If the specific 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 for example 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 why the normal design of a pressure transmitter with narrow pressure ports is not 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 to experience very low susceptibility to contamination. However, continuous operation in soiled media can lead to sticking of dirt particles on the stainless diaphragm. To obtain Fluid 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 must be carried out with caution. Always stay away from Marked Down or edged tools. Additionally it is strongly advised never to use the commonly used 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 due to denting or notching, even though it seems to be purely superficial, results in significant losses in the accuracy of level measurement. Solution 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 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 absolutely necessary.
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