Bearing Housing and Assembly of a Screw Compressor

Abstract

An improved bearing housing of a rotary screw compressor is described. The bearing housing is generally shorter than a convention bearing housing. The bearing housing can be configured to enclose and support radial bearings of the screw compressor. The bearing housing can be configured not to enclose axial bearings of the screw compressor in an axial direction.

What is claimed is: 
     
         1 . A bearing housing of a screw compressor, comprising:
 a cavity defined by the bearing housing, wherein a depth of the cavity is configured to be no larger than a length of a radial bearing of a screw compressor.   
     
     
         2 . The bearing housing of  claim 1 , wherein the bearing housing is configured to support a radial bearing of the screw compressor. 
     
     
         3 . The bearing housing of  claim 1 , wherein the bearing housing is configured to be positioned to cover an axial end of the screw compressor. 
     
     
         4 . A screw compressor, comprising:
 a rotor including a shaft;   one or more radial bearings attached to the shaft;   one or more axial bearings attached to the shaft; and   a bearing housing, wherein the bearing housing defines a cavity that is configured to support the one or more radial bearings but not the one or more axial bearings.   
     
     
         5 . The screw compressor of  claim 4 , wherein the cavity has a depth and the one or more radial bearings have a length, and the depth of the cavity is not larger than the length of the one or more radial bearings. 
     
     
         6 . The screw compressor of  claim 4 , further comprising:
 a bearing cover, the bearing cover configured to be attached to the bearing housing; wherein the bearing cover is configured to have a clearance with the one or more axial bearings.   
     
     
         7 . The screw compressor of  claim 4 , further comprising:
 a bearing cover, the bearing cover defined a space; wherein the space defined by the bearing cover is configured to enclose the one or more axial bearings.   
     
     
         8 . The screw compressor of  claim 4 , wherein the one or more radial bearings are positioned closer to the rotor than the one or more axial bearings. 
     
     
         9 . A variable capacity screw compressor comprising:
 a rotor housing comprising a suction port,   a working chamber,   a discharge port, and   at least two screw rotors that include a female screw rotor and a male screw rotor being positioned within the working chamber for cooperatively compressing a fluid;   wherein the suction port, the at least two screw rotors and the discharge port being configured in relation to a selected rotational speed;   the selected rotational speed operates at least one screw rotor at an optimum peripheral velocity that is independent of a peripheral velocity of the at least one screw rotor at a synchronous motor rotational speed for a rated screw compressor capacity;   a motor operable to drive the at least one screw rotor at a rotational speed at a full-load capacity that is substantially greater than the synchronous motor rotational speed at the rated screw compressor capacity; and   a variable speed drive to receive a command signal from a controller and to generate a control signal that drives the motor at the rotational speed.