Most often, in practice, the place of installation of air valves with large and small openings coincides, so, naturally, the design of an air valve with two balls was performed, which executes the functions of an air valve with both large and small openings.
Two-ball air valves remove air from the pipeline before commissioning, remove air that is released from the water during operation, and also prevent the occurrence of underpressure when emptying the pipeline or a breakdown in the pipeline system.
Two-ball air valves are installed at the highest breakpoints of the pipeline. They work completely automatically connecting the pipeline to the outside atmosphere. They are a combination of air valves with large and small openings, mounted on a common housing that connects to the pipeline.
Within these valves, there is also a shut-off valve, which is always open in the operating mode, and closes when it is necessary to perform some intervention on the valve.
The flange connection dimensions are in accordance with SRPS M.B6.011 and DIN 2501.
The housing, the shut-off body, the housing cover and the protective cover are made of structural steel.
The deep-drawing steel balls are protected against corrosion by plasticizing, and the resistance to hydraulic impact is provided by a special internal reinforcement of the balls.
The threaded spindle is made of stainless steel, the threaded sleeve is made of grey cast iron, and the sealings are made of EPDM.
Full specification find below