Combination flow control valve and reverse flow check valve

Abstract

A combination flow control and reverse flow check valve provides a compact valve unit for controlling the flow of fluid in a downstream direction and limiting undesired backflow of liquid into a source such as a reservoir. The flow control and reverse flow check valve may be provided as a unitary member having a housing with an upstream end configured for mounting to the liquid source, a fluid conveying channel within the housing, and a check element positioned in the channel between the flow control valve, such as a ball valve, and a seat which is complementally configured with the check element to normally seal against backflow. A blocking element may be provided to prevent interference of the check element with the operation of the flow control valve while permitting liquid to flow in an intended downstream direction. Because the occurrence of a backflow event is an undesired and infrequent event which may necessitate investigation, the check element may be sized and made of a material which will move past the seat during pressurized flow, thereby providing an indicator that a backflow event has occurred when the check element is found within the source.