Rotary compressor with wire gauze lubricant separator

The disclosed rotary compressor includes a wire gauze disposed in its shell to traverse a passage through which a compressed gaseous refrigerant from a delivery tube flows to a discharge tube within the shell. A lubricant included in the compressed refrigerant is separated from the latter by the wire gauze and falls on a sump disposed at the bottom of the housing. Further an L roof-shaped partition may be interposed between the top of a compressor unit and the housing to divide a space around the compressor unit into two space portions in which the delivery and discharge tubes open respectively.

BACKGROUND OF THE INVENTION 
This invention relates to a rotary compressor, and more particularly to 
improvements in a separator for separating lubricating oil from a gaseous 
refrigerant delivered into a shell for a rotary compressor. 
Rotary compressors are used in home refrigerators or home air conditioners 
because rotary compressors can be made in small sizes. In rotary 
compressors of the type referred to, however, compressed refrigerant 
delivered from the compression chamber thereof includes a large amount of 
lubricant. Feeding the compressed refrigerant including the lubricant to 
an associated refrigerating cycle causes a decrease in refrigerating 
capacity and therefore should be avoided as much as possible. To this end, 
conventional rotary compressors have included a separator disposed on the 
outside of the housing therefor to separate the lubricant from the 
refrigerant. Alternatively, the internal space within the shell itself can 
be large so that the lubricant will be spontaneously separated from the 
gaseous refrigerant during passage of the mixed refrigerant and lubricant 
through the large space. The former measure is expensive because of the 
provision of an additional part while the latter measure has led to the 
necessity of making the shell itself large-sized resulting in expensive or 
heavy compressors. Alternatively, the resulting compressors have not been 
adapted to be made in small issues. 
Accordingly, it is an object of the present invention to provide a rotary 
compressor including a new and improved separator for separating a 
lubricant from a gaseous refrigerant mixed with the latter inexpensively 
and efficiently and without using large-sized equipment. 
SUMMARY OF THE INVENTION 
The present invention provides a rotary compressor comprising a shell 
including a lubricant sump disposed at the bottom thereof, a compressor 
unit disposed within the shell to compress a gaseous refrigerant, a 
delivery tube connected to the main body of the compressor unit to deliver 
the compressed refrigerant to the space within the shell, a discharge tube 
connected to the shell to discharge the compressed refrigerant from the 
space within the shell to the exterior of the shell and wire gauze 
disposed between the delivery tube and the discharge tube in the space 
within the shell to separate the lubricant from the compressed 
refrigerant, the separated lubricant being returned to the lubricant sump. 
In order to increase the degree of separation of the lubricant, the wire 
gauze may be disposed within the shell perpendicular to the longitudinal 
axis of the shell and traverse fully the space within the shell thereby to 
divide the space into a first space and a second space, and a partition is 
disposed in the first space to divide the first space into a pair of space 
portions, the delivery tube opening into one of the space portions, and 
the discharge tube opening into the other space portion. 
The partition is preferably in the form of a roof having the L-shaped cross 
section including a central portion fixedly secured to a portion of an 
inner peripheral surface of the shell located in the vicinity of the top 
of the compressor unit and both ends abutting against portions of an outer 
wall of the compressor unit adjacent to the top thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1 of the drawings, there is illustrated a rotary 
compressor according to the present invention. The arrangement illustrated 
comprises a horizontally disposed shell 10 in the form of a hollow 
cylinder having one end closed, a cover plate 12 fixedly secured in 
sealing relationship to the other open end of the housing 10 such as by 
welding, and a compressor unit generally designated by the reference 
numeral 14 disposed within the space defined by the shell 10 and the cover 
plate 12. The compressor unit 14 includes a crank shaft 16, a cylinder 18, 
a rolling piston 20, a pair of opposite side shells 22 and 24, a vane 28 
and a vane spring 30 disposed as shown in FIG. 1. The compressor unit 14 
is fixedly secured to the cover plate 12 by a plurality of fastening bolts 
32 only one of which is illustrated. The components of the compressor unit 
14 are well known and form no part of the present invention so that they 
are not further described herein. 
A suction tube 34 for a gaseous refrigerant extends through and is sealed 
in the closed end of the shell 10 and opens into the interior of the 
compressor unit 14, and a delivery tube 36 extends from the lower portion, 
as viewed in FIG. 1, of the main body of the compressor unit 14 and opens 
in the upper portion, as viewed in FIG. 1, of the space within the housing 
10 adjacent to the cover plate 12. A wire gauze 38 is disposed within the 
shell 10 adjacent to the closed end with one edge fastened to the side 
shell 22 by the fastening bolts 32 and the other edge folded and fixedly 
secured to the inner cylindrical surface of the housing 10. 
