Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
` ~ 20639~2
The present invention relates to hermetic
ssors and, more particularly, to a suction
system for a hermetic ~ essor.
Hermetic compressors are utilized for
circulating a refrigerant gas through a closed
refrigerant system. In operation, the refrigerant
vapor is fed into the interior of the ~ _ essor
through an intake pipe in the sealed housing
defining the compressor. Once inside the
~ssor, the refrigerant vapor is introduced
into a ~ essuL cylinder wherein the vapor s
, ~ssed by a piston within the cylinder
resulting in an increase in temperature. The
vapor exits the cylinder through an exhaust valve,
consequently f lowing into the discharge portion of
the compressor to circulate through the external
refrigerant system to return to the ~ ~ssor
unit .
Present practice requires that the design of
,- essors be as compact as possible, thus the
limited available space within the ~ ssor
assembly imposes severe size constraints for the
suction assembly as well as the discharge
elements. Because of this, it is n~ cllary to
extend the internal suction system elements, e.g.
muf f lers, conduits, cavities, in close proximity
to other ~ I essor parts that generate and
transmit heat.
In the design of high efficiency compressors
it is also important to reduce or eliminate noise
generated by the suction process. In this regard,
60me hermetic motor compressors employ a shroud
over the open end of the motor assembly to
attenuate suction noise generated by pressure
pulsations produced by the compressor .
2 ~ ~ 3 ~ ~ 2
In addition, it is necessary to limit or
eliminate the transfer of heat from hot compressor
parts such as the wall of the housing, the
discharge system, the cylinder block, and the oil,
to the relatively cooler intake gas. The intake
gas must remain cool to facilitate ~ t:ssor
operation, as overheated intake gas causes an
increase in _ ~ssor work due to the lowering of
the specif ic gravity of the intake gas reducing
the amount of gas entering the cylinder chamber.
Various provisions have been made by the
prior art to rectify these problems, such as an ~ ~ ,"
intake pipe for the motor _ ~ssor being
directly connected to a suction muf f ler of a
cylinder head, and within the sealed housing, the
intake opening of the suction muffler or suction
conduit being disposed as opposed to the tip end
of the intake pipe at a minimum distance, or a
muffler shell and conduit being formed from a
plastic material of low thermal conductivity to
minimize heat transfer to the suction gas. Bypass
suction conduits, often equipped with the suction
mufflers, have also been provided to give
continuous unrestricted fluid passageway for
suction gas from the motor shroud or from the
intake pipe to the suction cavities in the
cylinder head. .!.. 1.
Commonly, compressor cylinder heads for
hs~n-ll inq the gas flow for both the discharge and
suction sides are manufactured from cast iron or
aluminum to provided side-by-side or adjacent
suction and discharge cavities separated by
dividing walls which were preferably made as thin
as possible to allow a maximum suction and
aischarge plenum volume in the limited amount o~
available space. In addition, some efforts to
2~63942
overcome the overheating of the suction gas in the
cylinder head suction plenum have resulted in
tubular liners fabricated from a low thermal
conductivity plastic preventing heat transfer to
the suction gas, eliminating the suction plenum in
the cylinder head and attaching a suction conduit
to the relatively thin valve plate, or
manufacturing the suction muffler out of a low
thermal conductivity plastic. Further
arrangements have included ut; l; ~ i ng separate - -
discharge and suction cylinder heads for the
discharge and suction chambers while the suction
cylinder head is formed of a plastic material of
low thermal conductivity to minimize heat transfer
between the suction and discharge cylinder heads. `~
}iowever, even with these modifications, the
compressors in the prior art are often not
acceptable because of various disadvantages such
that the transmission of vibration from the
compressor to the eYternal piping was increased
and that prevention of overheating of the suction
gas in the suction cavities of the cylinder head
was not sufficient. In addition, these
modif ications have increased restrictions on the
flow of suction gas at the suction port because of
the reduced cross-sectional area or the lack of an
immediately adjacent suction plenum, also
consequently increasing the noise level.
