U.S. patent number 3,658,442 [Application Number 05/044,131] was granted by the patent office on 1972-04-25 for compressor.
This patent grant is currently assigned to Northern Research and Engineering Corporation. Invention is credited to Robert O. Chambers, Arnold M. Heitmann.
United States Patent |
3,658,442 |
Heitmann , et al. |
April 25, 1972 |
COMPRESSOR
Abstract
A centrifugal compressor system has a compressor housing
partitioned into a plurality of chambers and a gear chamber that
has a common wall with the compressor housing. A compressor module
support structure is mounted in each chamber on the common wall and
receives a compressor module that has a pinion gear that extends
past the common wall for engagement with a bull gear mounted for
rotation in the gear chamber. Each compressor module has an inlet
shroud that is supported on an intermediate partition of the
compressor housing and a large plenum chamber is defined in front
of each compressor module in part by that intermediate
partition.
Inventors: |
Heitmann; Arnold M.
(Swampscott, MA), Chambers; Robert O. (Medford, MA) |
Assignee: |
Northern Research and Engineering
Corporation (Cambridge, MA)
|
Family
ID: |
21930673 |
Appl.
No.: |
05/044,131 |
Filed: |
June 8, 1970 |
Current U.S.
Class: |
417/243;
415/122.1; 415/230; 415/60; 415/179 |
Current CPC
Class: |
F04D
25/163 (20130101) |
Current International
Class: |
F04D
25/16 (20060101); F04D 25/00 (20060101); F04b
023/00 () |
Field of
Search: |
;415/60,179,219
;417/243,244 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Husar; C. J.
Claims
What is claimed is:
1. A centrifugal gaseous medium compressor system comprising a
compressor housing, means partitioning said housing into a
plurality of chambers, a gear casing having a common wall with said
compressor housing, a bull gear mounted for rotation in said gear
casing, a plurality of compressor module support structures mounted
directly on said common wall, a housing outer wall structure
opposite to and spaced from said common wall, said outer wall
structure having a plurality of ports therein aligned with
corresponding ones of said compressor module support structures,
and a corresponding plurality of compressor modules supported in
said module support structures, each said compressor module
including a shaft and bearing assembly, an impeller, a pinion gear,
a diffuser structure and an inlet shroud supported on said shaft
and bearing assembly, each said inlet shroud being supported on an
intermediate partition of said housing and each said pinion gear
being disposed in said gear casing for driving by said bull gear,
each said compressor module being removable as a unit from its
support structure through the corresponding port in said outer wall
structure of said housing.
2. A centrifugal gaseous medium compressor system comprising a
compressor housing, means partitioning said housing into a
plurality of chambers, a gear casing having a common wall with said
compressor housing, a bull gear mounted for rotation in said gear
casing, a plurality of compressor module support structures mounted
directly on said common wall, a corresponding plurality of
compressor modules supported in said module support structures,
each said compressor module including a shaft and bearing assembly,
an impeller, a pinion gear, a diffuser structure and an inlet
shroud supported on said shaft and bearing assembly, each said
inlet shroud being supported on an intermediate partition of said
housing and each said pinion gear being disposed in said gear
casing for driving by said bull gear, and an outer wall of said
housing opposite said common wall having corresponding ports
through which said compressor modules may be removed from said
housing as units, and a cooler module disposed in said housing in a
flow path between the discharge chamber of one compressor module
and the plenum chamber of another compressor module, said cooler
module including a series of heat exchanger surface elements, and
said outer wall further including a port through which said cooler
module may be withdrawn from said housing as a unit.
3. A centrifugal gaseous medium compressor system comprising a
compressor housing, means partitioning said housing into a
plurality of chambers, a gear casing having a common wall with said
compressor housing, a bull gear mounted for rotation in said gear
casing, a plurality of compressor module support structures mounted
directly on said common wall, a corresponding plurality of
compressor modules supported in said module support structures,
each said compressor module including a shaft and bearing assembly,
an impeller, a pinion gear, a diffuser structure and an inlet
shroud supported on said shaft and bearing assembly, each said
inlet shroud being supported on an intermediate partition of said
housing and each said pinion gear being disposed in said gear
casing for driving by said bull gear and an outer wall of said
housing opposite said common wall having corresponding ports
through which said compressor modules may be removed from said
housing as units, said partitioning means cooperating with each
said inlet shroud to define a plurality of plenum chambers between
said inlet shroud and said outer wall, and each said plenum chamber
being associated with a corresponding compressor module and having
a cross-sectional area at least four times the cross-sectional area
of the compressor module inlet passage as defined by said inlet
shroud.
