Gas compressor compressing well head casing gas

A gas compressor comprising:

• a. a drive power section for receiving a pressurized hydraulic drive fluid and discharging a non-pressurized spent hydraulic drive fluid with a hydraulic drive cylinder having a hydraulic drive cylinder stroke Y;
• b. a one-piece common rod connecting to a hydraulic drive piston of the drive power section;
• c. a dual activating compressor section connected to a common head, the dual activating compressor section configured for receiving a source of vapor or gas and providing a gas discharge, the dual activating compressor section comprising:
• (i) a compressor cylinder having a compressor cylinder stroke X identical to the hydraulic drive cylinder stroke Y, the compressor cylinder comprising:
• 1. an upper compression chamber;
• and
• 2. a lower compression chamber separated from the upper compression chamber by a compressor piston connected to the one-piece common rod through the seal assembly;
• (ii) a first piston locator sensor positioned adjacent the compressor cylinder for detection of the compressor piston at a first end of a stroke;
• and
• (iii) a second piston locator sensor positioned adjacent the compressor cylinder, for detection of the compressor piston at a second end of the stroke;
• d. a one-piece common head receiving the one-piece common rod, wherein a center section of the one-piece common head is a seal assembly separating the drive power section from the dual activating compressor, the one-piece common head joining the drive power section with the dual activating compressor, the seal assembly consisting of:
• a compressor seal consisting of a single ring positioned closest to the compressor cylinder;
• an upper hydraulic seal consisting of a single ring positioned closest to the hydraulic drive cylinder;
• and
• a lower hydraulic seal consisting of a single ring connected to the upper hydraulic seal;
• and
• wherein the compressor seal is in a first groove in the one piece common head and in a spaced apart relation to both the upper hydraulic seal and lower hydraulic seal which are both in a second groove in the one piece common housing and without being between the upper and lower hydraulic seals, the compressor seal preventing gas from exiting the compressor, the hydraulic seals preventing pressurized hydraulic drive fluid and non-pressurized spent hydraulic drive fluid from exiting the hydraulic drive cylinder while separating the hydraulic drive cylinder from the compressor cylinder and sealing the one-piece common rod;
• e. a controller configured to receive signals from the first piston locator sensor and the second piston locator sensor and repeatedly reverse direction of pressurized hydraulic fluid flow through hydraulic flow lines connecting a fluid reservoir to the hydraulic drive cylinder;
• f. a hydraulic drive pump that can pressurize and transfer the hydraulic drive fluid from the fluid reservoir to the drive cylinder;
• wherein the compressor piston moves between a first orientation and a second orientation;
• as the compressor piston moves, the first piston locator sensor transmits a signal to the controller causing entry of the pressurized hydraulic drive fluid into the hydraulic drive cylinder while simultaneously causing discharge of spent hydraulic fluid from the hydraulic drive cylinder moving the compressor piston towards the second piston locator sensor while simultaneously drawing the vapor or gas into the upper compression chamber and discharging compressed vapors at a line pressure from the lower compression chamber, the second piston locator sensor detects the compressor piston, and the controller upon receipt of the second signal and reverses the pressurized hydraulic drive fluid flow, the gas compressor causes the hydraulic drive piston and the compressor piston to move in tandem using the one-piece common rod for recovery of at least one of the vapors and gas.