For larger refrigeration and air conditioning
30` ` single and multi cylinder ' essors, such
modifications are often not acceptable because of
certain disadvantages such as complexity,
dimensions of the suction system and discharge
system with larger contact areas for the materials
with different coefficients of expansion due to
heat, limited space, higher oscillation forces of
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the suction system element due to pressure
pulsations, dif f iculties on assembly, and higher
costs.
The present invention provides, in a
compressor, a one-piece integral suction adaptor
A~ aAting suction porting while defining a
suction plenum, disposed on a cylinder head
defining separate discharge l~.h~ . and porting,
which draws
suction gas from the interior of the compressor
housing. The suction adaptor also includes
suction porting communicating with a passage in
the cylinder block allowing gas to f low through
the motor to effect cooling thereof while
providing a continuous circulating flow of
refrigerant gas into the integral suction adaptor.
The present invention, in one form thereof,
provides a one-piece integral suction adaptor
disposed on the cylinder head in which a main
portion of the refrigerant gas is drawn from the
interior of the ~ es~or housing located in the
close proximity of the compressor housing intake
pipe, or int~ - ';Ate suction muffler between the
intake pipe and the integral suction adaptor,
while another portion of the refrigerant gas is
drawn through the motor rotor-stator gap to effect
cooling of the motor thereof.
The integral suction adaptor is constructed
such that there is a continuous f low of the
3 0 refrigerant gas through the motor rotor-stator gap
necessary for motor cooling, and this portion of
rerrigerant gas combined with the main portion of
the refrigerant gas is delivered to one of the
cylinders without contacting any hot surface of
the cylinder head or other parts. The integral
suctivn adaptor is preferably made from plastic to
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~ .
reduee the tran6fer of heat from the eompressor
parts and walls of the housing to the intake
refrigerant gas. The exterior walls of the
diseharge cavities of the cylinder head adjaeent
to the exterior walls of the suction plenums of
the integral suction adaptor are spaced from each
other to provide an additional thermal barrier and
further reduce suction gas heating in the cavities
and passage of the cylinder head and integral
suction adaptor. O-rings are disposed in grooves
within the space between the exterior walls of the
discharge cavitie6 of the cylinder head and the
exterior walls of the suction plenums of the
integral suction adaptor allowing a press-fit
~oining of the integral suction adaptor onto the
cylinder head providing vibration dampening while
effeeting sealing.
A gas flow system eomprises a eylinder head
disposed on the valve plate having walls defining
20 ~ a closed discharge ehamber, motor eooling means ~ ~,
for eooling the motor by flowing refrigerant
through said motor, and a low thermal conductivity
suction tube def ining a suction plenum disposed on
said eylinder head having a suetion inlet port in
fluid eommunieation with the internal low pressure
eavity, ineluding an elongate eonduit and a first
adjutage extending through said eylinder suetion
opening and extending to the valve plate (but not
interfering with it) for bypassing the eylinder
head, a motor flowthrough opening eommunieating
with said internal low ~)LeS=iULe cavity and adapted
to reeeive refrigerant from the motor eooling
means .
It is thus an objeet of the present invention
35~ to minimize the transfer of heat from the
diseharge eavities in a eylinder head having
20S3~42
di6charge plenums formed integrally therein and
separated by internal walls to the suction plenums
of the integral suction adaptor and refrigerant
gas entering therein.
It is further an object of the present
invention to combine delivery of the refrigerant
gas intended to cool the motor and the suction gas
delivered to the cylinder suction chamber from the j ~,
interior of the ~_ es60r housing located in the
close proximity of the intake pipe.
It is still further an object of the present
invention to minimize the transfer of heat to the
suction gas from all internal ~ ~:ssor parts.
The above mentioned and other f eatures and
objects of this invention, and the manner of
attaining them, will become more apparent and the
invention itself will be better understood by
reference to the following description of
embodiments of the invention taken in conjunction
with the accompanying drawings, wherein:
FIG. 1 is an elevational view, partly in
6ection, of a compressor incorporating a pref erred
ho.~ of the present invention;
FIG. 2 i8 an elevational sectional view of a
compressor incorporating a preferred embodiment of
the present invention taken along line 2--2 of FIG.
l;
FIG. 3 is a sectional view of the cylinder
head and integral suction adaptor assembly of the
3 0 present invention taken along line 3 -3 of FIG . 4;
FIG. 4 is a bottom view of the cylinder head
and integral suction adaptor assembly of the
present invention;
FIG. 5 is a bottom view of the integral
suction adaptor of the present invention; and
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FIG. 6 is a side elevational view of the
integral suction adaptor of the pre6ent invention.
