in soiled media can lead to sticking of dirt particles on the stainless diaphragm. To get the highest accuracy and fastest response times in the event of level change, the thickness of the stainless steel diaphragm is already minimised ex factory to just a couple microns. Therefore, cleaning of the diaphragm should be carried out with caution. Always avoid using sharp or edged tools. It is also strongly advised never to use the popular screwdrivers or pens.
If cleaning of the sensor diaphragm is necessary, then rinse it utilizing a weak water jet or clean it carefully using compressed air. Damage of the diaphragm because of denting or notching, even though it appears to be purely superficial, leads to significant losses in the accuracy of level measurement. Deformation of the diaphragm often shifts the zero point of the pressure measurement in the internal electronic measurement system and also distorts the output signal linearisation which includes been adjusted ex works to the undamaged diaphragm. Thus, the submersible pressure transmitter with damaged diaphragm generates falsified measurement of the existing filling level and, therefore, can’t be considered a reliable measuring instrument any more. Thus, complete replacement of the damaged instrument is completely necessary.
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