U.S. patent number 3,853,433 [Application Number 05/454,304] was granted by the patent office on 1974-12-10 for refrigeration compressor defining oil sump containing an electric lubricant pump.
This patent grant is currently assigned to The Trane Company. Invention is credited to John H. Roberts, Gordon L. Temp.
United States Patent |
3,853,433 |
Roberts , et al. |
December 10, 1974 |
REFRIGERATION COMPRESSOR DEFINING OIL SUMP CONTAINING AN ELECTRIC
LUBRICANT PUMP
Abstract
A compression cycle refrigeration system is shown having a
two-stage direct-drive hermetic centrifugal compressor. The thrust
bearing for the compressor impeller is mounted remote from the
impeller for easy inspection and service. The centrifugal
compressor housing defines a lubricant pump incorporating an
electric motor driven lubricant pump.
Inventors: |
Roberts; John H. (La Crosse,
WI), Temp; Gordon L. (La Crosse, WI) |
Assignee: |
The Trane Company (La Crosse,
WI)
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Family
ID: |
26964083 |
Appl.
No.: |
05/454,304 |
Filed: |
March 25, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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286806 |
Sep 6, 1972 |
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Current U.S.
Class: |
417/423.13;
62/469; 184/6; 415/160 |
Current CPC
Class: |
F04D
27/0246 (20130101); F04D 25/0606 (20130101); F25B
1/053 (20130101); F04D 29/057 (20130101); F04D
17/125 (20130101) |
Current International
Class: |
F04D
29/04 (20060101); F25B 1/053 (20060101); F25B
1/04 (20060101); F04D 17/12 (20060101); F04D
25/06 (20060101); F04D 25/02 (20060101); F04D
17/00 (20060101); F04b 017/00 () |
Field of
Search: |
;417/423 ;184/6C,6L
;62/469 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Husar; C. J.
Parent Case Text
This is a continuation of application Ser. No. 286,806, filed Sept.
6, 1972, now abandoned.
Claims
We claim:
1. A refrigerant centrifugal compressor comprising: a compressor
housing; a shaft disposed within said housing; bearing means for
rotatably supporting said shaft in said housing; a centrifugal type
fluid impeller disposed within said housing and mounted for
rotation with said shaft; an annular inlet member disposed within
said housing to conduct fluid to the inlet of said impeller and
coaxially arranged with respect to said shaft; a plurality of inlet
control vanes disposed in said inlet member; portions of said inlet
member being radially inwardly spaced from said housing thereby
defining a substantially annular cavity between and axially
coextensive with said compressor housing and said inlet member; a
lubrication system for said compressor including first conduit
means for conducting lubricant to said bearing means; and second
conduit means for draining lubricant from said bearing means to
said annular cavity whereby said annular cavity defines as a
lubricant sump; means for mechanically adjusting said control vanes
disposed within said cavity; passage means for venting the upper
portion of said cavity to the inlet of said compressor; and
pressurizing means for pressurizing lubricant from said sump and
returning pressurized lubricant to said bearing means via said
first conduit means.
2. The apparatus as defined in claim 1 wherein said pressurizing
means is a lubricant pump disposed within said annular cavity.
3. The apparatus defined by claim 2 including a first electric
motor drivingly connect to said shaft.
4. The apparatus as defined by claim 3 including a second electric
motor drivingly connected to said pump; said second electric motor
being disposed within said annular cavity.
Description
SUMMARY OF THE INVENTION
This invention relates to centrifugal compressors for a
refrigeration machine. More particularly this invention relates to
a lubrication system for such a compressor in which the eye of the
compressor inlet and the compressor housing together define a
substantially annular chamber containing housing an electric motor
driven lubricant pump. The chamber functions as a lubricant sump
from which the lubricant is withdrawn by the pump and delivered to
the compressor bearings. The chamber is vented to compressor
suction inlet for removal of refrigerant vapors from the lubricant
sump.
Other aspects and advantages will be apparent as this specification
describes the invention in detail with reference to the drawing in
which the sole FIGURE shows a vertical section of a centrifugal
refrigerant compressor incorporating the invention and
schematically connected in a refrigeration system.
Now with reference to the drawing it will be seen that the
refrigeration system 10 has a centrifugal refrigerant compressor 12
connected to discharge compressed refrigerant into a refrigerant
condenser 14 which may be cooled by water as at 13. The condensed
refrigerant then passes through a flow control 16 which may be in
the form of a float or other device for regulating the flow of
condensed refrigerant to a refrigerant evaporator 18, the heat for
evaporation being provided by the refrigeration system load 19. The
vaporized refrigerant is returned to the suction side of the
compressor.
