Sealing system for magnetic levitating centrifugal compressor and magnetic levitating centrifugal compressor

Abstract

A sealing system for a magnetic levitating centrifugal compressor, the magnetic levitating centrifugal compressor including a motor cavity and a motor shaft disposed within the motor cavity, an end of the motor shaft extends out from the motor cavity and is mounted with an impeller, the sealing system includes: a seal which is sleeved on the outer side of the motor shaft and is disposed between the impeller and the motor cavity; a first magnet which is fixed at the outer surface of the motor shaft; and a second magnet which is fixed at a side of the seal facing the motor shaft; the first magnet and the second magnet form a radial repulsive force in the radial direction of the motor shaft, so that the seal can be levitated in relative to the motor shaft and move therewith.

What is claimed is: 
     
         1 . A magnetic levitating centrifugal compressor comprising a motor cavity, a motor shaft disposed within said motor cavity and a sealing system, wherein an end of said motor shaft extends out from said motor cavity and is mounted with an impeller, wherein said sealing system comprises:
 a seal, said seal is sleeved on an outer side of said motor shaft and is disposed between said impeller and said motor cavity, for reducing a flow of fluid from said impeller to said motor cavity;   a first magnet, said first magnet is fixed at an outer surface of said motor shaft; and   a second magnet, said second magnet is fixed at a side of said seal facing said motor shaft,   wherein said first magnet and said second magnet form a radial repulsive force in a radial direction of said motor shaft, so that said seal can be levitated relative to said motor shaft.   
     
     
         2 . The magnetic levitating centrifugal compressor according to  claim 1 , wherein a tension spring is provided on top of said seal for resisting the gravity of said seal, one end of said tension spring rests against said seal and the other end of said tension spring rests against a housing, said housing is fixedly connected to the shell of said motor cavity. 
     
     
         3 . The magnetic levitating centrifugal compressor according to  claim 1 , wherein a compression spring is provided at the bottom of said seal for resisting the gravity of said seal, one end of said compression spring rests against said seal and the other end of said compression spring rests against a housing, said housing is fixedly connected to the shell of said motor cavity. 
     
     
         4 . The magnetic levitating centrifugal compressor according to  claim 2 , wherein there are a plurality of said first magnets and a plurality of said second magnets, wherein the plurality of said first magnets are arranged at an outer surface of said motor shaft at equal intervals, and the plurality of said second magnets are arranged at equal intervals on the side of said seal facing said motor shaft. 
     
     
         5 . The magnetic levitating centrifugal compressor according to  claim 4 , wherein said motor shaft is provided with a sleeve, and said first magnets are fixed to said sleeve in an inserted manner. 
     
     
         6 . The magnetic levitating centrifugal compressor according to  claim 4 , wherein the plurality of said first magnets are fixed at the outer surface of said motor shaft by means of a carbon fiber tape in a winding manner. 
     
     
         7 . The magnetic levitating centrifugal compressor according to  claim 2 , wherein said sealing system further comprises an anti-rotation pin, said anti-rotation pin is inserted between said seal and said housing for preventing said seal from rotating relative to said housing. 
     
     
         8 . The magnetic levitating centrifugal compressor according to  claim 7 , wherein there are a plurality of said anti-rotation pins, and the plurality of said anti-rotation pins are arranged at equal intervals in a circumferential direction of said seal. 
     
     
         9 . The magnetic levitating centrifugal compressor according to  claim 2 , wherein a second side of said seal fits against said housing, fitting surfaces between said seal and said housing are provided with a wear resistant coating. 
     
     
         10 . The magnetic levitating centrifugal compressor according to  claim 2 , wherein said first magnet and said second magnet are radially magnetizing permanent magnets; or that said first magnet and said second magnet are axially magnetizing permanent magnets. 
     
     
         11 . A refrigeration system including the magnetic levitating centrifugal compressor according to  claim 1 . 
     
     
         12 . The magnetic levitating centrifugal compressor according to  claim 1 , wherein said end of the motor shaft includes a first end and a second end extending out from said motor cavity, said first end of said motor shaft is mounted with the impeller, said second end of said motor shaft is mounted with a second impeller:
 wherein the sealing system includes a first seal disposed between said first impeller and said motor cavity, for reducing the flow of fluid from said first impeller to said motor cavity;   the sealing system further comprising:   a second seal disposed between said second impeller and said motor cavity, for reducing the flow of fluid from said second impeller to said motor cavity;   a first magnet assembly, said first magnet assembly comprises the first magnet and the second magnet, said first magnet is fixed at an outer surface of said motor shaft and said second magnet is fixed at a side of said first seal facing said motor shaft; and   a second magnet assembly, said second magnet assembly comprises a third magnet and a fourth magnet, said third magnet is fixed at an outer surface of said motor shaft and said fourth magnet is fixed at a side of said second seal facing said motor shaft,   wherein said first magnet and said second magnet form the repulsive force in a radial direction of said motor shaft to keep said first seal and said motor shaft in a concentric levitation, and wherein said third magnet and said fourth magnet form a repulsive force in the radial direction of said motor shaft to keep said second seal and said motor shaft in a concentric levitation.   
     
     
         13 . A refrigeration system including with the magnetic levitating centrifugal compressor according to  claim 12 .