The double orifice air valves have been designed for automatic rapid pipe draining and filling and also for the automatic release of accumulated air during normal working conditions. The design is unique for which the air rushing out of the system cannot force the float upwards and prematurely close it down, this makes sure that the valve closes only after all the air has left the system and water has entered the chamber. All ductile iron components have been coated with approved fusion bonded epoxy for ensuring high durability. All the other components have been made by either a WRAS approved polymer material or stainless steel for minimizing the risks of corrosion. All of the seals have been made of WRAS approved EPDM rubber that features an excellent compression set and the ability for regaining its original shape. The design of air valves for waterworks involves both large and small orifices. The small orifice for the automatic release of accumulated air during normal operation. The air can enter a pipeline in a number of ways via pump glands, leaking joints, and is also contained in solution in the water itself. The air accumulates at the high points of the system, and unless the flow of water is fast enough for purging the line, large pockets of air form for seriously impeding the flow a condition which is known as air binding. Air valves at specific points in the system locate these air valves to achieve ventilation which increases the efficiency flow capacity of the pipeline. The large orifice makes way for automatic ventilation of the pipeline during emptying and filling. Air is exhausted at a very high capacity during filling for preventing restriction of the filling rate because of the built-up backpressure. When they are being emptied, the air is admitted to the pipeline at a rate of sufficient for preventing high vacuum pressures that are developing.
Material: Ductile Iron