Patent ID: 7219690

Claim:
A fluid flow control valve having an input and an output for maintaining a constant fluid flow at the output regardless of fluid pressure at the input, the control valve comprising: an inlet socket having a wall, transverse to fluid flow through the inlet socket, with a plurality of orifices, one of the orifices being larger than the others and on the longitudinal axis of the inlet socket; an outlet socket having a wall, transverse to fluid flow through the outlet socket, with a plurality of orifices, one of the orifices being larger than the others and on the longitudinal axis of the outlet socket, the outlet socket attached to the inlet socket forming a chamber between the wall of the inlet socket and the wall of the outlet socket; a pressure check piston having a first and second end with and a fluid flow orifice between the first and second end, the piston slidably engaging the longitudinal axis orifice in the wall of the inlet socket and slidably engaging the longitudinal axis orifice in the wall of the outlet socket; and a spring biasing the pressure check piston towards the inlet socket.