Vent valve rather than vent hole: With this particular option, the model PG43SA-S hygienic diaphragm pressure gauge is even ideal for pharmaceutical cleaning from the exterior 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 active ingredients and medicines from contamination is really a top 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 level 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 merely 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 carried out from the exterior at high temperatures and with chemicals which have a significantly higher concentration. Bloodcurdling include, for example, 30 percent30 % caustic soda and 60 percent60 % nitric acid ? both in diluted form. With one of 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 typical soap concentrations and temperatures. However, extremely aggressive substances, as in the application described, and/or 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 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 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. 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 quick access. It really is opened or closed without tools with a wing nut. The direction of rotation, and 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 every 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 brand new variant with vent valve and IP68 ingress protection has further extended the number of applications for the pressure gauge.
Note
Further information on the model PG43SA-S hygienic pressure gauge and other models of the PG43SA series can be found 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. If you have any questions on pressure gauges with the IP68 ingress protection option, your contact will gladly help you.
See also our post
Pressure gauges for pharmaceutical processes: Flush-mounted ?dry measurement?g