Vacuum Relief Valve. These valves are designed to protect the reservoirs and the pipes against excessive negative (vacuum) pressures. As the negative pressure exceeds the valve setting, the pallet arises allowing the vacuum relieving. Main Features : -Replaceable seat. -Antifreezing pallet; the drip around the pallet avoids condensate collecting around the seat. -Pallet guides located above the seat; this arrange ment assures a no-jamming guide of the pallet not affected by contaminant fluids as a close coupling between pallet and guides is not necessary. -Bird screen avoids the entering of foreign elements. -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. Flanges : ANSI 150, drilled to UNI PN 10 on request. Dwg. 102/A Valves : These valves are used when the setting values exceed 800 mm H2O. Dwg. 102/AC Valves : These valves are used on blanketed tanks. Through the valve an inert gas can be fed into the reservoir when its pressure value is below the blanketing pressure. Dwg. 102/TV Valves : Tightness by elastomeric 0-rings (Buna-N, Viton, Chemraz) to minimize the leakages.