4. A centrifugal gaseous medium compressor system comprising a
compressor housing, means partitioning said housing into a
plurality of chambers, a gear casing having a common wall with said
compressor hosuing, a bull gear mounted for rotation in said gear
casing, a plurality of compressor module support structures mounted
directly on said common wall, a corresponding plurality of
compressor modules supported in said module support structures,
each said compressor module including a shaft and bearing assembly,
an impeller, a pinion gear, a diffuser structure and an inlet
shroud supported on said shaft and bearing assembly, each said
inlet shroud being supported on an intermediate partition of said
housing and each said pinion gear being disposed in said gear
casing for driving by said bull gear and an outer wall of said
housing opposite said common wall having corresponding ports
through which said compressor modules may be removed from said
housing as units and an annular drain channel formed in said common
wall and communicating via said module support structures with said
shaft and bearing assemblies.
5. A centrifugal gaseous medium compressor system comprising a
compressor housing, means partitioning said housing into a
plurality of chambers, a gear casing having a common wall with said
compressor housing, a bull gear mounted for rotation in said gear
casing, a plurality of compressor module support structures mounted
directly on said common wall, a corresponding plurality of
compressor modules supported in said module support structures,
each said compressor module including a shaft and bearing assembly,
an impeller, a pinion gear, a diffuser structure and an inlet
shroud supported on said shaft and bearing assembly, each said
inlet shroud being supported on an intermediate partition of said
housing and each said pinion gear being disposed in said gear
casing for driving by said bull gear and an outer wall of said
housing opposite said common wall having corresponding ports
through which said compressor modules may be removed from said
housing as units and a drive motor disposed adjacent said gear
casing, said drive motor having a motor shaft extending into said
gear casing and said bull gear being mounted directly on said motor
shaft.
6. The system as claimed in claim 5 wherein each said plenum
chamber has a cross-sectional area at least four times the
cross-sectional area of the compressor module inlet passage as
defined by said inlet shroud.
7. The system as claimed in claim 6 wherein said partitioning means
cooperates with each said inlet shroud to define a plenum chamber
between said inlet shroud and said outer wall.
8. The system as claimed in claim 7 and further including a cooler
module disposed in said housing in a flow path between the
discharge chamber of one compressor module and the plenum chamber
of another compressor module, said cooler module including a series
of heat exchanger surface elements, and said outer wall further
including a port through which said cooler module may be withdrawn
from said housing as a unit.
9. The system as claimed in claim 8 and further including an
annular drain channel formed in said common wall and communicating
via said module support structures with said shaft and bearing
assemblies.
10. A centrifugal gaseous medium compressor system comprising a
compressor housing, a plurality of compressor module support
structures in said housing, a corresponding plurality of compressor
modules supported in said module support structures, partition
means in said housing dividing said housing into a plurality of
chambers with an inlet plenum chamber and a discharge chamber
associated with each compressor module, said partition means
further defining a flow path between the discharge chamber of one
compressor module and the inlet plenum chamber of another
compressor module, a cooler module support structure disposed in
said flow path, a cooler module including a series of heat
exchanger surface elements releasably secured to said cooler module
support structure, said housing having an outer wall with
individual spaced ports therein and aligned with corresponding ones
of said compressor module support structures and said cooler module
support structure through which said compressor and coller modules
may be withdrawn as individual units and means for sealing said
ports.
