Cryogen pump

Abstract

A cryogen pump, including: a pump section that includes: a bellow with an inlet opening at a first end and an exit opening, the inlet opening in direct fluid communication with a volume of a cryogen, the exit opening at least in fluid communication with a second end of the bellow opposing the first end, a pair of plugs configured to sealingly close the opposing ends of the bellow, the pair of plugs cooperating so that when one plug sealingly closes one of the ends, the other end of the bellow is open; and a drive section configured to drive the pump section in a reciprocating manner so as to move the plugs.

1 . A cryogen pump, comprising:
 a pump section that includes:   a bellow with an inlet opening at a first end and an exit opening, the inlet opening in direct fluid communication with a volume of a cryogen, the exit opening at least in fluid communication with a second end of the bellow opposing the first end,   a pair of plugs configured to sealingly close the opposing ends of the bellow, the pair of plugs cooperating so that when one plug sealingly closes one of the ends, the other end of the bellow is open; and   a drive section configured to drive the pump section in a reciprocating manner so as to move the plugs.   
     
     
         2 . The pump of  claim 1 , further comprising a container configured to retain the volume of a cryogen, wherein the bellow is submerged in the cryogen when the volume of cryogen is retained such that the inlet opening is disposed in the cryogen, and wherein, when the inlet opening is in an open condition, cryogen flows into the bellow. 
     
     
         3 . The pump of  claim 1 , wherein the bellow is a first bellow, and wherein the pump section includes a second bellow surrounding the first bellow and spaced from the first bellow by a vacuum space that insulates the first bellow. 
     
     
         4 . The pump of  claim 1 , wherein the drive section translates rotational motion into reciprocating, linear motion that is communicated to the plugs. 
     
     
         5 . The pump of  claim 1 , wherein the drive section includes a pneumatic piston that yields reciprocating, linear motion that is communicated to the plugs. 
     
     
         6 . A cryogen pump, comprising:
 a pump section that includes
 a cylinder having an inlet opening in communication with a cryogen and an exit valve, and 
 a piston having a tunnel extending therethrough, the piston configured to travel reciprocally in the cylinder along a travel axis therein between
 a load condition in which the piston is at a position of minimum displacement and the cryogen flows into the cylinder via the inlet opening and 
 a compressing condition in which the piston is at a position of maximum displacement, and the cryogen does not flow into the cylinder, and cryogen in the cylinder is compressed and pressed out of the exit valve; and 
 
   a drive section configured to drive the pump section in a reciprocating manner so as to move the piston.   
     
     
         7 . The pump of  claim 6 , further comprising a container configured to retain a volume of cryogen, wherein the cylinder is substantially submerged such that the inlet opening is under a fluid level, and wherein the exit valve is not in direct fluid communication with a retained volume of the cryogen. 
     
     
         8 . The pump of  claim 6 , wherein the cylinder is a double walled cylinder with two walls, the walls being separated by a vacuum space that insulates an interior one of the walls. 
     
     
         9 . The pump of  claim 6 , wherein the piston includes a groove that permits, by selective rotation of the piston with respect to the inlet opening, selection of an amount of the cryogen that fills the cylinder when the piston is in the load condition. 
     
     
         10 . The pump of  claim 6 , wherein the drive section translates rotational motion into reciprocating, linear motion that is communicated to the piston. 
     
     
         11 . The pump of  claim 6 , wherein the drive section includes a pneumatic piston that yields reciprocating, linear motion that is communicated to the piston. 
     
     
         12 . A pump, comprising:
 a cylinder having an inlet opening in communication with a cryogen and an exit valve; and   a piston having a pressure compensation section, the piston configured to travel reciprocally in the cylinder in a range between positions of minimum and maximum displacement,   wherein the cryogen flows into the cylinder via the inlet opening when the piston is at least near the position of minimum displacement,   wherein the cryogen does not flow into the cylinder when the piston is at least near the position of maximum displacement, and   wherein the pressure compensation section includes a passage that extends through the piston.   
     
     
         13 . The pump of  claim 12 , wherein the passage permits a gas to flow out of the piston into the cylinder when the piston moves toward the position of minimum displacement.