JPS603158B2 - Heat exchanger for helium refrigerator - Google Patents

Description

[Detailed description of the invention] This invention relates to a heat exchanger for a helium refrigerator.

In general, Collins type heat exchangers and plate-fin type heat exchangers are well known as representative heat exchangers for helium refrigerators.

These two types of heat exchangers are unsuitable for use in helium refrigeration and liquefaction machines, which require smaller size and lighter weight, for the following reasons: However, it was difficult to say that it was completely satisfactory. In other words, in a Collins-type heat exchanger, a pipe is installed in an annular space formed between an inner cylinder and an outer cylinder that constitute an outer container so that this annular space forms a single spiral flow path. Arranged in a spiral, high-pressure helium is passed through the pipe, and low-pressure helium is passed through the spiral flow path formed in the annular space, and heat is exchanged between the helium through the arm of the pipe. It is configured as follows.

Since the Collins-type heat exchanger configured in this way has a cylindrical external shape, it is possible to arrange multiple heat exchangers with different diameters concentrically, and as a result, heat exchangers with low temperature levels can be delivered. It is said that by arranging the exchanger in the center and having the heat exchanger on the outer periphery function as a heat shield plate, there is an advantage that heat intrusion into the low-temperature heat exchanger can be kept to a maximum of 4.5 times. However, in order to form a single spiral flow path within the annular space mentioned above, the Collins type heat exchanger is designed so that there is no gap between the outer surface of the pipe and the inner surfaces of the inner and outer cylinders. Since this type of heat exchanger needs to be manufactured, it is very complicated to work with, and therefore the heat exchanger itself has the disadvantage of being expensive. On the other hand, a plate-fin type heat exchanger is constructed by stacking a plurality of flat partition plates provided with corrugated fins.

This heat exchanger has the advantage that it can be easily manufactured because the technology of integrating and brazing the fins and the partition plate in a vacuum furnace has advanced, and the price can be made low. However, the conventional plate-fin type heat exchanger has a rectangular parallelepiped external shape, and has a structure in which the inside is divided by parallel partition walls and corrugated fins are housed in each space. The configuration was such that high-pressure helium and low-pressure helium alternately flowed through a plurality of spaces, that is, helium flow passages. Therefore, unlike the Collins type, it does not have a structure that reliably isolates the helium flow path in the low-temperature part from the outside. Storing a plate-fin type heat exchanger had the disadvantage of creating unnecessary space. In addition to the above-mentioned heat exchangers, the Collins type and plate-fin type heat exchangers have various advantages and disadvantages, but a heat exchanger having both of these advantages has not yet appeared or been proposed.

The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a small and lightweight heat exchanger for a helium refrigerator that has the advantages of both Collins type and plate fin type heat exchangers.

Another object of the present invention is to make the vacuum chamber of a helium refrigerator more compact by reducing the size and weight of the heat exchanger, thereby reducing the volume and weight of the entire refrigerator. Embodiments of the heat exchanger of the present invention will be described below with reference to the drawings.

FIG. 1 shows a combination of heat exchangers according to an embodiment of the present invention.

As shown in the figure, the heat exchangers 2 and 4 of the present invention have an outer shape in which a portion of a cylindrical shape having a predetermined thickness is taken out. That is, these heat exchangers 2 and 4
A pair of side plates 8, 10 having the same circular arc shape are arranged to face each other, and the space between the side plates 8, 10 is formed by an aluminum partition wall 12 also having the same circular arc shape.
The opening of the space is closed by an arc-shaped upper bar 14 and a lower bar 16. In the illustrated example, the interior of the heat exchangers 2 and 4 is divided into two spaces 20 and 22 by one partition wall 12, but it is clear that the interior of the heat exchangers 2 and 4 may be divided into more spaces by a larger number of partition walls 12. be. Also, for convenience of explanation in the drawings, headers are connected to both ends of the heat exchanger 2 in the circumferential direction, that is, end faces indicated by 6 and 18 in the drawings, and allow helium at different pressures to flow into the two spaces. is omitted. Said two spaces 20,2
Inside the 2 is a wavy aluminum plate fin 24.
, 26 are arranged to form a narrower space and a helium flow path. In the illustrated example, the outer space 20 is a high-pressure helium flow path, the inner space 22 is a low-pressure helium flow path, and both helium refrigerants flow in an arc shape. In another embodiment (not shown), the arrangement of the wave-shaped fins may be changed so that the helium refrigerant does not flow in a circular arc shape, but instead flows from the lower bar to the upper bar, or vice versa, in a substantially cylindrical heat exchanger. It may flow along the axis. Alternatively, the high-pressure helium and low-pressure helium may be configured to flow in different directions. The heat exchangers 28, 30 shown in FIG.
The heat exchanger 2 shown in the figure is divided into two parts,
By combining both heat exchangers 28 and 30, it becomes a substantially cylindrical shape.

The structure of each heat exchanger 28, 30 is the same as that of the heat exchanger 24 already described.
The same parts are given the same reference numerals. As previously mentioned, the heat exchanger according to the present invention is a plate-fin type that is easy to manufacture, and the external shape of the heat exchanger body is a part of the circumferential direction of a cylindrical body having a predetermined thickness. Because of the shape, many heat exchangers can be arranged in the same circular shape, and when placed in the cylindrical vacuum chamber of a helium refrigerator, unnecessary space is not created, and it is possible to arrange them inward. When the heat exchanger is used for low-temperature use, the heat exchangers arranged outward function as a heat shield and can prevent heat from entering the heat exchanger in the low-temperature section. As described above, according to the present invention, a small and lightweight heat exchanger for a helium refrigerator with excellent heat exchange efficiency is provided.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing an embodiment of the heat exchanger of the present invention. FIG. 2 is a perspective view schematically showing another embodiment of the invention. 2, 4... Heat exchanger, 6... Side part,
8, 10... Side plate, 12... Bulkhead, 1
4,16,18...bar, 20,22...space, 24,
26...Plate fin, 28,30...
···Heat exchanger. Ticket 1 picture hair Z mouse

Claims (1)

[Claims] 1 The external shape of the heat exchanger main body is formed in a shape obtained by taking out a part of the circumferential direction of a cylindrical body having a predetermined thickness, and a first helium flow path is provided in the heat exchanger main body that approximates the external shape. and a second helium flow path are formed through a partition wall with good thermal conductivity, and wave-shaped fins are respectively arranged in the first and second helium flow paths. Machine heat exchanger.