U.S. patent application number 12/810593 was filed with the patent office on 2010-12-09 for system for attenuating pulsation in the gas discharge of a refrigeration compressor.
Invention is credited to Eduardo De Souza Alvarenga.
Application Number | 20100310389 12/810593 |
Document ID | / |
Family ID | 40429125 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100310389 |
Kind Code |
A1 |
Alvarenga; Eduardo De
Souza |
December 9, 2010 |
SYSTEM FOR ATTENUATING PULSATION IN THE GAS DISCHARGE OF A
REFRIGERATION COMPRESSOR
Abstract
The attenuation system is applied to a compressor which
comprises: a cylinder (2) having an end closed by a valve plate (4)
provided with a discharge orifice (4a) and defining, with the
cylinder (2), a compression chamber (6), a cylinder cover (5) being
seated against the valve plate (4) and defining a discharge chamber
(7), which communicates with the exterior of the compressor through
a discharge tube (8). The attenuation system comprises: at least
one intermediary chamber (10) defined in the interior of the
discharge chamber (7), in order to receive, from the discharge
orifice (4a), the whole discharge flow coming from the compression
chamber (6); and at least one 4a connecting tube (20) mounted in
the interior 4b of the discharge chamber (7), having a first end
(21) open to the interior of the intermediary chamber (10) and a
second end (22) open to the interior of the discharge chamber
(7).
Inventors: |
Alvarenga; Eduardo De Souza;
(Joinville-Sc, BR) |
Correspondence
Address: |
GIFFORD, KRASS, SPRINKLE,ANDERSON & CITKOWSKI, P.C
PO BOX 7021
TROY
MI
48007-7021
US
|
Family ID: |
40429125 |
Appl. No.: |
12/810593 |
Filed: |
December 3, 2008 |
PCT Filed: |
December 3, 2008 |
PCT NO: |
PCT/BR08/00366 |
371 Date: |
August 10, 2010 |
Current U.S.
Class: |
417/312 |
Current CPC
Class: |
F04B 39/0055 20130101;
F01N 1/089 20130101; F04B 53/001 20130101; F04B 39/125 20130101;
F04B 39/12 20130101; F04B 39/0061 20130101; F04B 39/121 20130101;
F04B 39/123 20130101; F04B 39/0027 20130101 |
Class at
Publication: |
417/312 |
International
Class: |
F04B 39/00 20060101
F04B039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2007 |
BR |
PI0705357-6 |
Claims
1. A system for attenuating pulsation in the gas discharge of a
refrigeration compressor of the type which comprises: a cylinder
block (1) defining a cylinder (2); a valve plate (4) closing an end
of the cylinder (2) and provided with a discharge orifice (4a) and
defining, with the cylinder (2), a compression chamber (6); a
cylinder cover (5) seated against a face of the valve plate (4)
opposite to that turned to the compression chamber (6) and defining
a discharge chamber (7); a discharge tube (8) to communicate the
discharge chamber (7) with the exterior of the compressor,
characterized in that it comprises: at least one intermediary
chamber (10) defined in the interior of the discharge chamber (7),
so as to receive, from the discharge orifice (4a), the whole
discharge flow coming from the compression chamber (6); at least
one connecting tube (20) mounted in the interior of the discharge
chamber (7), having a first end (21) open to the interior of the
intermediary chamber (10) and a second end (22) open to the
interior of the discharge chamber (7), said connecting tube (20)
projecting, by a certain extension, to the interior of at least one
of the intermediary chamber (10) and discharge chamber (7).
2. The system, as set forth in claim 1, characterized in that the
first and second ends (21, 22) of the connecting tube (20) are
eccentrically disposed in the intermediary chamber (10) and
discharge chamber (7).
3. The system, as set forth in claim 2, characterized in that the
connecting tube (20) presents, between its first end and its second
end (21, 22), an extension calculated as a function of the main
pulsation mode of the gas under compression to be attenuated.
