 Hybrid heat pump and desiccant space conditioning system and control method |
| OF THE INVENTION Referring now to FIG. 1 there is shown in schematic form a multi wheel desiccant/... |
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| Absorption heat pump and desiccant assisted air conditioning apparatus |
| According to the first embodiment of the invention, a desiccant assisted air conditioning apparatus ... |
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| Absorption heat pump and desiccant assisted air conditioner |
| It is an object of the present invention to provide an absorption heat pump device for use in an ... |
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| Desiccant assisted air conditioning system |
| It is therefore necessary to develop a high efficiency air conditioning unit combining desiccant ... |
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| Desiccant assisted air conditioning apparatus |
| It is therefore an object of the present invention to achieve a desiccant assisted air conditioning ... |
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| System and method for controlling communication-executable refrigerator |
| Therefore, the present invention has been made in view of the above problems, and it is an object ... |
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| Film cartridges, films and cameras adapted for use therewith |
| It is a general object of the present invention to provide film cartridges, films and cameras ... |
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| Reflective beam concentrator |
| I claim: 1. A reflective beam concentrator consisting of an annular concave mirror and a conical ... |
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| Conical beam concentrator |
| I claim: 1. A conical beam concentrator comprising a single lens (1) having a planar section (2) ... |
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Method and a device for precooling the helium tank of a cryostat
| Details |
Inventors: Mraz, Beat; Notzli, Christoph; Ungricht, Ernst; Marek, Daniel;
Assignee: Spectrospin AG (CH)
Primary Examiner: Capossela; Ronald C.
Assistant Examiner:
Attorney, Agent or Firm: Hackler; Walter A.
In a method and a device for precooling the helium tank of a cryostat, in particular one for accommodating a superconductive magnet coil, contamination of the helium tank is avoided by the fact that helium gas is cooled down to the temperature of boiling nitrogen in a closed circuit, the helium gas is then circulated through the helium tank and thereafter cooled down again to the temperature of boiling nitrogen. The helium tank is cooled by means of the helium gas, which has a temperature of 77 K, until the tank has reached that temperature. The interior of the helium tank getting into contact exclusively with helium, the helium tank can be filled with liquid helium immediately after it has reached the precooling temperature, without the need to clean the tank first. |
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DETAILED DESCRIPTION Now, it is the object of the present invention to provide a method and/or a device for precooling the helium tank of a cryostat which avoid the before-mentioned disadvantages.
The method according to the invention achieves this object by the fact that helium gas is cooled down to the temperature of boiling nitrogen in a closed circuit, that the helium gas is then circulated through the helium tank and thereafter cooled down again to the temperature of boiling nitrogen.
The method according to the invention, therefore, provides that the helium tank of the cryostat is passed by helium gas which has been cooled down previously to the temperature of boiling nitrogen, i.
e.
to a temperature of 77 K.
On its path through the helium tank, the helium gas absorbs heat and then leaves the helium tank in this heated-up state in order to be cooled down subsequently to the temperature of boiling nitrogen during which process the heat previously absorbed is given off again.
Thanks to this circuit, during which helium gas at a temperature of 77 K is circulated through the helium tank, thermal energy is withdrawn from the tank until it finally has been cooled down to the same temperature of 77 K.
This method provides the considerable advantage that the interior of the helium tank gets into contact exclusively with helium so that it cannot be contaminated by nitrogen or other gases.
And given the fact that no other gas than helium gets into contact with the helium tank during this process, the tank need not be cleaned after it has been cooled down to a temperature of 77 K, but can be filled with liquid helium directly following the cooling-down process.
Now, a considerably smaller quantity of liquid helium is required to cool the magnet coil in the helium tank, and the latter as well, down from the temperature of 77 K to a temperature of 4 K, since the greatest part of the total heat of the cryostat has already been withdrawn by the fact that the tank has been cooled down before to a temperature of 77 K
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