Patent Application
20090090579
1. Field of the Invention
This invention relates to a silencer for a refrigeration cycle system for reducing the pressure pulsation of a refrigerant discharged from a compressor.
2. Description of the Related Art
In the prior art, the silencer for this type of refrigeration cycle system is designed to reduce the pressure pulsation of a refrigerant by interference of the pressure wave in the silencing chamber (see, for example, Japanese Unexamined Patent Publications Nos. 2002-61508 and 11-62827).
The conventional technique described in Japanese Unexamined Patent Publication No. 2002-61508 concerns a silencer which is known as a straight type for the refrigeration cycle system, in which the inlet pipe through which the refrigerant flows into the silencing chamber is aligned with the outlet pipe through which the refrigerant flows out of the silencing chamber. As a result, the refrigerant flows linearly in the silencing chamber.
The conventional technique described in Japanese Unexamined Patent Publication No. 11-62827 concerns a silencer which is known as an elbow-type for the refrigeration cycle system, in which the direction in which the inlet pipe is connected to the housing of the silencing chamber is orthogonal to the direction in which the outlet pipe is connected to the housing. As a result, the refrigerant flows substantially at right angles in the silencing chamber.
In the elbow-type silencer for the refrigeration cycle system, the refrigerant flows at right angles in the silencing chamber, and therefore interference of pressure waves occurs in the silencing chamber. As a result, a higher silencing effect can be achieved than by the refrigeration cycle system silencer of a straight-type in which the refrigerant flows linearly in the silencing chamber.
However, in the latter conventional technique, i.e., the refrigeration cycle system which uses an elbow-type silencer, the following phenomena occurs while the refrigerant flows at right angles in the silencing chamber.
First, the refrigerant that has flowed into the silencing chamber through the inlet pipe flows linearly under inertia and impinges on the part of the inner wall surface of the housing in opposed relation to the downstream end of the inlet pipe. As a result, the refrigerant speed rapidly decreases, and the velocity component in the running direction is reduced to zero. Thus, most of the velocity energy of the refrigerant is lost and converted into thermal energy. The pressure energy of the refrigerant is then converted into velocity energy, so that the refrigerant is accelerated again and flows out of the silencing chamber through the outlet pipe.
Therefore, in the latter conventional technique, the phenomenon described above increases the pressure loss of the refrigerant in the silencer.
In view of the points described above, the object of this invention is to reduce the pressure loss of the refrigerant while maintaining a high silencing effect.
In order to achieve the object described above, according to a first aspect of the invention, there is provided a silencer for a refrigeration cycle system, comprising:
a silencing chamber (15a) formed in a housing (16);
an inlet pipe (20) connected to the housing (16) to allow the refrigerant to flow into the silencing chamber (15a); and
an outlet pipe (21) connected to the housing (16) to allow the refrigerant to flow out of the silencing chamber (15a);
wherein the direction in which the inlet pipe (20) is connected to the housing (16) crosses the direction in which the outlet pipe (21) is connected to the housing (16);
wherein the upstream end (21b) portion of the outlet pipe (21) is formed with a bend (21c) projected into the silencing chamber (15a) and bent toward the downstream end (20b) of the inlet pipe (20); and
wherein the bend (21c) is formed with an opening (21d) to open the inside part of the bend (21c).
In this configuration, the upstream end (21b) portion of the outlet pipe (21) is formed with the bend (21c) projected into the silencing chamber (15a) and bent toward the downstream end (20b) of the inlet pipe (20), and therefore the refrigerant flowing into the silencing chamber (15a) through the inlet pipe (20) can be guided smoothly to the outlet pipe (21) by the bend (21c).
As a result, rapid deceleration of the refrigerant that has flowed into the silencing chamber (15) which otherwise might be caused by the bombardment of the inner wall surface of the housing (16) is suppressed. Thus, the pressure loss of the refrigerant in the silencer (15) can be reduced.
Further, since the opening (21d) for opening the inside part of the bend (21c) is formed on the bend (21c), the interference of the pressure wave can be caused by the opening (21d). Thus, the suppression of the interference of the pressure wave which otherwise might be caused by the bend (21c) projected into the silencing chamber (15a) can be avoided, and the silencing effect equivalent to that of the refrigeration cycle system silencer disclosed in Japanese Unexamined Patent Publication No. 11-62827 described above can be exhibited.
