U.S. patent application number 10/440763 was filed with the patent office on 2004-11-25 for discharge muffler having an internal pressure relief valve.
Invention is credited to Chumley, Eugene Karl, Hix, Scott Garrison, Majerus, Benjamin Alan, Marshall, Steve Edwin, Monk, David Turner.
Application Number | 20040234386 10/440763 |
Document ID | / |
Family ID | 33449861 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040234386 |
Kind Code |
A1 |
Chumley, Eugene Karl ; et
al. |
November 25, 2004 |
Discharge muffler having an internal pressure relief valve
Abstract
A muffler for use in a refrigerant compressor which includes a
muffler housing, an intake tube at one end of the muffler housing
for receiving a flow of refrigerant fluid, and an exhaust tube at
another end opposed of the muffler housing to exhaust the flow of
refrigerant fluid. The muffler housing is adapted to structurally
carry a pressure relief member therein. The pressure relief member
is in fluid communication with the intake tube. A discharge tube is
connected to the exhaust tube for transporting the flow of
refrigerant fluid from the exhaust tube to a compressor discharge
port for discharging the refrigerant fluid from the compressor.
Inventors: |
Chumley, Eugene Karl;
(Abingdon, VA) ; Marshall, Steve Edwin; (Abingdon,
VA) ; Monk, David Turner; (Bristol, VA) ;
Majerus, Benjamin Alan; (Bristol, VA) ; Hix, Scott
Garrison; (Bristol, VA) |
Correspondence
Address: |
MCNEES, WALLACE & NURICK
100 PINE STREET
P.O. BOX 1166
HARRISBURG
PA
17108-1166
US
|
Family ID: |
33449861 |
Appl. No.: |
10/440763 |
Filed: |
May 19, 2003 |
Current U.S.
Class: |
417/312 |
Current CPC
Class: |
F04B 49/10 20130101;
F04B 39/123 20130101; F04B 39/0061 20130101; F04B 49/03
20130101 |
Class at
Publication: |
417/312 |
International
Class: |
F04B 053/00 |
Claims
What is claimed is:
1. A discharge muffler system for use in a refrigerant compressor,
the discharge muffler system comprising: a tube having a first end
for receiving a flow of pressurized refrigerant fluid and a second
end opposite the first end for exhausting the flow of pressurized
refrigerant fluid; a housing surrounding the tube between the first
end and the second end, the housing and the tube defining a chamber
therebetween, the chamber being in fluid communication with the
flow of pressurized refrigerant fluid; a pressure relief member
connected to the housing and being configured and disposed to
regulate fluid pressure in the chamber; wherein the pressure relief
member regulates pressure in the chamber by actuating to an open
position to vent a portion of the refrigerant fluid from the
chamber in response to a pressure in the chamber exceeding a
predetermined pressure level; and a unitary discharge tube
connected to the second end of the tube to receive the flow of
pressurized refrigerant fluid.
2. The discharge muffler system of claim 1 wherein the tube, the
housing and the chamber form an acoustic muffler.
3. The discharge muffler system of claim 1 wherein the tube
comprises at least two apertures disposed within the housing
between the first end of the tube and the second tube of the tube,
the at least two apertures being configured to permit flow of
refrigerant fluid from the tube to the chamber.
4. The discharge muffler system of claim 3 wherein the tube has a
substantially vertical orientation upon installation of the tube
and at least one aperture of the at least two apertures is
configured and disposed to provide a maximum level of a lubricant
liquid received from the first end of the tube.
5. The discharge muffler system of claim 4 wherein the maximum
level of the lubricant liquid does not substantially alter an
attenuation frequency of a muffler formed from the tube, the
housing and the chamber.
6. The discharge muffler system of claim 1 comprising a discharge
port to exhaust the flow of pressurized refrigerant fluid from the
refrigerant compressor and an end of the unitary discharge tube is
connected to the discharge port and a portion of the unitary
discharge tube extends substantially coplanar with the discharge
port.
7. The discharge muffler system of claim 1 wherein a portion of the
unitary discharge tube is in thermal communication with an amount
of sump lubricant in the refrigerant compressor.
8. The discharge muffler system of claim 7 wherein the thermal
communication vaporizes at least a portion of refrigerant liquid in
the sump lubricant.
9. The discharge muffler system of claim 1 wherein a portion of the
unitary discharge tube is in physical contact with an amount of
sump lubricant in the refrigerant compressor.
