Mitsubishi Denki Kabushiki Kaisha

Shuji Ando

Takahiro Matsumoto

Takashi Inaguchi

Masashi Nagao

Hideto Yoshimura

Kazuki Moritsu

Mitsuhiro Kishida

Shuichi Nakagawa

Shuuichi Nakagawa

An object of the present invention is to obtain a superconductive magnet, the size of which can be reduced by shortening the radial length of a magnetic device thereof and the refrigerating performance of which can be improved. A cylinder for fastening a refrigerator has an end facing an ambience of helium gas evaporating in a helium chamber and another end which is substantially horizontally fastened to a vacuum chamber. Further, the three-stage regenerative refrigerator is inserted and fastened to the cylinder for fastening the refrigerator. A heat insulator, such as a convection prevention tube, made of a hollow Teflon tube is wound around the outer surface of each stage of the cylinder of the three-stage regenerative refrigerator. The convection prevention tube is enclosed into a gap between the cylinder for fastening the refrigerator and the three-stage regenerative refrigerator without no undesirable gap so that heat convection of the helium gas is prevented.

Superconductive magnet

A cold accumulation type refrigerating machine having a high refrigeration efficiency. Rotation output of a stepping motor is converted to a reciprocative motion of a displacement member carrying a cold accumulator and disposed within a cylinder in which first and second closed chambers are defined above and below the displacement member, respectively. A compressed gas discharged from a compressor is introduced into the second closed chamber through the cold accumulator upon opening of a suction valve and undergoes expansion within the second closed chamber, the gas being then fed back to the compressor through the cold accumulator upon opening of an discharge valve, whereupon one cycle of refrigerating operation is completed. Rotation speed of the stepping motor is varied during every one cycle of operation by means of a pulse oscillation controller such that a time taken for the displacement member to reach a top dead center position from a time point at which the discharge valve is opened is increased while the remaining period of the one cycle is correspondingly shortened.

Cold accumulation type refrigerating machine

Growing community of inventors

Ako, Japan

Shuji Ando