"FOCET" MAKE Double Acting Air Valve are basically a combination of small orifice and large orifice for automatically discharging air during pipe filling and ventilating the pipe during emptying.
The small orifice is basically provided with a float which operates when air accumulates and displaces water from the upper part of the chamber compressing the float to drop with the water level and allowing the air to escape until the returning the water again raises the float to seal the orifice.
The large orifice is provided with a buoyant float which during normal operation of the pipe line is maintained by the pressure in the main in contact with large orifice seating, the valves opens only when the pressure is reduced approximately to that of the atmosphere, which occurs during pipe filling and emptying.
The double ball air valve can be used in pipe lines with separate isolating valves for ease in maintenance.
