Patent ID: 8316943

Claim:
A valve for injecting fluid into a wellbore, comprising: a tubular mandrel having a bore formed therethrough and a port formed through a wall thereof; a piston axially moveable relative to the mandrel between a first position where the piston substantially seals the bore from the port and a second position where the bore is in fluid communication with the port, wherein the piston is movable from the first position to the second position using pressurized fluid at a first pressure, and wherein the piston automatically returns to the first position when the pressurized fluid is at a second pressure that is less than the first pressure; and a latch disposed between the piston and the mandrel, the latch operable to resist movement of the piston relative to the mandrel by engaging a first tapered surface when moved from the first position to the second position and by engaging a second tapered surface when moved from the second position to the first position, wherein the first and second tapered surfaces are disposed on one of the mandrel and the piston, wherein the first tapered surface has an angle greater than an angle of the second tapered surface.