Hydraulic actuator with built-in pressure compensator

A hydraulic actuator, comprising:

• an actuator housing;
• a built-in pressure compensator located within the housing, the built-in pressure compensator comprising:
• a compensator cylinder portion located within the actuator housing, the compensator cylinder portion being fixed relative to the housing, and the compensator cylinder portion having an internal chamber formed therein,
• a compensator piston portion slidably fitting within the compensator internal chamber, a first compensator piston chamber being formed between a first side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, a second compensator piston chamber being formed between a second side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, wherein a compensator hydraulic port is routed through the housing, one end of the hydraulic port opening outside of the housing and another end of the hydraulic port opening to the first compensator piston chamber;
• a first housing internal chamber formed within the housing;
• and
• a first hydraulic passageway formed through the compensator cylinder portion and fluidly coupling the second compensator piston chamber with the first housing internal chamber, wherein the compensator piston portion is unrestrained from sliding relative to the compensator cylinder portion within the compensator cylinder internal chamber.

A hydraulic actuator, comprising:

• an actuator housing;
• a built-in pressure compensator located within the housing, the built-in pressure compensator comprising:
• a compensator cylinder portion located within the actuator housing, the compensator cylinder Portion being fixed relative to the housing, and the compensator cylinder portion having an internal chamber formed therein,
• a compensator piston portion slidably fitting within the compensator internal chamber, a first compensator piston chamber being formed between a first side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, a second compensator piston chamber being formed between a second side of the compensator piston portion and the compensator cylinder portion within the compensator internal chamber, wherein a compensator hydraulic port is routed through the housing, one end of the hydraulic port opening outside of the housing and another end of the hydraulic port opening to the first compensator piston chamber;
• a first housing internal chamber formed within the housing;
• a first hydraulic passageway formed through the compensator cylinder portion and fluidly coupling the second compensator piston chamber with the first housing internal chamber;
• and
• a relief valve coupled to the compensator piston portion, wherein the relief valve is fluidly coupled to the second compensator piston chamber.

A hydraulic actuator for controlling a valve, comprising:

• a housing;
• an operating stem extending into the housing and slidably coupled to the housing, the operating stem being coupleable to the valve;
• a first cylinder portion slidably fitting within the housing, the first cylinder portion having a first cylinder internal chamber formed therein with a closed end and an open end, and the first cylinder portion being mechanically coupled to the operating stem;
• a first housing internal chamber formed within the housing between the housing and the first cylinder portion at the open end of the first cylinder internal chamber, such that the first cylinder internal chamber of the first cylinder portion opens to the first housing internal chamber;
• a second housing internal chamber formed within the housing between the housing and an exterior of the first cylinder portion;
• a spring located within the housing, the spring being biased between the housing and the first cylinder portion;
• a first piston portion located within the housing, being fixed relative to the housing, extending through the open end of the first cylinder internal chamber, and slidably fitting into the first cylinder internal chamber of the first cylinder portion;
• a first piston chamber formed between the first piston portion and the first cylinder portion within the first cylinder internal chamber;
• a second cylinder portion located within the housing, the second cylinder portion being fixed relative to the housing, and the second cylinder portion having a second cylinder internal chamber formed therein;
• a second piston portion located within the housing and slidably fitting within the second cylinder internal chamber;
• a second piston chamber formed between a first side of the second piston portion and the second cylinder portion within the second cylinder internal chamber;
• a third piston chamber formed between a second side of the second piston portion and the second cylinder portion within the second cylinder internal chamber;
• a first hydraulic port routing through the first piston portion and the housing, one end of the first hydraulic port opening outside of the housing and another end of the first hydraulic port opening to the first piston chamber;
• a second hydraulic port routing through the housing, one end of the second hydraulic port opening outside of the housing and another end of the second hydraulic port opening to the second piston chamber;
• a first hydraulic passageway formed through the second cylinder portion and fluidly coupling the third piston chamber with the first housing internal chamber;
• and
• a second hydraulic passageway formed through the first cylinder portion and fluidly coupling the first housing internal chamber with the second housing internal chamber.

A method of manufacturing an actuator, comprising:

• providing an actuator housing;
• disposing a compensator cylinder portion within the actuator housing, the compensator cylinder portion being fixed relative to the housing and having a compensator internal chamber formed therein;
• slidably fitting a compensator piston portion within the compensator internal chamber, wherein a first compensator piston chamber is formed between a first side of the compensator piston portion and the compensator cylinder portion, wherein a second compensator piston chamber is formed between a second side of the compensator piston portion and the compensator cylinder portion;
• forming a hydraulic port through the housing such that the hydraulic port opens to the first compensator piston chamber;
• forming a hydraulic passageway through the compensator cylinder portion to fluidly couple the second compensator piston chamber with a first housing internal chamber, wherein at least the compensator cylinder portion and compensator piston portion comprise a built-in pressure compensator;
• extending an operating stem into the housing, the operating stem being slidably coupled to the housing, the operating stem being coupleable to a valve;
• slidably fitting an actuator cylinder portion within the housing, the actuator cylinder portion having an actuator cylinder internal chamber formed therein with a closed end and an open end, and the actuator cylinder portion being mechanically coupled to the operating stem, wherein the first housing internal chamber is formed between the housing and the actuator cylinder portion at the open end of the actuator cylinder internal chamber, such that the actuator cylinder internal chamber of the actuator cylinder portion opens to the first housing internal chamber;
• biasing a spring within the housing between the housing and the actuator cylinder portion;
• and
• disposing an actuator piston portion within the housing, the actuator piston portion being fixed relative to the housing, extending through the open end of the actuator cylinder internal chamber, and slidably fitting into the actuator cylinder internal chamber of the actuator cylinder portion.