Pressure-compensated, subsea chemical injection valve

A gate valve for controlling fluid communication from an inlet to an outlet relative to a reference pressure, the valve comprising:

• a first body defining a passage in communication with the inlet at a first end of the gate valve;
• an outlet port disposed in the passage of the first body;
• a second body affixed to the first body, the second body defining a chamber in communication with the reference pressure, the first and second bodies defining an interface therebetween communicating the outlet port with the outlet at a second end of the gate valve;
• a piston disposed in the passage and being movable therein between first and second positions relative to the outlet port, the piston being movable in a first direction from the first position to the second position in response to an inlet pressure level at the inlet, the piston comprising a proximal end disposed toward the inlet and comprising a distal end;
• a gate disposed on the piston and biased transversely toward the outlet port, the gate moved by the piston adjusting flow from the passage to the outlet port;
• and
• a pressure compensator disposed in the chamber of the second body opposite the piston and biasing the piston in a second opposite direction from the second position to the first position, the pressure compensator comprising a seat component being separate from the first and second bodies, the seat component defining an orifice for passage of the distal end of the piston therein.

A gate valve for controlling fluid communication from an inlet to an outlet relative to a reference pressure, the valve comprising:

• a first body defining a passage in communication with the inlet at a first end of the gate valve;
• an outlet port disposed in the passage of the first body;
• a second body affixed to the first body, the second body defining a chamber in communication with the reference pressure, the first and second bodies defining an interface therebetween, the first body defining a first flow passage communicating the outlet port with the interface, the second body defining a second flow passage communicating the interface with the outlet at a second end of the gate valve;
• a piston disposed in the passage and being movable therein between first and second positions relative to the outlet port, the piston being movable in a first direction from the first position to the second position in response to an inlet pressure level at the inlet;
• a gate disposed on the piston and biased transversely toward the outlet port, the gate moved by the piston adjusting flow from the passage to the outlet port;
• and
• a pressure compensator disposed in the chamber of the second body opposite the piston and biasing the piston in a second opposite direction from the second position to the first position.