Metering fluid to fluid actuators

An apparatus comprising:

• a hydraulic actuator;
• a fluid chamber comprising a piston slidably movable between first and second ends of the fluid chamber and dividing the chamber into first and second chamber portions;
• and
• a hydraulic directional control valve operable to direct a fluid from a fluid source into the first chamber portion to cause a volume of fluid to be discharged out of the second chamber portion into the hydraulic actuator to actuate the hydraulic actuator by a distance corresponding to the volume of fluid received by the hydraulic actuator, wherein the hydraulic actuator is a first hydraulic cylinder, and wherein the apparatus further comprises:
• a second hydraulic cylinder;
• and
• a third hydraulic cylinder connectable with and operable to raise a mast and a substructure of a drill rig utilized in oilfield operations, wherein the first and second hydraulic cylinders are connectable with and operable to align the third hydraulic cylinder with one of the mast and the substructure to permit connection between the third hydraulic cylinder and the one of the mast and the substructure.

An apparatus comprising:

• a hydraulic actuator;
• a fluid chamber comprising:
• a piston slidably movable between first and second ends of the fluid chamber;
• a first port extending into the fluid chamber on one side of the piston;
• and
• a second port extending into the fluid chamber on an opposing side of the piston, wherein the second port of the fluid chamber is fluidly connected with the hydraulic actuator;
• and
• a hydraulic directional control valve comprising:
• a first port fluidly connected with a fluid source;
• a second port fluidly connected with a tank;
• a third port fluidly connected with the first port of the fluid chamber;
• and
• a fourth port fluidly connected with the second port of the fluid chamber;
• wherein the hydraulic directional control valve is operable to direct fluid from the fluid source into the first port of the fluid chamber to cause the piston to move from the first end to the second end and discharge a volume of fluid out of the second port of the fluid chamber into the hydraulic actuator to move the hydraulic actuator by an incremental distance corresponding to the volume of fluid received by the hydraulic actuator, wherein:
• the hydraulic actuator is a first hydraulic cylinder;
• the apparatus further comprises:
• a second hydraulic cylinder;
• and
• a third hydraulic cylinder connectable with and operable to raise a mast and a substructure of a drill rig;
• and
• the first and second hydraulic cylinders are connected with and operable to align the third hydraulic cylinder with one of the mast and substructure to permit connection between the third hydraulic cylinder and the one of the mast and substructure.

A method comprising:

• directing a fluid from a fluid source into a first portion of a chamber until a piston moves from a first end of the chamber to a second end of the chamber to:
• introduce a volume of fluid into the first portion of the chamber;
• and
• discharge the fluid from the second portion of the chamber;
• and
• directing the fluid from the fluid source into the second portion of the chamber until the piston moves from the second end of the chamber to the first end of the chamber to:
• introduce the fluid into the second portion of the chamber;
• and
• discharge the volume of fluid out of the first portion of the chamber into a hydraulic actuator to actuate the hydraulic actuator by an incremental distance, wherein the hydraulic actuator is a first hydraulic cylinder connected to a second hydraulic cylinder, wherein a third hydraulic cylinder is connected to the second hydraulic cylinder, and wherein the method further comprises:
• alternatingly directing the fluid from the fluid source into one of the first and second portions of the chamber to repeatedly actuate the first and third hydraulic cylinders until the second hydraulic cylinder is aligned with a mast or a substructure of a drill rig utilized in oilfield operations to permit connection between the second hydraulic cylinder and the mast or the substructure;
• connecting the second hydraulic cylinder with the mast or the substructure;
• and
• operating the second hydraulic cylinder to raise the mast or the substructure.