For the reason described above, the pressure loss of the refrigerant can be reduced while maintaining a high silencing effect equivalent to that of the refrigeration cycle system silencer disclosed in Japanese Unexamined Patent Publication No. 11-62827.
In this invention, the opening (21d) may be formed to extend at least from the upstream end (21b) to the central portion of the bend (21c) in the direction of the refrigerant flow. In this way, the effective interference of the pressure wave can be caused by the opening (21d).
In this invention, the outlet pipe (21) may be formed with an outward protrusion (21a) in contact with the outer surface of the housing (16).
With this configuration, the outlet pipe (21) can be positioned with respect to the housing (16) by the protrusion (21a), and therefore the outlet pipe (21) can be easily assembled on the housing (16).
According to a second aspect of the invention, there is provided a silencer for the refrigeration cycle system, comprising:
a silencing chamber (15a) formed in a housing (16);
an inlet pipe (20) connected to the housing (16) to allow the refrigerant to flow into the silencing chamber (15a); and
an outlet pipe (21) connected to the housing (16) to allow the refrigerant to flow out of the silencing chamber (15a);
wherein the direction in which the inlet pipe (20) is connected to the housing (16) crosses the direction in which the outlet pipe (21) is connected to the housing (16);
wherein the downstream end (20b) portion of the inlet pipe (20) is formed with a bend (20c) projected into the silencing chamber (15a) and bent toward the upstream end (21b) of the outlet pipe (21); and
wherein the bend (20c) is formed with an opening (20d) to open the inside part of the bend (20c).
In this configuration, the downstream end (20b) portion of the outlet pipe (20) is formed with the bend (20c) projected into the silencing chamber (15a) and bent toward the upstream end (21b) of the outlet pipe (21), and therefore the refrigerant flowing into the silencing chamber (15a) through the inlet pipe (20) can be directed toward the upstream end (21b) of the outlet pipe (21).
As a result, the refrigerant that has flowed into the silencing chamber (15a) is prevented from being rapidly decelerated by bombarding the inner wall surface of the housing (16). Thus, the pressure loss of the refrigerant in the silencer (15) can be reduced.
Further, since the opening (20d) for opening the inside part of the bend (20c) is formed in the bend (20c), the interference of the pressure wave can be caused by the opening (20d). Thus, the suppression of the interference of the pressure wave which otherwise might be caused by the bend (20c) projected in the silencing chamber (15a) can be avoided, and the silencing effect equivalent to that of the refrigeration cycle system silencer disclosed in Japanese Unexamined Patent Publication No. 11-62827 described above can be exhibited.
For the reason described above, the pressure loss of the refrigerant can be reduced while maintaining a high silencing effect equivalent to that of the refrigeration cycle system silencer disclosed in Japanese Unexamined Patent Publication No. 11-62827.
In this invention, the opening (20d) may be formed to extend at least from the downstream end (20b) to the central portion of the bend (20c) in the direction of the refrigerant flow. As a result, the effective interference of the pressure wave can be caused by the opening (21d).
In this invention, the inlet pipe (20) may be formed with an outward protrusion (20a) in contact with the outer surface of the housing (16).
With this configuration, the inlet pipe (20) can be positioned with respect to the housing (16) by the protrusion (20a), and therefore can be easily assembled on the housing (16).
In this invention, the openings (21d, 20d) may be formed by cutting a part of the pipe wall of the bends (21c, 20c). In this way, the openings (21d, 20d) can be easily formed.
In this invention, the silencing chamber (15a) is configured of a unit room. In this way, the construction can be simplified and the cost reduced.
The reference numeral inserted in the parenthesis following the name of each means described in this section and the claims indicates the correspondence with the specific means described in the embodiments later.
The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.
The first embodiment of the invention will be explained below with reference to
In the refrigeration cycle system 10 according to this embodiment, a compressor 11 for sucking in and compressing the refrigerant is rotationally driven by the vehicle engine (not shown) through an electromagnetic clutch 11a and a belt.
The compressor 11 employed in this embodiment may be either a variable displacement refrigerant compressor capable of adjusting the refrigerant discharge capability with the change in the discharge capacity or a fixed displacement refrigerant compressor adapted to adjust the refrigerant discharge capability by switching on/off the electromagnetic clutch 11 and thus changing the operating efficiency of the compressor. On the other hand, in the case where the electrically-operated compressor is used as the compressor 11, the refrigerant discharge capability can be adjusted by regulating the rotational speed of the electric motor.
