If the specific pressure sensor design of the submersible pressure transmitter or level probe is selected to gauge the filling levels, this can indicate that the probe can be used under environmental requirements which would cause failure of common level sensors.
The most unfortunate circumstances such as for example soiled media, abrasive ingredients and sludge when used in wastewater treatment plants, brackish and wastewater tanks and even digester towers, impose special requirements on the design of a submersible pressure transmitter. One of many requirements on a submersible pressure transmitter would be to have the lowest possible susceptibility to contamination or build-up of the pressure sensor by optimizing its design. Because of this , the typical design of a pressure transmitter with narrow pressure ports isn’t used within level probes since it would have a tendency to clog in such applications.
The look of the submersible pressure transmitter and its pressurised sensor diaphragm is optimised to experience 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 case 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 must be carried out with caution. Always stay away from sharp or edged tools. It is also strongly advised not 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 due to 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 additionally distorts the output signal linearisation which includes been adjusted ex works to the undamaged diaphragm. Thus, Avoid with damaged diaphragm generates falsified measurement of the current filling level and, therefore, can’t be considered a reliable measuring instrument any longer. Thus, complete replacement of the damaged instrument is completely necessary.
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