U.S. patent number RE29,378 [Application Number 05/596,364] was granted by the patent office on 1977-08-30 for compact housing for rotary compressor system.
This patent grant is currently assigned to Worthington Compressors, Inc.. Invention is credited to Carl Bloom.
United States Patent |
RE29,378 |
Bloom |
August 30, 1977 |
Compact housing for rotary compressor system
Abstract
A rotary compressor assembly constructed to prevent leakage from
the compressor housing to atmosphere through the interface between
the cylindrical section and the covers of the housing. The
compressor is disposed substantially within the tank which receives
the compressor discharge and is connected to the wall of the tank.
A seal between the compressor and the tank wall seals the tank and
thereby prevents leakage from the compressor to atmosphere.
Inventors: |
Bloom; Carl (Springfield,
MA) |
Assignee: |
Worthington Compressors, Inc.
(Holyoke, MA)
|
Family
ID: |
27082529 |
Appl.
No.: |
05/596,364 |
Filed: |
July 16, 1975 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
785304 |
Dec 9, 1968 |
03547164 |
Dec 15, 1970 |
|
|
Current U.S.
Class: |
55/473; 141/326;
418/93 |
Current CPC
Class: |
F01C
21/10 (20130101); F04C 23/00 (20130101); F04C
29/02 (20130101) |
Current International
Class: |
F04C
23/00 (20060101); F04C 29/02 (20060101); F01C
21/00 (20060101); F01C 21/10 (20060101); B01D
046/00 () |
Field of
Search: |
;141/326 ;418/93
;222/400.8,401,402 ;55/473 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bell, Jr.; Houston S.
Claims
I claim:
1. A rotary compressor assembly comprising:
tank means for receiving compressed fluid, said tank means having
one wall defining an opening and inner and outer wall surfaces,
said tank means also having a discharge outlet for compressed
fluid;
fluid compressing means including a housing disposed to extend into
said opening in said tank means and a rotor mounted within said
housing;
a drive means for said compressing means, said drive means
including a drive shaft connected to said rotor;
said compressing means having an inlet disposed at a point external
to said tank means and an outlet within said tank means to permit
compressed fluid to be discharged therein;
.Iadd.demister means mounted in said tank means for separating out
oil mixed in the discharge from said fluid compressing means;
.Iaddend.
said compressing means housing having cover means at the opposite
ends thereof, one cover means being connected to the inwardly
disposed end of the housing and the other cover means being
connected to the opposite end of the housing and the one wall of
the tank at the periphery of the opening, said other cover means
coacting with said housing and said rotor to provide an operative
seal between the outward end of said rotor and said other cover
means;
sealing means located between one of said wall surfaces and the
confronting surfaces of said other cover means adjacent the opening
in the one wall of said tank means;
means providing a mechanical seal for said drive shaft at a point
outboard of said other cover means; and
means to connect said other cover means at one end of said housing
to said tank means about said opening for mounting said compressing
means in operative relation to said tank and to permit said cover
means and said sealing means to form a fluid tight cover for said
opening in said tank means, and thereby prevent leakage from said
compressing means housing to atmosphere.
2. The combination claimed in claim 1 wherein said sealing means is
connected to the outer wall surface of the one wall on said tank
means.
3. The combination claimed in claim 1 wherein:
said other cover means includes a sealing flange; and
said sealing means comprises gasket means disposed between said
sealing flange of said other cover means and the one wall of said
tank.
4. The combination claimed in claim 3 wherein said sealing flange
of said other cover means is disposed outside the one wall of said
tank means.
5. The combination claimed in claim 4 wherein the inlet of said
compressor housing is disposed in said other cover means connected
to said tank means about said opening.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to compressors and particularly to devices
adapted to prevent leakage of the air or gas being compressed by
submerging or surrounding the compressor mechanism or some portion
thereof in a fluid.
