| 摘要 |
A backflow preventer assembly for a liquid supply line includes a single unitary valve body including flanged inlet and outlet end openings and a single access opening generally normal to the flow path defined by the inlet and outlet openings. The body houses a pair of check valve seats on opposite sides of the access opening for seating a pair of check valves mounted in series to permit flow from the inlet opening to the outlet opening. Adjustable compression rods interconnecting the two check valves seat the valves against their oppositely facing valve seats. The check valves and compression rods are sized to enable installation and removal of the valves through the access opening. In one embodiment the valve body has a predetermined length for installation in the liquid supply line between a pair of gate valve assemblies, such length being the same as a standard body length for a signel check valve assembly. In a second embodiment, the single unitary body incorporates, in addition to check valve assemblies, a pair of gate valve housings one on each of the opposite sides of the gate valve assemblies so that the single body can incorporate, as a unit, the complete backflow preventer assembly including gate valves and double check valves.
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