10. The discharge muffler system of claim 9 wherein the physical
contact between the unitary discharge tube and the sump lubricant
provides an amount of pressure pulse attenuation.
11. The discharge muffler system of claim 1 wherein the second end
of the tube and the connection between the second end of the tube
and the unitary discharge tube are substantially coaxial.
12. A method for assembling a discharge muffler system for use in a
refrigerant compressor, the steps comprising: providing a discharge
muffler having a muffler housing, an intake tube at a first end of
the muffler housing for receiving a flow of refrigerant fluid and
an exhaust tube at a second end of the muffler housing opposite the
first end to exhaust the flow of refrigerant fluid, the intake tube
being configured for connection with a cylinder head of a
refrigerant compressor, and the intake tube, the exhaust tube and
the connection with the cylinder head being substantially coaxial;
providing a discharge tube having an intake for connection to the
exhaust tube and having an exhaust for connection to a discharge
port of the refrigerant compressor, the discharge tube transporting
the flow of refrigerant fluid from the exhaust tube to the
discharge port for discharging the refrigerant fluid from the
compressor; providing a driving tool for connecting the discharge
muffler to the cylinder head, the driving tool having an aperture;
directing the aperture of the driving tool over the exhaust tube
until the driving tool and the discharge muffler are sufficiently
engaged, wherein the discharge muffler is actuated in response to
an actuating force being applied to the driving tool; directing the
intake tube of the discharge muffler in engagement with the driving
tool into mutual alignment with the cylinder head; applying the
actuating force to the driving tool until the discharge muffler is
connected to the cylinder head; connecting the second end to the
intake; and connecting the exhaust to the discharge port.
13. The method of claim 12 wherein discharge muffler includes a
pressure relief member, the muffler housing having a boss formed
therein to structurally carry the pressure relief member, and the
pressure relief member and the intake tube being in fluid
communication; and the step of directing the aperture of the
driving tool over the exhaust tube further comprising the step of
directing the aperture of the driving tool over the exhaust tube
until the boss and the driving tool are sufficiently engaged.
14. A discharge muffler system for use in a refrigerant compressor,
comprising: a muffler housing; an intake tube disposed at a first
end of the muffler housing for receiving a flow of pressurized
refrigerant fluid from a connection with a cylinder head of a
refrigerant compressor, the intake tube and the connection with the
cylinder head being substantially coaxial; an exhaust tube disposed
at a second end of the muffler housing opposite the first end of
the muffler housing to exhaust the flow of pressurized refrigerant
fluid, the muffler housing surrounding the intake tube and the
exhaust tube between the first end and the second end to define a
chamber therebetween, the chamber being in fluid communication with
the refrigerant fluid flowing in the intake tube, and the intake
tube and the exhaust tube being substantially coaxial; a pressure
relief member connected to the housing and being configured and
disposed to regulate fluid pressure in the chamber; and wherein the
pressure relief member regulates pressure in the chamber by
actuating to an open position in response to a pressure in the
chamber exceeding a predetermined pressure level to vent a portion
of the refrigerant fluid in the chamber to an exterior of the
housing; and a unitary discharge tube receiving the flow of
pressurized refrigerant fluid from the exhaust tube and exhausting
the flow of the pressurized refrigerant fluid from the refrigerant
compressor.
15. The discharge muffler system of claim 14 wherein a muffler
comprising the intake tube, the exhaust tube, the muffler housing
and the chamber is an acoustic muffler.
16. The discharge muffler system of claim 14 wherein the intake
tube and the exhaust tube are integral and continuous, defining a
combined tube.
17. The discharge muffler system of claim 16 wherein the combined
tube comprises at least two apertures disposed within the housing
between the first end of the combined tube and the second tube of
the combined tube, the at least two apertures being configured to
permit flow of refrigerant fluid from the combined tube to the
chamber.
Description
FIELD OF THE INVENTION
[0001] This Application is related to Application No. ______, filed
contemporaneously with this Application on May 19, 2003, entitled
"MUFFLER SYSTEM FOR A COMPRESSOR" assigned to the assignee of the
present invention and is incorporated herein by reference.
[0002] The present invention is directed to an internal muffler for
use with a compressor, and more specifically to a muffler for use
on the high-pressure discharge side of a compressor used in
refrigeration and heating and cooling systems.
BACKGROUND OF THE INVENTION
[0003] Compressors are one of several components in cooling and
heating systems. The compressor is typically used in combination
with a condenser, expansion valves, an evaporator and blowers to
heat or cool a space.