2. Description of the Prior Art
In the construction of sliding vane rotary type compressors, the
clearance between the end of the rotor and the end covers of the
compressor housing is critical to the functioning of the device. If
this clearance is too large, gas compressed in the pocket formed by
cylinder wall of the compressor housing, the rotor, adjacent
sliding vanes and the end covers of the compressor housing will
leak from one pocket to the adjacent pocket of lower pressure,
substantially reducing the efficiency and output of the compressor.
If the tolerance between the end of the rotor and the end covers of
the housing is too small, there will be an interference of the
parts which can result in damage to the machinery as well as
reduced performance. In view of these facts, it is not unusual to
find that maching tolerances measured in the ten thousandths of an
inch (0.0001) are required in order to properly position the end
covers to the cylindrical section of the compressor housing.
Because the tolerances are so important, it is not possible to use
any gasket type sealing means between the end covers of the
compressor housing and the cylindrical section of the housing to
prevent leakage from the compressor to the atmosphere. The
interposing of any .Iadd.gasket .Iaddend.between the end covers and
the cylindrical section would place a component of variable
dimension in the chain of elements whose overall dimension must be
held to within the above mentioned ten thousandths of an inch.
Therefore, to provide sealing between the front cover of the
compressor and the compressor housing, the prior art had to use an
O-ring type seal disposed between the circumferential surface of
the front cover and the inner wall of the cylindrical section of
the compressor housing. This type of construction is shown in FIG.
2 of U.S. Pat. No. 3,385,513 issued May 28, 1968 to C. R. Kilgore
where an O-ring 20 is disposed between the outer wall 11 of the
housing and the front cover 13a.
The problems with this type of sealing arrangement are the relative
inefficient seal provided by an O-ring seal assembly as compared to
a gasket sealing assembly, and the rapid deterioration of the
O-ring sealing member as compared to a gasket sealing member for
this type of application. The latter factor results from hardening,
cracking and permanent deformation of the O-ring due to the heat,
air and oil to which the O-ring is exposed in a typical compressor
application. Additionally, it is often necessary to remove the
covers of the compressor for periodic servicing of the vanes and
bearings within the compressor, and therefore the covers must be
slid out of engagement from the cylindrical section of the housing
thereby rubbing and scuffing the O-ring seal along the inner wall
of the housing.
To overcome the problems of the prior art the applicant has
provided a new, improved construction for a rotary compressor in
which leakage from the compressor to atmosphere through the
interface between the cylindrical section of the compressor housing
and the covers of the compressor housing is prevented by a gasket
type sealing means without in any way effecting the relative
position of the front cover to the compressor rotor.
A new construction accomplishes this end by placing the compressor
housing substantially in the tank which receives the compressor
discharge and seals the front cover of the compressor with a
gasket-type seal to the wall of the receiver tank. By this
construction, the interfaces between the cylindrical section of the
compressor housing and the covers of the housing are located in an
enclosed area sealed from the atmosphere. A gasket-type seal can be
used to seal the front cover of the compressor to the tank, without
effecting the performance of the compressor in any way, to prevent
leakage from the tank to atmosphere. If any leakage does occur it
would be "inward" leakage from the discharge tank back into the
compressor housing. This inward leakage is much less serious then a
comparable conventional leakage from the compressor housing to
atmosphere since the inward leakage does not have as great an
effect as conventional leakage on compressor efficiency and
output.
Accordingly, it is an object of the present invention to provide a
compressor assembly in which no special intervening sealing medium
is required between the covers of the compressor housing and the
cylindrical section of the compressor housing to effectively seal
the interfaces between these elements from the atmosphere.
Another object of the present invention is to provide a compressor
assembly in which the compressor is substantially located within
the tank which receives the compressor discharge.
Yet, another object of the present invention is to provide a
compressor assembly in which the sealing means to prevent leakage
from the compressor housing to the atmosphere can be effected by
gasket type sealing means without adversely effecting performance
or efficiency of the compressor.
Still another object of the present invention is to provide a
compressor system in which the clearance between the compressor
rotor and the front cover of the compressor is not affected by the
means used to seal leakage from the compressor to the atmosphere
through the interface between the covers and the cylindrical
section of the compressor housing.
