초록 ▼

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

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 openings. 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 single 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 valve body can incorporate, as a unit, the complete backflow preventer assembly including gate valves and double check valves.

대표청구항 ▼

A double check valve backflow preventer assembly for installation in a liquid supply line in a space of predetermined length dimension between a pair of gate valve assemblies normally occupied by a single check valve backflow preventer assembly, said double check valve backflow preventer assembly co

A double check valve backflow preventer assembly for installation in a liquid supply line in a space of predetermined length dimension between a pair of gate valve assemblies normally occupied by a single check valve backflow preventer assembly, said double check valve backflow preventer assembly comprising: a single unitary valve body having substantially said predetermined length dimension and opposite end coupling means for coupling to corresponding coupling means of said gate valve assemblies and defining opposite end liquid inlet and outlet openings; said valve body defining a single access opening between said opposite end inlet and outlet openings and a removable access cover for closing said access opening, a first annular valve seat within said valve body on the inlet side of said access opening, a second annular valve seat within said valve body on the outlet side of said access opening, a first check valve assembly for mounting within said valve body to open in a downstream direction with respect to said inlet and outlet openings and including a first stationary valve cage having a ring for seating against said first valve seat, a second check valve assembly for mounting within said valve body to open in a downstream direction with respect to said inlet and outlet openings and including a second stationary valve cage having a ring for seating against said second valve seat, and releasable seating means operable to seat said first valve cage ring against said first valve seat and said second valve cage ring against said second valve seat, said seating means being operable to seat and release said cage rings from their seated engagement with said valve seats through said single access opening.