[0004] The compressor itself typically is a hermetically sealed
device that has an intake port and a discharge port. The
hermetically sealed device typically is a metallic shell that
houses an electric motor and a mechanical apparatus for compressing
gas. For most compressor designs, the gas cavity enclosed by the
housing serves as a reservoir of low-pressure gas to be drawn into
the mechanical section of the compressor. The electric motor is
connected to a power source that provides line power for operation.
The motor in turn drives the mechanical apparatus for compressing
gas. Compressors are typically categorized by the mechanical
apparatus that compresses the gas. For example, compressors using a
piston device to compress the refrigerant gas are referred to as
reciprocating compressors. While there are differences among the
compressors as to how refrigerant gas is compressed, the basic
principles of operation are common among the compressors, i.e., gas
is drawn in through the gas intake during operation, the gas is
compressed in the mechanical apparatus of the compressor and the
highly compressed gas is discharged through an outlet port.
[0005] Various mufflers have been employed to eliminate, reduce or
otherwise attenuate compressor noise. Typically, mufflers are
positioned on the discharge or high pressure side of the
compressor, such as at the cylinder head of a piston-driven
compressor, and increase the length of flow of the gas by having it
travel a tortuous path through openings of varying size or
additionally define an elongate "expansion" chamber to effect sound
wave stability. Placement of an expansion chamber adjacent the
discharge side not only reduces operating efficiency of the
compressor, but increases the overall size of the compressor. The
muffler is then connected to a shockloop, also referred to as a
discharge tube, that extends to a discharge port in the compressor
housing that connects to a condenser that is outside the compressor
housing via a conduit. Collectively, the shockloop or discharge
tube is often referred as a "shockloop cane" which describes its
shape. However, to regulate the discharge gas pressure level, an
internal pressure relief valve (IPRV) is placed in fluid
communication along the discharge path. The IPRV typically employs
(within a cylindrical valve body) a spring that is maintained in a
compressed condition against a plunger. The plunger overcomes the
directed spring force and actuates toward an open position in the
valve body of the IPRV in response to excessive discharge gas
pressure levels until sufficient discharge gas is bled through the
IPRV, wherein the plunger returns to its closed position within the
valve body. The IPRV may be positioned downstream of the muffler,
such as along the discharge tube. This is accomplished by splicing
the IPRV into the discharge tube which requires the discharge tube
to be severed into two separate pieces, inserting a component, such
as an adapter for securing the IPRV between the severed ends of the
discharge tube, then reattaching the severed ends to opposite ends
of the component, which reattachment is usually accomplished by
brazing. Such operations increase the number of compressor parts,
the time required to assemble the compressor, and likewise, the
cost to fabricate the compressor. Further, any combination of
severing the discharge tube and then reattaching the severed ends
of the discharge tube to opposed ends of an inserted component to
achieve a contiguous discharge tube construction, especially when
the method of reattachment is a heat-intensive process, will
invariably impose prestresses in the discharge tube. The magnitude
of these prestresses may be significantly increased if the inserted
component and the discharge tube are constructed of different
materials having different coefficients of
expansion/contraction.
[0006] In addition to the slicing operation, the discharge tube
must be subsequently manipulated to connect its ends to the
respective parts inside the compressor housing. Alignment of the
ends of the discharge tube with the respective mating parts is
critical to minimize the introduction of additional prestresses in
the discharge tube. Typically, an end of the discharge tube is
connected to the muffler via a port formed in a sidewall of the
muffler housing. The muffler is typically vertically oriented
within the compressor housing by threaded engagement with the
cylinder head so that alignment between the muffler port and the
discharge tube occurs only at a specific angular position of the
muffler port about the axis of the threaded engagement. Even a
slight deviation from the aligned position may introduce additional
prestresses in the discharge tube possibly adversely affecting the
useful life of the compressor.
[0007] What is needed is a compact, discharge-side muffler design
for maintaining compressor operating efficiency while
simultaneously reducing the number of compressor parts and
improving the magnitude of prestresses to which the discharge tube
is subjected.
SUMMARY OF THE INVENTION
[0008] The present invention relates to a discharge muffler system
for use in a refrigerant compressor, including a tube inside a
refrigerant compressor having a first end for receiving a flow of
pressurized refrigerant fluid and a second end for exhausting the
flow of pressurized refrigerant fluid. A housing surrounds the tube
between the first end and the second end, the housing and the tube
defining a chamber therebetween, the chamber being in fluid
communication with the refrigerant fluid flowing in the tube. A
pressure relief member is connected to the housing and is
configured and disposed to regulate fluid pressure in the chamber.