4. The system, as set forth in claim 3, characterized in that the
first end (21) of the connecting tube (20) projects to the interior
of the intermediary chamber (10), by a determined extension
previously calculated as a function of the pulsation mode to be
attenuated.
5. The system, as set forth in claim 1, characterized in that the
connecting tube (20) presents a spiral development, from its first
end (21) and which extends at least along the extension of the
connecting tube (20) which is internal to the discharge chamber
(7).
6. The system, as set forth in claim 1, characterized in that the
connecting tube (20) is formed in a single piece with the
intermediary chamber (10).
7. The system, as set forth in claim 1, characterized in that at
least one of the parts of intermediary chamber (10) and connecting
tube (20) is provided in an acoustic insulating material.
8. The system, as set forth in claim 1, characterized in that the
second end (22) of the connecting tube (20) is disposed spaced from
the open end of the discharge tube (8).
9. The system, as set forth in claim 1, characterized in that the
intermediary chamber (10) is hermetically attached to the valve
plate (4).
10. The system, as set forth in claim 9, characterized in that the
intermediary chamber (10) is a hollow body having an opening whose
contour is defined by a peripheral edge (10a) to be seated and
affixed against the valve plate (4).
11. The system, as set forth in claim 10, characterized in that the
hollow body is rigid.
Description
FIELD OF THE INVENTION
[0001] The present invention refers to an attenuating pulsation
system to be applied in the gas discharge of a refrigeration
compressor, for example of the reciprocating hermetic type and
generally driven by a linear motor.
BACKGROUND OF THE INVENTION
[0002] Refrigeration compressors are generally provided with
pulsation attenuators or acoustic filters provided in the gas
discharge. Such attenuators have the purpose of attenuating the
pulsation of the gases which are pumped from the compressor to the
refrigeration system to which said compressors are generally
coupled or, in the generic case, to the high-pressure side of the
refrigeration circuit to which the compressor belongs, as well as
reducing the noise irradiated by the compressor to the external
ambient. The pulsation of the gases generates an excitation in the
ducts and components to which the discharge of the compressor is
coupled, which in turn generates noise.
[0003] The attenuation of pulsations in the gas discharge of a
compressor is generally carried out by: restricting the pumped
refrigerant fluid flow, by reducing the diameter of the discharge
tube, obtaining attenuation through load loss; or providing one or
more expansion volumes disposed in series with the discharge tube,
making the acoustic impedance discontinuity reflect pulsation
acoustic waves existing in said tube, thereby attenuating the
transmitted pulsation. In these constructions, the pulsation
attenuating devices are incorporated to the cylinder block and/or
to the discharge tube. The gas flow is forced to pass through a
well defined sequence of tubes, volumes and restrictions located in
the cylinder block and/or in the discharge tube, whose dimensions,
arrangement and particular characteristics depend on the
application, on the type and size of the compressor, on the mass
flow, on the working fluid, on the temperatures and operation
conditions, on the noise bands which are intended to attenuate,
etc.
[0004] Although this discharge system solution presenting a
configuration of volumes "in series" results in greater
attenuation, it has the disadvantage of producing a higher load
loss. This solution further presents the disadvantage of requiring
large dimensions for the cylinder block to allow machining the
volumes and discharge tubes. In compact compressors, for example,
of the type not presenting a massive block and in which the
cylinder block that defines part of the shell is very light, such
known solution is not applied, since there is no space for
incorporating an attenuator integrated to the cylinder block.
SUMMARY OF THE INVENTION
[0005] It is a generic object of the present invention to provide a
system for attenuating pulsation in the gas discharge of a
refrigeration compressor, particularly of small dimensions, which
enables attenuating discharge pulsations and noise, without
presenting the load loss of the conventional constructions.
[0006] Another object of the present invention is to provide a
system for attenuating pulsations and noise, as cited above, which
is easily constructed and mounted, mainly in a compressor without a
massive block, particularly of the linear type.
