US 3809493 A
A gear drive and a turbine drive are interchangeably connected to a compressor by means of compatible releasable fasteners between their respective housings and the compressor casing, and with identical releasable coupling means between the overhung compressor rotor and the output shaft of the gear drive or turbine wheel of the turbine drive. Thus, the sole bearing support for the rotor will be carried by the gear drive and the turbine drive. Accurate axial alignment of the compressor casing with the turbine drive and gear drive is obtained by means of abutting cylindrical surfaces of the drive housing and gear casing in telescopic engagement with an overlapping single cylindrical surface, which is preferably a fluid guide; for this purpose, the mounting of the drive housing is provided with radial play or radial adjustment. With the overhung rotor and removable barrel assembly comprising the fluid guide elements, the compressor rotor and fluid guide elements may be removed axially from one direction after uncoupling from the respective drive or axially in the other direction with the respective drive. The arrangement and selection of bearings cooperates with the selection of materials for the rotor, turbine wheel, housing and fluid guide elements to balance thermal expansion.
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Description (OCR text may contain errors)
llnited States Patent [191 Pilarczyk 11] 3,809,493 [451 May 7,1974
[ 1 INTERCHANGEABLE COMPRESSOR DRIVE  Inventor: Karol Pilarczyk, Loudonville, NY.  Assignee: Carrier Corporation, Syracuse, NY.
 Filed: Nov. 29, 1971 ] Appl. No.: 202,849
Related US. Application Data  Continuation of Ser No. 44,403, June 8, 1970.
415/122 R, 415/179  Int. Cl. F04d 25/02, F04d 25/06, F04d 29/44  Field of Search 4l5/l22, 199 A, 219 C, 415/110, 112; 417/406, 407, 374, 405, 409
 References Cited UNITED STATES PATENTS 3,010,697 1l/1961 Lazo et a1. 417/407 1,903,210 3/1933 Carrier 415/122 2,480,435 8/1949 Aspelin 415/199 A 2,695,131 11/1954 Price ..415/l22 2,888,193 5/1959 Greenwald. 415/199 A 3,174,680 3/1965 Young 415/122 3,619,086 11/1971 Johnson 415/122 FOREIGN PATENTS OR APPLICATIONS 917,976 9/1946 France 417/409 497,922 12/1938 Great Britain..... 417 406 626,021 6/1947 Great Britain 415/199 A 980,770 1/1951 France 415/122 at! \\\s\ k\\\\\\\\\\\\\\ V? Z \T%\W 4 E Primary Examiner-Henry F. Raduazo Attorney, Agent, or Firm-Harry G. Martin [5 7] ABSTRACT A gear drive and a turbine drive are interchangeably connected to a compressor by means of compatible releasable fasteners between their respective housings and the compressor casing, and with identical releasable coupling means between the overhung compressor rotor and the output shaft of the gear drive or turbine wheel of the turbine drive. Thus, the sole bearing support for the rotor will be carried by the gear drive and the turbine drive. Accurate axial alignment of the compressor casing with the turbine drive and gear drive is obtained by means of abutting cylindrical surfaces of the drive housing and gear casing in telescopic engagement with an overlapping single cylindrical surface, which is preferably a fluid guide; for this purpose, the mounting of the drive housing is provided with radial play or radial adjustment. With the overhung rotor and removable barrel assembly comprising the fluid guide elements, the compressor rotor and fluid guide elements may be removed axially from one direction after uncoupling from the respective drive or axially in the other direction with the respective drive. The arrangement and selection of bearings cooperates with the selection of materials for the rotor, turbine wheel, housing and fluid guide elements to balance thermal expansion.
1 Claim, 3 Drawing Figures PATENTEDMAY 7 I974 SHEET 1 [1F 3 1 INTERCHANGEABLE COMPRESSOR DRIVE This application is a continuation of application Ser. No. 44,403 entitled Interchangeable Compressor Drive," Karol Pilarczyk, inventor, filed June 8, 1970.
BACKGROUND OF THE INVENTION Compressors are required to be operated in different environments, which will determine the atmospheric conditions or power sources available. For this reason, at many times it is desirable to operate a compressor with a turbine drive or a gear drive. For example, if cheap electrical power is available a gear drive coupled to an electric. motor is desirable where if an explosive atmosphere is present a turbine drive with fluid controls would be most desirable. These drive requiremerits may change after a compressor has been purchased, which according to the prior art would require disposal of expensive equipment.
The interchangeability of drive units would be expected to create considerable problems with respect to alignment of the various parts.
