Manually driven transfer pump for liquefied gases

Abstract

This invention is a manually driven pump used to transfer a liquefied gas such as nitrous oxide or carbon dioxide between containers. The pump is designed to minimize friction, can be directly attached to a mother bottle, and has an automatic piston return on the pumping stroke, all of which optimize operator use for the particular gas which is being pumped. The pump is small, portable, and requires no additional power source in its operation, making it ideal for field use. The pump can be used to fill nursing bottles from a mother bottle or to raise the pressure of a nursing bottle to a desired operating level.

1 . In a pump used to transfer a liquefied gas from a first container to a second container,
 wherein said first container contains a liquefied gas in equilibrium with its vapor at a first pressure level,   and wherein said pump has a piston means,   the improvement wherein said piston means is moved by application of a manual force by an operator of said pump.   
   
   
       2 . The pump of  claim 1  wherein said pump is directly attached to said first container. 
   
   
       3 . The pump of  claim 2  wherein said pump is directly attached to said first container using an inlet fitting of said pump. 
   
   
       4 . The pump of  claim 1  wherein said second container contains a liquefied gas in equilibrium with its vapor,
 and wherein said second container has an initial second pressure and a higher desired second pressure,   and wherein said pump is operated to increase the pressure of said second container.   
   
   
       5 . The pump of  claim 1  wherein said piston means is contained in a bore of said pump,
 and wherein said piston means has a portion which passes through a sealing member,   and wherein said portion has a radial clearance to said bore,   and wherein said sealing means when relaxed has a radial thickness,   the improvement wherein said radial thickness is smaller than said radial clearance.   
   
   
       6 . The pump of  claim 5  wherein said piston has a movement in a first direction and a movement in a second direction,
 and wherein said sealing member prevents movement of said liquefied gas past said piston means when said movement in said first direction,   and wherein said sealing member allows movement of said liquefied gas past said piston means when said movement is in said second direction.   
   
   
       7 . The pump of  claim 1  wherein said liquefied gas is nitrous oxide. 
   
   
       8 . The pump of  claim 1  wherein said liquefied gas is carbon dioxide. 
   
   
       9 . The pump of  claim 1  wherein internal pressurization of said pump by said liquefied gas moves said piston means. 
   
   
       10 . The pump of  claim 9  wherein said piston moves in a first direction by said internal pressurization of said pump and in a second direction by said application of said manual force. 
   
   
       11 . The pump of  claim 9  wherein said pump has a pumping cycle consisting of a maximum displacement of said piston in a first direction and a subsequent maximum displacement of said piston in a second direction and wherein said maximum displacement of said piston in said first direction occurs due to said internal pressurization only. 
   
   
       12 . The pump of  claim 1  wherein said pump has a pumping cycle consisting of a maximum displacement of said piston in a first direction and a subsequent maximum displacement of said piston in a second direction, and wherein said pump has an actual mass transfer per cycle,
 and wherein knowledge of said actual mass transfer per cycle of said pump is used to estimate a mass which has been transferred with said pump.