Vent valve rather than 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 inside of the pressure gauge relative to IP68 ingress protection. In this way, it prevents the penetration of cleaning media.
In Backbone , protecting active ingredients and medicines from contamination is 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 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 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 carried out from the outside at high temperatures sufficient reason for 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 this operation, chemicals can enter the case of the pressure gauge through the vent hole. The materials of the measuring instrument can withstand the typical cleaning agent concentrations and temperatures. However, extremely aggressive substances, as in the application form described, and/or very high temperatures attack the within of the pressure gauge as time passes. The consequence: The measuring instrument should 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 exterior under extreme conditions? The solution: with 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. Simply because internal pressure accumulates in a closed case, that leads to a falsified measurement result.
Easy operability
The new vent valve is actually visible and mounted on top of the case for quick access. It can be 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 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 has an ingress protection of IP68. If the cleaning process is followed by sterilisation in an autoclave, the valve should be opened again. As a result 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 variety 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
More info on the model PG43SA-S hygienic pressure gauge and 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 find some o our standard designs. Assuming you have any questions on pressure gauges with the IP68 ingress protection option, your contact will gladly help you.
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