[0007] These objects are attained through a system for attenuating
pulsation in the gas discharge of a refrigeration compressor of the
type which comprises: a cylinder block defining a cylinder; a valve
plate closing an end of the cylinder and provided with a discharge
orifice and defining, with the cylinder, a compression chamber; a
cylinder cover seated against a face of the valve plate opposite to
that turned to the compression chamber and defining a discharge
chamber; and a discharge tube communicating the discharge chamber
to the exterior of the compressor. The attenuation system of the
present invention comprises: at least one intermediary chamber
defined in the interior of the discharge chamber, so as to receive,
from the discharge orifice, the whole discharge flow coming from
the compression chamber; at least one connecting tube mounted in
the interior of the discharge chamber, having a first end open to
the interior of the intermediary chamber and a second end open to
the interior of the discharge chamber, said connecting tube
projecting, by a certain extension, to the interior of at least one
of the intermediary chamber and discharge chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention will be described below, upon reference to the
enclosed drawings, given by way of example of an embodiment of the
invention and in which:
[0009] FIG. 1 schematically represents a longitudinal sectional
view of part of the discharge assembly of a linear motor
reciprocating compressor of the prior art, particularly of the
compact type, in which the shell is defined by the cylinder block
and by the cylinder cover;
[0010] FIG. 2 schematically represents as in FIG. 1, a longitudinal
sectional view of a linear motor compressor with the system for
attenuating discharge pulsation of the present invention;
[0011] FIG. 3 schematically represents a view similar to that of
FIG. 2, but illustrating the system for attenuating pulsation
provided with more than one intermediary chamber;
[0012] FIG. 4 schematically represents an enlarged longitudinal
sectional view of the cylinder cover of the compressor illustrated
in FIG. 2, in which is provided the system for attenuating
discharge pulsation of the present invention, for the embodiment
illustrated in FIG. 2;
[0013] FIG. 5 graphically represents the attenuation results
obtained for a prior art gas discharge system, having only one
discharge volume in the discharge chamber (dashed line), and for a
construction having a pulsation attenuation system, according to
the present invention, presenting two gas discharge volumes in the
interior of the cylinder cover; and
[0014] FIG. 6 graphically represents the attenuation results
obtained for a gas discharge arrangement for one and for two
discharge volumes in the discharge chamber, in the interior of the
cylinder cover, according to one of the ways of carrying out of the
present invention.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0015] The present invention will be described for a reciprocating
hermetic compressor which comprises a motor-compressor assembly
having a cylinder block 1, which defines a cylinder 2, inside which
a piston 3 is axially displaced by actuation of a motor (not
illustrated). In a particular compressor construction of the type
driven by a linear motor, the piston 3 is connected to a resonant
spring (not illustrated) and axially displaced in the interior of
the cylinder 2 by an actuating assembly (not illustrated), which
supports a magnetic component (not illustrated) and which is
axially driven upon energization of the linear motor.
[0016] The cylinder 2 has an open end, through which the piston 3
is housed, and an opposite end closed by a valve plate 4, against
which is seated a cylinder cover 5. The valve plate 4 carries at
least one of the suction valve and discharge valve, which regulate
the gas inlet and outlet in relation to the interior of the
cylinder 2. In the illustrated construction, the valve plate 4 is
provided with a discharge orifice 4a, closed by a corresponding
discharge valve 4b, and two suction orifices 4c, closed by a valve
element 4d. In this illustrated construction, the valve plate 4
carries, on each one of its opposite faces, said discharge valve 4b
and suction valve 4d. The valve plate 4 defines, with the interior
of the cylinder 2, a compression chamber 6. The construction
illustrated in FIG. 1 presents a conventional way of mounting the
cylinder cover 5 to a cylinder block 1, which results in the
deficiencies already discussed.
[0017] The cylinder cover 5 is seated against a face of the valve
plate 4, which is opposite to another face of the latter and turned
to the compression chamber 6, said cylinder cover 5 defining, with
the adjacent face of the valve plate 4, a discharge chamber 7,
which maintains a selective fluid communication with the
compression chamber 6, through the discharge orifice 4a and
discharge valve 4b, and a constant fluid communication with a
discharge side of a refrigeration system to which the compressor is
associated, through a discharge tube 8, which communicates said
discharge chamber 7 to the exterior of the compressor.