A radiator 12 is arranged on the refrigerant outlet side of the compressor 11. The radiator 12 cools a high-pressure refrigerant by heat exchange between the high-pressure refrigerant discharged from the compressor 11 and the atmospheric air (outdoor air) blown by a cooling fan not shown.
According to this embodiment, the subcritical cycle of vapor compression type is constructed using, as the refrigerant of the refrigeration cycle system 10, a refrigerant such as flon or HC in which the high pressure does not exceed the critical pressure. As a result, the radiator 12 operates as a condenser for condensing the refrigerant.
An expansion valve 13 making up a decompression means is arranged at the outlet of the radiator 12. This expansion valve 13 functions also as a pressure control valve with the opening degree thereof adjusted so that the pressure on the high-pressure side of the cycle reaches a target high pressure. The expansion valve 13 may be a mechanical expansion valve with the opening degree thereof adjusted by a mechanical means or an electrical expansion valve with the opening degree fixed or electrically controlled.
An evaporator 14 is connected to the outlet of the expansion valve 13. The evaporator 14 is an endothermic heat exchanger for cooling the blown air in such a manner that the low-temperature low-pressure refrigerant decompressed by the expansion valve 13 absorbs the latent heat of vaporization of the internal air (indoor air) or the atmospheric air (outdoor air) blown by an electrically-operated fan (not shown). The outlet of the evaporator 14 is connected to the inlet of the compressor 11 through the silencer 15.
The housing 16 of the silencer 15 is formed by integrally brazing the disk-like lids 18, 19 of aluminum at the ends of a cylindrical portion 17 of aluminum. Thus, the silencing chamber 15a is formed as a single chamber.
Of the lids 18, 19 at the ends of the cylindrical portion 17, the lid 18 has an opening 18a, into which the inlet pipe 20 is inserted to supply the refrigerant into the silencing chamber 15a. The upstream end of the inlet pipe 20 is connected to the outlet of the evaporator 14.
The part adjacent to the other lid 19 of the cylindrical portion 17 is formed with an opening 17a. An outlet pipe 21 for allowing the refrigerant to flow out of the silencing chamber 15a is inserted into the opening 17a. The downstream end of the outlet pipe 21 is connected to the inlet of the compressor 11.
According to this embodiment, the inlet pipe 20 and the outlet pipe 21 are formed of aluminum and integrally coupled to the housing 16 by brazing.
As understood from
Thus, the silencer 15 constitutes a silencer of elbow type for the refrigeration cycle system, and the direction in which the inlet pipe 20 is connected to the housing 16 is substantially orthogonal to the direction in which the outlet pipe 21 is connected to the housing 16, so that the refrigerant flows along a path curved by about 90 degrees in the silencing chamber 15a.
The part of the inlet pipe 20 located outside the housing 16 formed, by bulging, a protrusion 20a protected in annular fashion diametrically outward of the inlet pipe 20. When the inlet pipe 20 is inserted into the opening 18a of the lid 18, the protrusion 20a comes into contact with the outer surface of the lid 18 thereby to determine the position at which the inlet pipe 20 is to be inserted into the housing 16.
In similar fashion, the part of the outlet pipe 21 located outside the housing 16 is formed, by bulging, with a protrusion 21a projected in annular fashion diametrically outward of the outlet pipe 21. When the outlet pipe 21 is inserted into the opening 17a of the cylindrical portion 17, the protrusion 21a comes into contact with the outer surface of the cylindrical portion 17 thereby to determine the position at which the outlet pipe 21 is to be inserted into the housing 16.
The upstream end 21b portion of the outlet pipe 21 is formed with a bend 21c projected into the silencing chamber 15a and bent at about 90 degrees toward the downstream end 20b of the inlet pipe 20. The refrigerant flowing into the silencing chamber 15a through the inlet pipe 20 is smoothly led to the outlet pipe 21 by the bend 21c.
The bend 21c is formed with an opening 21d for opening the inside part of the bend 21c. The opening 21d is formed by cutting the pipe wall inside the bend 21c.
Also, the opening 21d is formed as a notch by cutting the outlet pipe 21 from the upstream end 21b. According to this embodiment, the opening 21d is formed over an area extending from the upstream end 21b beyond the central part of the bend 21c in the direction of the refrigerant flow.
The upstream end 21b of the outlet pipe 21 is formed in such a manner as to spread slightly outward (leftward in
The bend 21c is bent diametrically outward (upward in
The bend 21c assumes the shape of a substantially semicircular cylinder part. The bend 21c can be called also as an open elbow pipe lacking the inner half portion. The bend 21c can also be regarded as a substantially semicircular chute with the bottom thereof curved outward in arcuate form at about 90 degrees.
The forward end of the bend 21c presents the upstream end 21b directed substantially toward the downstream end 20b of the inlet pipe 20. The upstream end 21b portion has a substantially semicircular arcuate shape. The bend 21c provides the opening 21d starting with the linear pipe portion and reaching the upstream end 21b.
The opening 21d is sufficiently larger than the open area of the downstream end 20b of the upstream pipe 20 along the axial direction of the upstream pipe 20. The opening 21d is exposed toward the downstream end 20b along the smoothly curved surface of the bend 21c.
The bend 21c can be fabricated by cutting off about one half of a pipe as a blank (indicated by two-dot chain in
The operation of the silencer having the constitution described above will be explained. With the activation of the compressor 11 by the vehicle engine, the high-temperature high-pressure refrigerant compressed in and discharged from the compressor 11 flows into the radiator 12. In the radiator 12, the high-temperature refrigerant is cooled and condensed by the atmospheric air. The high-pressure refrigerant that has flowed out of the radiator 12 flows into the expansion valve 13.
The high-pressure refrigerant is decompressed by the expansion valve 13, and the refrigerant (low-pressure refrigerant) after passing through the expansion valve 13 flows into the evaporator 14. In the evaporator 14, the low-temperature low-pressure refrigerant is evaporated by absorbing heat from the blown air.
The refrigerant that has flowed out of the evaporator 14 passes through the inlet pipe 20 as indicated by arrow A in
The refrigerant that has flowed into the silencing chamber 15a through the inlet pipe 20 is changed about 90 degrees in its direction of flow by the bend 21c of the outlet pipe 21 as indicated by arrow B and flows into the outlet pipe 21. Then, the refrigerant flows out of the silencing chamber 15a and enters the compressor 11 as indicated by arrow C.
According to this embodiment, the refrigerant that has flowed into the silencing chamber 15a through the inlet pipe 20, though tending to flow linearly by inertia, is smoothly guided to the outlet pipe 21 by the bend 21c.
In addition, since the upstream end 21b of the outlet pipe 21 is formed in such a manner as to spread slightly outward of the downstream end 20b of the inlet pipe 20, the refrigerant that has flowed into the silencing chamber 15a through the inlet pipe 20 can be guided more smoothly into the outlet pipe 21.
As a result, a situation can be avoided in which the refrigerant that has flowed into the silencing chamber 15a through the inlet pipe 20 is rapidly decelerated by bombarding the inner wall surface of the lid 19 facing the downstream end 20b of the inlet pipe 20 on the inner wall surface of the housing 16. Therefore, stagnation of the refrigerant flow in the silencing chamber 15a can be suppressed, thereby reducing the pressure loss of the refrigerant in the silencer 15.
Further, in view of the fact that the bend 21c is formed with the opening 21d to open the inner side portion of the bend 21c, the pressure wave spreading in the silencing chamber 15a can be interfered with by the opening 21d.
In other words, the suppression of the interference of the pressure wave which otherwise might be caused by the bend 21c projected into the silencing chamber 15a can be avoided by forming the opening 21d of the bend 21c. As a result, the silencer according to this embodiment can exhibit as effective an silencing effect as the refrigeration cycle system silencer disclosed in Japanese Unexamined Patent Publication No. 11-62827 described above.
An in-depth study by the present inventor shows that in order to secure the effective interference of the pressure wave with the opening 21d, the opening 21d is desirably formed to extend at least from the upstream end 21b to the central portion of the bend 21c in the direction of refrigerant flow.
In view of this, according to this embodiment, the opening 21d is formed to extend from the upstream end 21b beyond the central portion of the bend 21c in the direction of refrigerant flow, and therefore the effective interference of the pressure wave can be secured by the opening 21d.
For the reason described above, the pressure loss of the refrigerant can be reduced while at the same time maintaining a high silencing effect.
Further, the opening 21d is formed easily by cutting a part of the pipe wall of the bend 21c.
According to this embodiment, the positions at which the inlet pipe 20 and the outlet pipe 21 are inserted into the housing 16 can be determined by the protrusions 20a, 21a formed on the inlet pipe 20 and the outlet pipe 21, respectively, and therefore the inlet pipe 20 and the outlet pipe 21 can be easily assembled on the housing 16.
Furthermore, the protrusions 20a, 21a are formed, by bulging, on the inlet pipe 20 and the outlet pipe 21, and therefore the protrusions 20a, 21a are easy to form.
Furthermore, the silencer 15 according to this embodiment has a very simple construction in which the inlet pipe 20 and the outlet pipe 21 are integrally brazed by being inserted into the housing 16 including the cylindrical portion 17 and the lids 18, 19.
As understood from the foregoing description, the silencer 15 can be fabricated at a very low cost.
According to this embodiment, as shown in
According to the second embodiment, as shown in
Specifically, the inlet pipe 20 is inserted into the opening 17a of the cylindrical portion 17 of the housing 16, while the outlet pipe 21 is inserted into the opening 18a of the lid 18 of the housing 16.
The bend 21c of the outlet pipe 21 is omitted, and a bend 20c projected into the silencing chamber 15a and curved about 90 degrees toward the upstream end 21b of the outlet pipe 21 is at the downstream end 20b portion of the inlet pipe 20.
This bend 20c is formed with an opening 20d for exposing the inner side portion of the bend 20c. The opening 20d is formed by cutting the inner pipe wall of the bend 20c.
According to this embodiment, the opening 20d is formed to extend from the downstream end 20b beyond the central portion of the bend 20c in the direction of refrigerant flow.
The downstream end 20b of the inlet pipe 20 is formed in such a manner as to spread slightly outward (leftward in
According to this embodiment, the refrigerant flowing through the inlet pipe 20 as indicated by arrow A and tending to flow into the silencing chamber 15a is changed about 90 degrees in direction by the bend 20c as indicated by arrow D. As a result, the refrigerant flow is redirected toward the upstream end 21b of the outlet pipe 21.
The refrigerant that has entered the silencing chamber 15a toward the upstream end 21b of the outlet pipe 21 flows straight into the outlet pipe 21. The refrigerant that has flowed into the outlet pipe 21 flows out of the silencing chamber 15a as indicated by arrow C into the compressor 11.
As a result, the stagnation of the refrigerant flow in the silencing chamber 15a can be suppressed, and therefore the pressure loss of the refrigerant in the silencer 15 can be reduced.
In addition, the situation in which the bend 20c projected into the silencing chamber 15a hampers the interference of the pressure wave can be avoided by forming the opening 20d of the bend 20c. Therefore, the silencer according to this embodiment can exhibit substantially the same silencing effect as the refrigeration cycle system silencer disclosed in Japanese Unexamined Patent Publication No. 11-62827.
As understood from the foregoing description, the second embodiment has a similar operational effect to the first embodiment.
According to the first embodiment, the opening 21d is formed as a notch by cutting the upstream end 21b portion of the outlet pipe 21. On the other hand, according to the third embodiment, as shown in
This embodiment can also exhibit substantially the same operational effect as the first embodiment.
According to each embodiment described above, the direction in which the inlet pipe 20 is connected to the housing 16 is substantially orthogonal to the direction in which the outlet pipe 21 is connected to the housing 16. Nevertheless, the invention is not limited to this configuration. Instead, the direction in which the inlet pipe 20 is connected to the housing 16 and the direction in which the outlet pipe 21 is connected to the housing 16 may cross each other.
According to each embodiment described above, the silencing chamber 15a is configured of a single room. However, the silencing chamber 15a may be formed of plural rooms by arranging partition plates in the housing 16.
Further, according to each embodiment described above, the inlet pipe 20 and the outlet pipe 21 are assembled integrally on the housing 16 by integrally brazing the housing 16, the inlet pipe 20 and the outlet pipe 21 to each other. Nevertheless, these members may alternatively be assembled integrally by screwing, caulking, welding or bonding instead of by brazing.
Although the foregoing explanation of the embodiments refers to the subcritical cycle of vapor compression-type using the refrigerant such as flon or HC with the high pressure thereof not exceeding the critical pressure, the invention is also applicable to the supercritical cycle of vapor compression-type in which the refrigerant with the high pressure exceeding the critical pressure such as carbon dioxide (CO2) may be used as a refrigerant.
In this embodiment, the refrigeration cycle system for automotive application will be explained. Nevertheless, the invention is not limited to automotive vehicles but applicable with effect also to the stationary refrigeration cycle system of such devices as a service refrigerator, a home refrigerator, a cooling system of a vending machine or a showcase with the cooling function.
While the invention has been described by reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-259643 | Oct 2007 | JP | national |