Referring to the drawings, and in particular
to FIGS. 1 and 2, there is shown a hermetically
sealed, reciprocating piston compressor 10
embodying the present invention. C~ ~s50~ 10
includes a sealed compressor housing 12
encapsulating the L. -; nd~r of the ~ e:ssor
cnrr~ nts and tl-'f ~ n; ng an internal, low pressure
cavity 14. Disposed within housing 12 i5 a
cylinder block 16 supporting a crankshaft 18 which
is driven by a motor 20 which includes a stator 22
and rotor 24 each having windings thereon. Shock
mounts 34 attached to cylinder block 16 and
housing 12 suspend the i~_.. ressor components
within housing 12.
By way of illustration, and without any
limitation on the invention, orientation of
compressor 10 in the illustrated preferred
~ ~;r ~ is with cylinder block 16 sl~r~n~l.od
vertically beneath motor 20. However, other
orientations of the ~ _ essor ~ ,..e1l1 s are
contemplated and fall within the scope and spirit
of the present invention.
Attached to crankshaft 18 within cylinder
block 16 are crankpins 26 and 27, respectively
connected to connecting rods 28 and 29, which are
in turn respectively connected to pistons 3 o and
31, within respective cylinders 32 and 33. The
lower end 36 of crankshaft 18 is radially
:,ur~u~ded by bushing 38 in outboard bearing 40
which is f ixedly mounted to cylinder block 16 by
bearing bolts 42.
A valve plate 44 is disposed on the end of
cylinders 32 and 33 and supports the suction and
discharge valving (not shown) to and from the
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cylinders. Valve plate 44 includes a suction
aperture 46 (Fig. 2) communicating with a cylinder
block passage 48 adjacent stator 22 of motor 20.
Valve plate 44 also includes cylinder suction
apertures 43 and 45 respectively communicating
with cylinders 32 and 33. Cylinder block passage
48 communicates with stator/rotor cavity 50 and
stator/rotor gap 52 to provide a continuous
suction path through the stator/rotor gap 52
effecting cooling of motor 20 and providing an
additional suction source. A cylinder head 54 is
mounted over valve plate 44 separated by a gasket
5 6 . In accordance with the present invention, an
' ~ integral suction adaptor 58 (to be de6cribed ~h " " ' ' ' ~ ~'
detail hereinbelow) is disposed on cylinder head
54 and is connected to suction muffler 60 by way
of suction connector 62.
As best shown in FIGS. 3 and 4, integrally
formed in cylinder head 54 are discharge cavities
64 and 65 which communicate with discharge port
66, discharge muffler 67, dlscharge tube 68, and
outlet 69 (see FIG. 1). A ~J:eSt~ULe relief valve
70 ls also in communication with discharge
cavities 64 and 65 should excess ~Les~uLe in
cylinder head 54 require venting. In addition,
integrally formed in cylinder head 54 are cylinder
suction npC~n;n~c 72 and 73, and a rotor/stator
flowthrough suction opening 74 separated from the
high pressure discharge cavities 64 and 65 by
cylindrical cylinder head walls 76, 77, and 78
respectively. Cylinder suction op~ni ngs 72 and 73
are disposed over cylinders 32 and 33,
respectively, while rotor/stator flowthrough
suction opening 74 is disposed over cylinder block
passage 48 so as to allow 6uction gas entry
flowing through motor 20. Formed ln the inside of
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cylinder head walls 76, 77, and 78 defining
cylinder suction opPn; n~s 72 and 73, and
rotor/stator suction opening 74 respectively, are
respective circular grooves 80, 81, and 82
designed to respectively acc~ ~te 0-rings 84,
85, and 86 made of a refrigerant and oil resistant
material such as polytetrafluoroethylene, although
other known materials may be used. In addition,
cylinder head 54 also includes bolt holes 88 in
which bolts 89 (shown in FIG. l) are ac ' ted
in order to secure cylinder head 54 to cylinder
block 16.
