JPS60169059A - Helium liquefying refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a helium liquefaction refrigeration system that utilizes the magnetocaloric effect, and particularly to a helium liquefaction refrigeration system that is capable of improving refrigeration efficiency.

[Background technology of the invention and its problems]

BACKGROUND ART Conventionally, helium liquefaction refrigeration equipment that utilizes the magnetocaloric effect of a magnetic material has been known. This refrigeration system uses a magnetic material that cools through adiabatic demagnetization to condense helium gas, which is the object to be cooled, and is said to have a higher refrigerating capacity per unit than ordinary compression type refrigeration equipment. It has advantages.

By the way, in the case of such a refrigeration system, a magnetic material such as trinium gallium garnet, that is, a working material, is rapidly introduced into a magnetic field to adiabatically magnetize it, and the heat generated in the working material at this time is absorbed. There is an exhaustion process in which heat is released to the outside, and an endothermic process in which the working material placed inside the magnetic field (+L) is rapidly introduced outside the magnetic field to adiabatic quenching, and the helium gas is cooled by the endothermic action of the working material at this time. It is necessary to perform the two heat exchange processes alternately, that is, it is necessary to place the work material within the magnetic field and place it outside the magnetic field.

For this reason, in conventional devices, the work material is fixed and a magnetic field generator made of a superconducting coil is fixed around the work material, and the magnetic field generator is energized during adiabatic magnetization. At the same time, the JFI thermal system is operated, and during adiabatic demagnetization, the energization of the magnetic field generator is stopped and the operation of the heat exhaust system is also stopped, and this control is performed alternately.

With this configuration, the freezing cycle can be executed using only electrical control, making the entire system more compact, and since the work material is stationary, the reliability of the heat exhaust process can be increased. There are advantages such as jin.

However, on the other hand, since the magnetic field generator, that is, the super 1L coil is energized in pulses, there is a problem that the loss in the energization process of the superconducting coil is large and the freezing efficiency is significantly low. Ta.

Therefore, in order to solve this problem, the magnetic field generator is always energized, and the workpiece is moved mechanically to remove the inside and outside of the magnetic field generated by the magnetic field generator. It is conceivable to alternately position them outside. However, with this configuration, heat must be removed from the moving work material, which poses a problem as to how to configure the heat exhaust system.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems (i).
The purpose of this is to use a method that constantly energizes the magnetic JXA generator and moves the working material mechanically, which allows heat to be efficiently exhausted from the working material during adiabatic magnetization. It is an object of the present invention to provide a helium liquefaction refrigeration device and y capable of improving refrigeration efficiency.

[Summary of the invention]

The present invention constantly energizes the magnetic field generator disposed on the upper blade of the helium 4n, and directs the work material into the magnetic field generated by the helium generator and outside the magnetic field in the space leading to the helium case. in which the working material is moved mechanically in an alternating manner, and when the working material is located in a magnetic field, a member with good thermal conductivity is provided in close proximity to the working material via a helium gas layer having a thickness of 500 μm or less, Furthermore, the present invention is characterized in that a means is provided for transferring the heat generated by the working substance to the outside of the helium tank via the helium gas layer and the well-thermal conductive member.

〔Effect of the invention〕

When removing heat from a moving work material and discharging it, moving the system for discharging heat together with the work material can avoid complicating the structure. There is no way to avoid heat invading the area.

However, as in the device of the present invention, a member with good thermal conductivity is provided that is sufficiently close to the working material through a helium gas layer only when the working material is located in a magnetic field, and the upper t4c helium gas nozzle and the above If heat is exhausted through part U, it is thinly constructed, and there is no need to move the above-mentioned good heat conductive member, that is, the entire heat exhaust system together with the workpiece (6). The helium gas layer, especially with the thickness mentioned above, acts as a good heat conductor.Therefore, good heat exhaustion can be achieved without complicating the 41q structure.
You can do it. In addition, for adiabatic demagnetization iq, the working material and a 11μ material with good thermal conductivity can be (stretched) at a distance of 1ζ1f. Therefore, 1′:)i
, heat can be prevented from entering the work material through the conductive member. Therefore, while suppressing the complexity of construction and heat infiltration, this method of moving the work material can be utilized to the fullest extent, which is the inherent disadvantage of this method in terms of refrigeration efficiency. can be done.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 indicates an outer tank, and 2 indicates an inner tank accommodated within the outer tank 1. The outer tank 1 is entirely formed of a member with poor thermal conductivity.

