U.S. patent application number 09/737935 was filed with the patent office on 2001-12-13 for muffler.
Invention is credited to An, kwang Hyup, Lee, In Seop, Myung, Hwan Joo.
Application Number | 20010050198 09/737935 |
Document ID | / |
Family ID | 19671730 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010050198 |
Kind Code |
A1 |
An, kwang Hyup ; et
al. |
December 13, 2001 |
Muffler
Abstract
Disclosed is a muffler in which a helicoil member is installed
in each conduit, through which refrigerant gas flows from or into
an expansion chamber during reciprocating movements of a piston in
a cylinder. The helicoil member has diverse twisted angles and
diverse twisted shapes, and serves to divide pulsation of noise,
generated during the reciprocating movements of the piston, into
pulsation of different phases, and then to merge the divided
pulsation together, while allowing the refrigerant gas to have the
form of a vortex flow. As pulsation of noise generated during an
operation of sucking refrigerant gas pass along different travel
paths defined by the helicoil member, a mutual interference occurs
between the pulsation respectively emerging from the travel paths
of the helicoil member. Therefore, an increased offset effect for
the pulsation of noise is obtained, which maximizes a noise
attenuation effect. It is also possible to prevent refrigerant gas
from flowing reversal due to a counter pressure gradient occurring
during the reciprocating movements of the piston. Accordingly,
enhanced compressor efficiency is obtained.
Inventors: |
An, kwang Hyup; (Seoul,
KR) ; Myung, Hwan Joo; (Gwangmyung, KR) ; Lee,
In Seop; (Seoul, KR) |
Correspondence
Address: |
BIRCH, STEWART, KOLASCH & BIRCH, LLP
P.O. Box 747
Falls Church
VA
22040-0747
US
|
Family ID: |
19671730 |
Appl. No.: |
09/737935 |
Filed: |
December 18, 2000 |
Current U.S.
Class: |
417/312 ;
181/280 |
Current CPC
Class: |
F01N 1/12 20130101; F04B
39/0072 20130101 |
Class at
Publication: |
181/403 ;
181/280 |
International
Class: |
F01N 001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 12, 2000 |
KR |
32153/2000 |
Claims
What is claimed is:
1. A muffler comprising: a muffler inlet arranged in the muffler
body, the muffler inlet communicating refrigerant lines extending
into the interior of the casing; a first reservoir defined, in the
form of an expansion chamber, in the muffler body above the muffler
inlet; a second reservoir defined, in the form of an expansion
chamber, in the muffler body beneath the first reservoir; a first
conduit having a reduced cross-sectional area, the first conduit
serving to connect the first and second reservoirs to each other; a
second conduit having a reduced cross-sectional area, the second
conduit serving to communicate the second reservoir with a muffler
outlet provided at the muffler body; a third reservoir defined, in
the form of an expansion chamber, defined in the muffler body
around the second conduit above the second reservoir, the third
reservoir serving as the Helmholtz reservoir; and an interference
member fixedly mounted in at least one of the first and second
conduits.
2. The muffler according to claim 1, wherein the interference
member comprises at least one helicoil foil fixedly mounted in an
associated one of the first and second conduits to extend in a
flowing direction of refrigerant gas in the associated conduit
while being twisted by a desired twisted angle to form a spiral
shape.
3. The muffler according to claim 2, wherein the at least one
twisted helicoil foil comprises at least two helicoil foils
arranged one after another in the flowing direction of refrigerant
gas so that adjacent ones of the helicoil foils cross each other at
facing ends thereof to form an angle of 90.degree. between the
facing ends.
4. The muffler according to claim 2, wherein the helicoil foil is
made of a micro-porous material.
5. The muffler according to claim 2, wherein the twisted angle
ranges from 90.degree. to 360.degree..
6. The muffler according to claim 2, wherein the at least one
helicoil foil comprises a plurality of helicoil foils combined
together depending on a frequency of noise.
7. The muffler according to claim 2, wherein the helicoil foil is
fixedly mounted in the second conduit.
8. The muffler according to claim 2, wherein the helicoil foil is
fixedly mounted in each of the first and second conduits.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a muffler, and more
particularly to a muffler used in a reciprocating compressor.
[0003] 2. Description of the Conventional Art
[0004] Generally, mufflers applied to compressors are classified
into a suction muffler connected to a fluid suction section of a
compressor and a discharge muffler connected to a fluid discharge
section of a compressor.
