Suitable for: Side channel blowers in pressure operation Function: Non-return valves prevent backflow into the unit when the side channel blower is at a standstill. Especially when the blower is working against a water column, the use of such a non-return valve is mandatory to prevent ingress of moisture.The non-return valves offered are made of brass and have either an EPDM, PTFE or Viton (on request) seal. In addition, they are equipped with a special spring to reduce the opening pressure. When used with side channel blowers, this results in lower pressure drops and thus energy savings. They can only be operated faultlessly in a horizontal installation position. technical data: Material: Housing: brassSpring: stainless steelSeal: EPDM, PTFE or Viton(*) Temperature range: EPDM: -20°C up to max. +90°CPTFE: -20°C up to max. +180°C Pressure range: max. 16 bar Action pressure: Special spring: Type G 1¼" - G 2½" : 30 - 45 mbarStandard spring(*): 150 mbar Options: - EPDM = EPDM seal- PTFE = PTFE seal- V = Viton seal(*) * on request