The pressure relief member regulates pressure in the chamber by
actuating to an open position in response to a pressure in the
chamber exceeding a predetermined pressure level to vent a portion
of the refrigerant fluid in the chamber to an exterior of the
housing. A unitary discharge tube receives the flow of pressurized
refrigerant fluid from the second end and exhausts the flow of the
pressurized refrigerant fluid from the refrigerant compressor.
[0009] The present invention also relates to a method for
assembling a discharge muffler and discharge tube for use in a
refrigerant compressor, the steps include: providing a discharge
muffler having a muffler housing; providing an intake tube at a
first end of the muffler housing for receiving a flow of
refrigerant fluid, the intake tube being configured for connection
with a cylinder head of a refrigerant compressor; providing an
exhaust tube at a second end of the muffler housing opposite the
first end to exhaust the flow of refrigerant fluid from the
discharge muffler, the exhaust tube being configured for connection
with a discharge tube, and the intake tube, the exhaust tube and
the connection with the cylinder head being substantially coaxial;
providing a discharge tube having an intake for connection to the
exhaust tube and having an exhaust for connection to a discharge
port of the refrigerant compressor, the discharge tube transporting
the flow of refrigerant fluid from the exhaust tube to the
compressor discharge port for discharging the refrigerant fluid
from the compressor; providing a driving tool for connecting the
discharge muffler to the cylinder head; the driving tool having an
aperture; directing the aperture of the driving tool over the
exhaust tube until the driving tool and the discharge muffler are
sufficiently engaged wherein the discharge muffler is actuated in
response to an actuating force being applied to the driving tool;
directing the intake tube of the discharge muffler in engagement
with the driving tool into mutual alignment with the cylinder head;
applying the actuating force to the driving tool until the
discharge muffler is connected to the cylinder head; connecting the
exhaust tube to the intake of the discharge tube; and connecting
the exhaust of the discharge tube to the discharge port.
[0010] An advantage of the present invention is the inclusion of a
compact compressor muffler for permitting reduction in the overall
size of the compressor while maintaining compressor efficiency.
[0011] Another advantage of the present invention is that the
muffler of the present invention is adapted to accept an IPRV
therein, thereby reducing part count, labor costs and the
likelihood of introducing prestresses in the discharge tube.
[0012] Another advantage of the present invention is that the
assembly of the discharge tube to connect the muffler to the
exhaust port in the compressor housing is greatly simplified.
[0013] Another advantage of the present invention is that the IPRV
will not actuate as often within the compressor by virtue of
pressure damping.
[0014] Other features and advantages of the present invention will
be apparent from the following more detailed description of the
preferred embodiment, taken in conjunction with the accompanying
drawings which illustrate, by way of example, the principles of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross-section of a refrigerant compressor that
incorporates a muffler system of the present invention;
[0016] FIG. 2 is a partial elevation view of the discharge tube of
the present invention taken along line 11-11 of FIG. 1;
[0017] FIG. 3 is a perspective view of a muffler of the present
invention;
[0018] FIG. 4 is a cross-section of the muffler being joined to the
discharge tube of the present invention;
[0019] FIG. 5 is a perspective view of a tool for the installing
the muffler of the present invention;
[0020] FIG. 6 is an enlarged cross section of an alternate
embodiment of the muffler being joined to the discharge tube of the
present invention; and
[0021] FIG. 7 is an elevation view of a discharge tube of the
present invention.
[0022] Wherever possible, the same reference numbers will be used
throughout the drawings to refer to the same or like parts.
DETAILED DESCRIPTION OF THE INVENTION
[0023] One embodiment of a compressor that incorporates the
discharge muffler and discharge tube or shockloop of the present
invention is depicted in FIG. 1. The compressor 2 is connected to a
conventional refrigeration or heating, ventilation and air
conditioning (HVAC) system (not shown), such as may be found in a
refrigerator, home or automobile, having a condenser, expansion
device and evaporator in fluid communication. Compressor 2 is
preferably a reciprocating compressor connected to an evaporator
(not shown) by a suction line that enters the suction port 14 of
compressor 2. Suction port 14 is in fluid communication with
suction plenum 12. Refrigerant gas from the evaporator enters the
low pressure side of compressor 2 through suction port 14 and then
flows to the suction plenum 12 before being compressed.
