ROTARY JOINT

• US 20110018255A1
• Filed: 02/13/2009
• Published: 01/27/2011
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Eagle Industry Company Limited
• Original Assignee: Eagle Industry Company Limited
• Inventors: Uchiyama, Mami, Takahashi, Hidekazu
• Granted Patent: US 9,695,942 B2
• Time in Patent Office: Days
• US Class Current: 285/125.1
• CPC Class Codes: F16J 15/3484 Tandem seals
• CPC Class Codes: F16J 15/43 kept in sealing position by magnetic force
• CPC Class Codes: F16L 27/087 Joints with radial fluid passages
• CPC Class Codes: F16L 39/04 allowing adjustment or movement of the multiline swivel type F16L39/06
• CPC Class Codes: F16L 59/185 Adjustable joints, joints allowing movement in general F16L27/00
• CPC Class Codes: H02K 5/124 Sealing of shafts
• CPC Class Codes: H02K 55/00 Dynamo-electric machines having windings operating at cryogenic temperatures
• CPC Class Codes: H02K 55/04 with rotating field windings
• CPC Class Codes: Y02E 40/60 Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment

Abstract

The present invention provides a rotary joint which is available to maintain a cryogenic supplying refrigerant which flows in a fluid passage by a vacuum thermal insulation so that a cooling portion is cooled certainly. The rotary joint of the present invention comprises a vacuum use cylindrical shaft (10) supported in rotatable condition to an inner circumferential face of a main body having a vacuum passage, a rotary seal ring (1A) fitted to an outer circumferential face with a space and provided with seal faces at both end faces, a stationary seal (2A) ring provided at both sides of the respective rotary seal rings and provided with a counter seal face contacting hermetically with the seal face, a resilient bellows (2B) joint with a circumferential face of end portion of the stationary seal ring to press the stationary ring resiliently to the seal face side, a spaced fluid passage (20B) formed between the respective resilient bellows for passing through the supplying refrigerant by joining with a first fluid passage providing the supplying refrigerant, a second fluid passage (20C) communicating with the spaced fluid passage provided at the rotary seal ring, a connecting fluid passage (20D) communicating with the second fluid passage, a first pipe (20E) communicating through the spaced fluid passage so as to provide the supplying refrigerant to be vacuum thermally insulated in the vacuum use cylindrical shaft to a cooling portion, a connecting cover (42) having a suction bore for vacuumizing in the vacuum use cylindrical shaft and a magnetic fluid seal device (40) having a projection constituted as multiple gaps in the axial direction corresponding to a pressure of the vacuumizing.

Claims

1. A rotary joint for a refrigerant configured to connect fluid passages between a refrigerant supplying apparatus on a stationary side and a cooling portion on a rotary side, comprising:

a vacuum use cylindrical shaft supported by a main body in rotatable condition, and having a vacuum passage penetrating in the axial direction, a coupling portion at one end of said vacuum passage for communicating said vacuum passage with a communication passage of said cooling portion, an opening at another end of said vacuum passage for vacuum suction, and a connecting portion at a middle of said coupling portion and said opening;

a rotary seal ring hermetically fitted to said connecting portion of said vacuum use cylindrical shaft, and having seal faces at both end faces;

a pair of stationary seal rings provided on both sides in an axial direction of said rotary seal ring, and having counter seal faces respectively contacting hermetically with said seal faces facing thereto;

resilient bellows for pressing said stationary seal rings resiliently to said seal faces, and having a joint portion and a fixed portion respectively, said joint portion being provided at one end of said resilient bellows and being connected hermetically with an opposite face from said counter seal face of said stationary ring, said fixed portion being provided at another end of said resilient bellows, enclosing said vacuum use cylindrical shaft, and being fixed to said main body;

a first spaced fluid passage formed between said resilient bellows sandwiching said rotary seal rings and communicated with a first fluid passage to introduce a supplying refrigerant;

a second fluid passage penetrating through said rotary seal ring in the radial direction and communicated with said first spaced fluid passage;

a connecting fluid passage provided in said connecting portion, communicated with said second fluid passage at one end of said connecting fluid passage, and having a connecting bore at another end of said connecting fluid passage;

a first pipe arranged in said vacuum passage of said vacuum use cylindrical shaft, and having a fluid passage connected with said connecting bore at one end of said fluid passage to be communicated with said connecting fluid passage and communicated with a fluid passage on said cooling portion side at another end of said fluid passage;

a connecting cover having a suction port for exerting the vacuum suction on the inside of said vacuum passage through said opening of said vacuum use cylindrical shaft, and

a magnetic fluid seal device having a magnetic fluid seal cover, pole blocks, magnets, a shaft cover, and magnetic fluid, and wherein said magnetic fluid which magnetic force is exerted on shuts off a gap between a space between said projections and said pole blocks against the vacuum suction force, said magnetic fluid seal cover being hermetically coupled with said connecting cover to enclose said vacuum use cylindrical shaft, said pole blocks being for magnets, being arranged in parallel, and being hermetically fitted on one circumferential face of an inner circumferential face of said magnetic fluid seal cover or an outer circumferential face of said vacuum use cylindrical shaft, said magnets being arranged in spaces between said pole blocks arranged in parallel, said shaft cover having a projection group in which a plurality of projections are arranged in a manner that said respective projections are close to and facing to circumferential faces of said respective pole blocks and being fitted on another circumferential face of an inner circumferential face of said magnetic fluid seal cover or an outer circumferential face of said vacuum use cylindrical shaft, said magnetic fluid existing between said projections and said pole blocks.

2. The rotary joint as set forth in claim 1, wherein two sets of said rotary seal ring and said stationary rings of both sides of said rotary seal ring are arranged in the axial direction, a second spaced fluid passage is provided between adjacent stationary seal rings of one set and other set of said at least two sets, said second spaced fluid passage communicates with a second pipe arranged in said vacuum passage of said vacuum use cylindrical shaft, so that a discharging refrigerant after cooling said cooling portion is returned back through said second pipe and said second spaced fluid passage.

3. The rotary joint as set forth in claim 1, wherein an inner circumferential portion of said connecting portion is formed as a circular face, an oval face, a convex-concave face or a toothed gear shape face along the circumferential direction, and a connecting bore is formed in the connecting portion at an end of said first pipe side.

4. The rotary joint as set forth in claim 1, wherein said rotary seal ring comprises a plurality of said second fluid passages arranged along the circumferential direction, said connecting portion comprises said connecting fluid passages along the circumferential direction which communicate with said respective second fluid passages, and said fluid passages of respective said first pipes communicate with said connecting fluid passages respectively corresponding to thereof.