JPS5993158A - Magnetic 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 magnetic refrigeration device capable of improving refrigeration efficiency.

[Prior art and its problems]

2. Description of the Related Art Magnetic refrigeration devices that utilize the magnetocaloric effect of magnetic materials have been known. This magnetic refrigeration system uses a magnetic material cooled by adiabatic demagnetization to remove heat from the object to be cooled, and has the advantage of having a higher refrigerating capacity per unit volume than ordinary gas refrigeration equipment. Iru.

By the way, in the case of magnetic refrigeration equipment, there is a heat exhaustion process in which the heat generated in the magnetic material, that is, the work material, is released to the outside through adiabatic magnetization, and an endothermic process in which heat is removed from the cooled object by the work material cooled by adiabatic demagnetization. It is necessary to perform the two heat exchange processes alternately. In this way, in order to perform the two heat exchange processes alternately and realize a highly efficient refrigeration cycle, it is necessary to reliably cut off the heat transfer from the working material to the object to be cooled in the exhaust heat overculm. In the endothermic process, it is necessary to quickly transfer heat from the object to be cooled to the work material.

For this reason, conventional apparatuses are provided with a chamber for carrying out the heat removal process and a chamber for carrying out the heat absorption process, and the working material is allowed to alternately enter both chambers in an airtight manner.

However, in a device configured as above,
A highly reliable sealing mechanism is required to allow the work material to enter both chambers alternately in an airtight manner, and since it is difficult to construct such a sealing mechanism in practice, it is difficult to improve refrigeration efficiency. There was a problem that could not avoid the decline. Furthermore, since it is necessary to mechanically move the working material, which is the most important element, there is also the problem that the structure becomes complicated.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic refrigeration device that can exhibit high refrigeration efficiency despite having a simple configuration.

[Summary of the invention]

The present invention provides a working material that generates heat when it enters a magnetic field and absorbs heat when it exits the magnetic field, a device that periodically positions the working material within the magnetic field, and a part of the surface of the working material that condenses. a sealed container as a part; when the working material is inside a magnetic field, the working material is cooled with a refrigerant; and when the working material is out of the magnetic field, the refrigerant is caused to flow through a condensing section of the sealed container; The magnetic refrigeration system consists of a cooling device.

〔Effect of the invention〕

With the above configuration, since a sealed container is used in which a part of the surface of the material to be prepared is a direct condensing part, the temperature of the condensing part of the predistribution sealed container can be made equal to the surface temperature of the working material during the heat absorption process. Heat loss between the two can be eliminated. Therefore, by making a part of the surface of the work material the condensation part of the sealed container, the efficiency of refrigeration can be greatly improved. Furthermore, since the refrigeration efficiency can be increased without mechanically moving the work material, the structure can be significantly simplified compared to conventional devices.

[Embodiments of the invention]

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

In the figure, only the main parts are shown.

In the figure, reference numeral 1 is a working material formed by processing a single crystal block of gadolinium gallium garnet into a cylindrical shape, and arranged with the axis line parallel to the direction of gravity. A superconducting coil 2 is arranged concentrically with the working material 1.

A cap-shaped member 3 is fixed to the upper end surface of the working material 1, and a cavity 4 formed between this member 3 and the upper end surface of the working material 1 is filled with pipes 5a, 5b, valves 6,
, 7 to a refrigerant inlet pipe 10 of a small refrigerator 8. Further, a bypass valve 11 is connected between the refrigerant outlet pipe 9 and the refrigerant inlet pipe 10. In practice, the above-mentioned refrigeration system is used which generates helium gas of 20K or less.

On the other hand, a sealed container 13 is disposed around the working material 1, and the outer peripheral surface of the working material 1 directly serves as a condensing portion 12, and is connected to the cap-shaped member 3.

This sealed container 13 is arranged concentrically on the outer peripheral surface of the work material 1 with a gap 14 therebetween, and has an upper end hermetically connected to the outer peripheral edge of the member 3 and a lower end that is connected to the work material 1. A storage portion 5 made of a metal material and extending downward from the lower end surface of the storage portion 5 is provided. Note that the sealed container 13, the working material 1, and the superconducting coil 2 are housed integrally in a vacuum container (not shown).

Then, the superconducting coil 2 is energized and the valves 6 and 7 are energized.
, 11 are controlled by a control device 21 according to the relationship described later.

Next, the operation of the apparatus configured as described above will be explained.

First, the valves 6 and 7 are held "closed" and the valve 11 is held "open", and the helium gas of 20K or less discharged from the refrigerator 8 is transferred from the refrigerant outlet pipe 9 to the valve 11 to the refrigerant inlet pipe 10.
Assume that it circulates along the route.

In this state, when a command to start operation is given to the postal control device 21,
The control device 21 first energizes the superconducting coil 2, and then controls the valves 6 and 7 to be "open" and the valve 11 to be "closed". When the superconducting coil 2 is energized, the working material 1 is placed in a magnetic field, so it becomes adiabatic magnetized and generates heat.At this time, since helium gas of 20K or less is flowing in the cavity 4, , the heat generated in the working material 1 is directly removed by the helium gas. Therefore, the temperature rise of the working material 1 is suppressed and a heat removal process is carried out.

Subsequently, the control device 21 controls the valve 11 to "open" and the valve 6 to "close", and then stops the energization of the superconducting coil 2. As a result, the work material 1 comes out of the magnetic field and is therefore in a state of adiabatic demagnetization, resulting in a rapid temperature drop.

When the temperature of the work material 1 drops to below 4.2K, helium gas from the refrigerator 8 passes through the valves 7 and 11 and flows into the gap 14 of the sealed container 13, and the helium gas condenses in the sealed container 13. It liquefies at the portion 12, that is, the outer peripheral surface of the work material 1, and falls into the storage tank portion 15 of the sealed container 13. In this way, an endothermic process is carried out. The control device 21 then repeats the series of controls described above. Therefore, the helium gas supplied from the refrigerator 8 is cooled and liquefied, and the function of the refrigerator is exhibited here.

Note that when helium gas is supplied from the refrigerator 8 to cool the work material 1, the helium gas does not enter the storage tank 5 of the sealed container 13 because the sealed container 13 is filled with helium gas. On the other hand, when the work material 1 is placed outside the magnetic field, the work material 1 performs heat absorption work, so the helium gas supplied from the refrigerator 8 is cooled and liquefied, so the pressure inside the sealed container 13 is reduced, and further helium gas is supplied from the refrigerator 8. Gas will be drawn into the sealed container 13.

In the embodiment described above, the working material is alternately moved in and out of the magnetic field by energizing and stopping the energization of the superconducting coil, but it is not possible to keep the superconducting coil energized. The working material may be moved in and out of the magnetic field alternately by periodically moving the coil in the axial direction. Moreover, it is not limited to superconducting coils. Further, it goes without saying that the support for the coil and the work material can be set arbitrarily.

[Brief explanation of drawings]

The drawing is an explanatory diagram of the configuration of a magnetic refrigeration system according to an embodiment of the present invention, with some parts cut away.

Claims (1)

[Claims] A working substance that generates heat when it enters a magnetic field and absorbs heat when it leaves the magnetic field, a device that periodically positions this working substance within the magnetic field, and a closed container that has a part of the surface of the working substance as a condensation part. , a cooling device that cools the working material with a refrigerant when the working material is within the magnetic field, and causes the refrigerant to flow through the condensation section of the sealed container when the working material is out of the magnetic field. A magnetic refrigeration device characterized by: