Cleaning of submersible pressure transmitters or level probes

If the specific pressure sensor design of the submersible pressure transmitter or level probe is selected to gauge the filling levels, this often means that the probe is used under environmental requirements which would cause failure of common level sensors.
Alienated as soiled media, abrasive ingredients and sludge when used in wastewater treatment plants, brackish and wastewater tanks or even digester towers, impose special requirements on the look of a submersible pressure transmitter. One of many requirements on a submersible pressure transmitter is to have the lowest possible susceptibility to contamination or build-up of the pressure sensor by optimizing its design. This is the reason the typical design of a pressure transmitter with narrow pressure ports is not used within level probes because it would tend to clog in such applications.
The look 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 may 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 this stainless steel diaphragm is already minimised ex factory to just a couple microns. Therefore, cleaning of the diaphragm should be completed with caution. Always avoid using sharp or edged tools. Additionally it is strongly advised not to use the popular screwdrivers or pens.
If cleaning of the sensor diaphragm is essential, then rinse it using a weak water jet or clean it carefully using compressed air. Damage of the diaphragm because of denting or notching, even if it seems to be purely superficial, results in 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 also distorts the output signal linearisation which has 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, cannot be considered a trusted measuring instrument any more. Thus, complete replacement of the damaged instrument is completely necessary.
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