Automatic Air Release Valves

Automatic Air Release Valves

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 50 m of water reduces celerity from about 1100 m/ s to 160m/s for a typical pipe line. On the other hand air in a rising main, whether in solution or in bubble form can have number of ill effects

• Cavitation - The formation of vacuous cavities which subsequently rapidly collapse and erodes the pump or pipe
• Headloss - Accelerating water past air pockets formed in pipes, leading to head losses
• Other form amy include surging, corrosion, reduced pump efficiency, malfunctioning of valves or vibrations.

A pipeline designer therefore has to factor in all of aforesaid, the critical level of permissible vacuum inside a pipeline to prevent collage 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 equipment.

Air Suction Capacity (Anti Vacuum Valves)