11. A centrifugal gaseous medium compressor system comprising a
compressor housing, means partitioning said housing into two
chambers, an aperture in said partitioning means, a gear casing
having a common wall with said compressor housing, a bull gear
mounted for rotation in said gear casing, a compressor module
support structure on said common wall and extending into one of
said chambers, a housing outer wall on the opposite side of said
chambers from said common wall, said outer wall having a port
therein aligned with said compressor module support structure, a
compressor module supported in said module support structure, said
compressor module including shaft and bearing assembly, an
impeller, a pinion gear, a diffuser structure and an inlet shroud
supported on said shaft and bearing assembly, said inlet shroud
being secured in sealing relation in said aperture of said
partitioning means, the second of said chambers being a plenum
chamber through which the medium to be compressed is supplied and
having a cross-sectional area at least four times the
cross-sectional area of the compressor module inlet passage as
defined by said inlet shroud, and said shaft and bearing assembly
extending through said common wall so that said pinion gear is
disposed in said gear casing for driving by said bull gear, said
compressor module being removable as a unit from its support
structure through said port in said outer wall of said housing.
12. Centrifugal gaseous medium compressor apparatus comprising a
housing, a compressor assembly mounted within the housing, said
compressor assembly including an impeller assembly and an inlet
shroud that defines an inlet passage to said impeller assembly,
structure defining a plenum chamber through which the gaseous
medium to be compressed passes immediately adjacent the compressor
assembly inlet shroud, said plenum chamber being within a distance
equal to the inlet diameter of said inlet shroud from the forward
blade edge of said impeller assembly and having a cross-sectional
area at least four times the cross-sectional inlet area of said
compressor assembly as defined by said inlet shroud.
13. The compressor assembly as claimed in claim 12 wherein the
cross-sectional area of said plenum chamber is at least ten times
said cross-sectional inlet area of said compressor assembly.
14. The apparatus as claimed in claim 13 wherein said apparatus
includes a plurality of compressor assembly modules and associated
close coupled plenum chambers and further including a cooler module
disposed in said housing in a flow path between the discharge
chamber of one compressor module and the plenum chamber of another
compressor module, said cooler module including a series of heat
exchanger surface elements, and said housing further including a
port through which said cooler module may be withdrawn from said
housing as a unit.
15. The apparatus as claimed in claim 14 and further including
partitioning means cooperating with each said inlet shroud to
define a plenum chamber between said inlet shroud and the outer
wall of said housing.
16. The apparatus as claimed in claim 15 and further including a
drive motor having a motor shaft, and a bull gear mounted directly
on said motor shaft for engaging drive pinions of said compressor
assembly modules.
Description
SUMMARY OF INVENTION
This invention relates to centrifugal gaseous medium compressors,
and more particularly to multi-stage centrifugal compressor
systems.
An object of this invention is to provide a novel and improved
multi-stage centrifugal compressor system which incorporates
modular components, and which facilitates manufacture and
maintenance.
Another object of the invention is to provide a novel and improved
compressor arrangement.
Another object of the invention is to provide a novel and improved
multi-stage centrifugal compressor arrangement employing a modular
arrangement of impeller shafts having graduated rotational speeds
so as to achieve advantageous compression conditions per compressor
stage for the several impellers while providing a convenient and
economical drive arrangement.
A further object of the invention is to provide novel and improved
multi-stage centrifugal compressor arrangement which has a compact
flow path arrangement through the impeller and cooler stages,
requires a small amount of space and presents an attractive
appearance.
A further object of the invention is to provide a novel and
improved multi-stage centrifugal compressor arrangement having
conveniently arranged cooling and lubrication arrangements.
Still another object of the invention is to provide novel and
improved arrangements for driving a multi-stage centrifugal
compressor assembly.
A further object of the invention is to provide a gaseous medium
compressor arrangement having improved efficiency.
In accordance with one feature of the invention there is provided a
centrifugal gaseous medium compressor system having a compressor
housing, with a plurality of compressor module support structures
in the housing which support a corresponding plurality of
compressor modules each of which includes an impeller and bearing
assembly. Partition means in the housing divides the housing into a
plurality of chambers with an inlet plenum chamber and a discharge
chamber associated with each compressor module. The partition means
further defines a flow path between the discharge chamber of one
compressor module and the inlet plenum chamber of the next
compressor module, and a cooler module including a series of heat
exchanger surface elements is disposed in that flow path. The
housing has an outer wall with individual ports in it through which
the compressor and cooler modules may be withdrawn as individual
units.
In a preferred embodiment each compressor module includes a
centrifugal compressor impeller, a diffuser, and the necessary
seals, bearings and pinion gear in a modular assembly, and each
cooler module is a self-contained unit having heat exchanger
surface elements and water manifolds and the partition means. The
system further includes a gear casing that has a common wall with
the compressor housing. A bull gear is mounted in that casing and
the pinion gears of the compressor modules extend through the
common wall into the gear casing and are engaged by the bull gear.
