Low-loss closed-loop supply system for transferring liquified gas from a large container to a small container

Abstract

A liquified gas is transferred from a supply tank to a saddle tank by gravity flow. After a predetermined amount of the liquified gas has been transferred, gravity flow is stopped and pressure is equalized between the saddle tank and the container to be filled. Thereafter, vapor from the container flows into the supply tank causing liquified gas to flow from the saddle tank into the container. After the container has received a predetermined amount of liquified gas, liquid flow ends and pressure is equalized between the supply and saddle tanks. BACKGROUND OF THE INVENTION

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A low-loss method of filling a container for liquified gas from a supply system comprising the steps of: transferring liquid from a first vessel into a second vessel, and transferring vapor from said second vessel to said first vessel whereby the pressure between said first and second vessels remains equalized as said liquid is transferred;   isolating said first vessel from said second vessel;   equalizing the pressure between said second vessel and said container for liquid gas;   connecting said first vessel to said container for liquified gas to permit vapor to flow therebetween;   connecting said second vessel to said container for liquified gas so that said liquid from said second vessel flows into said container for liquified gas, and maintaining the connection between said first vessel and said container for liquified gas to permit vapor from said container for liquified gas to flow into said first vessel.   
     
     
       2. A low-loss method of filling a container for liquified gas from a supply system as claimed in claim 1 including the additional step of: disconnecting said container for liquified gas from said first and second vessels.   
     
     
       3. A low-loss method of filling a container for liquified gas from a supply system as claimed in claim 1 wherein said liquified gas is liquid oxygen. 
     
     
       4. The method of claim 1 including the step of connecting the vapor phase of said container to the vapor phase of said second vessel during said step of equalizing the pressure between said second vessel and said container. 
     
     
       5. The method of claim 1 including the step of isolating the vapor phase of said second vessel from the vapor phase of said container after said step of equalizing the pressue between said second vessel and said container. 
     
     
       6. A low-loss method of filling a container for liquified gas from a supply system as claimed in claim 1 wherein said liquid is transferred from said first vessel into said second vessel by gravity. 
     
     
       7. A low-loss method of filling a container for liquified gas from a supply system as claimed in claim 6 wherein said liquified gas is liquified oxygen. 
     
     
       8. The method of claim 1 including the step of condensing vapors from at least one of said first and second vessels. 
     
     
       9. The method of claim 8 including the step of returning the condensate to the liquid phase of at least one of said first and second vessels. 
     
     
       10. The method of claim 1 including an additional equalization step after said container is filled wherein the vapor phases of said first and second vessels are connected to bring the pressure of said second vessel down to the pressure of said first vessel. 
     
     
       11. The method of claim 10 including the step of condensing vapors from at least one of said first and second vessels. 
     
     
       12. The method of claim 11 including the step of returning the condensate to the liquid phase of at least one of said first and second vessels. 
     
     
       13. A pump-free low-loss supply system for filling a container for liquified gas comprising: a supply tank for housing said liquified gas;   an intermediate tank for temporarily storing said liquified gas;   first interconnecting means for interconnecting said intermediate tank to said supply tank for allowing liquid to flow from said supply tank to said intermediate tank and vapor to flow from said intermediate tank to said supply tank; and   second interconnecting means for interconnecting said intermediate tank and supply tank to said container so as to allow gas from said container to flow from said container to said intermediate tank and thereafter allow liquid from said intermediate tank to flow into said container while vapor from said container for liquified gas flows into said supply tank, said liquid being transferred pump-free from said supply tank to said container.   
     
     
       14. A low-loss supply system for filling a container for liquified gas as claimed in claim 13 wherein said liquified gas is liquified oxygen. 
     
     
       15. A low-loss supply system for filling a container for liquified gas as claimed in claim 13 wherein said intermediate tank is mounted at a lower elevation than said supply tank whereby liquid flows from said supply tank to said intermediate tank by gravity. 
     
     
       16. A low-loss supply system for filling a container for liquified gas as claimed in claim 15 wherein: said supply tank includes an input/output vapor line and an input/output liquid line;   said intermediate tank includes an input/output vapor line and an input/output liquid line; and,   said first interconnecting means comprises:   a first valve;   a first pipeline for interconnecting said first valve, said input/output vapor line of said supply tank and said input/output vapor line of said intermediate tank;   a second valve; and,   a second pipeline for interconnecting said input/output liquid line of said supply tank, said second valve and said input/output liquid line of said intermediate tank.   
     