[0024] Compressor 2 includes an electrical motor 18. A standard
induction motor having a stator 20 and a rotor 22 is shown. However
any other suitable type of electrical motor may be used. A shaft
assembly 24 extends through rotor 22. The bottom end 26 of shaft
assembly 24 opposite the motor 18 extends into a lubrication sump
28 and includes a series of apertures 27. Connected to shaft
assembly 24 below the motor is at least one piston assembly 29. The
compressor 2 illustrated in FIG. 1 has a cylinder head 30 having
two piston assemblies 29. A connecting rod 32 is connected to the
piston head 34 which moves back and forth within cylinder 36.
Cylinder head 30 includes a gas inlet port 38 and a gas discharge
port 40. These ports 38, 40 are associated respectively with
suction valves and discharge valves assembled in a manner well
known in the art. Gas inlet port 38 is connected to an intake tube
54 which is connected to the suction plenum 12 enclosed within
compressor housing 16.
[0025] Upon activation of motor 18, shaft assembly 24 begins to
turn or rotate. Rotation of shaft assembly 24 causes reciprocating
motion of the piston assemblies. As one piston assembly moves to an
intake position, i.e., as piston head 34 moves away from gas
discharge port 40, a suction valve opens and refrigerant gas or
vapor is introduced into an expanding cylinder 36 volume. This gas
is pulled from within suction plenum 12 through intake tube 54 to
gas inlet port 38 where it passes through the suction valve(s) and
is introduced into cylinder 36. When a piston assembly reaches a
first end (or top) of its stroke, shown by movement of piston head
34 to the right side of cylinder 36 in FIG. 1, suction valve(s)
close. The piston head 34 then compresses the refrigerant gas by
reducing the cylinder 36 volume. When piston assembly 29 moves to a
second end (or bottom) of its stroke, shown by movement of piston
head 34 to the left side of cylinder 36 in FIG. 1, discharge
valve(s) are opened and the highly compressed refrigerant gas is
expelled through gas discharge port 40 into a muffler 50 then
through a discharge tube or shockloop 52, exiting the compressor
housing 16 via an exhaust or discharge port 15. A second muffler 56
can be connected between the exhaust or discharge port 15 outlet
and the condenser. This comprises one cycle of the piston assembly
which is continuously repeated during operation of the
compressor.
[0026] The cyclic opening and closing of the suction valve(s) along
with the periodic starting and stopping of the flow of refrigerant
gas generates a high level of noise over a broad frequency range.
The placement of muffler 56 physically outside compressor housing
16 along the conduit connecting compressor 2 and the condenser
assists in absorbing the broadband sound generated by the cyclic
motion of the suction valve(s) and the cyclic surging of the gas.
Further, locating muffler 56 outside compressor housing 16, not
only permits a reduction in size of the compressor housing 16, but
enhances the effectiveness of muffler 56 without adversely
affecting the efficiency of the compressor 2. Furthermore, muffler
50 additionally regulates the cyclic gas surges by employing an
IPRV 60, or any other suitable pressure relief member or valve.
[0027] Referring to FIGS. 2-5, muffler 50 helps regulate cyclic gas
surges by employing the IPRV 60 therein as previously discussed.
Muffler 50 preferably includes a tube 62 having opposed ends 76,
78. A threaded member 64 having a lip 80 at one end is positioned
over end 78 of tube 62 for threadedly engaging the cylinder head 30
to maintain tube 62 in fluid communication with gas discharge port
40. Preferably, the end 78 of tube 62 and the end of threaded
member 64 opposite lip 80 are substantially coincident to ensure
the parts are sufficiently engaged therebetween. Alternately,
threaded portion 64 may be integrally formed with tube 62 or tube
62 may have external threads formed along its length, wherein
housing opening 72 would be similarly sized with that of housing
opening 70 so that the external threads of tube 62 would just slide
inside the housing openings 70, 72 for ease of securing the housing
openings 70, 72 of housing 68 to the tube 62. A housing 68 includes
opposed openings 70, 72 which permits opening 70 of housing 68 to
be positioned over end 78 of tube 62 and moved along tube 62 until
opening 72 of housing 68 is in a position to sufficiently contact
lip 80 when assembled. Preferably, housing 68 is coaxial with tube
62 along axis 84. Alternatively, housing 68 and threaded portion 64
may be of unitary construction. Methods of securing tube 62,
housing 68 and threaded portion 64 into their respective positions
can include spot welding, soldering, brazing, or by press-fit.