[0005] Such suction and discharge mufflers serve to attenuate a
pulsation phenomenon periodically generated during repeated fluid
suction and discharge operations of a compressor, to which those
mufflers are applied, thereby allowing the compressor to smoothly
suck and discharge fluid. These mufflers also serve to shield
impact noise generated in opening and closing operations of a valve
and noise resulting from flowing of fluid so that those noise
cannot be externally transmitted from the compressor, thereby
achieving a silent operation of the compressor.
[0006] FIG. 1 is a sectional view illustrating an example of a
hermetic reciprocating compressor respectively provided with
conventional mufflers at suction and discharge sections
thereof.
[0007] As shown in FIG. 1, the reciprocating compressor includes a
casing 1 filled with a desired amount of oil, an electric motor
mechanism installed in a lower portion of the casing 1 in the
interior of the casing 1 and adapted to generate a drive force in
response to electric power externally applied thereto, and a
compression mechanism installed at an upper portion of the casing 1
in the interior of the casing 1 and adapted to receive the drive
force from the electric motor mechanism so as to conduct gas
sucking and compressing operations.
[0008] The compression mechanism includes a frame 2 fixedly mounted
to the casing 1 in the interior of the casing 1, a cylinder 3
fixedly mounted to a portion of the frame 2, and a drive shaft 5
extending vertically through a central portion of the frame 2 while
being fitted in a rotor 4B included in the electric motor mechanism
so that it is coupled to the rotor 4B. The drive shaft 5 is
provided at an upper end thereof with an eccentric portion. The
compression mechanism also includes a connecting rod 6 coupled to
the eccentric portion of the drive shaft 5 and adapted to convert a
rotating movement into a reciprocating movement, a piston 7
connected to the connecting rod 6 and slidably received in the
cylinder 3 in such a fashion that it reciprocates in the cylinder
3, a valve assembly 8 coupled to the cylinder 3 and adapted to
control suction and discharge of refrigerant gas, and a head cover
9 coupled to the valve assembly 8 and defined with a desired
discharge space. The compression mechanism further includes a
suction muffler 10 coupled to a portion of the head cover in such a
fashion that it communicates with a suction inlet of the valve
assembly 8, and a discharge muffler DM mounted to the cylinder 3 in
such a fashion that it communicates with a discharge outlet of the
valve assembly 8.
[0009] In association with respective orientations of the
above-mentioned elements, the upward direction corresponds to the
direction toward the upper portion of the plane in FIG. 1.
[0010] As shown in FIG. 2, the muffler 10 is provided with a
muffler inlet 11 directly communicated with a refrigerant line SP
extending through the casing 1 or arranged in the interior of the
casing 1.
[0011] The muffler inlet 11 communicates with a first reservoir S1
defined, in the form of an expansion chamber, in a central portion
of the muffler 10.
[0012] The first reservoir S1 communicates with a second reservoir
S2 defined, in the form of an expansion chamber, beneath the first
reservoir S1 via a first conduit having a small cross-sectional
area. A third reservoir S3 is defined, in the form of an expansion
chamber, above the first reservoir S1. The third reservoir S3
serves as the Helmholtz reservoir.
[0013] The second reservoir S2 communicates with a muffler outlet
12 communicating with the valve assembly 8 via a second conduit 16
extending vertically into the second reservoir S2 through the third
reservoir S3.
[0014] A resonant aperture 17 is formed at an upper portion of the
second conduit 16 arranged in the third reservoir S3 so that it
constitutes the Helmholtz Resonator, together with the third
reservoir S3.
[0015] In FIGS. 1 and 2, the reference numeral or character 4A
denotes a stator, 18 an oil discharge port, C a support spring, and
O an oil feeder. In addition, the reference numerals 13 and 14
denote partition walls, respectively.
[0016] Now, an operation of the hermetic reciprocating compressor
provided with the above mentioned conventional mufflers will be
described.
