Air release valves play a vital yet underappreciated role in pressurized piping infrastructure by venting accumulating air from rising mains and water storage tanks. Without adequate air removal, pockets of gas can stall pumps, damage pipes through water hammer, and cause undesirable operational issues. To meet the demanding performance needs of pressurized air elimination, carefully engineered cast iron bodies provide critical durability.
Cast Iron Air Valves – Two Prominent Styles Predominate
Combined models consolidate air release and vacuum protection functions into a single compact unit. These multitalented valves by valve d'air à double orifice manufacturer, automatically exhaust air during system filling and admit air on drain down to prevent vacuum collapse. Integrating dual mechanisms streamlines piping configurations where both air release and vacuum breaking are required together.
Double orifice air valves take a specialized approach by housing parallel upper and lower float operated orifices within a shared casting. The upper port releases air while the lower admits make-up air during vacuum conditions. By segregating air admission and release into independent orifices, double cavity air valves precisely control the venting processes. They protect sensitive piping networks against potential over-pressurizing due to excessive air in-flows.
Both Combined & Double Orifice Air Valve Are Cast Iron
At the foundation of both combined and double orifice air valve designs are exacting cast iron bodies:
Spheroidal graphite (SG) or ductile iron materials provide optimal strength, resistance to shock loading, and dimensional stability during temperature fluctuations. Cast construction uniformly distributes material stresses compared to welded steel alternatives. It also enables intricate valve cavity shapes that promote self-cleaning through turbulent vented air streams.
Robust castings protect critical internal operating mechanisms, from float assemblies and sealing seats to vent piston rods and linkage hardware. AWWA C512 approved castings withstand frequent valve cycling and corrosive onslaughts from waterborne contaminants or condensation buildup. Internal epoxy liners supplement cast iron’s natural corrosion resistance for protracted service life.
Accessibly Positioned Air Vents
Accessibly positioned air vents eliminate problems locating and servicing air valves in buried applications. Flanged outlets project from valve bodies to interface with discharge piping, while bleed screws allow trapped air venting during installation and maintenance. Top mounted air release mechanisms rise above valve cover flanges for manual priming if floats malfunction. Extension bonnets extend operating rods upward through access boxes to grade level for actuation.