Marine Type Approvals held for these valves: American Bureau of Shipping, Bureau Veritas, DNV, Germanischer Lloyd, Lloyds Register. Angular shaped spring loaded overflow valves made of gunmetal with stainless steel spring – externally adjustable. Suitable for the protection of pumps against overloading in closed circuits for neutral/non neutral, non-sticking liquids and for the control of systems under pressure for neutral / non-neutral gases and vapours and – depending on the sealing material – also for steam. with bellows without lifting device. Available models:853 bGFO with bellows, for gases and liquids without lifting device. Available seals: NBR, EPDM, FKM, PTFE, FFKM. Valves can be delivered unset within a pressure range or set and sealed at the factory. Series also available in Stainless Steel: Series 453. Series 853 (Gunmetal): Model 453bGFO