Air & Vacuum Air Valves
These type of air valves discharge large quantities of air from non-pressurized pipelines and are used mainly during pipe filling. Air discharge is critical for efficiently filling pipelines with liquid. Air and Vacuum Valves also enable the intake of large quantities of air when lines are drained, when the pressure drops suddenly and at water column separation. Air intake is essential when draining lines during maintenance and for preventing pipe collapse when vacuum conditions exist. These valves operate when the line is NOT pressurized and remain closed when the line is under pressure. When pressure drops below atmospheric pressure, the valves open.
Automatic Air Valves
These type of air valves continuously release accumulated air entrapped in a pressurized line. This entrapped air is found mostly at the peaks of the pipeline. As air accumulates in the air release valve, water is displaced, the float lowers with the drop in the water level and air is released from the exposed orifice. As water refills the air release valve, the float rises and reseals the valve.
Combination Air Valves
These type of air valves fulfill the tasks required of both types – Air and Vacuum and Automatic Air Release Valves. They discharge large volumes of air when the system is being filled, admit large volumes of air during system drainage and continuously release entrapped air when the line is under pressure.
