Systems and methods for a gas-driven compressor

Abstract

A gas-driven compressor system includes a compressor body with first and second piston cavities and a shuttle valve cavity. The system has a low pressure outlet and high pressure inlet communicating with the first piston cavity via the shuttle valve cavity, and compressor inlet/outlet ports communicating with the second piston cavity. A shuttle valve moves between first and second positions within its cavity. The piston has a first head portion movable by pressurized inlet flow and a second head portion that compresses fluid in the second cavity. The piston selectively directs flow from the high pressure inlet to either side of the shuttle valve cavity based on piston position, thereby directing pressurized flow to either side of the first head portion. This arrangement powers the reciprocating movement of the piston.

1 . A gas-driven compressor system comprising:
 a compressor body defining a first piston cavity, a second piston cavity, and a shuttle valve cavity;   a low pressure port in fluid communication with the first piston cavity, via the shuttle valve cavity, to vent the first piston cavity;   a high pressure port in fluid communication with the first piston cavity, via the shuttle valve cavity, to provide pressurized inlet flow to the first piston cavity;   a compressor inlet in fluid communication with the second piston cavity;   a compressor outlet in fluid communication with the second piston cavity;   a shuttle valve movable between a first position and a second position within the shuttle valve cavity; and   a piston having:
 a first head portion movable within the first piston cavity by the pressurized inlet flow; and 
 a second head portion movable within the second piston cavity by the movement of the first head portion within the first piston cavity to compress a fluid in the second piston cavity; 
 the piston fluidly coupling a signal flow from the high pressure inlet selectively to a first side or a second side of the shuttle valve cavity, depending on a position of the piston, to selectively direct the pressurized inlet flow to the first piston cavity on, respectively, a first side or a second side of the first head portion of the piston to power reciprocating movement of the piston. 
   
     
     
         2 . The gas-driven compressor system of  claim 1 , wherein the piston is configured to move in a first direction to draw the fluid into the second piston cavity and in a second direction to compress fluid within the second piston cavity. 
     
     
         3 . The gas-driven compressor system of  claim 1 , wherein the piston defines a first groove and a second groove arranged to fluidly couple the signal flow from the high pressure port selectively to the first side or the second side of the shuttle valve cavity. 
     
     
         4 . The gas-driven compressor system of  claim 3 , wherein the first groove is aligned with a first shuttle valve signal line when the first head portion of the piston is in a first position in the first piston cavity, and wherein the second groove is aligned with a second shuttle valve signal line when the first head portion of the piston is in a second position in the first piston cavity. 
     
     
         5 . The gas-driven compressor system of  claim 3 , wherein the first groove is spaced axially from the second groove along the piston and the high pressure port is in communication with the piston along: a first inlet signal line arranged to pressurize the first groove when the first head portion of the piston is at a first end of the first piston cavity; and a second inlet signal line arranged to pressurize the second groove when the first head portion of the piston is at a second end of the first piston cavity. 
     
     
         6 . The gas-driven compressor system of  claim 3 , wherein the first and second grooves are included on the second head portion of the piston. 
     
     
         7 . The gas-driven compressor system of  claim 1 , further comprising:
 a lever that couples the first head portion to the second head portion.   
     
     
         8 . The gas-driven compressor system of  claim 1 , wherein the first head portion of the piston separates the first piston cavity into a first volume and a second volume;
 wherein the shuttle valve in the first position provides the pressurized inlet flow to the first volume and vents the second volume to the low pressure port, to move the piston in a first direction; and   wherein the shuttle valve in the second position provides the pressurized inlet flow to the second volume and vents the first volume to the low pressure port, to move the piston in a second, opposite direction.   
     
     
         9 . A method of compressing a fluid using a process gas driven compressor, comprising:
 providing a high pressure port of a compressor body in communication with a first pressure;   providing a low pressure port of the compressor body in communication with a second pressure; and   moving a first piston with reciprocating movement within a first piston cavity, by moving a shuttle valve in response to a pressure differential between the high pressure port and the low pressure port, the movement of the shuttle valve selectively directing pressurized fluid from the high pressure port to opposite sides of the first piston within the first piston cavity, dependent on a position of a piston assembly that includes the first piston;   the movement of the first piston moving a second piston of the piston assembly with reciprocating movement in a second piston cavity to compress a fluid within the second piston cavity.   
     
     
         10 . The method of  claim 9 , further comprising:
 aligning a first circumferential groove of the piston assembly with a first shuttle valve signal line when the piston assembly is in a first position, to direct the pressurized fluid from the high pressure port to a first side of the shuttle valve, to move the shuttle valve from a first position to a second position; and   aligning a second circumferential groove of the piston assembly with a second shuttle valve signal line when the piston assembly is in the second position, to direct high pressure fluid to a second side of the shuttle valve to move the shuttle valve from the second position back to the first position.   
     
     
         11 . The method of  claim 9 , further comprising:
 discharging the compressed fluid from the second piston cavity, through a compressor outlet port, when the compressed fluid reaches a predetermined threshold pressure.   
     
     
         12 . The method of  claim 9 , further comprising:
 selectively blocking, with the piston assembly, fluid connection between the high pressure port and shuttle valve signal lines during the reciprocating movement of the first and second pistons.   
     
     
         13 . The method of  claim 9 , wherein drawing fluid into the second piston cavity includes:
 drawing fluid through an inlet port and a first check valve into the second piston cavity during movement of the piston from the first position to the second position.   
     
     
         14 . The method of  claim 9 , wherein the fluid compressed in the second piston cavity is further compressed in a second stage compression by the reciprocating movement of the piston assembly. 
     
     
         15 . The method of  claim 14 , wherein the reciprocating movement of the piston assembly directs the compressed fluid from the second piston cavity to a third piston cavity to be compressed by the reciprocating movement of the piston assembly. 
     
     
         16 . A gas-driven compressor system, comprising:
 a high pressure port;   a low pressure port;   a piston assembly, including:
 a first piston movable within a first piston cavity in response to a pressure differential between the high pressure port and the lower pressure port; and 
 a second piston moveable within a second piston cavity by movement of the first piston, to compress a fluid in the second piston cavity; and 
   a shuttle valve movable between a first position and a second position in response to the pressure differential between the high pressure port and the low pressure port to cause reciprocating movement of the piston assembly by selectively directing pressurized fluid from the high pressure port to opposite sides of the first piston, dependent on a position of the piston assembly.   
     
     
         17 . The gas-driven compressor system of  claim 16 , further comprising:
 a lever mechanically coupled between the first piston and the second position to multiply a force applied by the first piston to the second piston.   
     
     
         18 . (canceled) 
     
     
         19 . The gas-driven compressor system of  claim 16 , wherein the second piston includes a first diaphragm, and a second diaphragm secured together by a piston rod. 
     
     
         20 . The gas-driven compressor system of  claim 19 , wherein the first diaphragm forms a first chamber including an inlet port and an outlet port, and wherein the second diaphragm forms a second chamber including a port open to the atmosphere.