Clueless of vent hole: With this option, the model PG43SA-S hygienic diaphragm pressure gauge is even ideal for pharmaceutical cleaning from the outside with particularly aggressive agents. The closed valve seals the inside of the pressure gauge in accordance with IP68 ingress protection. In this way, it prevents the penetration of cleaning media.
In the pharmaceutical industry, protecting substances and medicines from contamination is really a top priority. Therefore, thorough cleaning of the equipment after each batch is indispensable. However, its effectiveness depends critically on the concentration of the substances used and the amount of the temperatures.
Hygienic diaphragm pressure gauges like the WIKA model PG43SA-S are suitable for monitoring the pressure of mobile tanks in the pharmaceutical industry.
Cleaning: Caustic soda and nitric acid
In various cases, the equipment not merely undergoes cleaning on the process side (CIP, SIP), but additionally cleaning from the outside. This also applies to a pharmaceutical company that uses the WIKA model PG43SA-S for pressure monitoring in mobile tanks. Here, the cleaning process is completed from the exterior at high temperatures sufficient reason for chemicals which have a significantly higher concentration. The media include, for instance, 30 %30 % caustic soda and 60 %60 % nitric acid ? both in diluted form. With these substances, the measuring instrument is cleaned from all sides in a cleaning system using nozzles.
During such an operation, chemicals can enter the case of the pressure gauge through the vent hole. The materials of the measuring instrument can withstand the normal cleaning agent concentrations and temperatures. However, extremely aggressive substances, as in the application form described, and/or high temperatures attack the inside of the pressure gauge over time. The consequence: The measuring instrument must be replaced.
WIKA diaphragm pressure gauge model PG43SA-S in the brand new version with vent valve: The sectional view shows the valve in open position. The safety ring is marked in red.
Pressure measurement with open valve
WIKA therefore addressed the question: How do the service life of the PG43SA-S be extended, even when cleaned from the exterior under extreme conditions? The solution: by using a version with a vent valve. The closed valve (IP68) seals off the within of the instrument from cleaning substances. However, during its actual function, pressure monitoring, it should be open. Otherwise, correct measurement of the gauge pressure is impossible. This is due to internal pressure accumulates in a closed case, that leads to a falsified measurement result.
Easy operability
The new vent valve is actually visible and installed on top of the case for easy access. It could be opened or closed without tools via a wing nut. The direction of rotation, and also open and closed positions, are clearly marked on the case. The nut and the valve seal are in hygienic design. A safety ring prevents the valve from being unscrewed.
Sterilisation within an autoclave
Before every external cleaning, the vent valve is closed. The pressure gauge then comes with an ingress protection of IP68. If the cleaning process is accompanied by sterilisation in an autoclave, the valve should be opened again. Because of the saturated steam conditions that occur there, internal pressure would otherwise also build-up ? with negative consequences for the measuring instrument.
Conclusion
The model PG43SA-S diaphragm pressure gauge has been specifically designed for a wide selection of sanitary applications. The brand new variant with vent valve and IP68 ingress protection has further extended the range of applications for the pressure gauge.
Note
Further information on the model PG43SA-S hygienic pressure gauge along with other models of the PG43SA series are available on the WIKA website. Would you like to buy hygienic pressure gauges? Inside our WIKA online-shop you will discover some o our standard designs. In case you have any questions on pressure gauges with the IP68 ingress protection option, your contact will gladly assist you to.
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Pressure gauges for pharmaceutical processes: Flush-mounted ?dry measurement?