[0017] When the rotor 4A is rotated by a mutual electromagnetic
force generated between the stator 4A and the rotor 4B in response
to electric power applied to the electric motor mechanism, the
drive shaft 5 rotates along with the rotor 4B. The rotation of the
drive shaft 5 is converted into straight reciprocating movements by
the connecting rod 6 coupled to the eccentric portion of the drive
shaft 5. The reciprocating movements is transmitted to the piston 7
which, in turn, reciprocates in the interior of the cylinder 3 to
compress refrigerant gas and to discharge the compressed
refrigerant gas. Pressure pulsation and noise, which may be
generated during the above-mentioned operations of the piston 7,
flow in a direction opposite to the flowing direction of the
refrigerant gas so that they are attenuated by the muffler 10.
[0018] The procedure for attenuating the pressure pulsation and
flowing noise by the conventional mufflers will now be
described.
[0019] During a stroke of the piston 7 from an upper dead point to
a lower dead point, refrigerant gas filled in the second reservoir
S2 is forced to be sucked into the interior of the cylinder 3, that
is, a compression chamber, via the second conduit 16 and muffler
outlet 12 while opening a suction valve of the valve assembly 8.
Simultaneously, new refrigerant gas is introduced into the second
reservoir S2 via the muffler inlet 11, first reservoir S1 and first
conduit 15. On the other hand, during a stroke of the piston 7 from
the lower dead point to the upper dead point, the suction valve of
the valve assembly 8 is closed. In this state, a discharge valve of
the valve assembly 8 is simultaneously opened. Therefore,
compressed refrigerant gas is discharged into a discharge space DS
defined in the head cover 9.
[0020] In the procedure in which the suction and discharge of
refrigerant gas are repeated, a repetitive pressure pulsation
occurs continuously in the muffler 10 and head cover 9. Such
pressure pulsation is propagated to each flow path defined in the
muffler 10. As this pressure pulsation passes the second conduit
16, second reservoir S2, first conduit 15, and first reservoir S1,
they are gradually attenuated, and finally dissipated. Therefore,
there is little pressure pulsation at the muffler inlet 11.
Accordingly, the refrigerant gas can be smoothly introduced.
[0021] Meanwhile, noise generated during the suction of refrigerant
gas is converted into heat energy in accordance with a diffusion
and dissipation thereof occurring when it passes through the
conduits 15 and 16, and reservoirs S1, S2 and S3, so that it is
attenuated. In particular, noise of a specific frequency is
attenuated by the helmholtz Resonator composed of the resonant
aperture 17 of the second conduit 16 and the third reservoir
S3.
[0022] In the above mentioned noise attenuation method, in which
attenuation of noise is achieved using a simple resonation effect
and the Helmholtz Resonator, however, it is necessary to use an
excessively large volume for each reservoir. Therefore, there is a
problem in that the whole muffler volume is undesirably
increased.
[0023] Furthermore, the procedure of converting pulsation energy of
noise into heat energy in accordance with a diffusion and
dissipation causes an increase in muffler temperature resulting in
an increase in the specific volume of refrigerant gas. Therefore,
there is a problem in that the efficiency of the compressor is
degraded.
[0024] The periodic pressure pulsation of the compression also
causes a periodic pulsation of the internal muffler pressure
resulting in a momentary counter pressure gradient serving to
generate a reverse flow of refrigerant gas. Therefore, the
introduction amount of refrigerant gas is reduced, thereby causing
degradation in the efficiency of the compressor.
SUMMARY OF THE INVENTION
[0025] Therefore, an object of the invention is to provide a
muffler capable of having a reduced volume while providing an
improved muffling effect, and reducing a generation of heat
energy.
[0026] Another object of the invention is to provide a muffler
capable of avoiding the generation of a reverse flow of refrigerant
gas resulting in a reduced introduction amount of refrigerant gas,
thereby preventing a degradation in the efficiency of a compressor
to which the muffler is applied.
[0027] In accordance with the present invention, these objects are
accomplished by providing a muffler comprising: a muffler inlet
arranged in the muffler body, the muffler inlet communicating a
refrigerant line extending into the interior of the casing; a first
reservoir defined, in the form of an expansion chamber, in the
muffler body above the muffler inlet; a second reservoir defined,
in the form of an expansion chamber, in the muffler body beneath
the first reservoir; a first conduit having a reduced
cross-sectional area, the first conduit serving to connect the
first and second reservoirs to each other; a second conduit having
a reduced cross-sectional area, the second conduit serving to
communicate the second reservoir with a muffler outlet provided at
the muffler body; a third reservoir defined, in the form of an
expansion chamber, defined in the muffler body around the second
conduit above the second reservoir, the third reservoir serving as
the Helmholtz reservoir; and an interference member fixedly mounted
in at least one of the first and second conduits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a sectional view illustrating an example of a
conventional hermetic reciprocating compressor.