A further object of the present invention is to provide a
compressor assembly which does not require a separate line from the
outlet of the compressor to the tank which receives the compressor
discharge.
Yet, a further object of the present invention is to provide a
compressor assembly having a compact envelope in which the tank
which receives the discharge of the compressor also acts as an oil
sump for the lubrication system of the compressor.
Still a further object of the present invention is to provide a
compressor assembly in which the tank which receives the discharge
of the compressor contains means to separate oil from the discharge
of the compressor and acts as a sump for the lubrication system of
the compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a compressor assembly built in accordance
with the teachings of this invention.
FIG. 2 is an enlarged view of FIG. 1 partially in section.
FIG. 3 is a view taken along lines 3--3 of FIG. 2.
FIG. 4 is an enlarged fragmentary view of a portion of FIG. 2.
FIG. 5 is a view taken along lines 5--5 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1 through 5, a compressor generally indicated at
10 is mounted in a tank generally indicated at 12 which receives
the discharge from the compressor and is driven by an electric
motor 14 through a shaft assembly 16, all of which are mounted on
top of a compressed gas storage tank 18 and are controlled from
control panel 20. The compressor-tank combination is positioned
with relation to electric motor 14 by fastening all of the units to
a mounting frame 22 which in turn is fixed to tank 18 by means of
legs 24 on the mounting frame which are welded or connected by any
other convenient method to arms 26 protruding from the compressed
air storage tank. Control panel 20 is connected to mounting frame
22 by bracket 28, while tank 12 by means of legs 30 is connected to
mounting frame 22 by welding or any other means of attachment such
as bolting or vibration mounts, etc. Motor 14 is fastened to
pedestal 32 by means of bolts 34 to coaxially position the motor 14
and the compressor 10. A flexible coupling 35 in shaft assembly 16
compensates for any slight misalignment between the compressor and
motor. A radiator 36 whose function will be explained later is
connected to mounting frame 22 by means of brackets 38 which are
bolted to the base of the radiator by bolts 40 and are connected to
the mounting frame by welding or any other convenient methods of
attachment.
Mounted substantially within compressor discharge tank 12 are the
compressor 10 and air oil separator 42 which separates out the oil
mixed in the discharge of the compressor from the compressed gas
before the compressed gas passes from the receiving tank 12 through
line 44 to the compressed gas storage tank 18. The oil separated by
the air oil separator 42 drops to the sump portion at the bottom of
tank 12. Tank 12 consists of three sections, a cylindrical portion
46, an end plate 48 in which demister 42 is mounted, and a front
wall 50 in which the compressor 10 is mounted as will be further
explained below.
As seen from FIGS. 2 through 5 the compressor 10 has a cylindrical
section of the compressor housing generally indicated at 52, a rear
cover 53 including an end plate 55, and an inlet housing 54 on the
front cover 56 of the compressor. The compressor is of the rotary
vane type having a compressor rotor 58 with sliding vanes 60
mounted therein and it is driven by the end 62 of shaft assembly 16
which delivers power from motor 14. Air to be compressed enters the
inlet assembly through air cleaner 64 which is connected by fitting
66 to the suction control assembly 68 which throttles the inlet gas
flow to the compressor in response to the pressure in storage tank
18 to unload compressor 10 during periods of nonoperation. The
suction control assembly 68 is connected to inlet housing 54 by
inlet pipe 70. The fluid to be compressed after reaching the inlet
housing 54 passes through the suction inlet opening 72 in front
cover 56 to enter the cylinder of the compressor. Compression
occurs in the cylinder in the normal manner found in a rotary
compressor, namely by varying the volume of the pocket formed
between the adjacent vanes extending from the compressor rotor and
the inner wall of the cylindrical section of the housing of the
compressor. The pocket varies in size during the rotary cycle of
the rotor, diminishing as compression occurs until the compressed
air is exhausted from the compressor housing at a point not shown
in the drawings.