A drive motor is disposed adjacent the gear casing and has a motor
shaft that extends into the gear casing and the bull gear is
mounted directly on that motor shaft.
In accordance with another features of the invention there is
provided centrifugal gaseous medium compressor apparatus having a
housing and a compressor assembly mounted within the housing. The
compressor assembly includes an impeller assembly and an inlet
shroud defining an inlet passage. A plenum chamber through which
the gaseous medium to be compressed passes is immediately adjacent
the compressor assembly inlet shroud; the plenum chamber being
within a distance equal to the inlet diameter of the inlet shroud
from the forward blade edge of the impeller and having a
cross-sectional area at least four times the cross-sectional inlet
area of the compressor assembly as defined by its inlet shroud. In
preferred embodiments the cross-sectional area of the plenum
chamber is at least ten times the cross-sectional inlet area of the
compressor assembly. This close coupled plenum chamber-compressor
assembly arrangement provides a significant increase in compressor
efficiency. Such arrangement also permits the close positioning of
an inlet throttle valve without adversely affecting the performance
of the compressor.
In a particular embodiment, the compressor housing is a rectangular
housing in which three compressor modules and three cooler modules
are mounted. This housing has dividing partitions which define the
air passages and close coupled plenum chambers that route the air
in the required sequence through the compressor and cooler modules.
The compressor and cooler modules are assembled into the housing
through access ports in the front of the housing and are easily
inspectable from these ports and easily removed without
disconnecting drive structure or piping. Water connections to the
cooler modules are made on the back side of the compressor housing
through appropriately sealed ferrule assemblies that facilitate
insertion and removal.
The drive motor is of the face mounting configuration and an
adapter plate bolted to the face of the motor serves as the rear
wall of the gear casing. The bull gear is mounted directly on the
drive motor shaft, thus eliminating the need for bull gear bearings
and the problems of couplings and coupling misalignment. A common
base for the compressor housing and the drive motor contains a
lubrication oil module and control cabinet. The lubrication module
is an assembly of the necessary lubrication oil conditioning
equipment and typically includes a lubrication oil cooler, a pump,
pressure regulating valves and temperature sensors.
Compressor controls include throttling means for throttling the
compressor inlet to maintain constant discharge pressure and also
to prevent surge. Other controls include sensing, drive motor
overload protection and lube oil temperature pressure sensing,
cooling water pressure and vibration sensors. Any one of the key
elements of the assembly can be removed without disturbing other
elements, including any of the rotor assemblies, any of the
coolers, the lubrication oil module, or the control module.
Other objects, features and advantages of the invention will be
seen as the following description of a particular embodiment
progresses, in conjunction with the drawings, in which:
FIG. 1 is a perspective view of a three-stage centrifugal air
compressor system constructed in accordance with the invention,
showing a compressor module and a cooler module spaced from the
compressor assembly housing;
FIG. 2 is a top plan view with parts broken away of the compressor
system shown in FIG. 1;
FIG. 3 is side elevational view with parts broken away of the
compressor system shown in FIG. 1;
FIG. 4a is a diagrammatic view of components of the compressor
system;
FIG. 4b is an exploded diagrammatic view corresponding to FIG. 4a,
showing the air flow path through components of the compressor
system;
FIG. 5 is a sectional view showing details of a compressor module
employed in the system shown in FIG. 1;
FIG. 6 is a perspective view with parts broken away showing details
of a cooler module employed in the system shown in FIG. 1;
FIGS. 7-10 are sectional views taken along the lines 7--7, 8--8,
9--9, and 10--10, respectively, of FIG. 2; and
FIGS. 11 and 12 are sectional views taken along the lines 11--11
and 12--12, respectively, of FIG. 3.
DESCRIPTION OF PARTICULAR EMBODIMENT
With reference to FIGS. 1-3, the apparatus includes a base 10 on
which a compressor assembly housing 12 is mounted at its left end
and a prime mover 14 in the form of an electric motor is mounted at
its right end. A control panel 16 is mounted on one side of motor
14 and a system for supplying lubricating oil to the compressor
assembly is mounted on the opposite side of motor 14. Chamber 20
disposed between motor 14 and compressor housing 12 houses a bull
gear 22 that is mounted directly on the shaft 24 of motor 14.
