Patent ID: 7926746

Claim:
An irrigation sprinkler pressure regulating valve comprising: a valve body defining a bore with an inner surface and an edge portion of the bore defining a valve seat; a biasing member for controlling the pressure regulating valve; a valve piston coupled to the biasing member and configured to move between at least a first position and a second position, the valve piston including: a seating surface mounted for movement with the valve piston and arranged to engage the valve seat when the valve piston is in the first position and to be spaced from the valve seat when the valve piston is in the second position; a flow-control portion having an outer surface and extending from the seating surface and arranged for movement therewith, the flow-control portion received in the valve bore upstream of the valve seat; at least one gap extending generally radially through the flow control portion and generally transverse to the movement of the valve piston, the at least one gap defined by walls of the flow-control portion that are inclined toward each other in a radial direction generally transverse to and generally parallel to the movement of the valve piston so that the at least one gap narrows as the gap extends radially outward; at least a portion of the outer surface of the flow-control portion contacting the inner surface of the bore upstream of the valve seat in both the first and second positions of the valve piston during normal operation thereof; and a valve outlet defined by a portion of the valve bore and a portion of the at least one gap, the valve outlet having a variable flow area based on the movement of the valve piston between the first and second positions.