Hydraulic valve with linear adjustable throttling gate and a hydraulic velocity fuse throttling gate

A passive heave tensioner assembly supported upon a floating platform and adapted for use with a marine riser, the platform connected, via any number of extending supports, to a tensioner ring in turn secured to an outer barrel portion of a slip joint assembly, with a further inner telescopic barrel portion displace-ably supported relative to the outer barrel portion in order to facilitate vertical heave compensating adjustment between the portions responsive to up and down motion, said assembly comprising:

• a plurality of tensioner cylinders arranged in a circumferential array around the platform, said tensioner cylinders each further including internally displacing pistons with extending piston rods connected to the tensioner ring at remote ends thereof;
• a plurality of hydraulic isolation type valves, each supplied by an inlet line extending from a hydraulic fluid accumulator, said valves each including an outlet line extending to a selected one of said tensioner cylinders;
• said valves each further including:
• a body having an inlet communicating with said inlet line and an outlet communicating with said outlet line;
• a motor supported by said body and operating a shaft extending through an interior of said body, said shaft terminating in a gate;
• a spring supported within said housing and influencing said gate in an open position to permit fluid flow between the inlet and outlet;
• upon occurrence of a pressure differential resulting from a fluid flow through the inlet exceeding a biasing force of said spring, said gate being caused to displace against a valve seat communicating the inlet with the outlet in order to interrupt fluid flow to said tensioner cylinder in a standby mode and to define a closed position;
• and
• said motor operating in a throttling mode to linearly and incrementally displace said gate between the open and closed positions in order to adjust flow through the outlet to said tensioner cylinder.