[0029] FIG. 2 is a sectional view illustrating an example of a
muffler mounted to a suction section of the conventional hermetic
reciprocating compressor.
[0030] FIG. 3 is a sectional view illustrating an example of a
hermetic reciprocating compressor provided with mufflers according
to an embodiment of the present invention.
[0031] FIG. 4 is a sectional view illustrating the muffler of the
present invention mounted to a suction section of the hermetic
reciprocating compressor shown in FIG. 3.
[0032] FIG. 5A is a sectional view corresponding to a portion A of
FIG. 4, illustrating a helicoil member according to an embodiment
of the present invention.
[0033] FIG. 5B is a sectional view corresponding to a portion A of
FIG. 4, illustrating a helicoil member according to another
embodiment of the present invention.
[0034] FIG. 5C is a sectional view corresponding to a portion A of
FIG. 4, illustrating a helicoil member according to another
embodiment of the present invention.
[0035] FIG. 5D is a sectional view corresponding to a portion A of
FIG. 4, illustrating a helicoil member according to another
embodiment of the present invention.
[0036] FIG. 6A is a schematic view illustrating a procedure in
which acoustic waves interfere with each other in the muffler of
the present invention.
[0037] FIG. 6B is a schematic view illustrating a procedure in
which refrigerant gas is sucked in the muffler of the present
invention.
[0038] FIG. 7 is a sectional view illustrating a muffler according
to another embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Hereinafter, a muffler according to the present invention
will be described in detail, with reference to the annexed drawings
illustrating an embodiment of the present invention.
[0040] In the drawings, the same elements as those of the
conventional configuration are denoted by the same reference
numerals, respectively. In addition, no description will be made in
conjunction with the same configurations and operations as those of
the conventional case.
[0041] Referring to FIG. 3, a reciprocating compressor provided
with the muffler of the present invention is illustrated. As shown
in FIG. 3, the reciprocating compressor includes an electric motor
mechanism fixedly mounted in a casing 1 and adapted to generate a
drive force, and a compression mechanism connected to the electric
motor mechanism by a drive shaft 5 and adapted to conduct sucking
and compressing operations for refrigerant gas.
[0042] As shown in FIG. 4, the muffler 10 is provided with a
muffler inlet 11 directly communicated with a refrigerant line SP
extending through the casing 1 or arranged in the interior of the
casing 1.
[0043] The muffler inlet 11 communicates with a first reservoir S1
defined, in the form of an expansion chamber, in a central portion
of the muffler 10.
[0044] The first reservoir S1 communicates with a second reservoir
S2 defined, in the form of an expansion chamber, beneath the first
reservoir S1 via a first conduit having a small cross-sectional
area. A third reservoir S3 is defined, in the form of an expansion
chamber, above the first reservoir S1. The third reservoir S3
serves as the Helmholtz reservoir.
[0045] The second reservoir S2 communicates with a muffler outlet
12 communicating with the valve assembly 8 via a second conduit 16
extending vertically into the second reservoir S2 through the third
reservoir S3.
[0046] A resonant aperture 17 is formed at an upper portion of the
second conduit 16 arranged in the third reservoir S3 so that it
constitutes the Helmholtz Resonator, together with the third
reservoir S3.
[0047] Helicoil members 100, each of which is made of a spiral
foil, are fixedly mounted in the first and second conduits 15 and
16, respectively.
[0048] Hereinafter, the mounting of the helicoil members 100 will
be described in detail.
[0049] In accordance with an embodiment shown in FIG. 5A, each
helicoil member 100, which is fixedly mounted in an associated one
of the first and second conduits 15 and 16, comprises a
360.degree.-twisted helicoil foil 110 extending in a flowing
direction of refrigerant gas while being twisted by an angle of
360.degree. in a counter-clockwise direction when viewed on the
plane of FIG. 5A.
[0050] Alternatively, each helicoil member 100 may comprise a
plurality of alternating 180.degree.-twisted helicoil foils 121 and
122 arranged one after another in the flowing direction of
refrigerant gas in such a fashion that adjacent ones thereof cross
each other at their facing ends to form an angle of 90.degree.
between those facing ends, as shown in FIG. 5B.
