Magnetic refrigerator

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[0001]This application claims the benefit of U.S. Provisional Application No. 61,243,384, filed Sep. 17, 2009.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a refrigerator, especially to a magnetic refrigerator which adapting magneto-caloric material.[0004]2. Description of the Related Art[0005]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 exc...

AI Technical Summary

Benefits of technology

[0010]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.

[0011]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.

Problems solved by technology

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.

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