US20110061398A1

US20110061398A1 - Magnetic refrigerator

Info

Publication number: US20110061398A1
Application number: US12/884,782
Authority: US
Inventors: Cheng-Yen Shih; Gwo-Jiun Sheu; Mao-Jen Hsu; Shi-Pin Meng
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2009-09-17
Filing date: 2010-09-17
Publication date: 2011-03-17

Abstract

A magnetic refrigerator has reciprocated and rotated motions. The body of the apparatus has a nearly tubular shape and contains working pieces at corners, wherein the working pieces surround a shaft with permanent magnet. Compared with existing rotational models, the magnetic refrigerator of the present invention has a relative smaller volume, and the motion of the shaft will be back and forth. Furthermore, a torque eliminating device of the magnetic refrigerator will eliminate the reverse torque when the shaft is driven reverse so that improve cooling efficiency.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61,243,384, filed Sep. 17, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to a refrigerator, especially to a magnetic refrigerator which adapting magneto-caloric material.
2. Description of the Related Art
As mentioned to nowadays' technology development, well-known magnetic refrigerators are roughly divided into two fields, reciprocating and rotating models. The reciprocating magnetic refrigerator, for example, disclosed by U.S. Pat. No. 5,934,078 patent has regenerator beds disposed at the center shaft, and adapts a driving machine to drive the shaft to do reciprocated motion in an axis horizontally or vertically, and force the regenerator beds into or out off a magnetic field so as to magnetize or demagnetize magneto-caloric material (MCM) periodically. Finally, there are a hot heat exchanger and a cold heat exchanger both connected to the regenerator beds to carry out hot water or cold water which flows through the regenerator beds.
The rotating magnetic refrigerator, for example, disclosed by Japanese patent publication number 2008-51409 has refrigerator beds in a round body made by yoke, wherein a permanent magnet shaft is driven by an outer driving apparatus so as to pass by different refrigerator beds in a circle motion loop so as to magnetize or demagnetize MCM wrapped in the refrigerator beds periodically.
However, reciprocating magnetic refrigerator has some drawbacks such as large volume, high noise and low reliability. On the other hand, rotating magnetic refrigerator (referred to Japan patent number 2008-51409) has some drawbacks such as large torque, high loading and difficulty in setting torque eliminating devices. It is necessary to improve the reciprocating and rotating magnetic refrigerators.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a magnetic refrigerator which overcomes both reciprocating and rotating magnetic refrigerators' drawbacks.
To achieve the above, the magnetic refrigerator of the invention comprising a body which is substantially a cylinder in exterior but flat at both sides, so that the magnetic refrigerator has a smaller volume and a more compact structure. Besides, there are four working pieces disposed at four corners inside the body, wherein the working pieces contain magneto-caloric material (MCM), such as MnFePAs, MnFePGe, MnFePSi, LaFeSi, LaFeCoSi, Gd or Gd-based alloy, etc., and the shape of MCM can be particle, mass, pillar, porous, or periodic structure. Besides, both sides of the working piece are disposed interfaces of fluid tubes or heat pipes, and therefore the working pieces are connected to each other through the fluid tubes or heat pipes, wherein the heat pipe is filled with heat conducting fluid which flows in or out of the working piece to exchange heat with MCM contained in the working piece. The heat conducting fluid is pressured by a pump or hydraulic cylinder to flow through a fluid distributor and then flow through the working piece and the heat dissipating unit, wherein the fluid distributor is driven by a shaft which will be later described to control flowing direction of the heat conducting fluid, and so that the pressured fluid will turn a specific direction with the working pieces synchronously.
In addition, the invention also discloses a driving device disposed at one side of the magnetic refrigerator, wherein the driving device may comprising or not comprising a decelerating device to drive the shaft moving back and forth between pairs of working pieces. There is a magnetic structure disposed on the shaft so as to oscillate with the shaft when the shaft is driven by the driving device. Furthermore, in order to eliminate loading of the driving device, this invention provides a torque eliminating device disposed at both sides of the surface of the body to eliminate reverse torque when the driving device reverses the shaft. The torque eliminating device controls route of the shaft and provides sufficient buffer, especially timing of brake, for the shaft while the shaft is driven moving back and forth by the driving device hence the magnetic refrigerator has the best working efficiency.
In an embodiment of the invention, for getting stronger magnetic field, the magnetic structure is changed into U-Shape, wherein three permanent magnets with different magnetic pole directions are combined to form the U-shaped magnetic structure, and the mouth of the U-shaped magnetic structure comprising soft magnetic ferrite faces the working piece to enhance magnetic field toward the working pieces so as to enhance efficiency of freezing. Besides, there can be attached a plurality of auxiliary soft iron around the U-shaped magnetic unit to further enhance total magnetic field, and so as to unify magnetic lines surround the working pieces.
As mentioned above, the present invention discloses a magnetic refrigerator having smaller volume but higher efficiency, and the refrigerator overcomes above-mentioned drawbacks of whether reciprocating or rotating magnetic refrigerators.
A detailed description is given in the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 is a schematic view of the magnetic refrigerator of the invention;