In addition, only the upper wall 2a of the inner chamber 2 is made of a thick material with good thermal conductivity, and the remaining part is made of a material with poor thermal conductivity. A space 3 existing between the outer tank 1 and the inner tank 2 is evacuated and formed into a vacuum insulation JΔ.

In the 211th place of the upper wall 2a of 41!12 above, the upper 1:
Cylindrical portions 4a and 4 that connect the upper and lower sides in the figure of 21N
b protrudes downward in parallel and with the same dimensions. These cylindrical parts 4&, 4b are thickly formed from the same material as the material forming the upper wall 28 or a material with better thermal conductivity than that, and have a predetermined length from the lower end thereof. Part 5a.

The inner diameter of 5b is smaller than other parts. The upper and lower inner edges of the portions 5h and 5b are each formed into a tapered curve.

Thus, a helium tank 6 is housed in the inner tank 2 via a vacuum insulation j and i between the inner tank 2 and the inner tank 2. The helium tank 6 is entirely made of a non-magnetic and heat-conductive material, and is specifically constructed as follows. That is, the tank body 7, the partition wall 8 provided to vertically divide the interior of the tank body 7 into two, and the upper wall 9 of the tank body 7 are provided to connect the cylindrical portions 4a and 4b without contacting each other. The holes 117a and 10h are fitted into the holes 117a and 10a.

The cylinders 11a, 11b extend the edge 141 (of the partition wall 8) at the top ridge of the partition wall 8, and these cylinders 11a, ll
Flange portions 12a, 12b, and 13a are provided on the outer circumferential surface of b in a two-stage, 1"-4 configuration projecting in the vertical direction.

13b. And “;1 body 1
1 a.

At the outer periphery of 11b, between the flanges 12a, 12b and the upper wall 9, there are main magnetic field generators ``1''), tl', ``2''.
Coils 14a and 14b are attached, and the twisted cylinder 11
h, between the flanges 13a, 13b and the partition wall 8 on the outer periphery of llb, there is a
ff, i Uni 41115m, 15b are installed. Each superconductive coil 14g, 14b and 15a.

15b uses the so-called liquid helium II at the bottom of the helium tank 6 as a cooling source, and is cooled to a required temperature via a helium 4i'J 4+5 material. The super'l pillar conducting coils 15a, 15b are super mountain: Ujun coils 14a, 1.
A magnetic field in the opposite direction to the magnetic field generated by the coil 4b is generated, thereby causing the ultra-iL barrel coil 14a.

The lower intensity gradient of the magnetic field generated in 14 hours is made steeper.

The partitions (holes 16a, 16, which are larger than the inner diameter of the portions 5a, 5b and smaller than the outer diameter of the cylindrical portions 4a, 4b, are provided at positions facing the lower end surfaces of the joint portions 4m, 4b of the layer 8.
b is formed.

A cylindrical body 17a formed of a material with poor thermal conductivity is provided at the inner edge of the holes 16a and 16b.

17b is connected to the lower end (1111), and the upper end sides of these cylindrical bodies 17a and 17b are airtightly connected to the lower end surfaces of the cylindrical parts 4a and 4b, respectively. , 4b, ft'+) body 1
The same diameter as the inner diameter of holes 7a and 17b (D) The holes 18h and 18b are provided coaxially.The edges of the holes 18a and 18b and the upper edges of the cylindrical parts 4a and 4b and kJ are made of a material with poor thermal conductivity. The cylinders 19th and 19b are airtightly connected to each other.

That is, the hole 18a1 cylinder body 19a1 cylinder part 4&, cylinder body 17
a and the hole 16h are coaxially connected to form a cylinder 20h that communicates the outside with the space in which liquid helium (I) is accommodated. 16b are coaxially connected to form a similar cylinder 20b.

Rods 21h and 21b are inserted into each of the cylinders 20a and 20b from the outside so as to be movable up and down.

The rods 21a and 21b are members having poor thermal conductivity, and are the aforementioned cylindrical portions 4a.

