Abstract: An improved valve coupling method and apparatus is provided that resists the many forces associated with constant insertion and removal of access keys. The coupler apparatus is made of a non-corrosive metal alloy and includes a pair of specially formed integrated vertical wings which extend out in a tangential, as opposed to radial, direction from opposite sides of the coupler. Each of the wings is offset and includes at least one horizontal shelf portion. When buried in the soil, the vertical wings provide the coupler with frictional resistance to the screwing and unscrewing rotational forces imparted whenever a key is inserted or removed from the coupler, or from the movement of a hose attached to the key. Similarly, the horizontal shelf portions provide lateral support to resist the downward and upward forces associated with insertion and removal of a key, or contact with lawn maintenance equipment.

Abstract: 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.