Oil which has been separated from the compressor discharge by
baffle means in the tank (not shown) and air oil separator 42 falls
to the sump portion of tank 12 and because of the high pressure in
the tank is forced through conduit 74 to radiator 36 where the oil
is cooled and then returns to the inlet of the compressor. Fan 76
driven by shaft assembly 16 pushes air through radiator 36 to
produce the necessary cooling. A shroud 78 on the radiator
increases the efficiency of the fan, and a shield 80 is mounted
around the fan for purposes of safety.
Sealing of Interface Between Compressor Housing and Atmosphere
As shown from FIGS. 2, 3 and 4, the front cover 56 of compressor 10
consists of a sealing flange 82, a shaft seal housing 84 and a
shaft seal housing cover 86 connected to shaft seal housing 84 by
bolts 88 or any other convenient fastening means. A gasket 90
maintains an air tight seal between the shaft seal housing and the
shaft seal housing cover. The shaft 62 passes through the shaft
seal housing cover and rear wall 92 of the shaft sealing housing to
drive the compressor rotor 58. A mechanical seal 94 attached to
shaft 62 coacts with collar 96 on the shaft seal housing cover to
maintain an airtight seal between the interior of the shaft seal
housing and the atmosphere. As seen in FIG. 2, front cover 56 of
compressor 10 is connected by through bolts 98 to the flange 100
protruding from the rear cover 53 of the compressor housing thereby
holding cylindrical section 52 of the compressor housing in
operative position between the ends of the compressor.
The front cover 56 of the compressor housing is aligned in the
cylindrical section 52 of the compressor housing by means of a step
104 on the front cover of the compressor which is concentrically
fitted without lip 102 on the end surface of the compressor housing
52.
The abutting surfaces on lip 102 of compressor housing 52 and on
step 104 of front cover 56 are carefully machined to provide a seal
between the housing and the cover. A similar arrangement not shown
in the drawings is used to align and seal the rear cover 53 to the
cylindrical portion of the housing.
The compressor 10 is mounted to the tank by means of sealing flange
82 of front cover 56 which is connected to front wall 50 of tank 12
by means of bolts 106. A seal is effected between the inner space
of tank 12, which receives the compressor discharge and the ambient
atmosphere by a gasket seal 108 which is disposed above the opening
in wall 50 of the tank.
Since no sealing medium need be interposed between either end 53 or
56 and the cylindrical section 52 of the compressor housing, the
distance between the inner wall 110 of front cover 56 and the inner
wall of rear cover 53 (not shown in the drawings) can be accurately
set and maintained for the life of the compressor. Therefore, the
position of the compressor rotor 58 relative to the inner surface
110 of the front cover 56 and the corresponding surface of the rear
cover 53 is also uneffected. This is a significant advantage
because the clearance between the ends of the compressor rotor and
the vanes therein and the inner surfaces of the front and the rear
covers is of prime importance for effective operation of a
compressor, as previously explained.
It should be noted that sealing the front cover of the compressor
to the front wall of the tank prevents any leakage from the
interfaces of the compressor housing to the ambient atmosphere but
instead exposes the compressor housing interfaces to the pressure
within the tank. Any "inward" leakage which does occur from the
tank into the compressor housing will be much less serious for the
effective performance of the compressor than would a comparable
amount of leakage from the compressor housing to the
atmosphere.
It should also be noted that placing the compressor substantially
within the tank which receives the compressor discharge has other
advantages as for example, drastically reducing the overall size of
the compressor assembly package. Additionally, by locating the
compressor within the discharge package it is significantly easier
to soundproof or suppress the noise produced by the rotary
compressor.
It should be further noted that the invention set forth above is
not limited to sliding vane type rotary compressors. The invention
is equally applicable to rotary screw type compressors.
It will be understood that various changes in the details,
materials, and arrangements or parts which have been herein
described and illustrated in order to explain the nature of the
invention may be made by those skilled in the art without the
principle and scope of the invention, as expressed in the appended
claims.
* * * * *