Approximately 200 μm from the inner diameter of portions 5a and 5b in 4b
It is formed into a cylindrical shape with a small outer diameter. At the lower ends of the neck rods 21a, 21b, working materials 22a, 2 are formed by processing a magnetic material such as gadolinium gallium garnet into a columnar shape with an outer diameter equal to the outer diameter of the rods 21a, 21b.
2b is inserted in the 11″:L column.

Support members 23h and 23b are attached to the ends of the rods 21h and 21b located outside the outer tank 1.
Racks 24'a and 24b are fixed to the distal ends of 3a and 23b in a mutually opposing relationship. At a central position between the racks 24a and 24b, a shaft 25 extending in the direction of firing directly with respect to the plane of the paper is rotatably supported by a bearing (not shown). A pinion 26, which is commonly engaged with the racks 24a and 24b, is fixed to a portion of the outer periphery of the shaft 25 located approximately 1" between the racks 24& and 24b. Note that the binion 26 and each rack 241L, 24b match the IQ relationship as follows. That is, the workpiece '1+(22a, 2zb) inserted into the lower end of the rod 21a r 21b
is the manure, and the cylindrical part 4a (4
The top dead center is defined as when it is located inside part 5a (5b) of b), and it is also located between the partition wall 8 and the liquid level of liquid helium jI as shown in Figure C11. When one of the working materials falls down and is located at the top dead center, the other working material is located at the bottom dead center. Another pinion (not shown) is fixed to the outer periphery of the shaft 25, and this pinion meshes with a rack (not shown). The rack is connected to a dynamic drive source (not shown).

Thus, a thick interior 31 is formed at the peripheral edge of the upper wall 2a of the inner tank 2, and a cylindrical recess 32 with an opening facing laterally is formed in the thick wall 31. ing. Outside (mortar 1
A hole 33 with a larger diameter than the fourth part 32 is formed in the side wall of the hole 33 facing the recess 32, and a flange 34 projecting outward is connected to the flange 34 on the periphery of the hole 33. Then, the fourth part 3 is passed through the above seven runs 34.
2, one end side of a heat transfer rod 35 formed of a material with good thermal conductivity is lowered and enlarged. A flange portion 36 is provided on the outer periphery of the heat transfer rod 35, and this flange portion 36 connects to the flange 3 through a sealing material.
4 is fixed with +F+il. The other end of the heat transfer rod 35 is thermally connected to a cooler 37 such as a small refrigerator. In FIG. 1, 38h and 38b indicate sealing members. Next, the operation of the helium liquefaction refrigeration system constructed as described above will be explained.

First, superconducting coils 14a, 14b and 151L,
It is assumed that a persistent current that can generate a magnetic field having the above-mentioned relationship flows through 15b. It is assumed that the cooler 37 is still in operation.

When the cooler 37 operates, heat is removed from the upper wall 2a via the heat transfer rod 35f. Therefore, the cylindrical portions 4a, 4
b is also kept at a sufficiently low temperature.

When the reciprocating drive source is operated in such a state II (1), the pinion 26 moves in the reciprocating direction as shown by the solid line arrow P in FIG.
M Rotate. As a result, the rods 21m and 21b are
As shown by the solid line arrows Q, , Q in the figure, it is raised to f. That is, when the rod 21a starts to descend, the mouth and door 21b start to rise, respectively, moving up and down to the position 19j. Therefore, the workpieces '41122a and 22b move up and down with a phase difference of 180 degrees between the top dead center and the bottom dead center. '' When it is located at the second dead center, it is completely located within the magnetic field generated by the superconducting coil, as seen in the working material 22th in FIG. Therefore, the insulation M
It becomes a state of transformation. On the other hand, when it is located at bottom dead center,
As seen in the working material 22b in FIG. 1, it is located outside the magnetic field. Therefore, it becomes an adiabatic demagnetized state. In the adiabatic demagnetization state, the working material 22b (22a) absorbs heat.

For this reason, the helium gas floating on the pipe at night is 52% of the workpiece. 'b(2,?a) is condensed into Table 1IIi.

The droplets formed by this condensation fall naturally and liquefy the helium.

