Abstract: A dual check valve backflow prevention apparatus of lightweight, compact construction which provides low flow losses and which maintains a small positive pressure differential under static flow conditions via use of a magnetic valve closure mechanism. The apparatus comprises a main valve housing which contains two check valve assemblies. Each check valve assembly has a clapper valve which uses a low friction magnetic pull closure force and drip tight seals in the forward flow direction for maintaining a small positive pressure differential under static conditions. The magnetic bias for the closure force is preferably located in the center of the flow stream. An additional closure force may be provided by a spring or gravity assistance.

Abstract: A combination diaphragm and seal device for valves which replaces a conventional bolt down diaphragm, and which permits automatic control valves and other valves to be closured by an industry standard groove coupler rather than a plurality of bolts through an external flange on the valve body. The diaphragm portion has a flat circular section with a central bore. This portion may be reinforced by a fabric layer and may or may not include a convolute for extra flexibility. The diaphragm portion is overlaid within and across the interior diameter of the groove coupler seal portion at about the midpoint thereof.

Abstract: A valve actuator for an automatic fluid control valve actuator which fits an Ames Company predetermined size valve housing and which is also suitable for use in a Cla-Val automatic fluid control valve housing of the same predetermined size and which valve actuator is interchangeable with the actuator of each respective manufacturer. The valve actuators range from 4 inches up to 12 inches and can be used as the original actuator of a set size within the range in either manufacturer's housing. The actuator includes a main body disposed on a shaft with a diaphragm and a diaphragm disk plate adjacent the main body on the shaft, all of which are retained by nuts threadedly engaged to the shaft.