Further a discharge tube 40 extends from that portion of the cylindrical 
surface connected to the closed end of the housing to the exterior 
thereof, that is, to a condenser (not shown). 
Also a lubricant sump 42 is disposed in the bottom of the shell 10 and has 
an oil level located somewhat above the longitudinal axis of the shell 10 
and leaving an internal space thereabove divided into a first and a second 
space A and B respectively by the wire gauze 38. The outlet 36a of the 
delivery tube 36 is positioned in the first space A above the oil level of 
the sump 42 and the discharge tube 40 extends from the second space B. 
In operation, a gaseous refrigerant from an evaporator (not shown) is 
sucked into the compressor unit 14 through the suction tube 34. The 
gaseous refrigerant is compressed in the compressor unit 14 and the 
compressed refrigerant is delivered to the first space A in the shell 10 
through the delivery tube 36. Then the compressed refrigerant from the 
first space A passes through the wire gauze 38 and then enters the second 
space B. Thereafter the compressed refrigerant is discharged to the 
condenser (not shown) through the discharge tube 40. 
It will readily be understood that when compressed, the refrigerant may be 
mixed with the lubricant within the compressor unit 14 so that the 
compressed refrigerant entering the first space A may include a large 
amount of the lubricant. When the mixed refrigerant and lubricant passes 
through the wire gauze 38, the lubricant is separated from the refrigerant 
and then goes along the wire gauze 38 and the side shell 22 by the action 
of the gravity until it is returned to the sump 42. On the other hand, the 
refrigerant separated from the lubricant is introduced into and occupies 
the second space B from which the discharge tube 40 extends. Thus the wire 
gauze 38 serves as an oil separator for separating the lubricant from the 
mixture. Also as a matter of course the lubricant is prevented from being 
discharged to the condenser (not shown). This prevents a decrease in 
refrigerating capacity due to the lubricant entering the refrigerant. 
In the arrangement of FIG. 1, the oil separator is formed of the wire gauze 
38 fixedly secured to the compressor unit 14 and the shell 10 to divide 
the interior of the shell 10 into the first and second spaces A and B 
respectively, but the oil separator can alternatively have a structure as 
shown in FIGS. 2 and 3. In the arrangement illustrated a cylindrical wire 
gauze 4 is positioned so as to encircle coaxially the outlet 36a of the 
delivery tube 36 and it is closed at the upper end as viewed in FIGS. 2 
and 3 with an upper tray-shaped cover 46 which is located above the outlet 
36a with a predetermined size space therebetween. Then a lower annular 
cover 48 is attached to the lower end of the cylindrical wire gauze 44 
around the delivery tube 36. 
Therefore the first space A as shown in FIG. 1 corresponds to the space 
defined by the cylindrical wire gauze 44, that portion of the delivery 
tube 36 encircled by the gauze 44 and the covers 46 and 48 while the 
second space B corresponds to a space disposed outside of the cylindrical 
wire gauze 44. 
Since the upper cover 46 is close to the outlet 36a of the delivery tube 36 
as shown best in FIG. 2, the compressed refrigerant mixed with the 
lubricant strikes against the upper cover 46 thereby to promote the 
separation of the lubricant or oil from the gaseous refrigerant. At the 
same time, the refrigerant with the lubricant changes the direction of its 
flow to form a uniform stream thereof. Therefore the desired result can be 
achieved although the space defined by the cylindrical wire gauze 44 and 
the covers 46 and 48 is relatively small. 
Also, in order that the lubricant separated from the refrigerant by the 
cylindrical wire gauze 44 can go along the lower cover 48 and then return 
to the sump 42, it is desirable to dispose the whole separator at a 
position where the lower cover 48 is contacted by the sump 42. 
In FIG. 4, wherein like reference numerals designate components identical 
to or corresponding to those shown in FIG. 1, there is illustrated a 
modification of the present invention intended to increase the extent to 
which refrigerant is separated from the lubricant. The arrangement 
illustrated is different from that shown in FIG. 1 principally in that in 
FIG. 4, the wire gauze cooperates with a partition so as to divide the 
interior of the housing into three spaces to cause the compressed 
refrigerant including the lubricant to pass through the wire gauze twice 
as it flows along a U-shaped path for the purpose of increasing the degree 
of separation of the lubricant. 