[0018] The reciprocating movement of the piston 3 in the interior
of the cylinder 2, in relation to the valve plate 4, determines,
respectively, the gas suction operation and the gas compression
operation in the compressor.
[0019] In some constructions of a compressor driven by a linear
motor, the motor-compressor assembly is mounted in the interior of
a shell, which forms a hermetic environment in relation to the
exterior, said mounting being usually carried out on a set of
suspension springs positioned in the interior of the shell. In the
compact linear compressor constructions, the cylinder block 1 and
the cylinder cover 5 define part of the shell.
[0020] According to the present invention, the refrigeration
compressor includes a discharge attenuation system which comprises
at least one intermediary chamber 10, defined in the interior of
the discharge chamber 7, so as to receive, from the discharge
orifice 4a of the valve plate 4, the whole discharge flow coming
from the compression chamber 7, said intermediary chamber 10
maintaining constant fluid communication with the discharge chamber
7, through at least one connecting tube 20 mounted in the interior
of the discharge chamber 7 and having a first end 21 open to the
interior of the intermediary chamber 10, and a second end 22 open
to the interior of the discharge chamber 7, said connecting tube 20
projecting, for example, by a certain extension, to the interior of
at least one of the intermediary chamber 10 and discharge chamber
7.
[0021] The solution of the present invention refers to a concept
for an acoustic muffler of the volume-tube-volume type, which is
not provided in the cylinder block 1 or in the discharge tube 8,
but in the interior of the cylinder cover 5, presenting, as a first
volume, an intermediary chamber 10 in which the gas is discharged
through the opening of the discharge valve 4b and, as the last
volume, the one defined adjacent to the discharge tube 8 in the
cylinder cover 5, at least one of said volumes maintaining
communication with an adjacent volume through a connecting tube 20
having an end open to the interior of the discharge chamber 7 and
an end open to an adjacent intermediary chamber, as illustrated in
FIG. 1.
[0022] The volume of each intermediary chamber and of the discharge
chamber, as well as the determination of the dimensions of each
connecting tube 20 (extension, shape, cross-section) and the
definition of the extension projecting from the latter to the
interior of each chamber in which said connecting tube actuates,
are defined as a function of the attenuation effect to be obtained
and the pulsation range to be attenuated.
[0023] According to the present invention, in case a plurality of
intermediary chambers are provided in series, as illustrated in
FIG. 3, they can be interconnected to each other by different
connecting tube constructions, the fluid communication between each
two consecutive and sequential intermediary chambers being carried
out by at least one connecting tube 20 presenting, between its
first end 21 and its second end 22, an extension calculated at
least as a function of the main pulsation mode of the gas under
compression to be attenuated.
[0024] In a particular construction form with volumes in series,
these are provided with overlapped intermediary chambers 10, a
first of which in fluid communication with the discharge orifice
4a. In another particular construction, the intermediary chambers
are disposed in surrounding layers, concentric or not.
[0025] In another way of carrying out the present invention, the
volumes and tubes in series can be obtained with a sequence of
volumes which are spaced apart and interconnected by connecting
tubes 20.
[0026] In a variant for any of these constructions, as well as for
those illustrated herein, the first intermediary chamber 10, which
receives the compressed gas directly from the compression chamber
6, is seated against the valve plate 4. In another constructive
variant, within the concept presented herein, there is provided,
between the discharge orifice 4a and a first of said intermediary
chambers 10, a connecting tube 20, which maintains the first of the
intermediary chambers 10 spaced from a seating condition against
the valve plate 4.
[0027] For any of the constructions of volumes and tubes of the
present invention, these are provided in order not to interrupt an
intermittent gas mass flow being discharged to the discharge
chamber, during compression, while attenuating the pulsations of
this gas mass under compression.
