If the precise pressure sensor design of the submersible pressure transmitter or level probe is selected to measure the filling levels, this can indicate that the probe is used under environmental requirements which would cause failure of common level sensors.
The most unfortunate circumstances such as soiled media, abrasive ingredients and sludge when used in wastewater treatment plants, brackish and wastewater tanks as well as digester towers, impose special requirements on the look of a submersible pressure transmitter. One of the main requirements on a submersible pressure transmitter would be to obtain the lowest possible susceptibility to contamination or build-up of the pressure sensor by optimizing its design. This 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 own pressurised sensor diaphragm is optimised in order to achieve suprisingly low susceptibility to contamination. However, Liberated in soiled media may lead to sticking of dirt particles on the stainless steel diaphragm. To obtain 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 few microns. Therefore, cleaning of the diaphragm should be completed with caution. Always avoid using sharp or edged tools. It is also strongly advised never to use the commonly used screwdrivers or pens.
If cleaning of the sensor diaphragm is essential, 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 if 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 inner electronic measurement system and additionally 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 trusted measuring instrument any more. Thus, complete replacement of the damaged instrument is absolutely necessary.
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