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 can be used under environmental requirements which may cause failure of common level sensors.
The most unfortunate circumstances 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 look of a submersible pressure transmitter. One of the main 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. 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 pressurised sensor diaphragm is optimised in order to achieve very low susceptibility to contamination. However, Threatened in soiled media can 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 this stainless steel diaphragm has already been minimised ex factory to just a few 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 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 if it seems 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 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.
Please find further information with this topic on our information platform ?Hydrostatic level measurement?