[0051] In accordance with another embodiment shown in FIG. 5C, each
helicoil member 100 comprises a plurality of 90.degree.-twisted
helicoil foils 131, 132, 133, and 134 arranged in parallel in the
flowing direction of refrigerant gas.
[0052] In accordance with another embodiment shown in FIG. 5D, each
helicoil member 100 comprises a 180.degree.-twisted helicoil foil
141, and a pair of 90-twisted helicoil foils 142 and 143
respectively arranged adjacent to opposite ends of the
180.degree.-twisted helicoil foil 141 in the flowing direction of
refrigerant gas in such a fashion that each of the
90.degree.-twisted helicoil foils cross the 180.degree.-twisted
helicoil foil 141 at facing ends thereof to form an angle of
90.degree. between those facing ends.
[0053] Of course, the configuration of each helicoil member 100 is
not limited to the above mentioned embodiments. Each helicoil
member 100 may be configured by other combinations of the above
mentioned helicoil foils made to have diverse twisted angles,
twisted lengths, and twisted directions, depending on the frequency
characteristics of noise.
[0054] Each helicoil member 100 is preferably made of a
micro-porous material so that it has a sound absorbing function by
itself. However, such a micro-porous material is expensive. Taking
this fact into consideration, the helicoil members 100 may be made
of an inexpensive material such as a rubber material, plastic, or
steel.
[0055] In FIGS. 3 and 4, the reference numeral or character 4A
denotes a stator, 18 an oil discharge port, C a support spring, and
O an oil feeder. In addition, the reference numerals 13 and 14
denote partition walls, respectively.
[0056] An operation of the hermetic reciprocating compressor
provided with the above mentioned mufflers according to the present
invention will now be described.
[0057] When electric power is applied to the electric motor
mechanism, the piston 7 reciprocates straight movement, thereby
conducting a compression of refrigerant gas and a discharge of the
compressed refrigerant gas.
[0058] Hereinafter, the procedure for attenuating pressure
pulsation and flowing noise by the muffler of the present invention
will be described in detail.
[0059] During an expansion stroke of the piston 7 from an upper
dead point to a lower dead point, a negative pressure is exerted in
the interior of the cylinder 3, thereby causing a suction valve of
the valve assembly 8 to be opened. As a result, refrigerant gas
filled in the second reservoir S2 is sucked into the interior of
the cylinder 3 via the muffler outlet 12 until the internal
pressure of the cylinder corresponds to the pressure of the muffler
10. Simultaneously, the second reservoir S2 is replenished with new
refrigerant gas fed via the first reservoir S1 and first conduit
15.
[0060] On the other hand, during a compression stroke of the piston
7 from the lower dead point to the upper dead point, the internal
pressure of the cylinder 3 is gradually increased. When the
internal pressure of the cylinder 3 is higher than the biasing
force of the support spring C applied to the discharge valve of the
valve assembly 8, the discharge valve is opened, thereby causing
the high-pressure compressed refrigerant gas in the cylinder 3 to
be discharged into a discharge space DS defined in the head cover
9.
[0061] At this time, noise generated during the suction of
refrigerant gas is converted into heat energy in accordance with a
diffusion and dissipation thereof occurring when it passes through
the conduits 15 and 16, and reservoirs S1, S2 and S3, so that it is
attenuated. In particular, noise of a specific frequency is
attenuated by the helmholtz Resonator composed of the resonant
aperture 17 of the second conduit 16 and the third reservoir
S3.
[0062] Meanwhile, acoustic waves propagated from a noise source are
propagated along two travel paths defined by each helicoil member
100, and then meet together at a downstream end of the helicoil
member 100. Two acoustic waves emerging from respective travel
paths have different phases, so that they interfere with each
other. Therefore, the amplitudes of the acoustic waves are reduced.
In accordance with this principle, refrigerant gas can flow without
any considerable resistance in a state in which the level of noise
is reduced.
[0063] Accordingly, the amount of heat energy generated in the
reservoirs S1 and S2 is reduced, thereby decreasing the temperature
of the muffler 10. This results in a reduction in the specific
volume of refrigerant, thereby achieving an improvement in the
efficiency of the compressor.