In accordance with the present invention, and
with additional reference to FIGS. 5 and 6, there
is shown the integral suction adaptor 58 of the
present invention. Integral suction adaptor 58 is
made from a thPr~-l ly low cnn~ ct;vity plastic
such as Nylon, or Valox,, although other known
thPrr-l ly low conductivity plastics or materials
may be utilized, in order to reduce the transfer
of heat to the intake refrigerant gas from the
compressor parts and walls of the housing.
Integral suction adaptor 58 includes suction
connector 62 integral with a tubular-like conduit
90 defining a suction plenum. Along the
longitudinal length of conduit 90 nearest suction
connector 62 is a rotor/stator suction port 92
defined by a circular protruding wall 94 radially
extending from conduit 90 and which is adapted to
be received through rotor/stator suction opening
74 of cylinder head 54. Likewise, along the
longitudinal length of conduit 90 are two cylinder
intake ports 96 and 97 defined by adjutages 98 and
99 radially extending from conduit 90 and which
are adapted to be respectively received through
cylinder suction openings 72 and 73 of cylinder
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~ .
head 54. It i5 to be noted, however, that the
integral suction adaptor 58 cam be modified to
accommodate a one cylinder ~ a~sv~ by having
only one cylinder intake port def ined by one
ad j utage .
As best shown in FIG. 3, integral suction
adaptor 58 is coupled to cylinder head 54 by
fitting the radially extending ports 92, 96, and
97, which preferably extend (but not interfere)
substantially to the surface 49 of valve plate 44,
respectively into rotor/stator suction opening 74
and cylinder intake ports 96 and 97, being held
into place by 0-rings 86, 84, and 85. By reason
of the resilience of the o-rings, the integral
suction adaptor 58 can be slightly displaced to
all sides in a plane perpendicular to the axes of
cylinders 32 and 33. This connection feature also
facilitates assembly because the integral suction
adaptor 58 can be pushed in the cylinder head
openings. In addition to the retention
characteristics of the 0-rings, the integral
suction adaptor 58 can also be strapped across the
cylinder head. The 0-rings also act as damping
elements which oppose the transmis~ion o~ sounds
and vibrations from cylinder head 54 to the
thinner wall of the integral suction adaptor 58.
In addition, the 0-rings work as sealing elements
which separate the interior of the rotor/stator
suction port and the cylinder intake ports from
the interior ~ OL cavity 14.
During operation of compressor 10,
refrigerant enters housing 12 through inlet pipe
100. Because inlet pipe 100 opens into interior
~ ~ cavity 14 of housing 12, the ~ es~vL 10 of
FIGS. 1 and 2 is a low back pressure compressor
operating at suction pressure. The direction of
11 2~639~2
refrigerant f low is depicted by arrows . The main
portion of the intake refrigerant gas is drawn
into suction muffler 60 and into plenum conduit 90
which is in fluid communication with cylinder
intake ports 96 and 97 which are respectively
arranged over and in fluid communication with
`~ ` cylinders 32 and 33 . In addition, since integral `~
suction adaptor is in f luid communication with
cylinder block passage 48 via suction aperture 46
in valve plate 44 and rotor/stator suction port 72
of the integral suction adaptor 58, a portion of
the refrigerant gas is drawn through the
stator/rotor gap 52 into the stator/rotor cavity
50 to effect nP~C~ ry cooling of motor 20, which
also provides a continuous flow of refrigerant gas
into plenum conduit 90 of the integral suction
adaptor 58.
It will be appreciated that the foregoing
description of a preferred iL ' _ ';T' I of the
present invention along with an alternative
embodiment thereof, is presented by way of
illustration only, and not by way of any
limitation, and that various alternatives and
modif ications may be made to the illustrated
embodiment without departing from the spirit and
scope of the invention.
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