FIGS. 2A and 2B are cross-sectional views of the body of the refrigerator as mentioned in FIG. 1;

FIGS. 3A, 3B and 3C are embodiments of working pieces of the refrigerator as mentioned in FIG. 1;

FIG. 4 is an embodiment of magnetic unit of the refrigerator as mentioned in FIG. 1;

FIG. 5 is another embodiment of magnetic unit of the refrigerator as mentioned in FIG. 1; and

FIGS. 6A, 6B, 6C and 6D are schematic views of the driving device and the torque eliminating device of the refrigerator as mentioned in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
This invention is related to a magnetic refrigerator which has smaller volume, less power consumption and more freezing capability. Please refer to FIG. 1, the magnetic refrigerator 1 at least comprises a body 10, a shaft 20, a driving device 30 (as shown in FIG. 6C), a torque eliminating device 40, a magnetic structure 50, a plurality of working pieces 60 and a heat dissipating unit 70.
Please further refer to FIG. 2A, wherein the body 10 is a hollow body made by, for example, magnetic conductive materials. The shaft 20 is disposed substantially at the center inside of the body 10 and partially penetrated a first side wall 111 of the body 10 to be connected to the driving device 30 (as shown in FIG. 6C), wherein the driving device 30 is adapted to be connected with a part of the shaft 20 from outside of the body 10 to drive the shaft 20. In an embodiment of the invention, the shaft 20 is driven moving back and forth.
The torque eliminating device 40 is disposed corresponding to the shaft 20 to eliminate the reverse torque appropriately when the shaft 20 is driven reverse by the driving device 30, and so as to eliminate power consumption of the driving device 30 while the magnetic refrigerator 1 is operating.
The magnetic structure 50 is disposed accordingly to the shaft 20, in an embodiment of the invention wherein the magnetic structure 50 is adapted to be oscillated with the shaft 20 when the shaft 20 is driven by the driving device 30, and the magnetic structure 50 can generate magnetic flux.
The working pieces 60, or so called refrigerating beds, which contain MCM inside are disposed corresponding to the oscillation track of the magnetic structure 50, in an embodiment of the invention, wherein the working pieces 60 are disposed on a second side wall 113 and a third side wall 115 of the body 10 so as to create a relative motion with the working pieces 60 when the magnetic structure 50 is oscillated.
Furthermore, this kind of disposition keeps a proper distance D between the working pieces 60 and the magnetic structure 50 so as to make the working pieces 60 receiving magnetic flux generated by the magnetic structure 50 properly. The heat dissipating unit 70 is adapted to be connected to the working pieces 60 with a plurality of heat pipes 71 thereof, wherein the heat pipes 71 are filled with heat conducting fluid 73 (as shown in FIG. 3C) which is used to exchange heat with the MCM of the working pieces 60 therein the heat conducting fluid 73 flows through, and thus completing thermal cycle to achieve cooling effect.
To achieve higher efficiency, the above-mentioned body 10 is made of magnetic conductive materials, hence providing a better route for magnetic force line to enhance working efficiency of the magnetic refrigerator 1 of the invention. Furthermore, please refer to FIG. 2B, wherein the body 10 is, for example, in a shape of rectangular box, thus the body 10 is smaller in volume than cylindrical body disclosed by Japanese patent publication number 2008-51409 as mentioned. Therefore the overall volume of the magnetic refrigerator 1 of the invention can be shrunk mostly relative to what of the JP patent as mentioned and can be favorably adapted to down-sizing family or business machines.
Besides, the above-mentioned second side wall 113 and third side wall 115 of the body 10 are adapted to be in a shape of arc, and inner sides of the second side wall 113 and the third side wall 115 of the body are adapted to be disposed few concaves 13 to contain the working pieces 60. In detail, the disposition of the second side wall 113, the third side wall 115, and the concaves 13 thereof is corresponding to the shape of the magnetic structure 50 (as shown in FIG. 2A), the location of the magnetic structure 50 which disposed to the shaft 20, and the shapes of the working pieces 60. Hence the magnetic flux generated by the magnetic structure 50 can possibly wrap or penetrate the working pieces 60 most while the magnetic structure 50 is oscillated by the shaft 20, and so that the MCM contained in the working pieces 60 suffer a largest quantity of magnetic flux and reach a better working efficiency.
