These valves are designed to protect the reservoirs against the overpressures. As the reservoir pressure exceeds the valve setting, the pallet arises allowing the vapour discharging. Main Features : -Replaceable seat. -Antifreezing pallet ; the drip around the pallet avoids condensate collecting around the seat. -Pallet guides located above the seat; this arrangement assures a no-jamming guide of the pallet not =affected by contaminant fluids as a close coupling between pallet and guides is not necessary. -Setting: any setting available, charging the pallet's dead weight load, between + 20 mm H2O and _+ 400 mm H2O. (On request higher sets) Standard Materials : -Body : carbon steel AISI 304, AISI 316. -Seat and pallet: AISI 304, AISI 316. -Guide and bird screen : 18/8 Stainless Steel. -Hood : cast Aluminium or carbon Steel. -Diaphragms : FEP, P.T.F.E., BUNA-N, VITON etc Dwg. 9/A Valves : These valves are used when the setting values exceed 800 mm H2O; the pallet is spring loaded. Dwg. 209, Rielief Valves with Flame Arrester : These valves are adopted when a relief valve has to be coupled to a flame arrester. The relief valve body is now machined from the flame arrester upper flange. Dwg. 9/TV Valves : Tightness by elastomeric 0-rings (Buna-N, Viton, Chemraz) to minimize the leakages.