Auxiliary Cryogenic Cooling Systems Based on Commercial Cryo-Coolers

Abstract

A novel apparatus and method for distributing the cooling capacity provided by a commercial cryo-cooler. The cryo-cooler is connected to a first application housed in a first cryostat. A second application is provided—typically in a second cryostat. A heat exchanger is added to the first application. Circulating gas lines connect this heat exchanger to the second application contained in the second cryostat. Helium is circulated in the gas lines, with the flow of the helium being regulated so that it may be throttled between a zero flow condition and a maximum flow condition. The circulating helium gas transfers some of the available cooling capacity from the first application to the second application. This circulation regulates the temperature of both applications.

Having described our invention, we claim: 
     
         1 . A method of distributing the cooling capacity of a cryocooler from a first application located in a first cryostat to an auxiliary application located in a second cryostat, comprising:
 a, providing a first cryostat and a second cryostat;   b. providing a first application located within said first cryostat;   c. providing an auxiliary application located within said second cryostat;   d. providing a crycooler connected to said first cryostat by a delivery line and a return line;   e. said cryocooler providing a cold cryogenic gas through said delivery line and receiving said cryogenic gas through said return line;   f. providing a heat exchanger within said first cryostat;   g. providing a closed loop circulation system between said heat exchanger and said auxiliary application, said closed loop circulation system circulating helium gas;   h. providing a tunable helium flow system within said closed loop circulation system, said tunable helium flow system being capable of continuously varying the flow rate in said closed loop circulation system; and   i. using said tunable helium flow system to vary the flow rate of said circulating helium gas within said closed loop circulation system in order to maintain a desired temperature for said auxiliary application.   
     
     
         2 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 1 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive; and   b. a rotational speed of said variable speed drive is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         3 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 1 , wherein:
 a. said tunable helium flow system includes a throttling valve; and   b. a position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         4 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 1 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive;   b. said tunable helium flow system includes a throttling valve; and   c. a rotational speed of said variable speed drive is varied and said position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         5 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 1 , wherein:
 a. said cryocooler delivery and return lines are connected to a cold head connected to said first cryostat; and   b. said heat exchanger is connected to said cold head.   
     
     
         6 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 5 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive; and   b. a rotational speed of said variable speed drive is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         7 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 5 , wherein:
 a. said tunable helium flow system includes a throttling valve; and   b. a position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         8 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 5 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive;   b. said tunable helium flow system includes a throttling valve; and   c. a rotational speed of said variable speed drive is varied and said position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         9 . A method of distributing the cooling capacity of a cryocooler from a first application located in a first cryostat to an auxiliary application located in a second cryostat, comprising:
 a. providing a first cryostat and a second cryostat;   b. providing a first application located within said first cryostat;   c. providing an auxiliary application located within said second cryostat;   d. providing a crycooler connected to said first cryostat by a delivery line and a return line;   e. said cryocooler providing cold cryogenic gas through said delivery line and receiving said cryogenic gas through said return line;   f. providing a heat exchanger within said first cryostat;   g. providing a closed loop circulation system between said heat exchanger and said auxiliary application, said closed loop circulation system circulating cold cryogenic gas;   h. providing a tunable flow system within said closed loop circulation system, said tunable flow system being capable of continuously varying the flow rate in said closed loop circulation system; and   i. using said tunable flow system to vary the flow rate of said circulating cryogenic gas within said closed loop circulation system in order to maintain a desired temperature for said auxiliary application.   
     
     
         10 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 9 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive; and   b. a rotational speed of said variable speed drive is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         11 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 9 , wherein:
 a. said tunable helium flow system includes a throttling valve; and   b. a position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         12 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 9 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive;   b. said tunable helium flow system includes a throttling valve; and   c. a rotational speed of said variable speed drive is varied and said position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         13 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 9 , wherein:
 a. said cryocooler delivery and return lines are connected to a cold head connected to said first cryostat; and   b. said heat exchanger is connected to said cold head.   
     
     
         14 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 13 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive; and   b. a rotational speed of said variable speed drive is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         15 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 13 , wherein:
 a. said tunable helium flow system includes a throttling valve; and   b. a position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.   
     
     
         16 . A method of distributing the cooling capacity of a cryocooler as recited in  claim 13 , wherein:
 a. said tunable helium flow system includes a centrifugal pump attached to a variable speed drive:   b. said tunable helium flow system includes a throttling valve; and   c. a rotational speed of said variable speed drive is varied and said position of said throttling valve is varied in order to vary said flow rate within said closed loop circulation system.