Therefore, when the work material 22a (22b) becomes adiabatic and magnetized as described above, it generates heat. This heat is led to the outside in the following manner. That is, workpiece% 22a, 22
When b is located at top dead center, part 58.5 is always
There are two positions within b. The inner diameter of portions 5a and 5b is
In this embodiment, the outer working materials 22a, 22b are approximately 2
It is set to a value 00 μm larger. For this reason, when the workpieces 22b, 22b are located within the portions 5m, 5b, approximately 100μ
This means that a gap G of m exists. Parts 5h, 5b
Since there is helium gas inside, the workpiece
A helium gas layer with a thickness of approximately 100 μn1 exists between 22 a (22 b) and the inner surface of portion 5 a (5 b).

There is a relationship between the thickness of the helium gas layer and the heat transfer coefficient:
There is a relationship shown in Figure 3, and the thickness of the helium gas layer is 500 mm.
At micrometers or less, extremely good heat transfer properties are exhibited.

Therefore, the heat generated in the working materials 22&, 22b is transferred to the helium gas layer and the cylindrical portion 4a.

4b and the upper wall 2a, the heat is quickly exhausted to the outside. Therefore, working materials 22th, 22b
The temperature inside the helium tank 6 does not rise due to the heat generated, and this is a good f! :,? 11 Freeze Recycle is realized.

In this way, only when the working materials 22h, 22b are in the adiabatic magnetization f history, a thermally conductive member is provided sufficiently close to these striped materials 2'2a, 22b via the helium gas layer to prevent the heat conduction. The heat is dissipated to the outside IXμ via the gender member.

Therefore, unlike the system in which the C1 exhaust heat system is transferred together with the working materials, the overall structure can be simplified. Further, during adiabatic demagnetization, a long adiabatic distance can be inevitably ensured between the heating element 2# and the work material. Therefore, during adiabatic demagnetization, there is no heat intrusion through the thermally conductive member, and the above-mentioned effect is achieved after all.

In addition, if a main magnetic field generator and an auxiliary magnetic field generator f2 are provided as in Example 2, and the auxiliary magnetic field generator is used to steepen the intensity gradient at the edge of the magnetic field, the work material will come out of the magnetic field. The travel stroke required for this can be reduced. Therefore, it is possible to downsize the entire device. In addition, if the method of lifting and lowering two working materials exclusively using one driving source as in the example is used, when one working material attempts to leave the magnetic field, the other working material will be moved by the magnetic field. Since they are in a close relationship, the magnetic attraction force generated between one magnetic field and the working substance can eventually reduce the magnetic attraction force generated between the other magnetic field and the working substance. Therefore, there are some publications that can reduce the driving power. Also,
The present invention is not limited to those that employ an elevating system as in the above-mentioned embodiments, but can also be applied to systems that employ a rotation system.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a magnetic refrigeration device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing only the main parts of the device, and FIG. 3 is a thermal conductivity J coefficient characteristic of a helium gas layer. FIG. 1... Sunset 7s, 2... Inner tank, 6, 41... Helium tank, 4a, 4b... Cylindrical part formed of good heat conductive material, 14 a, 14 b, 15 a, 15
b --- jti' as a magnetic field generator! ? lt
Man: Coil, 20a, 2θb...Cylinder, 218,
21b...Rod, 22a. 22b...saku g, +3 things evening^, 24 a, 24
b ・-9 hook, 26... pinion, G... gap.

Claims (3)

[Claims] (1) A helium tank, a magnetic field generator that constantly generates a magnetic field above the helium tank, and a space that communicates with the helium tank and generates heat when placed within the magnetic field generated by the magnetic field generator. a working substance that absorbs heat and liquefies helium gas in the helium tank when located outside the magnetic field; and a drive that applies power from outside the helium tank to alternately move the working substance into and out of the magnetic field. means, a highly thermally conductive member that is close to the working material through a helium gas layer having a thickness of 500 μm or less when the working material is located in the magnetic field; 1. A helium liquefaction refrigeration apparatus comprising: a helium gas layer and means for exhausting heat to the outside of the helium tank via the well-thermal conductive member. (2) The helium liquefaction refrigerator according to claim 1, wherein the magnetic field generator includes an auxiliary magnetic field generator that steepens the intensity gradient at the end of the magnetic field. (3) At least one pair of elements consisting of the magnetic field generating device, the working material, and the highly thermally conductive member,
Each pair of work materials is controlled to move exclusively into and out of the magnetic field generated by each magnetic field generator by one driving means. A helium liquefaction refrigeration system according to claim 1, characterized in that the helium liquefaction refrigeration system is characterized by: