Air valves with a large opening are intake and exhaust valves that serve for the proper functioning of the pipeline. They are used to remove air from the pipeline before commissioning and to prevent the forming of underpressure when emptying the pipeline or a breakdown in the pipeline system.
They are installed at the highest turning points of the pipeline and connect it to the outside atmosphere, acting completely automatically.
Air valves with a large opening consist of a housing in which a ball is placed, which acts as a sealing element. The upper part of the housing is closed with a cover under which there is the rubber on which the ball rests while sealing.
During the filling of the pipeline with water, air exits through the valve opening until the water reaches the housing and due to the increase in pressure it lifts and presses the ball against the sealing rubber. When the pressure in the pipeline drops below atmospheric, the ball lowers due to its own weight and releases the air inlet.
Air valves work only when the pressure in the pipeline is equal to or less than atmospheric, and they seal when Δp≥1 (bar). The air released from the water during operation cannot be removed from the pipeline by these valves. The flange connection dimensions are according to SRPS M.B6.011 and DIN 2501.
The housing in the welded construction, the housing cover and the protective cover are made of structural steels.
The sealing rubber is made of EPDM, and the ball is made of steel for deep drawing. Protection of balls from corrosion is achieved by plasticizing the outer surface, and resistance to hydraulic shock is provided by a special internal supporting of the balls.
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