Pressure-compensated, subsea chemical injection valve

A gate valve 200 controls fluid communication from an inlet 54 to an outlet 58 relative to a reference pressure. A body 202 defines a passage 262 disposed in communication with the inlet 54, and an outlet port 280 disposed in the passage 262 communicates the passage 262 with the outlet 58. A piston 270 disposed in the passage 262 is movable therein between first and second positions relative to the outlet port 280. The piston 270 is movable in a first direction from the first position to the second position in response to an inlet pressure at the inlet 54. A gate 290 disposed on the piston 270 is biased transversely toward the outlet port 280. The gate 290 moved by the piston 270 adjusts flow from the passage 262 to the outlet port 280. A pressure compensator 220 disposed opposite the piston 270 biases the piston 270 in a second opposite direction from the second position to the first position. The pressure compensator 220 has a chamber 222 in communication with the reference pressure.