Patent ID: 7216668

Claim:
A fluid valve for the interruption of fluid flow when backpressure ceases and automatic resetting when backpressure is restored which comprises: a) a valve body having an inlet and an outlet, with a flow conduit positioned therebetween, wherein the flow conduit having a thru-bore within permitting fluid communication between the inlet and the outlet, said body having a piston chamber adjacent to the inlet and the outlet, said body having a backpressure port between the body outlet and the piston chamber permitting fluid communication therebetween, said body having a stem bore disposed within the valve body between the flow conduit and the piston chamber permitting association therebetween, b) a piston having a restricting stem on a first side and a spring retaining boss on a second side slideably confined within said piston chamber, with the restricting stem positioned completely within said stem bore, when no backpressure in the flow leaving the outlet exists, fluid flow is restricted through the flow conduit, and when sufficient backpressure exists the piston stem is automatically forced away from the flow conduit by the piston permitting full flow therethrough, c) a spring housing hermetically sealed to said valve body providing an area for compressible fluid, said area defined as a dead air space, d) a compression spring disposed within said spring housing intimately engaging said piston spring retaining boss on a first end, and in contact with said spring housing on a second end, for urging the piston with its piston restricting stem into the stem bore, restricting fluid flow when no backpressure exists, and urging the piston restricting stem away from the flow conduit against spring pressure when sufficient backpressure is created at the valve outlet, e) means for adjusting tension on said compression spring for obtaining optimum flow restriction characteristics.