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 exterior with particularly aggressive agents. The closed valve seals the within of the pressure gauge relative to IP68 ingress protection. In this manner, it prevents the penetration of cleaning media.
In the pharmaceutical industry, protecting active ingredients and medicines from contamination is a priority. Therefore, thorough cleaning of the equipment after every 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 such as 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 additionally cleaning from the exterior. 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 carried out from the exterior at high temperatures sufficient reason for chemicals that have a significantly higher concentration. Portfolio include, for instance, 30 percent30 % 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 soap concentrations and temperatures. However, extremely aggressive substances, as in the application described, and/or very high temperatures attack the inside of the pressure gauge as time passes. 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 outside under extreme conditions? The answer: by using 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. This is due to internal pressure accumulates 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 quick access. It is usually opened or closed without tools via a wing nut. The direction of rotation, in addition to open and closed positions, are clearly marked on the case. The nut and the valve seal come in hygienic design. A safety ring prevents the valve from being unscrewed.
Sterilisation within an autoclave
Before each 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 within an autoclave, the valve must 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 designed for a wide selection 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. Do you want to buy hygienic pressure gauges? Inside our WIKA online-shop you will discover some o our standard designs. Should 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?