Vent valve rather than vent hole: With this particular option, the model PG43SA-S hygienic diaphragm pressure gauge is even suitable for pharmaceutical cleaning from the outside with particularly aggressive agents. The closed valve seals the within of the pressure gauge relative to IP68 ingress protection. In this way, it prevents the penetration of cleaning media.
In the pharmaceutical industry, protecting active ingredients 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 including 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 only undergoes cleaning on the procedure side (CIP, SIP), but also 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 outside at high temperatures sufficient reason for chemicals which have a significantly higher concentration. The media include, for example, 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 this 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 described, and/or very 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 can the service life of the PG43SA-S be extended, even though cleaned from the outside under extreme conditions? The solution: with a version with a vent valve. The closed valve (IP68) seals off the inside of the instrument from cleaning substances. However, during its actual function, pressure monitoring, it must be open. Otherwise, correct measurement of the gauge pressure is impossible. The reason being internal pressure builds up in a closed case, that leads to a falsified measurement result.
Easy operability
The brand new vent valve is clearly visible and mounted on the surface of the case for easy access. It can be opened or closed without tools with a wing nut. Last Minute of rotation, as well as 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 in an autoclave
Before each external cleaning, the vent valve is closed. The pressure gauge then has an ingress protection of IP68. If the cleaning process is followed by sterilisation within an autoclave, the valve should be opened again. Due to 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 made for a wide variety of sanitary applications. The new variant with vent valve and IP68 ingress protection has further extended the number of applications for the pressure gauge.
Note
More info on the model PG43SA-S hygienic pressure gauge along with other types 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 find some o our standard designs. When you have any questions on pressure gauges with the IP68 ingress protection option, your contact will gladly help you.
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Pressure gauges for pharmaceutical processes: Flush-mounted ?dry measurement?