JPH0427462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cryogenic freezing device that can be suitably used in cryopumps, helium liquefaction devices, and the like.

(b) Prior Art Cryopumps, small helium liquefaction equipment, etc. use small cryogenic refrigerators that utilize gas cycles such as the Gifford-McMahon cycle, the Solvay cycle, and the Stirling cycle.

By the way, conventional cryopumps, for example,
As shown in FIG. 1, there is a cold box a with heat insulation measures, cryopanels b and c disposed inside this cold box a that successively liquefy and adsorb the gas inside the box a, and this cryopanel b. , c, and a Solvay cycle type cryogenic freezing device d. The refrigeration system d includes an expander e that is connected to a generator m for energy absorption and adiabatically expands the introduced gas to lower its temperature, a regenerator f whose low temperature end is connected to the expander e, and a regenerator f. An air supply path h or suction port g2 is connected to the high temperature end of the regenerator f and communicates with the discharge port g1 of the compressor g.
and a timing valve j for selectively connecting an exhaust path i communicating with the cryopanels b and c, and a cold head k provided in the casing of the expander e can cool the cryopanels b and c. There is. However, in the conventional system, the entire cold storage device e, which is a precooling means, is housed in the cold box a, which is supposed to house the cold head h, resulting in the inconvenience that the entire cold box a becomes unnecessarily large. That is, in the conventional type, the expander and the entire precooling means are integrated in the cold head portion, which results in an increase in size and weight of the cold head portion and, by extension, the cold box a. As a result, not only does the production cost of the cold box, which is a vacuum insulated container, become high, but the main body of the cryopump, whose main component is the cold head of this refrigeration system, becomes unduly large, making it difficult to install. There are problems in that the degree of freedom is reduced and it becomes difficult to secure installation space.

(c) Purpose The present invention was made with attention to the above-mentioned circumstances, and its purpose is to provide a cryogenic refrigeration system that can reduce the size of the cold head section installed in the cold box. shall be.

(D) Structure In order to achieve the above object, the present invention provides an insulating tube communicating with the cold box outside the cold box in which the heat load such as the cryopanel, the cold head, and the expander are housed, and which communicates with the cold box. It is characterized in that part or all of the precooling means is housed within this heat insulating tube.

(E) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a schematic sectional view of the cryopump, and FIG. 3 is an explanatory diagram of its circuit. This cryopump consists of a cold box 1 that is airtight and has heat insulation measures, cryopanels 2 and 3 disposed inside this cold box 1, and an extremely low temperature pump that cools these cryopanels 2 and 3. It is equipped with a refrigeration device 4. Cryopanel 2,
3 is formed by forming a thin metal plate with good heat conduction into a cylindrical shape with a bottom, and a second-stage cryopanel 3 is disposed inside the first-stage cryopanel 2. Further, the cryogenic refrigeration apparatus 4 is of a Claude cycle type, and has a pair of expanders 5 and 6 and a high-pressure refrigerant gas A such as helium discharged from a compressor 7. an air supply path 8 for supplying to the ports 5a, 6a; an exhaust path 9 for returning the low-temperature, low-pressure refrigerant gas B discharged from the low-pressure ports 5b, 6b of each of the expanders 5, 6 to the compressor 7; A cold head 11 provided in the casing of each of the expanders 5 and 6 is provided. , 12 cool the cryopanels 2 and 3, which are the heat loads. The expanders 5 and 6 are rotary bodies 5 connected to a generator (not shown) for energy absorption.
As the rotating bodies 5c and 6c rotate, the rotating bodies 5c and 6c
Expansion chambers 5d to 5g, 6d to 6 formed around the outer periphery of
It is a rotary type that is configured so that the volume of g can be increased or decreased. And the high pressure port 5a,
6a communicates with the expansion chambers 5d, 6d whose volumes are about to increase as the rotating bodies 5c, 6c rotate, and the low pressure ports 5b, 6b communicate with the expansion chambers 5f, whose volumes are about to decrease. 5g, 6f, 6g
It has been communicated with. Further, the precooling means 10 includes each trunk 8a of the air supply path 8 and the exhaust path 9,
The main heat exchanger 13 and the first auxiliary heat exchanger 14 are interposed between the main heat exchanger 13 and the first auxiliary heat exchanger 14 interposed between the main heat exchanger 13 and the first auxiliary heat exchanger 14, and the second
and an auxiliary heat exchanger 15. A main heat exchanger 13, which is a part of this precooling means 10, is housed in a heat insulating tube 16 and is disposed outside the cold box 1. Insulation tube 16
has an outer shell 17 surrounding both the paths 8 and 9, and a vacuum heat insulating layer 18 is provided between the outer shell 17 and both the paths 8 and 9 to prevent heat from entering from the outside. be. Furthermore, if necessary, this vacuum heat insulating layer 18 is provided with a super insulation (not shown) made of aluminum foil or the like. One end of this heat-insulating tube 1 is connected to the cold box 1, and the non-heat exchanger accommodating portion 16a of the tube 16 is made flexibly deformable.