Housing 68 is substantially cylindrical in profile and defines an
annular chamber 82 between tube 62 and housing 68. Tube 62 and
housing 68 are preferably maintained in fluid communication by a
pair of apertures 66 formed in tube 62. However, any number of
apertures 66 can be used to maintain this fluid connection.
[0028] An additional aspect of the apertures 66 is to regulate the
amount of lubricant oil, also referred to as lubricant liquid, that
may collect within the housing 68 of the muffler 50 during
operation of the compressor. If the amount of lubricant oil 67
within the housing 68 is not regulated below a certain maximum
level, the lubricant oil may adversely affect the noise attenuation
capability of the muffler 50, possibly including shifting the
attenuating frequency to which muffler 50 is tuned. Since the
muffler is oriented substantially vertical within the compressor
housing 68, the lower aperture 66 is vertically positioned along
tube 62 to maintain the lubricant oil 67 at an acceptable level
within the housing 68. When the level of the lubricant oil 67 in
the housing 68 rises sufficiently above the lower portion of
aperture 66, the lubricant oil 67 simply drains through the lower
aperture 66 down tube 62, returning to the cylinder head 30.
[0029] Chamber 82 of muffler 50 displaces significantly less volume
than mufflers which employ an expansion chamber. Although not
necessarily drawn to scale in FIG. 4, chamber 82 displaces a
comparable volume as compared to tube 62. By virtue of this lack of
pronounced volumetric increase of chamber 82 that is adjacent the
discharge port 40, compressor efficiency is maintained.
Additionally, the small size of housing 68 permits reduction in
size of the compressor housing 16.
[0030] Muffler 50 further provides for the integral mounting of
IPRV 60 therein. A boss 74 preferably is formed in housing 68,
which extends outwardly or inwardly from housing 68 such as by
extrusion or other suitable techniques, permitting IPRV 60 to be
secured therein by any usual method known in the art such as press
fit, threading, adhesive or metal-joining processes involving
elevated temperatures. Preferably, boss 74 extends radially outward
from axis 84 which defines a side branch mounting for IPRV 60 that
saves further space within the compressor housing 16. Alternately,
an aperture may be formed in housing 68 without boss 74 that is
sized to receive the IPRV 60. In addition to the space savings made
possible by the integral muffler/IPRV construction, due to the pair
of apertures 66 formed in tube 62 being in fluid communication with
chamber 82 of housing 68, the pressure pulses from the discharge
port 40 are dampened, thus significantly reducing the number of
IPRV 60 "actuations" to resolve such over-pressure conditions.
Among the over-pressure conditions causing IPRV 60 actuations are
compressor start-ups and changes in compressor operating
conditions. The noise generated by the IPRV 60 is generally
considered undesirable.
[0031] Due to the compact construction of housing 68, for a given
material thickness, housing 68 has enhanced stiffness and strength
as compared to a conventional muffler having an expansion chamber.
This enhanced stiffness not only helps support the IPRV 60, but
also permits muffler 50 to be collectively threadedly installed
onto the cylinder head 30 by a slotted driving tool 86 (see FIG. 5)
having an aperture 90 of sufficient size and depth to collectively
slide over tube 62 and housing 68 of muffler 50. Driving tool 86
further has at least one slot 92 formed along its peripheral edge
93 that is adapted or configured to engage the boss 74 protruding
from housing 68. In other words, to utilize driving tool 86, the
driving tool 86 and the muffler 50 are brought into mutual axial
alignment with axis 84. Peripheral edge 93 of driving tool 86 is
then directed along axis 84 in direction 97 so that peripheral edge
93 first slides over end 76 of tube 62 of muffler 50. Driving tool
86 is then continually directed incrementally in direction 97 to
slide over muffler 50 until slot 92 of driving tool 86 sufficiently
engages boss 74 of housing 68 of muffler 50. Once the driving tool
86 is engaged with muffler 50, end 78 of threaded portion 64 of
muffler 50 is then further axially aligned along axis 84 and
brought into threaded engagement with the corresponding threaded
discharge aperture in the cylinder head 30. By then applying a
rotational force 88 about axis 84 to driving tool 86, slot 92
imparts a rotational force along a portion of boss 74 thereby
urging muffler 50 into rotational movement about axis 84 until
threaded portion 64 is sufficiently threadedly engaged with the
cylinder head 30. If there is sufficient clearance, IPRV 60 may be
mounted in housing 68 of muffler 50 prior to installing muffler 50
in the cylinder head 30.
