Air Valves. Features of Construction Each Dual chamber air valves with inbuilt sluice valve shall be provided. Air Valve shall be capable of exhausting air from a pipeline when it is being filled with water. Air shall be released at a sufficiently high rate to prevent the restriction of the inflow rate. Similarly the valve shall be capable of ventilating a pipeline automatically when it is being emptied. The air inflow rate should be sufficiently high to prevent the development of vacuum within the pipeline. The valve shall automatically release air accumulating in the pipeline during normal operating conditions. Air valves shall be double acting type. For double acting type valves, a buoyant rigid ball (float) shall seal the large orifice and the chamber housing shall be designed to avoid premature closing of the valve by the air being discharged. A buoyant ball shall seal the small orifice at all pressures above atmospheric except when air accumulates in the valve chamber. All air valves shall be provided with an inbuilt valve and a flanged end connection. The aperture of each valve must be properly designed for the proper air release and inlet rates. All branched outlets including air valve tees shall be provided with one ½” BSP tapped coupling duly plugged for measurement of pressure. The closing plug shall be in Stainless Steel (AISI 304 or equivalent) with a hexagonal head. The head shall be provided with a copper washer for sealing. Pressure rating of the air valves shall be PN 1.6 (16 kg/cm2 operating pressure). The valves shall be conforming to IS 14845.
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Samples: gmdwsb.assam.gov.in, gmdwsb.assam.gov.in, gmdwsb.assam.gov.in