     
       17. A low-loss supply system for filling a container for liquified gas as claimed in claim 16 wherein said second interconnecting means comprises: a third valve;   a fourth valve having first and second terminals on a first side and first and second terminals on a second side, the first terminal on said first side connected through an intermediate valve to the first terminal on said second side and the second terminal on said first side connected through another intermediate valve to the second terminal on the second side;   a third pipeline, said third pipeline interconnecting   the input/output liquid line of said supply tank, said third valve and the first terminal on the first side of said fourth valve;   a fourth pipeline, said fourth pipeline interconnecting the input/output liquid line of said intermediate tank to the second terminal on the first side of said fourth valve; and,   a fifth valve, interconnecting the first and second terminals on the first side of said fourth valve, the first and second terminals of the second side of said fourth valve connected to said container.   
     
     
       18. A low-loss supply system for filling a container for liquified gas as claimed in claim 17 wherein said liquified gas is liquified oxygen. 
     
     
       19. A low-loss supply system for filling a container for liquified gas as claimed in claim 17 wherein said supply tank and said intermediate tank are cryogenic storage vessels and wherein said first, second, third and fourth pipelines are insulated pipelines. 
     
     
       20. The structure of claim 13 including condensing loop means for condensing vapors from at least one of said tanks. 
     
     
       21. The structure of claim 20 wherein said loop means is located so that condensed vapors are returned to the liquid phase of one of said tanks. 
     
     
       22. The structure of claim 20 wherein said loop means is located inside of one of said tanks. 
     
     
       23. The structure of claim 13 including: a source of condensing fluid;   a condenser; and   means for directing said condensing fluid to said condenser located so that vapors from at least one of said tanks is brought into contact therewith and causes said vapors to condense.   
     
     
       24. The structure of claim 23 wherein said condenser is located so that condensed vapors are returned to the liquid phase of one of said tanks. 
     
     
       25. The structure of claim 23 wherein said condenser is located inside of one of said tanks. 
     
     
       26. The structure of claim 13 wherein said second interconnecting means includes a pipeline for connecting the vapor phase of said container to the vapor phase of said intermediate tank. 
     
     
       27. The structure of claim 26 including a one-way valve in said pipeline for preventing the flow of gas in said pipeline in a direction out of said intermediate tank. 
     
     
       28. The structure of claim 26 including: a source of condensing fluid; a condenser, and,   means for directing said condensing fluid to said condenser located so that vapors from at least one of said tanks is brought into contact therewith and causes said vapors to condense.   
     
     
       29. The structure of claim 28 wherein said condenser is located so that condensed vapors are returned to the liquid phase of one of said tanks. 
     
     
       30. The structure of claim 29 wherein said condenser is located inside of one of said tanks. .Iadd. 31. A low-loss method of filling a container for liquified gas from a supply system comprising the steps of: transferring liquid from a first vessel into a second vessel, and transferring vapor from said second vessel to said first vessel whereby the pressure between said first and second vessels remains equalized as said liquid is transferred;   isolating said first vessel from said second vessel;   connecting said second vessel and said container for liquified gas to equalize the pressure between said second vessel and said container for liquified gas;   connecting said first vessel to said container for liquified gas to permit vapor to flow therebetween;   vapor thereby being permitted to flow from said container for liquified gas into said first vessel and liquid thereby being permitted to flow from said second vessel into said container for liquified gas..Iaddend..Iadd. 32. The method of claim 31 including the step of permitting the pressure of said second vessel to become higher than the pressure of said container for liquified gas. .Iaddend. .Iadd. 33. A pump-free low-loss supply system for filling a container for liquified gas comprising:   a supply tank for housing said liquified gas;   an intermediate tank for temporarily storing said liquified gas;   first interconnecting means for interconnecting said  intermediate tank to said supply tank for allowing liquid to flow by gravity from said supply tank to said intermediate tank and vapor to flow from said intermediate tank to said supply tank; and   second interconnecting means for interconnecting said intermediate tank and supply tank to said container so as to allow liquid from said intermediate tank to flow into said container and vapor from said container for liquified gas to flow into said supply tank, said liquid thereby being transferred pump-free from said supply tank to said container. .Iaddend..Iadd. 34. The system of claim 33 including means for raising the pressure of said intermediate tank above the pressure of said container for liquified gas. .Iaddend.