Air valves are hydro-mechanical devices designed to automatically release air and wastewater gases or admit air during the filling, draining or operation of liquid piping systems for water and wastewater services.
Air can be drawn in the pipeline through pipeline leaks, at damaged joint seals, through leaking valve packing, and through any loose and leaking flange connection. Noisy water pipes caused by air will sound like vibrating and rapid ticking. The sound can be loud and annoying. The presence of air in pipeline which is in the process of being charged or is in service may cause :
- Delayed filling
- Reduction in flow capacity
- Reduction in pumping efficiency
- Increased risk of water hammer
- Increased risk of corrosion on internal pipe surfaces
- Increased energy consumption
Suitably designed SIGMAFLOW air valves carry out the following functions :
- Automatically exhaust air from the pipeline during filling
- Release air accumulating during pressurised operation
- Admit air when the pipeline is emptying
Air release valves are installed at the highest points in a pipeline where air naturally collects. Air bubbles enter the valve and displace the liquid inside, lowering the liquid level. When the level drops to where it no longer buoys the float, the float drops.