The above-mentioned MCM have been disclosed in many patents, journals, papers, . . . etc., and the fact that MCM is not primary part to be improved in this invention, such that what kind of MCM to be adapted is not an important concern in this invention. Besides, this invention does not limit the shape of MCM after it is produced, that is the shape of MCM can be geometric particle with proper grain size, irregular mass, pillar, mesh, or sheet, ant it depends on actually necessary.
Please refer to FIGS. 3A, 3B, and 3C, wherein each working piece 60 of an embodiment of the invention is connected to two heat pipes 71 at both ends respectively, that is the working piece 60 is connected to four heat pipes 71 in this embodiment. Besides, there are a plurality of filtering or heat isolating sheets 61 disposed inside the working piece 60 and so as to divide the working piece 60 into a plurality of chambers 63 as shown in FIG. 3B, wherein the separated chambers 63 and the filtering or heat isolating sheets 61, for example, can only let the heat conducting fluid 73 to flow through and then block MCM in the chambers 63. The chambers 63 can be in same volume, different volume or proportional increase or decrease in a temperature gradient direction.
Furthermore, it is possible for different MCM to be adapted to different chambers 63 as shown in FIG. 3C, thus a user can properly arrange different MCM in different orders to meet different requirements. However, this kind of arrangement is up to general concern of cost and efficiency, and is not limited in the invention.
Please refer to FIG. 4, wherein the above-mentioned magnetic structure 50 is a source of magnetic flux and is selected from, for example, a single permanent magnet, multiple permanent magnet, electromagnet, or the combination thereof. The permanent magnet mass, for example, is attached to the shaft 20 of the magnetic refrigerator 1 of the invention. Hence the permanent magnet mass oscillates with the shaft to create a relative motion with the working pieces 60 so as to make the magnetic flux generated by the permanent magnet mass flowing through or not flowing through a specific working piece 60 at a specific moment.
Please refer to FIG. 4, which shows an embodiment of the invention, wherein the magnetic structure 51 comprises two permanent magnet masses 511, wherein the two permanent magnet masses 511 attaching to both sides of the shaft 20 and their longitudinal directions pass through the axis AX1 of the shaft 20. The magnetic structure 51 provides a better magnetic route so as to enhance cooling efficiency.
Please refer to FIG. 5, shows another embodiment of the invention, wherein the magnetic structure 53 comprises six permanent magnet masses 531 and a plurality of auxiliary soft iron masses 532. The six permanent magnet masses 531 are arranged into two sets of magnetic units 533, wherein each magnetic unit 533 comprises three of the six permanent magnet masses 531 and is connected to the side of the shaft 20. To detail, every three permanent magnet masses 531 are combined to form a U-shaped magnetic unit 533, thus two magnetic units 533 are connected to both sides of the shaft 20 and are disposed symmetrically to the axis AX1 of the shaft 20.
The auxiliary soft iron masses 532 are disposed to where between the shaft 20 and the magnetic units 533, that is to attach to and wrap the magnetic units 533. The above-mentioned two embodiments are solutions for enhancing magnetic flux or improving density of route of magnetic force to enhancing cooling efficiency (or so called working efficiency), and it seems no need to describe further variations or applications of the magnetic structure which can be easily though for a laborer in the art.
Please refer to FIGS. 1, 6A, 6B, 6C, and 6D the above-mentioned driving device 30 can further comprising or not comprising a decelerating device 31, wherein the decelerating device 31 can be controlled by the driving device 30 to properly generate a deceleration which, for example, towards along a reverse direction to a circular direction of the moving shaft 20.
The deceleration can make the shaft 20 stop or even turn reversely if necessary, and similarly, while the shaft 20 is driven by the driving device 30 turning along a newly circular direction, the decelerating device 31 can be controlled by the driving device 30 once again to stop or even turn reversely if necessary. Hence the decelerating device 31 can repeatedly controlled by the driving device 30 to drive the shaft 20 to start turning, to stop, and then to turn reversely.
Please further refer to FIG. 2A, wherein the first side wall 111 of the body 10, for example, is adapted to set an opening 15 with a particular length L, wherein the shaft 20 has at least a location limiting mechanism 21 limited according to the opening 15 to keep the shaft 20 moving back and forth. To detail, the location limiting mechanism 21 limits or defines a finite vibrating range for the shaft 20 and the magnetic structure 50 attached to the shaft 20 is driven back and forth, so as to shrink overall volume of the magnetic refrigerator 1 of the invention in advance. Certainly, arrangements of the opening 15, for example, location, width, length, and arrangements of the vibrating range of the shaft, can be adjusted according to necessary. This specification will not specifically limit the embodiment as mentioned.
