Multi stage compressor

Abstract

Disclosed is a compressor device for compressing fluid, comprising a motor-compressor housing side portion; a fixed group; and a rotatable group, wherein the fixed group comprises a second stage compressor wheel housing comprising a gap.

What is claimed: 
     
         1 . A compressor device for compressing fluid, comprising:
 a motor-compressor housing side portion;   a fixed group;   a rotatable group;   wherein all elements of the fixed group are fixed relative to the motor-compressor housing side portion so that they do not move relative to the motor-compressor housing side portion;   wherein all elements of the rotatable group are fixed to one another so that they do not move relative to one another;   wherein the motor-compressor housing side portion, the fixed group, and the rotatable group are configured, so that the rotatable group is rotatable about to an axis of rotation relative to the motor-compressor housing side portion and the fixed group, and so that the rotatable group is constrained from moving along the axis of rotation, constrained from rotating perpendicular to the axis of rotation, and constrained from translating perpendicular to the axis of rotation relative to the motor-compressor housing side portion and the fixed group;   wherein the fixed group comprises a motor stator section, a first stage compressor wheel housing, a diffuser structure, and a second stage compressor wheel housing;   wherein the rotatable group comprises a permanent magnet, a first stage compressor wheel; and a second stage compressor wheel;   wherein the motor-compressor housing side portion extends from a motor-compressor housing side portion rear end to a motor-compressor housing side portion front end;   wherein the motor-compressor housing side portion has interior surfaces that define a motor chamber;   wherein the motor stator section and the permanent magnet reside in the motor chamber;   wherein the motor-compressor housing side portion, the fixed group, and the rotatable group are configured to provide a fluid flow path for fluid to flow to a first stage compression passage and then to a second stage compression passage;   wherein the second stage compressor wheel housing comprises a rear disk portion, a front disk portion, and an axially extending neck portion;   wherein the axially extending neck portion comprises a rear region that extends from the rear disk portion and a front region that extends from the front disk portion;   wherein the axially extending neck portion extends from the rear region to the front region;   wherein the rear disk portion has a substantially radially extending rear surface region and a substantially radially extending first portion of a front surface region;   wherein the front disk portion has a substantially radially extending rear surface region and a substantially radially extending front surface portion;   wherein the first stage compression passage includes a first stage initial region and a first stage final region;   wherein the first stage initial region comprises space between a generally cylindrically shaped outer surface region of the first stage compressor wheel and an opposing surface of the first stage compressor wheel housing;   whereby rotation of the rotatable group in a first direction of rotation about the axis of rotation urges fluid in the first stage initial region to move along the fluid flow path towards the first stage final region;   wherein the first stage final region comprises space between opposing surfaces of the diffuser structure and a rear surface region of the rear disk portion;   wherein fluid flowing from the first stage initial region through the first stage final region enters the second stage compression passage;   wherein the second stage compression passage comprises a second stage first region and a second stage second region;   wherein the second stage first region is formed by opposing surfaces of the axially extending neck portion and a generally cylindrically shaped outer surface region of the second stage compressor wheel;   whereby rotation of the rotatable group in the first direction about the axis of rotation urges fluid in the second stage first region to move along the fluid flow path towards the second stage second region;   wherein the second stage second region has one surface formed by the substantially radially extending front surface portion of front disk portion; and   wherein the substantially radially extending first portion of the front surface region of the rear disk portion opposes, and is spaced, along a direction of the axis of rotation, from the substantially radially extending rear surface region of the front disk portion, defining a gap there between.   
     
     
         2 . The compressor device of  claim 1  wherein an aspect ratio of the gap is between 0.3 and 1000. 
     
     
         3 . The compressor device of  claim 1  wherein an aspect ratio of the gap is between 1 and 100. 
     
     
         4 . The compressor device of  claim 1  wherein an aspect ratio of the gap is between 2 and 100. 
     
     
         5 . The compressor device of  claim 1  wherein an aspect ratio of the gap is between 3 and 20. 
     
     
         6 . The compressor device of  claim 1  wherein an aspect ratio of the gap is between 3 and 10. 
     
     
         7 . The compressor device of  claim 1  wherein a thermal ratio is between 0 and 0.8. 
     
     
         8 . The compressor device of  claim 1  wherein a thermal ratio is between 0 and 0.5. 
     
     
         9 . The compressor device of  claim 1  wherein a front disk periphery thickness to gap length ratio is between 0.5 and 10. 
     
     
         10 . The compressor device of  claim 1  wherein a front disk center thickness to gap length ratio is between 0.3 and 10. 
     
     
         11 . The compressor device of  claim 1  wherein the second stage compressor wheel housing further comprises an axially and radially extending support wall extending radially out from the axially extending neck portion and extending axially from the rear disk portion to the front disk portion. 
     
     
         12 . The compressor device of  claim 1  wherein:
 the substantially radially extending rear surface region extends at an angle of within plus or minus thirty degrees from a plane perpendicular to the axis of rotation; 
 the substantially radially extending first portion extends at an angle of within plus or minus thirty degrees from a plane perpendicular to the axis of rotation; and 
 the substantially radially extending front surface portion extends at an angle of within plus or minus thirty degrees from a plane perpendicular to the axis of rotation. 
 
     
     
         13 . The compressor device of  claim 1  wherein:
 the substantially radially extending rear surface region extends at an angle of within plus or minus ten degrees from a plane perpendicular to the axis of rotation; 
 the substantially radially extending first portion extends at an angle of within plus or minus ten degrees from a plane perpendicular to the axis of rotation; and 
 the substantially radially extending front surface portion extends at an angle of within plus or minus ten degrees from a plane perpendicular to the axis of rotation. 
 
     
     
         14 . The compressor device of  claim 1  wherein the diffuser structure comprises a diffuser cover and a diffuser back plate, and wherein the diffuser cover is press fit onto the diffuser back plate. 
     
     
         15 . The compressor device of  claim 1 , further comprising:
 a motor-compressor housing end cap;   wherein a first rear surface region of the motor-compressor housing end cap opposes the substantially radially extending front surface portion of front disk portion and forms a surface of the second stage second region.   
     
     
         16 . The compressor device of  claim 15 , wherein the second stage second region opens to a volute defined by a recessed region of the motor-compressor housing end cap extending azimuthally around axis of rotation  2 , and an opposing front surface portion of the front disk portion. 
     
     
         17 . The compressor device of  claim 16 , and wherein the volute has an opening to a compressor fluid outlet conduit which terminates at a compressor fluid outlet port to space outside the compressor device. 
     
     
         18 . The compressor device of  claim 1 , wherein the interior surfaces of the motor-compressor housing side portion define a motor-compressor housing outlet port. 
     
     
         19 . The compressor device of  claim 18 , wherein the motor-compressor housing side portion, the fixed group, and the rotatable group are configured to provide a fluid flow path for fluid to flow from the motor-compressor housing outlet port to the first stage compression passage.