The compressor assembly in housing 12 includes three compressor
stages 30, 32 and 34 and three cooler structures 36, 38 and 40
disposed in rectangular housing 12. Each compressor stage and
cooler structure is removable as a unit through an access port in
the left end wall 42 of housing 12, compressor stages 30, 32 and 34
being removable through ports 44, 46 and 48 covered by plates 50,
52 and 54, respectively; and cooler stages 36, 38 and 40 being
removable through ports 56, 58, 60 and having integral cover plates
62, 64 and 66, respectively. Inlet conduit 68 is attached to plate
50 and may include a throttling valve; and outlet conduit 70
extends upwardly from the top wall 72 of housing 12.
A diagrammatic view of the compressor assembly is shown in FIG. 4a
and a corresponding exploded view is shown in FIG. 4b. Air is
introduced into the compressor assembly through inlet conduit 68 to
plenum chamber 74 which communicates with the inlet of first
compressor stage 30. That compressor stage discharges air into
discharge chamber 76 which translates the compressed air through
cooler 36 to plenum chamber 78 at the inlet to compressor stage 32.
The compressed air from that stage is discharged into chamber 80
for transfer to cooler 38 to plenum chamber 82 which communicates
with the inlet to compressor stage 34. Compressor stage 34 is
mounted to discharge air into discharge chamber 84 and transfer
that air through aftercooler 40 and chamber 86 to outlet conduit
70.
A sectional view of compressor module stage 30 and plenum chamber
74 which is illustrative of the construction of module stages 32
and 34 (although those stages are of graduated smaller size) and
their associated plenum chambers, is shown in FIG. 5.
The compressor module is received directly in a mounting boss 90
that projects forwardly from the front wall 92 of the gear case 20
and receives its primary support from this mounting structure.
Additional support is provided by the interconnection of the inlet
shroud 94 of the module with partition 96 in the compressor case
between chambers 74 and 76. The compressor impeller 98 and shaft
100 are an integral assembly, the impeller 98 being cast from a
corrosion resistant steel and welded to shaft 100. The pinion gear
102 is press fitted on shaft 100. Shaft housing 104 includes
hydrodynamic radial bearings 106, 108, the impeller end bearing 106
of the three lobed type and the pinion end bearing 108 is of the
simple journal type. Thrust bearing 110 is of the simple stepped
type. The main thrust is towards the impeller and a thrust washer
112 captured by the pinion 102 provides the main positioning
surface. A position control thrust bearing 114 located at the end
of the bearing housing 104 uses the back face of the pinion as a
runner surface. The shaft seal 116 is a two-stage seal, the primary
seal or oil side being a mechanical or nose type seal and the
second stage a simple labyrinth. The oil to the radial and thrust
bearings is supplied from the lubrication supply line 118 into the
compressor cartridge via an annular passage 120 formed by the
stepped diameter of the bearing housing 104 and the receiving bore
in the support boss 90. Lubrication flow control is established by
the sizing of the drilled holes required to port the oil to various
bearing supply areas. Passage 122 provides a vent. Drainage from
the bearings is ported away from the bull gear and flows to an
annular recess 124 covered by plate 126 in the forward face of the
bull gear chamber 20.
The compressor diffuser 128 is formed by a flat plate having a
series of vanes 130 cast thereon. This plate is bolted to the
housing 104 and the shroud 94 is secured in accurately centered
relation to the diffuser 128 and bearing cartridge 104 by dowel
pins and bolts. The entire compressor module may be removed as a
unit by unbolting the inlet bellmouth shroud structure 94 from
partition 96 and sliding the unit out to initially disengage pinion
102 from bull gear 22 and then to remove the unit through the
plenum chamber 74 and port 44.
Plenum chamber 74 is close coupled to compressor module 30, wall 96
being a partition separating plenum chamber 74 from compressor
discharge chamber 76. The plenum chamber side of wall 96 is located
at a distance from the front end 132 of impeller blades 134 of
about one-half the compressor inlet diameter indicated by dimension
136 and chamber 74 has a cross-sectional area about 25 times the
cross-sectional area of the compressor inlet and a length of about
twice the inlet diameter 136.