CROSS REF ERENCING TO RELATED APPLICATIONS The features of the invention of this application may be used in combination with the features of the inventions in applicants following related applications of the same filing date and assignee as the present application, the disclosures of which are incorporated herein in their entirety by, reference: fCompressor Barrel Assembly, Ser. No. 44,446 now issued as United States Letters Patent 3,7 17,418; Compressor Power Recovery, Ser. No. 44,463 now issued as United States Letters Patent 3,680,973; Method of Changing Capacity of Fluid Reaction Device, attorneys Ser. No. 44,263 now issued as United States Letters Patent 3,664,001; Compressor Base and Intercoolers," Ser. No. 44,034 now issued as United States Letters Patent 3,644,054.
SUMMARY OF THE INVENTION The compressor of the present invention employs a gear drive and a turbine drive, each having housings that are releasably fastened to the compressor casing of a compressor unit employing an overhung rotor and fluidguide elements arranged as a removable barrel assembly. Axial alignment between the drive housing and compressor casing is obtained by means of abutting equal'diameter cylindrical guide surfaces respectively on the compressor casing and drive housing in telescopic engagement with a single cylindrical guide surface, which is preferably on a fluid guide element. To further this alignment, the drive housing is preferably mounted on the compressor base with radial play or radial adjustment.
The compressor rotor is provided with a releasable coupling for rigid driving engagement with the releasable couplingend of the gear unit output shaft and the turbine wheel shaft. In this manner, the drive unit may be interchanged without disturbing the compressor unit and the compressor unit may be withdrawn as a removable barrel without disturbing the drive unit.
Further objects, features and advantages of the present invention will becomemore clear from the follow- 7 s ta d st p o lstfiiels m 32' ferred embodiment of the present invention is specifi- V al y. !9 d BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial cross-sectional view taken in a vertical' plane passing through the axis of rotation of a complete compressor assembly according to the present invention including an electric motor and gear drive;
FIG. 2 is an enlarged cross-sectional view of a portion of FIG. 1; and
FIG. 3 is a view identical to FIG. 2, but with the turbine drive unit assembled.
DETAILED DESCRIPTION OF THE DRAWING As shown'in FIG. 1, a three-stage centrifugal com pressor is provided with a base 1 rigidly mounting thereon by means of bolts or the like, a fluid inlet 2 having, an inlet valve 3 for controlling the passage of fluid to the compressor stages. A one-piece cast iron compressor casing 4 is rigidly secured to the base 1 and provided with a cylindrical opening having axially stacked annular air guiding elements 5, which cooperate with a single one-piece rotor 6.
The rotor is driven by means of an electric motor 7 that drives gear means 8 through the inter-position of a flexible coupling 9. When the rotor 6 is driven,fluid enters through the inlet 2, is compressed in the first stage of the rotor and discharged through a first pas sage l0 integrally cast in the casing 4. From the passage 10, the fluid passes downwardly through an intercooler 11, upwardly through a demister l2, upwardly through a central passage (not shown) in the base 1 leading to the second passage 13 cast in the casing 4 and finally to the inlet of the second stage. From the second stage the fluid is discharged downwardly through third passage 14 cast in the casing 4, downwardly throught inter-cooler 15, upwardly through demister l6, upwardly through central passage 17, up-
' wardly through fourth passage 18 cast in the casing 4,
and upwardly through the fluid guide elements 5 to thethird stage of the rotor 6.
The gear means 8 are contained within a gear housing 19 that is bolted directly to the compressor casing 4 as will be explained in more detail hereafter. Preferably, the gear housing 19 is cast in one piece from iron and the base 1 is welded, fabricated steel.
As shown more clearly in FIG. 2, the gear casing 19 has opposed side walls 20,21, which are provided with axially extending passages 22,23 receiving therein high speed tilting pad-babitted face bearings 24,25, respectively. The bearings rotatably support an output shaft 26 that drivingly carries a pinion gear 27, which pinion gear 27 is in meshing engagement with a drive gear 28. As shown in FIG. 1, the drive gear 28 is drivingly carried by an input shaft 29 rotatably mounted by opposed low speed, sleeve babitted face bearings 30, 31. The outer axial end of the passage 23 is closed by means of a cover plate secured by bolts 33, with the interposition of a gasket 34, to the gear housing 19. The outer end of the axial passage 23 and the cover plate 32 form a lubricating oil receiving chamber 35 draining through a passage 36 to the oil sump of FIG. l.