More specifically, the wire gauze 38 in the form of a segment of a short 
cylinder is fixedly secured on the short cylindrical surface to the inner 
cylindrical surface of the shell 10 and fastened to the side shell 22 by 
the fastening bolts 32 so that it extends perpendicularly to the 
longitudinal axis of the shell 10 while contacting the side shell 22. The 
wire gauze 38 includes a straight edge immersed in the sump 42 located in 
the bottom portion of the housing 10. Thus the wire gauze 38 is disposed 
within the shell 10 perpendicular to the longitudinal axis thereof and 
traverses fully the space within the shell above the sump 42 thereby to 
divide the latter into a first and a second space A and B respectively. 
As best shown in FIG. 5, a partition 50 in the form of a roof having an 
L-shape cross section is disposed between the top as viewed in FIG. 5 of 
the compressor unit 14 and the adjacent portion of the inner cylindrical 
surface of the shell 10. More specifically, the roof-shaped partition 50 
extends axially of the housing to the cover plate 12 and includes a 
central portion fixedly secured to that portion of the inner cylindrical 
surface of the shell located in the vicinity of the top of the compressor 
unit 14 and both ends abutting against to those portions of the outer wall 
adjacent to the top of the compressor unit 14. Therefore the partition 50 
divides the first space A into a pair of space portions A1 and A2. 
The delivery tube 36 opens into the space portion A1 at a position located 
above the surface of the lubricant in the sump 42, in this case, located 
on the lower portion of the shell 10 and the discharge tube 40 is 
connected in fluid communication with the space portion A2 through a short 
tube radially outward extending from the inner cylindrical surface of the 
shell 10 at a position adjacent to the roof-shaped partition 50. 
As in the arrangement of FIG. 1, a gaseous refrigerant is drawn into the 
compressor unit 14 where it is compressed and also mixed with the 
lubricant from the sump 42. The refrigerant thus compressed and mixed with 
the lubricant is delivered to the space portion A1 within the shell 10 
through the delivery tube 36 and then passed through the wire gauze 38 to 
enter the second space B. At that time, some of the lubricant included in 
the compressed refrigerant is separated from the latter by the wire gauze 
38 and the separated lubricant falls along the wire gauze 38 until it is 
returned to the sump 42. 
On the other hand, the compressed refrigerant which has entered the first 
space B again passes through the wire gauze 38 and then flows into the 
space portion A2. As a result, the refrigerant flows along a U-shaped path 
within the shell 10. When the refrigerant again passes through the wire 
gauze 38, the lubricant still included in the refrigerant is separated 
from the latter by the wire gauze 38 and similarly returned to the sump 
42. Therefore the refrigerant entering the space portion A2 is 
substantially free from the lubricant and discharged via the discharge 
tube 40 to the exterior of the compressor, in this case, a condenser (not 
shown). 
In the arrangement shown in FIGS. 4 and 5, the refrigerant passes through 
the wire gauze 38 twice resulting in an increase in degree of separation 
of the lubricant. 
From the foregoing it will be seen that the present invention provides a 
compact rotary compressor having a simple construction and a high 
efficiency without decreasing the refrigerating capacity. This is because 
lubricant mixed with the compressed gaseous refrigerant is separated from 
the latter by a wire gauze after which only the compressed refrigerant is 
discharged to an associated condenser while the separated lubricant falls 
along the wire gauze by the action of the gravity to return to a lubricant 
sump disposed at the bottom of the housing for the compressor. 
While the present invention has been illustrated and described in 
conjunction with a few preferred embodiments thereof it is to be 
understood that numerous changes and modifications may be resorted to 
without departing from the spirit and scope of the present invention. For 
example, the arrangement of FIG. 4 may include, in addition to the wire 
gauze 38, another wire gauze 44 operatively coupled to the delivery tube 
36 as shown in FIG. 8. Also the partition 50 may be formed of a wire gauze 
as shown in FIG. 7. Further the partition 50 may be omitted, as shown in 
FIG. 6, provided that the top edge of the compressor unit is spaced from 
the adjacent portion of the inner peripheral surface of the shell by a 
small distance and simultaneously the amount of the refrigerant from the 
space portion A1 directly entering the space portion A2 is sufficiently 
small as compared with an amount of the refrigerant from the space portion 
A1 flowing into the first space B.