Gas compressor

Abstract

A compressor is provided suitable for compressing natural gas from a pressure associated with a residential gas supply to a pressure suitable for an automotive gas tank. The compressor utilizes a par of pneumatic cylinders driven by a hydraulic cylinder to compress the gas in a multi-stage process. Various embodiments are provided with respect to the gas compressor portion and the drive portion. A pressure boost system is also provided which utilizes an internal control valve and internal orifice through the piston of one of the pneumatic cylinders.

1 . A gas compressor comprising:
 a first pneumatic cylinder having a piston separating a first pneumatic cylinder chamber and a second pneumatic cylinder chamber;   a second pneumatic cylinder having a piston separating a third pneumatic cylinder chamber and a fourth pneumatic cylinder chamber;   a drive mechanism operatively coupled to each piston to move the piston of each pneumatic cylinder;   a gas conduit circuit selectively connecting a gas compressor inlet to the first pneumatic cylinder chamber, selectively connecting the first pneumatic cylinder chamber to the fourth pneumatic cylinder chamber, and selectively connecting the fourth pneumatic cylinder chamber to the gas compressor outlet.   
     
     
         2 . The compressor of  claim 2 , wherein the gas conduit circuit includes a plurality of check valves to control the flow of gas within the gas conduit circuit. 
     
     
         3 . The compressor of any of  claims 1 - 2 , wherein the gas conduit connects the inlet of the first pneumatic cylinder to a source of residential gas. 
     
     
         4 . The compressor of any of  claims 1 - 3 , wherein the gas conduit connects the gas compressor outlet of the second pneumatic cylinder to a gas storage tank. 
     
     
         5 . The compressor of any of  claims 1 - 4  further comprising one or more additional pneumatic cylinders. 
     
     
         6 . The compressor as in any one of  claims 1 - 5 , wherein the drive mechanism comprises a hydraulic cylinder selectively driven by a hydraulic pump through a directional control valve. 
     
     
         7 . The compressor as in  claim 6 , wherein the hydraulic pump comprises a first hydraulic pump and a second hydraulic pump driven by an electric motor. 
     
     
         8 . The compressor as in any of  claims 6 - 7  wherein the drive cylinder has an axis of the drive cylinder which is substantially coaxial with an axis of one of the first and second cylinders. 
     
     
         9 . The compressor of any of  claims 1 - 8 , wherein the gas conduit circuit selectively connects the gas compressor inlet to the second pneumatic cylinder chamber, and the piston in the first pneumatic cylinder includes a check valve in series with an orifice formed through the piston and selectively connecting the second pneumatic cylinder chamber to the first pneumatic cylinder chamber. 
     
     
         10 . The compressor as in any of  claims 1 - 8 , wherein the gas conduit circuit selectively connects the gas compressor inlet to the third pneumatic cylinder chamber, and the piston in the second pneumatic cylinder includes a check valve in series with an orifice formed through the piston and selectively connecting the third pneumatic cylinder chamber to the fourth pneumatic cylinder chamber. 
     
     
         11 . The compressor as in any of  claims 1 - 10 , wherein the first pneumatic cylinder is connected to the second pneumatic cylinder by an end cap, the end cap including a check valve in series with an orifice formed through the end cap and selectively connecting third pneumatic cylinder chamber to the second pneumatic cylinder. 
     
     
         12 . The compressor as in any of  claims 1 - 8 , wherein the gas conduit circuit selectively connects the gas compressor inlet to the second pneumatic cylinder chamber,
 the first cylinder including an internal inner diameter flow passage formed by a portion of an inner cylindrical wall being formed at a radius larger that the radius of the inner diameter of the cylinder.   
     
     
         13 . The compressor as in any of  claims 1 - 8 , the compressor further comprising:
 the gas conduit circuit selectively connects the compressor inlet to the second pneumatic cylinder chamber and the third pneumatic cylinder chamber, and selectively connects the second pneumatic cylinder chamber to the first pneumatic cylinder chamber, and selectively connects the third pneumatic cylinder chamber to the first pneumatic cylinder chamber,   a shut off valve selectively enabling and disabling flow for the second and third pneumatic cylinder chamber to the first pneumatic cylinder chamber; and   a gas reservoir.   
     
     
         14 . A method of compressing gas utilizing the compressor of  claim 10  comprising the steps of:
 activating the drive mechanism to extend the cylinder pistons from a fully retracted position causing the gas to flow from the gas supply into the first pneumatic cylinder and into the third pneumatic cylinder chamber and from the second pneumatic cylinder chamber to the gas reservoir and from the fourth pneumatic cylinder chamber to the gas storage tank; 
 disengaging the shut off valve to allow gas to flow from the gas reservoir to the first pneumatic cylinder chamber when the pistons are fully extended; 
 engaging the shut off valve while the pistons are retracted to allow gas to flow from the first pneumatic cylinder chamber to the fourth pneumatic cylinder chamber and from the third pneumatic cylinder chamber to the gas reservoir and from the gas source to the second pneumatic cylinder chamber. 
 