[0064] Where each helicoil member 100 is configured using a
plurality of alternating 180.degree.-twisted helicoil foils 121 and
122 arranged in such a fashion that adjacent ones thereof cross
each other at their facing ends to form an angle of 90.degree.
between those facing ends, as shown in FIG. 5B, acoustic waves are
first traveled along the upstream 180.degree.-twisted helicoil foil
121 while being divided into two acoustic waves in a lateral
directional when viewed on the drawing plane. These two acoustic
waves emerging from the upstream 180.degree.-twisted helicoil foil
121 primarily interfere with each other at the downstream end of
the upstream 180.degree.-twisted helicoil foil 121. The
primarily-interfered acoustic waves are then traveled along the
180.degree.-twisted helicoil foil 122 following the upstream
180.degree.-twisted helicoil foil 121 while being divided into two
acoustic waves in a vertical direction when viewed on the drawing
plate. These two acoustic waves emerging from the
180.degree.-twisted helicoil foil 122 secondarily interfere with
each other at the downstream end of the 180.degree.-twisted
helicoil foil 122. Thus, an increased offset effect for acoustic
waves is obtained.
[0065] As shown in FIG. 6B, respective flows of refrigerant gas
sucked from the second reservoir S2 toward the muffler outlet 12
and sucked from the first reservoir S1 into the second reservoir S2
during the expansion stroke of the piston 7 move along spiral flow
paths defined by the helicoil members 100 respectively installed in
the second conduit 16 and the first conduit 15. As a result, the
refrigerant gas flows emerging from the helicoil members 100 have
the form of a vortex flow having velocity components in an axial
direction (that is, a direction parallel to the extending direction
of the helicoil member) and strong velocity components in a
circumferential direction. Accordingly, it is possible to prevent
the refrigerant gas flows from flowing reversal during a
compression stroke of the piston 7 following the expansion stroke,
by virtue of the strong circumferential velocity components of the
refrigerant gas flows, even when a so-called "counter pressure
gradient" occurs due to a momentary stagnation (inertial force) of
refrigerant gas.
[0066] Since the helicoil members 100 installed in the conduits 15
and 16 serve to provide improved effects of preventing a reverse
flow of refrigerant gas and attenuating noise, the muffler of the
present invention can exhibit effects similar to those of the
conventional muffler configuration, without using an excessively
increased internal muffler volume and a complex inner muffler
construction. In this regard, a muffler having a simpler
configuration may be designed. An example of such a simple muffler
is illustrated in FIG. 7. In FIG. 7, the muffler is denoted by the
reference numeral 20.
[0067] In FIG. 7, the reference numeral 21 denotes a reservoir
having the form of an expansion chamber, 22 a first conduit which
also serves as a muffler inlet, 23 a second conduit which also
serves as a muffler outlet, and 100 a helicoil member.
[0068] As apparent from the above description, the present
invention provides a muffler in which a helicoil member is
installed in each conduit, through which refrigerant gas flows from
or into an expansion chamber during reciprocating movements of a
piston in a cylinder. The helicoil member has diverse twisted
angles and diverse twisted shapes, and serves to divide pulsation
of noise, generated during the reciprocating movements of the
piston, into pulsation of different phases, and then to merge the
divided pulsation together, while allowing the refrigerant gas to
have the form of a vortex flow. As pulsation of noise generated
during an operation of sucking refrigerant gas pass along different
travel paths defined by the helicoil member, a mutual interference
occurs between the pulsation respectively emerging from the travel
paths of the helicoil member. Therefore, an increased offset effect
for the pulsation of noise is obtained, which maximizes a noise
attenuation effect. It is also possible to prevent refrigerant gas
from flowing reversal due to a counter pressure gradient occurring
during the reciprocating movements of the piston. Accordingly,
enhanced compressor efficiency is obtained.
[0069] The noise attenuation also results in a reduction in the
rate of heat energy generated in the expansion chamber.
Accordingly, the specific volume of refrigerant gas is reduced,
thereby achieving an improvement in compressor efficiency.
[0070] Moreover, the helicoil member of the present invention can
be inexpensively manufactured. The installation of this helicoil
member also can be easily and conveniently carried out. By virtue
of the helicoil member, the muffler can have a considerably reduced
size, as compared to those using no helicoil member. The helicoil
member also makes it possible to achieve an easy manufacture of the
muffler and an easy installation of the muffler in the interior of
a compressor in which there are various geometrical
limitations.
[0071] Although the preferred embodiments of the invention have
been disclosed for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *