JPH03199854A - Very low temperature refrigerator - Google Patents

Abstract

PURPOSE:To increase the quantity of radiation from the high temperature end portion of a pulse tube by partitioning a passage portion in parallel to the central axis of the pulse tube. CONSTITUTION:A pulse tube 8 is partitioned into passage portions 12, 12... parallel to the central axis of the pulse tube 8. In the compression process of this very low temperature refrigerator, a gaseous refrigerant compressed by the piston 3 of a compressor 1 is cooled while passing a precooling type heat exchanger 4, a cold accumulator 5 and a very low temperature end portion 7 and flows into the pulse tube 8. The gaseous compressed refrigerant which has flowed into the pulse tube 8 is fed with a pressure toward the high temperature end portion 10 and a halfway thermal diffusion to outside in a radial direction is prevented. As a result, a thermal gradient is increased from an inflow portion 9 to the high temperature end portion 10, its temperature rises and the quantity of radiation is increased whereby the refrigeration efficiency of the very low temperature refrigerator is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cryogenic refrigeration device equipped with a pulse tube.

(B) Prior Art In the conventional cryogenic refrigeration apparatus described in Japanese Patent Application Laid-Open No. 1-114670, which precedes the present invention, a pulse tube is connected to a compressor, and a gaseous The refrigerant is moved back and forth, and during the reciprocation, this gaseous refrigerant flows into the pulse tube and is compressed until it reaches the high-temperature end. By dissipating the heat of compression from this high-temperature end, the temperature is reduced to a cryogenic temperature by the amount of heat dissipated. A refrigeration device is configured to provide cooling.

However, in this type of conventional cryogenic refrigeration equipment, the entire inside of the pulse tube is one large cavity, so the gaseous refrigerant in this pulse tube does not flow in the direction of the central axis, but rather perpendicularly to the central axis. This internal heat diffusion reduces the thermal gradient between the vicinity of the inlet and the high-temperature end of the pulse tube, and as a result, the temperature rise at the high-temperature end is prevented, the amount of heat radiation decreases, and the refrigeration efficiency decreases. There are drawbacks to doing so.

(c) Problems to be Solved by the Invention The present invention solves the above-mentioned drawbacks by increasing the heat radiation amount at the high temperature end by increasing the thermal gradient near the inlet and between the high temperature end of the pulse tube. This increases the refrigeration efficiency of cryogenic refrigeration equipment.

(d) Means for Solving the Problems The present invention is constructed by sequentially communicating a compressor with a regenerator, a low-temperature end, and a pulse tube, and reciprocating gaseous refrigerant between the pulse tube and the compressor. In the pulse tube, a passage section parallel to the central axis of the pulse tube is defined inside the pulse tube.

(E) Function According to the present invention, the gaseous compressed refrigerant that has flowed into the pulse tube is guided through each passage section parallel to the central axis of the pulse tube, and is smoothly pumped toward the high-pitched end. Internal heat diffusion in the outward direction is now prevented, resulting in a larger thermal gradient towards the hot end, increasing the temperature of the hot end and increasing the amount of heat dissipation, thus reducing the cryogenic temperature. The refrigeration efficiency of the refrigeration equipment increases.

(f) Example Next, one embodiment of the present invention will be described.

In Fig. 1, (11 is a compressor), which houses a piston (3) in a cylinder (2).

(4) is a pre-cooling heat exchanger connected to the compressor (1), and is cooled by cooling water. (5) is a regenerator connected to the pre-cooling system heat exchanger (4), and stores a regenerator material (6). (7) is a low-temperature end of the heat exchanger type connected to the regenerator (5), and (8) is a stainless steel pulse tube connected to the low-temperature end (7), which carries gaseous compressed refrigerant during the compression process. It is pumped from the inlet (9) towards the hot end (lO). The hot end (10) is a pulse tube (8)
It is heated by the compression heat generated inside, and the heat is radiated to the cooling water etc. of the high temperature end heat exchanger (11).

As shown in FIG. 2, the pulse tube (8) has a passage section (1) parallel to the central axis of the pulse tube (8).
2) (121...) are formed into sections inside this pulse tube (8). Each passage section (121 (121...
... has a large number of thin tubes (1) inside the pulse tube (8).
3) (13)... are formed inside each thin tube (13) (13)... by arranging them in a high density state. Each tubule (13)! As for +31..., a configuration in which each end protrudes and extends from the end of the pulse tube (8) and communicates with the low temperature end (7) 4 is also implemented. Each passage section (12) (
12) For..., polygonal or modified cross-sectional shapes are also implemented, and pulse tubes (8
) with a honeycomb installed inside it.

In the cryogenic refrigeration system, during the compression process, the gaseous refrigerant compressed by the piston (3) of the compressor (1) is transferred to the precooling system heat exchanger (4), the regenerator (5), and the low temperature end (7). ) and flows into the pulse tube (8), the residual refrigerant in this pulse tube (8) is compressed and the heat of compression is dissipated at the high temperature end (lO), and then in the expansion process, The piston (3) is pulled up, and the gaseous refrigerant moves back and expands adiabatically within the pulse tube (8), further reducing the temperature and cooling the low temperature end (7) and regenerator (5), and returns to the compressor (1). By repeating this reciprocating cycle, the low temperature end (7)
Cryogenic temperatures below 100°C can be obtained.

Further, in the cryogenic refrigeration apparatus, the gaseous compressed refrigerant that has flowed into the pulse tube (8) during the compression process is transferred to each passage section (121 () parallel to the central axis of the pulse tube (8).
12) Guided by ..., the material is smoothly pumped toward the high temperature end (lO), and internal heat diffusion to the outside in the radial direction during pumping is prevented. As a result, as shown in Fig. 3, In addition, the thermal gradient from the inflow part (9) toward the high temperature end (10) becomes large, and compared to the conventional example shown in FIG. 4 where the thermal gradient is small, the high temperature end ( It has been experimentally confirmed that the temperature of lO increases, the amount of heat dissipated increases, and therefore the refrigeration efficiency of the cryogenic refrigeration system increases. 3 and 4, the horizontal axis represents the distance in the central axis direction, and the vertical axis represents the temperature, and the thermal gradient characteristic line (S
l) and the conventional example thermal gradient characteristic line (S2) are shown. It is guided through each passage parallel to the high temperature end and is smoothly pumped toward the high temperature end, preventing internal heat diffusion to the outside in the radial direction during pumping, and as a result, the thermal gradient toward the high temperature end is becomes larger, the temperature at the high-temperature end increases, and the amount of heat dissipated can be increased, thereby increasing the refrigeration efficiency of the cryogenic refrigeration system.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a perspective view of essential parts of the embodiment, FIG. 3 is a thermal gradient characteristic diagram of a pulse tube provided in the embodiment, and FIG. The figure is a thermal gradient characteristic diagram of a conventional pulse tube. (1)...Compressor, (5)...Regenerator, (
7)...Low temperature end, (8)...Pulse tube, (1
2)...Aisle section. Figure 1

Claims (1)

[Scope of Claims] 1) A compressor is sequentially connected to a regenerator, a low temperature end, and a pulse tube, and a gaseous refrigerant is reciprocated between the pulse tube and the compressor, wherein the pulse A cryogenic freezing device characterized in that a passage section parallel to the central axis of the pulse tube is defined inside the tube.