[0028] Each intermediary chamber 10 is defined by a hollow body, of
rigid of flexible structure, and which affixes a portion of a
connecting tube 20, for example, by means of weld or glue, or also
incorporating said tube portion in a single piece. Each
intermediary chamber 10 is provided in the interior of the cylinder
cover 5, so that the only fluid communication thereof with an
adjacent volume of an intermediary chamber 10, or with the
discharge chamber 7, is made through one or more connecting tubes
20.
[0029] In order to improve the attenuation of pulsations, at least
one of the parts of intermediary chamber 10 and connecting tube 20
is provided or coated with acoustic insulating material.
[0030] In the constructions in which the intermediary chambers 10
are seated against the valve plate 4, each said intermediary
chamber 10 is attached to the valve plate 4 by an appropriate
fixation means 40, such as glue, screw, weld, etc., or by a simple
mounting interference of the cylinder cover 5, said fixation being
carried out so as to prevent compressed gas leakage between a
peripheral edge of the intermediary chamber 10 and an adjacent face
of the valve plate 4.
[0031] In a constructive form for affixing the intermediary chamber
to the valve plate 4, said intermediary chamber presents its hollow
body having an opening, whose contour is defined by a peripheral
edge 10a, to be seated against the valve plate 4, and from which
externally projects a peripheral flange 11, for example continuous,
and which allows the fixation to the valve plate 4, through, for
example, screws, as illustrated in FIG. 4. In another constructive
option, the peripheral flange of the intermediary chamber 10
presents a determined extension, which is sufficient to externally
seat, in its periphery, a peripheral edge portion of the cylinder
cover 5, which is affixed to the cylinder jointly with said
intermediary chamber.
[0032] According to a way of carrying out the present invention,
each connecting tube 20 presents its respective first and second
ends 21, 22 eccentrically disposed in the intermediary chamber 10
and discharge chamber 7, the second end 22 of the connecting tube
20 being disposed spaced from an open end of the discharge tube 8,
turned to the interior of the discharge chamber 7.
[0033] According to another aspect of the present invention, each
connecting tube 20 presents at least one of its first and second
ends 21, 22 projecting to the interior of the respective
intermediary chamber 10 and discharge chamber 7, by a determined
extension previously calculated as a function of the pulsation mode
to be attenuated. In the illustrated constructive form, the
connecting tube 20 has each of its first and second ends 21, 22
projecting to the interior of the respective intermediary chamber
10 and discharge chamber 7 by a respective extension calculated as
exposed above.
[0034] According to another aspect of the present invention, each
connecting tube 20 can be substituted by one or more holes defined
in the part provided with said holes and so that the thickness of
said part defines a tube extension presenting the ends as already
described, without impairing the function thereof. In this case,
the attenuation curve is that illustrated in FIG. 6.
[0035] Each intermediary chamber 10 carries the respective
connecting tube(s) 20, which are incorporated thereto by fixation
or formed in a single piece with the body of said intermediary
chamber 10, upon obtention of the latter.
[0036] As a function of the extension to be presented by the
connecting tube, said connecting tube 20 should be provided so as
to present a spiral development, to the interior of at least one of
the intermediary chamber 10 and discharge chamber 7, from a portion
of its extension projecting to the interior of the respective
chamber. In the construction illustrated in FIG. 4, the connecting
tube 20 presents a spiral development, from its first end 21, in
the portion of its extension externally projecting from the hollow
body of the intermediary chamber 10 that carries it. As a function
of the reduced space available in the interior of the cylinder
cover 5, the connecting tube 20 presents its spiral portion
accompanying at least part of the outer peripheral contour of the
intermediary chamber. However, it should be understood that the
illustrated constructive form should not be considered as
limitative for the development arrangement of the connecting tube
20, but only as a constructive option.
[0037] It should also be observed that the constructive variants
described herein can be individually presented in particular
constructions, or also partially or totally combined to each
other.
[0038] As can be observed in FIGS. 5 and 6, the solution for the
pulsation attenuation system of the present invention presents a
substantial attenuation gain in a wide band spectrum, said
attenuation being of up to 50 decibel in some specific bands in
relation to the prior art constructions.
* * * * *