The Sewer Air Valve (NuVent ISFbl Series) is a double-acting, triple-function anti-slam air valve purpose-built for sewage and slurry duty. It discharges large air volumes during pipeline filling, admits air to break vacuum during draining or pump trip, and releases pressurised air during normal operation — with an integral anti-slam (bias) mechanism that controls the rate of air discharge to prevent slam and protect wastewater rising mains and pump stations.

Features & Specifications

• Triple-acting / double-acting design with anti-slam orifice for controlled air discharge

• Purpose-built for sewage, slurry and other solids-bearing media

• Non-clogging isolated floats with screen mesh to protect the sealing surfaces

• Barrel, flanges, screen mesh and fasteners in 304/316 stainless steel

• HDPE anti-slam, nozzle and control floats; AISI 316 nozzle; EPDM/NBR nozzle seat and O-rings; SS 302 bias spring

• Standard sizes 50–200 mm (larger on request); DN50–DN300 range; pressure classes PN10–PN16

• Operating pressure 0.2–16 bar; operating temperature 0–80 °C

• End connections screwed BSP / NPT or flanged studded

• Factory tested in accordance with AWWA C512-15

Dimensions & Technical Data