[0032] By directly mounting the IPRV 60 in the housing 68 of
muffler 50, the compressor part count is reduced, and parts
handling is reduced as to the discharge tube 52, which reduces
prestresses in discharge tube 52. Alternately, if housing 68 of
muffler 50 is constructed without the boss 74, such as the aperture
previously discussed, and there is insufficient clearance to
install the IPRV 60 prior to installing the muffler 50, the driving
tool 86 could simply be modified to employ an inwardly directed
member (not shown) to engage the aperture, but would otherwise
operate the same as previously discussed. Additionally, by virtue
of the connection of muffler 50 and discharge tube 52 being
substantially coincident along axis 84, or coaxial, alignment
between the muffler 50 and end 98 of the discharge tube 52 is
maintained irrespective a deviation from a reference position about
axis 84. In other words, unlike a side-mounted prior art muffler
port for receiving the discharge tube, which only aligns with the
discharge tube at a specific rotation position or orientation about
its axis of rotation, the muffler 50 and end 98 of discharge tube
52 of the present invention are always in alignment. Therefore,
installation of the discharge tube is greatly eased, since the
installer must only be concerned with a proper installation torque
to install the muffler 50 in the cylinder head, not the possibility
of applying insufficient or excessive installation torque to the
muffler in an attempt to achieve the specific alignment orientation
required between the muffler and the discharge tube.
[0033] One end of discharge tube 52 is connected to muffler 50. The
other end of discharge tube 52 is connected to the discharge outlet
15 of compressor 2. A portion of the discharge tube 52 adjacent
muffler 50 preferably has a cane or inverted "J" shape, but can
have any suitable shape. Referring to FIG. 7, the discharge tube 52
is preferably of continuous, integral construction extending
between the muffler and the discharge outlet 15. The shape of
discharge tube 52 is primarily driven by the location and attitude
of the two interface locations within the compressor housing 16
while maintaining sufficient spacing from compressor components.
Thus, the path of the unitary discharge tube 52 typically follows a
path adjacent the compressor housing 16, preferably including from
end 98 a substantially straight portion 116 which extends into a
substantially curved portion 118 and which similarly extends into a
remaining portion 120 that terminates at end 106. Referring back to
FIGS. 1, 4 and 6, both tube 62 of muffler 50 and a portion of
discharge tube 52 share a coincident axis 84. The segment or
portion of discharge tube 52 that extends along axis 84 is of an
extended length which more evenly distributes prestresses along the
collective axial length of tube 52. Additionally, the joint formed
between discharge tube 52 and tube 62 of muffler 50 is also
coincident with axis 84. In one embodiment, tube 62 of muffler 50
has an enlarged diameter portion 94 that extends into a shoulder 96
formed therein that is coincident with axis 84.
[0034] To establish the joint between tube 62 of muffler 50 and
discharge tube 52, an end 98 of exhaust tube 52 is directed inside
the enlarged diameter portion 94 of tube 62 past end 76 to the
extent required to form the joint, up to "bottoming out" at the
shoulder 96. In an alternate embodiment, referring to FIG. 6, tube
62 may be configured to slide inside discharge tube 52. That is,
end 76 of tube 62 is of substantially constant diameter. End 98 of
discharge tube 52 has an enlarged diameter portion 108 which
extends into a shoulder 110. After aligning end 98 of discharge
tube 52 and end 76 of tube 62 with axis 84, end 76 of tube 62 is
incrementally directed inside enlarged diameter position 108 until
"bottoming out" on shoulder 110 of discharge tube 52.
[0035] Discharge tube 52 connects in a similar way to discharge
outlet 15. Discharge outlet 15 includes a fitting 100 that extends
through an aperture 112 in the compressor housing 16. The fitting
100 is provided with a secure joint between itself and the
compressor housing 16 that is both fluid tight and rigid, both to
prevent the leakage of refrigerant through aperture 112 and avoid
unnecessary flexure to the subsequent joints formed between both
the fitting 100 and the discharge tube 52 inside the compressor
housing 16 and between the conduit and the fitting 100 located
outside the compressor housing 16. A fitting portion 114 of fitting
100 extends inside the compressor housing 16 which axially aligns
along axis 99 with end 106 of tube 52. Fitting portion 114 that is
inside compressor housing 16 includes an end 102 having an enlarged
diameter portion 104.
