Flanges : ANSI 150, drilled to UNI PN 10 on request. These valves are designed to protect the reservoirs against overpressures and when the vapours are to be collected in an exhaust line. 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 : cast Aluminium, WCB, CF8 (304) CF8M(316). -Seats and pallets : AISI 304, AISI 316. -Bird screen and guides: 18/8 Stainless Steel. -Diaphragms: FEP, P T.F E., BUNA-N, VITON, etc. Dwg. 121/TV Valves : Tightness by elastomeric 0-Rings (Buna-N, Viton, Chemraz) to minimize the leakages. Dwg. 121/A and 121/TV-A Valves : These valves are used when the setting values exceed 800 mm H2O; the pallet is spring loaded.