Centrifugal compressor

Abstract

The present invention provides a centrifugal compressor that inhibits possible leakage while reducing a destabilizing fluid force generated in a seal to prevent the possible instable vibration of a rotor. The centrifugal compressor includes a casing, a rotor rotatably installed in the casing and having an impeller, and seals provided in the clearance between the casing and the rotor to prevent a fluid from leaking through the clearance from a high pressure side to a low pressure side. The rotor rotates to compress gas. For example, the balance piston seal is composed of a damper seal with a plurality of holes and a labyrinth seal with an annular parallel groove; the damper seal and the labyrinth seal are continuously provided. The damper seal is disposed on the high pressure side in a leakage flow direction. The labyrinth seal is disposed on the low pressure side in the leakage flow direction.

1 . A centrifugal compressor comprising
 a casing,   a rotor comprising a rotating shaft rotatably installed in said casing and an impeller installed on said rotating shaft, and   a seal preventing a fluid from leaking between said casing and said rotor from a high pressure side to a low pressure side,   wherein said seal has a damper seal with a plurality of cavity formed on a seal surface and a labyrinth seal with a plurality of annular grooves.   
   
   
       2 . The centrifugal compressor according to  claim 1 , wherein said labyrinth seal is provided juxtaposed to said damper seal. 
   
   
       3 . The centrifugal compressor according to  claim 2 , wherein said damper seal is disposed on a high pressure side in a leakage flow of said seal, and said labyrinth seal is disposed on a low pressure side in the leakage flow of said seal. 
   
   
       4 . The centrifugal compressor according to  claim 3 , wherein a length of said damper seal in a leakage flow direction is set to at most half of that of said seal. 
   
   
       5 . The centrifugal compressor according to  claim 4 , wherein a length of said damper seal in a leakage flow direction is set to or larger than a length of said seal multiplied by 0.05.