The fluid guide elements 5 are most clearly shown in FIG. 2, and include three axially stacked annular, aluminum fluid guides or diaphragms 37,38,39, which are clampingly secured axially to the gear housing 19 by means of a fastener comprising a bolt 40 threaded into the gear housing 19 at one end and provided with a nut 3 r a 41 at its other end. The fluid guides 37, 38, 39 are telescopically received within'the' cylindrical portion of the compressor casing 4 for fluidv communication with the passages 10, 18, 14, 13. The fluid guide elements 5 further include shrouds 42, 43, 44 and diffusers 45, 46, 47, respectively for the individual stages.
The rotor 6 has an axis of rotation axially aligned with the axis of rotation -of output shaft 26, and further has a free terminal axial end 48 and a coupling terminal axial end 49. At the coupling end 49, the rotor 6,t elescopically receives the coupling end of output shaft 26, with a hydraulic shrink fit. This telescopic connection may be tapered and/or splined in any known manner so that it will provide an independently rigid driving coupling that may be released without destroying the respective parts. In this manner, it is seen that the rotor 6 is cantilevermounted solely by means of its coupling end 49, which is rotatably carried by the output shaft 26, whichis in turn rotatably mounted by means of bearings 24, 25; thus, the bearings, 24, 25 provide the only rotatable support bearings for the overhung rotor 6. The rotor 6 comprises a first-stage set of'peripherally arranged blades 50, a second-stage of peripherally arranged blades 51, and a third-stage set of peripherally arranged blades 52. The entire rotor, including blades 50, 51, 52, is constructed integrally in any known manner, for example by casting in one piece, welding fabrication of the three pieces, or shrink fitting fabrication of three pieces. Preferably, the rotor 6 is constructed of stainless steel and has labrinth interstage portions.
The compressor may be disassembled by removal of nut 41 and axial withdrawal of the fluid guide elements 5 along with the rotor 6, which may be accomplished after the coupling at terminal end 49-is disengaged between output shaft 26 and rotor 6 through a central passage within rotor 6 covered by a cap at the free terminal end 48 or the rotor 6 may be removed with the output shaft 26, pinion 27 and bearings 24, 25 secured thereto; in any event, the rotor and fluid guide elements 6, 5 may be axially removed from the compressor casing 4 from the coupling end 49 toward the free terminal end 48. Similarly, these same elements may be removed in the other axial direction by removal of the bolts 53 that secure the gear housing 19 to the .compressor casing 4. Thus, with removal of these bolts 53 the gear casing 19,may be withdrawn tothe right as shown in FIG. 2 to carry with it the gear means 8, the rotor 6 and the fluidguideelements 5; with this withdrawal, the fluid inlet 2 may remain untouched due to the telescopic connection illustrated. Alternately, the gear casing 19 may be removed by uncoupling the output shaft 26 and rotor 6 at the coupling end 49 and removal of the bolts 53, 40, without otherwise disturbing the rotor 6 and fluidguide elements 5.
For proper axial orientation of the gear means 8 and fluid guide elements 5, the bolt 53 is received within an oversize hole in the gear casing 19, to provide for relative radial play and the axial alignment between the I tween the gear housing 19 and base 1, or alternatively the bolts 53 may be eliminated and the gear housing supported solely by the base 1 with radial clearance or shims. In any event, the axial alignment between the gear housing 19 and compressor casing 4 is obtained by respective axially aligned cylindrical guide surfaces overlapping witha cylindrical guide member, with the cylindrical guide member preferably being a fluid guide. The single preferred embodiment of the present invention further includes a turbine drive unit for the rotor 6, which is interchangeable with the previously described gear drive unit. The turbine drive is shown specifically in FIG. 3. e t
In FIG. 3, all of the structural components bearing numerals identical with the numerals employed in FIG.
2 are correspondingly identical with the components of .FIG. 2.
fluid guide elements 5 or base 1 will be the same or compatible. And, the previous discussions with respect to axial alignment and various types of mountings are applicable.
The turbine housing 55 is composed of two iron castings 56, 57 having respective axial passages in opposed walls for mounting the bearings 24, 25; the castings 56, 57 being secured together by means of a bolt 58.
The bladed turbine wheel 59 is rotatably mounted by means of the bearings 24, 25 and has at one axial end releasable coupling means complimentary to the releasable coupling means of rotor 6 at end 49. The releasable coupling means of the turbine wheel 59 is identical to the releasable coupling means of the output shaft 26 of FIG. 2, ie preferably telescopically force fit engaging frusto conical surfaces, which might have alignment splines. Suitable turbine working fluid passages are contained within the turbine housing 55, in a known manner. The actual turbine construction may be of any known type, but is preferably centrigugal.
