A valve controls, changes or closes flow directions of liquid, gaseous and powdery media in piping systems.
The standard hygienic/sanitary valves of Gebr. Rieger have an O-ring seal on the valve seat and the gasket at the stem seal to the environment. There is no difference between sanitary and hygienic. Only different words for the same thing.
The standard aseptic of Gebr. Rieger own as a sealing medium only pure PTFE bellows. This seals both the seat as well as the spindle hermetically against the atmosphere. Thus, 100 % guaranteed that no bacterias from the environment can reach the product.
In food production, it is mandatory that the cleaning medium and the final product must be leak-proof separated by two separate seals. Thus, in the case of a defective seal, the final product is not contaminated by acid, water or a disinfectant. This task is performed in Gebr. Rieger valve program by the valves of the N1, N2, N3, N4, N5, N7, N9 and N13er series.
There are at Rieger all common elastomers (EPDM, NBR, HNBR, FPM or FKM[= Viton ™], ... ) and polymers (PTFE [Teflon ™] , ... ) as sealing materials available. The respective applicability must be examined in the application!
PTFE as pure material is resistant to more than 200 °C. In our application, as valve bellows PTFE is SIP capable by the increase in surface area with 121 °C for 20 min. temperatures higher than 135 °C and extended SIP cycles are to be coordinated with Rieger in individual cases!
Both valves keep the selected set pressure constant. The pressure reducing valve regulates on the downstream side (= valve on the gas bottle). The pressure retaining valve controls on the inflow side (= valve downstream of the heat exchanger).
The safety valve is to dissipate safely the medium at a fixed set point at a certain pressure relief process. → save lives. The overflow/relief valve limits the pressure upstream of the valve to the set (but variable ) set point . The overflow valve is always off only as much media to achieve the desired value → system control