The above-mentioned torque eliminating device 40 coordinates with the decelerating device 31 of the driving device 30 to transfer movement inertia generated by the shaft 20 when the shaft 20 is driven moving back an forth into potential energy and then storages the potential energy. Once the shaft 20 is driven moving reversely, the torque eliminating device 40 provides pre-stored potential energy and transfers the potential energy into reverse movement initial, and effectively reduce a part of reverse torque which the driving device 30 will provide, thus total consumption of the magnetic refrigerator 1 of the invention will be reduced, too.
In the same logic, any kind of device or component which can adjust movement, potential energy and/or spring energy is adapted to eliminate the reverse torque of the shaft as the eliminating device 40 as mentioned, for example, spring, spring sheet, rubber washer, rubber ball, magnetic module, electromagnetic buffer, hydraulic buffer, gas buffer and the combination thereof will be suitable substitutes.
The above-mentioned heat dissipating unit 70 is connected to the working pieces 60 through a plurality of heat pipes 71, wherein a heat conducting fluid 73 (as shown in FIG. 3C) flows through the heat pipes 71, and then flows through the working pieces 60 to exchange heat with MCM so as to achieve better heat dissipation efficiency. The heat conducting fluid 73 can be, for example, water, oil, organic solvent with or without water, and inorganic solvent.
Besides, for the purpose to against fluid corrosion, the surfaces of the MCM can be suffered a surface anti-corrosion treatment, or the heat conducting fluid 73 can be adopted anti-corrosion agents. Furthermore, for the purpose to prevent fluid solidifying or sticky during lower temperature, the heat conducting fluid 73 can be adopted anti-freeze agents.
Please refer to FIG. 1, wherein the above-mentioned heat dissipating unit 70 is, for example, heat sink, heat dissipating fin, heat dissipating manifold, water tank, or their reasonable combinations. Besides, the heat dissipating unit 70 can further comprises at least one heat exchanger 77, in an embodiment of the invention there are a pair of heat exchangers, connected to heat pipes 71 so as to exchange heat with heat pipes 71. Furthermore, the heat dissipating unit 70 may also comprises an auxiliary dissipating device 79, such as a fan or a blower, connecting to the heat exchanger. The auxiliary dissipating device 79 dissipates heat from the heat exchanger to help heat dissipating and enhancing heat dissipating efficiency.
The heat dissipating unit 70 can further comprising a fluid conducting device 75, please refer to FIG. 1, wherein the fluid conducting device 75 at least comprising a pump or a hydraulic cylinder 751 and a fluid distributor 753. The pump or a hydraulic cylinder 751 of the fluid conducting device 75 is adapted to pressurize and conduct the heat conducting fluid 73 and enhance the quantity and speed of the flow, so as to enhance heat dissipating efficiency.
The fluid distributor 753 of the fluid conducting device 75 is, for example, connected to the pump or a hydraulic cylinder 751 to properly control flowing direction of the heat conducting fluid 73 according to timing when the working pieces 60 rise or down in temperature, such that enhancing working efficiency and therefore enhancing cooling efficiency.
The fluid distributor 753 is, for example, driven by the shaft 20 synchronously so as to easily control the flowing direction of the heat conducting fluid 73 by mechanical or physical manners. Besides, the fluid distributor 753 may be further connected to a controlling unit 755 to control the flowing direction more precisely, and this embodiment or improvement is easily considered by labor in the art, thus the specification has no description on this.
To sum up, the magnetic refrigerator of the invention has at least advantages:
(1) Shape of the body is properly cut at both side walls of the body, and the body of the invention has a smaller overall volume than a body of prior art.
(2) The magnetic structure is oscillated less in vibrating range or so called amplitude to enhancing working efficiency and cooling efficiency.
(3) The torque eliminating device reduces an overall power consumption of the magnetic refrigerator to save more energy.
(4) The magnetic structure is improved to enlarge magnetic flux flowing through thereof so as to enhancing cooling efficiency.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.