The compressor 12 has a compressor housing 24 including a motor
portion 26 and a compressor portion 28. Motor potion 26 is provided
with a pair of spaced bearings 30 and 32 which rotatably support a
compressor drive shaft 34. Mounted for rotation with shaft 34
between bearings 30 and 32 is a motor rotor 36 operatively
associated with motor stator 38 of compressor motor 37 supported
within portion 26 of housing 24.
One end of drive shaft 34 extends beyond bearing 32 into the
compressor portion 28 of housing 24. First and second stage
centrifugal fluid impellers 40 and 42 respectively are mounted at
this end of shaft 34 which is cantilevered beyond bearing 32.
Impellers 40 and 42 are appropriately rigidly secured to shaft 34
for rotation therewith. The impellers 40 and 42 are surrounded by
the compressor stator members 44 fixedly secured within portion 28
of housing 24 which defines diffuser passages for receiving fluid
from each of the impellers and an interstage passage for conveying
fluid from the first stage diffuser to the inlet of the second
stage impeller. This interstage passage has a plurality of
circumferentially spaced second stage inlet guide vanes 46 which
are adjustable through a linkage 48 and guide vane control shaft
50. An annular inlet member 52 is disposed within housing 24 for
conducting fluid from the suction line to the inlet of the first
stage impeller 40. Annular inlet member 52 contains a plurality of
circumferentially spaced first stage inlet guide vanes 54 which are
adjustable through linkage 56 and guide vane control shaft 50.
The annular cavity defined between housing portion 28 and inlet
member 52 serves as a lubrication system sump 22 in addition to
providing space for linkage 56. Oil return lines 58 are connected
to drain lubricating oil from bearings 30 and 32 to sump 22.
The lower portion of housing portion 28 is provided with an
aperture 60 which is closed by a removable cover plate 62.
Connected at the inner side of plate 62 is a lubricant pump 64
positioned to receive lubricant from the lower portion of sump 22
through an inlet 66 and from whence lubricant is discharged under
pressure to bearings 30 and 32 through lubricant supply lines 68.
Pump 64 is driven by an electric motor 70 also supported on the
inner side of plate 62 within the annular cavity between housing 24
and inlet member 52. This cavity is further provided with a vent 72
to the first stage impeller inlet downstream of inlet control vanes
54 through a standpipe 74. Standpipe 74 effectively places the vent
for sump 22 at the upper most location so that even if there be
foaming of lubricant within sump 22, such foam is unlikely to reach
an elevation sufficient to allow oil to enter the top of standpipe
74. Oil is also prevented from passing through the annular space
between impeller 40 and inlet guide member 52 by reason of an
O-ring seal 76.
During operation of the system, the impellers 40 and 42 exert a net
axial force on shaft 34 due to the unbalance of pressures on
opposite sides of the impellers as dictated by the location of
seals associated therewith as at 29, 33, and 35. In the particular
impeller arrangement shown, this force would be to the right. To
oppose this force shaft 34 is provided with an annular thrust plate
78 which is secured to shaft 34 for rotation therewith as by thrust
plate retainer nut 80. Thus during operation of the compressor
thrust plate 78 is caused to bear against a plurality of
circumferentially spaced thrust pads 82 pivotly supported on a flat
annular face 84 within the member defining bearing 30 adjacent the
other end of shaft 34 opposite from the end supporting impellers 40
and 42. The thrust bearing 81 formed by plate 78 and pads 82 is
lubricated by lubricant overflow from bearing 30. A shoulder on
shaft 34 in abutment with the end of bearing 30 as at 31 limits
movement of the shaft to the left such as may occur during
shipment. The compressor motor is provided with a seal 86 between
bearing 30 and motor 37, to maintain the bearing lubricant separate
from the cooling medium (usually refrigerant) within the motor. The
lubricant supply and drain lines 68 and 58 are provided with
shutoff valves 88. By closing valves 88 and removing bearing cover
plate 90, thrust bearing 81 may be inspected and replaced if
necessary. During this period when plate 90 is removed seal 86 will
minimize leakage between the compressor motor and the
atmosphere.
Having now described the preferred embodiment of the invention, it
is contemplated that many changes may be made without departing
from the scope or spirit of the invention as limited only by the
claims.
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