[0036] To establish a joint between the discharge tube 52 and
fitting portion 114, the end 106 of discharge tube 52 is directed
past end 102 of fitting portion 114 along axis 99 into the enlarged
diameter portion 104 until a joint is formed. The joint may be
secured by soldering or other appropriate bonding method.
Preferably, the joints for each end 98, 106 of discharge tube 52 is
established prior to securing the joints. That is, end 98 of
discharge tube 52 is directed into enlarged diameter portion 94 and
end 106 of discharge tube 52 is directed into enlarged diameter
portion 104 of fitting portion 114. Although the order of
establishing each joint is not critical, by permitting ends 98, 106
of discharge tube 52 tube to slide along the respective mutual axes
84, 99 with respect to the respective enlarged diameter portions
94, 104 after each joint is created, at least a portion of the
prestresses normally inherent with the installation of the
discharge tube 52 may be avoided. In other words, by virtue of this
variable, coincident insertion distance along enlarged diameter
portion 94 between discharge tube 52 and tube 62 of muffler 50 and
between discharge tube 52 and fitting portion 114, prestresses in
the discharge tube 52 caused by non-alignment installation
conditions may be further reduced, thereby improving the structural
integrity of the compressor. Further, by providing a substantially
straight or linear portion 116 in discharge tube 52 adjacent end
98, establishing the joint between end 98 of discharge tube 52 is
made easier for the installer and may also reduce the magnitude of
prestresses in the discharge tube 52 by permitting the improved
distribution of forces due to the collective extended lengths of
portions 116, 118, 120. Finally, depending upon the differences
between the outer diameter of discharge tube 52 along ends 98, 106,
and between respective enlarged diameter portions 94, 104, an
amount of lateral movement of ends 98, 106 within the respective
enlarged diameter portions 94, 104 may occur which would act to
further reduce prestresses in discharge tube 52.
[0037] In an alternate embodiment, end 106 of discharge tube 52
extends through aperture 112 of discharge outlet 15 a sufficient
length for connection with fitting 114. Preferably, a single brazed
joint placed along aperture 112 collectively provides a secure,
fluid tight seal between the housing 16, the discharge tube 52 and
fitting 114 while subjecting the discharge tube 52 to minimal
prestresses. In this embodiment, end 98 of tube 52 is provided with
an amount of both vertical and horizontal adjustment between end 98
of tube 52 and enlarged diameter portion 94 of muffler 50 as
previously discussed. End 106 of discharge tube 52 must only extend
through aperture 112 of housing 16 and is not otherwise
constrained, instead of being constrained to extend along the axis
of another component. Further, it is possible to install discharge
tube 52 after all of the other compressor components have been
installed in the lower half of the compressor housing. This
advantageous combination of slidable connections at each end of
discharge tube 52 subjects discharge tube 52 to few if any
installation prestresses.
[0038] Discharge tube 52 further provides several additional
benefits regarding both improved sound attenuation and reduction of
liquefied refrigerant that may collect in the sump of the
compressor housing 16. Referring back to FIG. 1, remaining portion
120 of discharge tube 52 extends adjacent the bottom of compressor
housing 16 before exiting at discharge port 15. Preferably a
segment of remaining portion 120 extends substantially coplanar
with discharge port 15. Since the level of lubricant 39 at the
lubrication sump 28 is preferably maintained above or at least in
contact with remaining portion 120, remaining portion 120 which
receives heated discharge refrigerant fluid from the cylinder head
30 is maintained in thermal communication with lubricant 39. By
virtue of this thermal communication with remaining portion 120,
which becomes heated during compressor operation, the temperature
of the lubricant 39 is raised such that condensed refrigerant fluid
mixed with the lubricant 39 is vaporized for use by the suction
side of the compressor. This removal of refrigerant from the sump
lubricant 39 helps prevent the introduction of liquid refrigerant
into the bearings associated with the crankshaft and motor shaft,
which is undesirable, thereby minimizing the possibility of
premature failure of the bearings. Additionally, since remaining
portion 120 is at least partially, if not totally, submerged by
lubricant 39, this maintained intimate contact with the lubricant
39 provides improved pressure pules attenuation as compared to an
identical length of remaining portion 120 that is exposed only to
refrigerant vapor.
[0039] While the invention has been described with reference to a
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended
claims.
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