Claims

What is claimed is:

1. A magnetic refrigerator, comprising:

a body;

a shaft disposed at a center of the body;

a driving device connected to a first side wall of the body outwardly to drive the shaft back and forth;

a torque eliminating device disposed to the shaft to eliminate reverse torque when the driving device reverses the shaft;

a magnetic structure disposed to the shaft to be oscillated with the shaft;

a plurality of working pieces disposed to a second side wall and a third side wall of the body according to oscillation track of the magnetic structure respectively to create a relative motion with the magnetic structure when the magnetic structure is moving with the shaft, wherein the working pieces are filled with magneto-caloric materials; and

a heat dissipating unit connected to the working pieces to exchange heat with the magneto-caloric materials.

2. The magnetic refrigerator according to claim 1, wherein the body is hollow and made of magnetic conductive materials.

3. The magnetic refrigerator according to claim 2, wherein the working pieces are in the shapes of arc, and the second side wall and the third side wall having a plurality of concaves containing the working pieces.

4. The magnetic refrigerator according to claim 1, wherein the driving device further comprises a decelerating device to drive the shaft moving back and forth.

5. The magnetic refrigerator according to claim 4, wherein the first side wall of the body has an opening with a particular length, and the shaft has at least one location limiting mechanism limited according to the particular length of the opening to keep the shaft moving back and forth in a finite range.

6. The magnetic refrigerator according to claim 1, wherein the torque eliminating device comprises spring, spring sheet, rubber washer, rubber ball, magnetic module, electromagnetic buffer, hydraulic buffer, gas buffer and the combination thereof.

7. The magnetic refrigerator according to claim 1, wherein the magnetic structure is a permanent magnet mass.

8. The magnetic refrigerator according to claim 1, wherein the shaft has an axis and the magnetic structure comprises:

six permanent magnet masses forming into two sets of U-shaped magnetic units, wherein the magnetic units are connected to both sides of the shaft respectively, and are disposed symmetrically to the axis of the shaft; and

a plurality of auxiliary soft iron masses attaching to and wrapping the magnetic units.

9. The magnetic refrigerator according to claim 1, wherein the magneto-caloric materials are in the shape of geometric particles, irregular masses, pillars, porous, or periodic structure.

10. The magnetic refrigerator according to claim 1, wherein the working pieces are connected to the heat dissipating unit by a plurality of heat pipes, and heat conducting fluid flowing through the heat pipes.

11. The magnetic refrigerator according to claim 10, wherein the heat conducting fluid comprises anti-corrosion agent.

12. The magnetic refrigerator according to claim 10, wherein the heat conducting fluid comprises anti-freeze agent.

13. The magnetic refrigerator according to claim 10, wherein the heat dissipating unit further comprises at least one heat exchanger connecting to the heat pipes.

14. The magnetic refrigerator according to claim 13, wherein the heat dissipating unit further comprises a fluid conducting device disposed between the working pieces and the heat exchanger, wherein the fluid conducting device comprises:

a pump or a hydraulic cylinder to pressurize and conduct the heat conducting fluid; and

a fluid distributor connected to the pump or hydraulic cylinder to control flowing direction of the heat conducting fluid.

15. The magnetic refrigerator according to claim 14, wherein the fluid distributor is driven by the shaft synchronously.

16. The magnetic refrigerator according to claim 13, wherein the heat exchanger comprises heat sink, heat dissipating fin, heat dissipating manifold, or water tank.

17. The magnetic refrigerator according to claim 13, wherein the heat dissipating unit further comprises a fan or a blower to dissipate heat from the heat exchanger.