Centrifugal compressor with controlled tolerance stack and methods of assembling the same
A centrifugal compressor includes a compressor housing, a motor and a rotatable shaft. A bearing housing defines a center bore that receives the shaft, and a volute assembly is positioned in the socket adjacent the bearing housing. The volute assembly has a back axial surface facing the bearing housing, stops protruding from the back axial surface. The stops abut the datum to limit tolerance stack between the bearing housing and the volute assembly. Each of the bearing housing and the volute assembly are secured to the datum.
1 . A method of assembling a compressor that includes a compressor housing, the compressor housing having a datum, the method comprising:
positioning a motor and a rotatable shaft in the compressor housing;
positioning a bearing housing in the compressor housing, the bearing housing defining a center bore that receives the shaft, wherein positioning the bearing housing comprises abutting the datum with the bearing housing and aligning the compressor housing with the bearing housing using a first fit band; and
positioning a volute assembly in the compressor housing adjacent to the bearing housing, the volute assembly comprising a diffuser plate, a volute plate defining a back axial surface of the volute assembly facing the bearing housing, one or more stops protruding from the back axial surface, and a second fit band, wherein positioning the volute assembly comprises:
positioning the volute plate in the compressor housing adjacent the bearing housing;
abutting the datum with the one or more stops and aligning the compressor housing with the volute assembly using the second fit band, wherein abutting the datum with the bearing housing and the one or more stops limits axial tolerance stack between the bearing housing and the volute assembly;
securing the volute plate to the datum via holes extending through the one or more stops that abut the datum; and
positioning the diffuser plate in the compressor housing adjacent the volute plate to form the volute assembly;
wherein the first fit band and the second fit band limit axial tolerance stack to a centerline of the compressor housing.
2 . The method of claim 1 , wherein a radial bearing is positioned in the center bore of the bearing housing for rotatably supporting the shaft, wherein abutting the datum with the bearing housing and the one or more stops limits tolerance stack between the bearing housing and the volute assembly from causing axial misalignment of the radial bearing.
3 . The method of claim 1 , wherein the volute assembly defines an impeller area, wherein the method further comprises:
attaching an impeller to the shaft such that the impeller is positioned in the impeller area; and
sealing the impeller in the impeller area using mechanical seals;
wherein abutting the datum with the bearing housing and the one or more stops limits tolerance stack between the bearing housing and the volute assembly from causing axial misalignment of the mechanical seals.
4 . The method of claim 1 , further comprising connecting an end cap to the compressor housing and securing the volute assembly in the compressor housing with the end cap.
5 . The method of claim 1 , wherein the bearing housing includes one or more slots, wherein positioning the volute assembly comprises passing each one of the stops through one of the slots to abut the datum.
6 . The method of claim 1 , wherein positioning the volute assembly comprises angularly aligning the volute assembly relative to the bearing housing.
7 . The method of claim 6 , wherein angularly aligning the volute assembly relative to the bearing housing comprises inserting an alignment member through the bearing housing and the volute assembly.
8 . The method of claim 1 , wherein each fit band comprises a raised portion.
9 . The method of claim 1 , wherein a diameter of each fit band is less than a diameter of the compressor housing.
10 . The method of claim 1 , further comprising securing the bearing housing to the datum prior to positioning the volute assembly in the compressor housing.
11 . The method of claim 1 , further comprising angularly aligning the diffuser plate relative to the volute plate using one or more alignment members.
12 . The method of claim 1 , further comprising positioning a thrust disk between the bearing housing and the back axial surface of the volute assembly.
13 . The method of claim 1 , further comprising:
assembling an inlet guide vane assembly with an end cap; and
connecting the end cap assembled with the inlet guide vane assembly to the compressor housing.
14 . The method of claim 1 , wherein the compressor housing has a second datum, the method further comprising:
positioning a second bearing housing in the compressor housing, the second bearing housing defining a second center bore that receives the shaft, wherein positioning the second bearing housing comprises abutting the second datum with the second bearing housing; and
positioning a second volute assembly in the compressor housing adjacent the second bearing housing, the second volute assembly having a second back axial surface facing the second bearing housing and one or more stops protruding from the second back axial surface, wherein positioning the second volute assembly comprises abutting the second datum with the one or more stops, wherein abutting the second datum with the second bearing housing and the one or more stops of the second volute assembly limits tolerance stack between the second bearing housing and the second volute assembly.