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 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 adverse conditions 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 the main requirements on a submersible pressure transmitter is to obtain the lowest possible susceptibility to contamination or build-up of the pressure sensor by optimizing its design. For this reason the typical design of a pressure transmitter with narrow pressure ports isn’t used within level probes because it would tend to clog in 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, continuous operation in soiled media can 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 this stainless steel diaphragm has already been minimised ex factory to just a few microns. Therefore, cleaning of the diaphragm must be completed 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 necessary, then rinse it using a weak water jet or clean it carefully using compressed air. Courageous 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 internal 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 current filling level and, therefore, can’t be considered a trusted measuring instrument any more. Thus, complete replacement of the damaged instrument is completely necessary.
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