Vent valve instead of vent hole: With this 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 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 level of the temperatures.
Hygienic diaphragm pressure gauges including the WIKA model PG43SA-S are ideal for monitoring the pressure of mobile tanks in the pharmaceutical industry.
Cleaning: Caustic soda and nitric acid
In various cases, the gear not only undergoes cleaning on the process 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 completed from the exterior at high temperatures and with chemicals that 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 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 over time. The consequence: The measuring instrument must be replaced.
WIKA diaphragm pressure gauge model PG43SA-S in the 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 though 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 Compare , pressure monitoring, it should be open. Otherwise, correct measurement of the gauge pressure is impossible. Simply because internal pressure builds up 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 quick access. It really is 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 in 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 followed by sterilisation in an autoclave, the valve must 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 made for a wide variety of sanitary applications. The brand 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 can be found on the WIKA website. Do you want to buy hygienic pressure gauges? In 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.
See also our post
Pressure gauges for pharmaceutical processes: Flush-mounted ?dry measurement?