A diagrammatic view of a cooler module is shown in FIG. 6. In a
typical module, the intercooler includes a multipass,
cross-counterflow arrangement having tube-fin heat exchange
surfaces. The air side is formed of aluminum plates 140 spaced
approximately 0.050 inch apart and the water side formed by 3/4
inch copper tubing 142. Each intercooler module has two headers
144, 146, both headers having baffling 148 to provide the
appropriate number of water passes. The inner header 146 containing
inlet and discharge ports 150, 152. The flow is from header section
146-1 through tubes 142 to header section 144-1 and return through
a second set of tubes 142 to header section 146-2 and then return
again to header section 144-2 for final pass back through still
another set of tubes 142 to header section 146-3 and discharge
through connection 152. These ports match up with appropriate water
supply and drain port structures 154, 156 in wall 92 of the
compressor case and the interface junction is sealed by O-ring seal
ferrules 158. Moisture condensed out during the intercooling
process is collected by the fins 140 and drained to the bottom of
the intercooler chamber chamber 160 and to a sump 162 (FIG. 8)
which is piped through usual water traps to an overboard drain.
Flexible seal structures 164 are mounted on either side of the
cooler module and engage two opposed walls 166, 168 of the chamber
160 in which the module is received. At the front end of the cooler
module is a flange structure which is bolted with appropriate seals
to the wall 42 of the compressor assembly housing 12, securing the
module in position in the flow path in the compressor system. The
entire cooler module may be removed as a unit by unbolting the
plate structure and sliding the unit out to remove the unit through
the port.
Further details of the assembly are indicated in FIGS. 7-12. An end
view of the compressor assembly in FIG. 7 shows the access plates
over the access ports in wall 42. In FIG. 8 there are indicated the
cooling water inlet line 200 and cooling water outlet line 202 that
communicate with each of the three cooler modules, lubrication
supply line 204 which communicates with supply manifold 122 and
lubrication drain line 206 which communicates with annular drain
manifold 124. This manifold, as indicated in FIGS. 5 and 8, may be
machined directly in the wall 92. With reference to FIGS. 9-12,
plenum chamber 74 is defined by partitions 210, 212, 214, top wall
72, transverse wall 96 and front wall 42. Discharge chamber 76 is
defined by rearward extension of wall 210, side wall 218, top wall
216, lower wall 220, partition walls 96, 212 and 214, and wall 92
between the compressor compartment and the bull gear compartment.
Thus discharge chamber 76 has common walls with plenum chamber 74.
Intercooler module 36 is disposed in a chamber whose upper wall is
an extension of partition 214 and lower wall is a portion of the
drain floor wall 220, the inner side wall is partition 222; and
front and rear walls are structures 42 and 92, respectively.
The plenum chamber 78 has as a top wall a portion of partition 214,
a bottom wall part of partition 220, a side wall as partition 224,
front wall 42 and rear wall 96. The discharge chamber 80 for
compressor module 32 is defined by partitions 214, 220, 222, 224,
front wall 42 and rear wall 92. Intercooler 38 is disposed between
the discharge chamber 80 and inlet plenum chamber 82 to the third
compressor module. Chamber 82 is bounded by side wall 226,
partitions 96 and 214, top wall 216, and front wall 42. The
discharge chamber 84 for the third stage is formed between
partition 230 and top wall 216, partition 210 and side wall 226,
and partition 96 and rear wall 92. Aftercooler 40 is disposed in
this chamber and the air after flowing through that aftercooler is
discharged to conduit 70.
As an illustrative example, in this compressor assembly with an 800
horsepower motor, compressor stage 30 has a shaft speed of 61,800
rpm, compressor stage 32 has a shaft speed of 42, 400 rpm, and
compressor stage 34 has a shaft speed of 29,100 rpm. A compressor
unit of this frame size has an overall width of 4 feet and an
overall height of 5 feet and is 6 feet, 9 inches long.
While a particular embodiment of the invention has been shown and
described, various modifications thereof will be apparent to those
skilled in the art and therefore it is not intended that the
invention be limited to the disclosed embodiment or to details
thereof and departures may be made therefrom within the spirit and
scope of the invention as defined in the claims.
* * * * *