The compressor of the present invention is a high speed compressor with a direct turbine drive, which by its nature is of high speed, and a gear drive employing only two spur gears with a transmission ratio of 15 to 1. With an electric motor operating at 3,600 rpms the compressor rotor would be driven at approximately 54,000 rpms. The advantage of a single spur gear set, as appreciated with respect to compactness at such a high speed,are readily seen. To enhance the meshing engagement in a known manner, the gears 27,28 are provided with helical teeth, which are angled to offset the-net thrust produced by the three stages of the rotor 6. The inter-cooperation between the gear drive and the turbine drive is further seen by means of this thrust balancing in that the helical gear teeth are matched to produce an axial thrust approximately equal to the expected axial thrust of the turbine bladed wheel 59. In this manner, the effect upon the rotor 6 of the gear drive and turbine drive is substantially identical.
The present invention is so constructed that the net thermal expansion, in the axial direction, of the drive units is correspondingly equal between themselves and correlated tooffset the net thermal expansion, in the axial direction, of the compressor unit rotor and stacked fluid guide elements. For this purpose, the turbine rotor, compressor rotor and gear drive unit output shaft are constructed of steel, with the compressor rotor preferably being stainless steel, the turbine drive unit housing and gear drive unit housing are constructed of cast iron, and the fluid guide elements, including fluid guides, shrouds and diffusers, are constructed of aluminum. The bearing arrangement is such that the outside bearing is the only thrust bearing for establishing the thermal expansion reference point to gain additional shaft length for expansion purposes in offsetting the high expansion rates of the aluminum fluid guide elements that are subjected to high heat. Considerable expansion problems would be encountered if the inside bearing were a thrust bearing, because of the considerable difference between the expansion factors of the stainless steel'compressor rotor and the aluminum air guide elements taking into consideration the temperatures involved; however,the additional expansion length gained by the turbine rotor and output shaft 26 with location of the thrust bearing at the outside, the low expansion values of the cast iron relatively cool drive unit housing are brought into play for their considerable compensating effect. Thus, the gear drive unit and the turbine drive unit are matched with respect to thermal expansion for the embodiment of the present invention.
From the foregoing description it is seen that the complete embodiment of the present invention includes a compressor unit that may be releasably coupled to a gear drive unit and a turbine drive unit, with the understanding that the electric motor is not needed with the turbine drive unit. This affords considerable versatility as the compressor drive may be adapted to the environment and changed as needs change. Further, it is seen that the releasable coupling between the compressor rotor and its drive provides for maximum flexibility and disassembly from either axial direction for required servicing of either the drive or the compressor unit, or interchange of drive units.
Further, axial alignment is assured by axially aligned cylindrical abutting surfaces of the compressor casing and the drive unit housing telescopically received on a single cylindrical guide surface, which is preferably the outer cylindrical portion of the fluid guide 39. Thus, the accuracy needed for high speed operation is maintained.
Further, each of the drive units are so related that they will produce a net thrust to substantially equal the net thrust produced by the compressor rotor, and so related that they will produce a net thermal expansion substantially equal to the net thermal expansion of the compressor rotor, and fluid guide elements.
While a single embodiment of the present invention has been described in detail for purposes of illustrating the invention, along with contemplated variations, there is no intention to be limited solely thereto, as further embodiments, variations and modifications are contemplated.
What is claimed is:
l. Fluid compression apparatus of the radial flow type comprising a substantially cylindrical casing; a rotor positioned within the casing; a plurality of impellers mounted on the rotor; flow guide means arranged within the casing including diaphragms, shrouds and diffusers positioned about the impellers to define paths of fluid flow to and from the impellers, said flow guide means being axially aligned to present a substantially cylindrical outer surface complementary to the inner surface of the casing, the outer surface of the innermost member of the flow guide means extending axially beyond the casing to form a radial shoulder, and detachable closure and rotor drive shaft means including bearing means assembled therein serving to support the rotor in cantilever fashion, said drive means including rigid coupling means for connecting the rotor to the drive shaft in axial alignment therewith, and-an annular flange encircling the radial shoulder formed by the axially extending flow guide means while engaging the member of said casing, and means rigidly connecting the flow guide means to the closure and rotor drive shaft means said last-mentioned means including means whereby limited relative radial movement between the closure and rotor shaft drive means and the casing is obtained.