     
     
         15 . A method of compressing gas utilizing the compressor of  claim 9  comprising the steps of:
 activating the drive mechanism to extend the cylinder pistons from a fully retracted position to a fully extended position causing the gas to flow from the gas supply into the first pneumatic cylinder chamber and from the second pneumatic cylinder chamber to the first pneumatic cylinder chamber and from the fourth pneumatic cylinder chamber to the gas storage tank; 
 activating the drive mechanism to retract the cylinder pistons from a fully extended position to a fully retracted position causing the gas to flow from the gas supply into the second pneumatic cylinder chamber and from the first pneumatic cylinder chamber to the fourth pneumatic cylinder chamber. 
 
     
     
         16 . A gas compressor connectable to a supply of gas and to a gas storage tank, the compressor comprising:
 a first pneumatic cylinder having a piston separating a first pneumatic cylinder chamber and a second pneumatic cylinder chamber;   a second pneumatic cylinder having a piston separating a third pneumatic cylinder chamber and a fourth pneumatic cylinder chamber;   an end cap connecting the first pneumatic cylinder and the second pneumatic cylinder;   a drive mechanism operatively coupled to move the piston of each pneumatic cylinder;   a gas conduit circuit selectively connecting the supply of gas to the first pneumatic cylinder chamber, selectively connecting the supply of gas to the second pneumatic cylinder chamber, selectively connecting the supply of gas to the third pneumatic cylinder chamber, and selectively connecting the fourth pneumatic cylinder chamber to the gas storage tank;   the piston in the first pneumatic cylinder includes a check valve in series with an orifice formed through the piston and selectively connecting the first pneumatic cylinder chamber to the second pneumatic cylinder chamber;   the end cap including a check valve in series with an orifice formed through the end cap and selectively connecting the second pneumatic cylinder chamber to the third pneumatic cylinder;   the piston in the second pneumatic cylinder includes a check valve in series with an orifice formed through the piston and selectively connecting the third pneumatic cylinder chamber to the fourth pneumatic cylinder chamber.   
     
     
         17 . A gas compressor comprising:
 a cylinder;   a piston moveably positioned within the cylinder and forming an internal chamber on either side of the piston within the cylinder, the piston having a check valve in series with an orifice formed through the piston and selectively connecting the internal chambers of the cylinders;   a gas inlet connected to each chamber of the cylinder; and   a compressed gas outlet connected to one chamber of the cylinder.   
     
     
         18 . A method of compressing gas using a cylinder having a piston moveably positioned within the cylinder and forming a boost chamber on one side of the piston and a boosted chamber on the other side of the piston, the method comprising the steps of:
 extending the piston to compress a volume of gas in the boost chamber and allowing gas provided by a source of gas to enter the boosted chamber;   allowing a portion of the gas in the boost chamber to pass through a piston check valve and orifice through the piston when the pressure in the boost chamber surpasses the check valve activation pressure;   retracting the piston to compress a volume of gas in the boosted chamber, and allowing gas provided by the source of gas to enter the boost chamber;   allowing a portion of the gas in the boosted chamber to pass through a check valve of a cylinder exit line when the pressure in the boosted chamber surpasses the check valve activation pressure.   
     
     
         19 . A method of compressing gas using a gas compressor comprising a first cylinder having a piston separating a first cylinder chamber and a second cylinder chamber, a second cylinder having a piston separating a third cylinder chamber and a fourth cylinder chamber, each piston having a check valve in series with an orifice formed through the piston and selectively connecting the chambers of the respective cylinders; a means for moving the piston of each cylinder, a gas reservoir, and a gas storage tank, the method comprising the steps of:
 moving the pistons of each cylinder from a retracted position to an extended position forcing gas to flow from a source of gas into the first cylinder chamber and the third cylinder chamber, and   forcing gas to flow from the second cylinder chamber to the gas reservoir, and forcing gas to flow from the fourth cylinder chamber to the storage tank;   opening a valve to allow gas flow from the gas reservoir to the first cylinder chamber when the pistons are in a fully extended position;   closing the valve and retracting the pistons until they are fully retracted which forces gas flow from the first cylinder chamber to the fourth cylinder chamber, and from the third cylinder chamber into the reservoir, and from the gas source into the second cylinder chamber.   
     
     
         20 . A method of compressing gas using a gas compressor comprising a first cylinder having a piston separating a first cylinder chamber and a second cylinder chamber, a second cylinder having a piston separating a third cylinder chamber and a fourth cylinder chamber, a means for moving the piston of each cylinder, a gas reservoir, and a gas storage tank, the method comprising the steps of:
 moving the pistons of each cylinder from a retracted position to an extended position forcing gas to flow from a source of gas into the first cylinder chamber and the third cylinder chamber, and forcing gas to flow from the second cylinder chamber and from the fourth cylinder chamber to the storage tank;   retracting the pistons from the extended position until they are fully retracted forcing gas flow from the first cylinder chamber and the third cylinder chamber into the gas storage tank, and forcing gas flow from the source of gas into the second cylinder chamber and the fourth cylinder chamber.