Double Orifice Air Release Valve (EV4020)

This type of air release valve contains two different-sized balls for operation. A Double Orifice Air Release Valve is in charge of releasing small pockets or bubbles of trapped air from a pressurized pipeline automatically.
A smaller orifice releases small air bubbles as the pipeline fills with liquid, whereas a larger orifice releases a large volume of air as the pipeline fills with liquid.

Its operation mechanism is performed by automatically venting the air through up-thrusting the water level to uplift/floating the ball, which seal the valve releasing nut and when the water level drops down, it creates a clear path for expelling the air out of the pipelines.