With such a configuration, the refrigeration system 4 operates a Claude cycle and continues to absorb the heat existing in its cold heads 11 and 12.
The cryopanels 2 and 3 connected to the cryopanels 2 and 3 can be cooled and function as a cryopump. Moreover, in this apparatus, the main heat exchanger 13, which is a part of the precooling means 10 of the refrigeration apparatus 4, is housed in a heat insulating tube 16 and is disposed outside the cold box 1. Therefore, the cold box 1 includes a very small auxiliary heat exchanger 14,
15, the components integrated into the cold heads 11 and 12 are small,
You can measure weight reduction. That is, in this case, most of the components integrated into the cold head 11, 12 are the expander 5,
6, making it possible to store it in an extremely small cold box 1. Therefore,
Not only can the manufacturing of the cold box 1 be facilitated to reduce costs, but also the main body of the cryopump, whose main parts are the cold heads 11 and 12 of the refrigeration device 4, can be made small and lightweight. I can do it. Therefore, the degree of freedom in installation is increased, and the installation space can be easily secured.

In the above embodiment, a part of the precooling means is arranged outside the cold box, but the present invention is of course not limited to this, and the entire precooling means is arranged outside the cold box. It may be placed outside. That is, in this case, for example, the main heat exchanger 13 shown in FIG. 2 is made slightly larger, and the auxiliary heat exchangers 14 and 15 are
will be omitted.

Further, the gas cycle is not limited to the Claude cycle, and may be, for example, a Sorbet cycle, a Gifford-McMahon cycle, a Stirling cycle, or the like. FIG. 4 shows the case where the present invention is applied to a sorbet cycle type refrigeration device 4'. In this device 4', a precooling means 24 is constituted by a heat exchanger 21 and a pair of regenerators 22 and 23. The heat exchanger 21, which is a part of the precooling means 24, is housed in the heat insulating tube 16 and is disposed outside the cold box 1. In FIG. 4, 25 is a timing valve, and 26 is a generator connected to the expanders 5 and 6. In still another embodiment of the present invention, the timing valve 25 is disposed closer to the compressor 7 than the heat exchanger 21, and the heat exchanger 2
A configuration in which 1 acts as a regenerator is also conceivable.

Furthermore, the heat load is not limited to the cryopanel, and various modifications can be made without departing from the spirit of the present invention.

Effects Since the present invention has the above-described configuration, it is possible to provide a cryogenic refrigeration apparatus that can reduce the size of the cold head portion disposed within the cold box.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing a conventional example. Second
The figure is a schematic sectional view showing one embodiment of the present invention, and FIG. 3 is an explanatory diagram of the same circuit. FIG. 4 is a schematic sectional view showing another embodiment of the present invention. 1... Cold box, 2, 3... Heat load (cryo panel), 4, 4'... Refrigeration device, 5, 6... Expander, 7... Compressor, 8... Air supply route, 9... Exhaust route,
10, 24... Precooling means, 11, 12... Cold head, 16... Insulating tube.

Claims (1)

[Claims] 1. An expander that expands and lowers the temperature of high-pressure refrigerant gas supplied from the compressor, and a regenerator that uses the cold air of the refrigerant gas derived from the expander to pre-cool the refrigerant gas introduced into the expander. Alternatively, a refrigeration system is equipped with a pre-cooling means such as a heat exchanger, and is configured so that a heat load can be cooled by a cold head provided in the vicinity of the expander, in which the heat load, the cold head, and the expander are accommodated. A cryogenic freezing apparatus characterized in that an insulating tube communicating with the cold box is provided outside the cold box, and a part or all of the precooling means is housed in the insulating tube.