Air Release Valve
MODERN Automatic Air Valves for Water Mains
- Single Orifice Air Valve - Air relief during normal running
- Single Orifice Air Valve - Air release /Suction during filling or draining
- Dual Orifice Air Valve - Combination air valve
- IS 14845 and AWWA C512
- Anti Vacuum Valve
Cluster for large main
The presence of free air in pipeline can reduce the severity of water hammer considerably. Celerity(speed) of an elastic wave with, say 2% of air at a pressure head of 50m of water reduces celerity from about 1100m/s to 160 m/s for a typical pipe line. On the other hand air in a rising main, whether in solution or in bubble from can have number of ill effects.
- Cavitation - The formation of vacuous cavities which subsequently rapidly collapse and erode the pump or pipe
- Head loss - Accelerating water past air pockets formed in pipes, leading to head losses
- Other forms may include surging, Corrosion, reduced pump efficiency, malfunctioning of valves or vibrations
A pipeline designer therefore has to factor in all the aforesaid, the critical level of permissible vacuum inside a pipeline to prevent collapse vis-a-vis the suction and discharge capacity of an air valve (curves on request) before deciding upon the type, size, spacing and location of these air valves.
Valve size |
For Mains size |
50ø |
Upto 200ø |
80ø |
225 - 350ø |
100ø |
400 - 500ø |
150ø |
600 - 900ø |
200ø |
1000 - 1200ø |
Air Valve - GUIDELINE FOR USAGE:
- Normally 10 bar rated, 16 bar or higher pressure on request.
- Single Air Valve of size 1” as per IS: 14845 can be supplied, suitable for 100 NB mains.
- Not recommended for sewage application.
For mains size larger than 1200 NB, it is recommended that a cluster of 2 or 3 air valves be used in one location
Single Air Valve
Double Air Valve
Kinetic Air Valve
Air Cushion Valve
Double jet
Tamper proof air valve