JP2013178007A - Parallel flow heat exchanger and device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for a muffler formed in a header pipe of a parallel flow heat exchanger, configured so that noise can be effectively reduced and a possibility of fatigue fracture is low.SOLUTION: A heat exchanger 1 includes: two header pipes 2, 3 arranged in parallel with each other at intervals; and a plurality of flat tubes 4 arranged between the header pipes 2, 3 and having refrigerant passages 5 provided inside thereof and communicating with the inside of the header pipes 2, 3. At a position separated in an axial direction of the header pipe 3, the header pipe 3 is provided with a plurality of mufflers 33U, 33D projecting in a side surface direction of the head pipe 3 with respect to the same internal space 34 of the header pipe 3. A refrigerant pipe allowing a refrigerant to flow into the header pipe 3 is configured such that one refrigerant pipe 35 is branched at a branch part 35a and divided into the mufflers 33U, 33D. Length of a path to a part with the mufflers 33U, 33D opened from the branch part 35a to the internal space 34 of the header pipe 3 is different with respect to each muffler.

Description

  The present invention relates to a parallel flow heat exchanger and a device including the same.

  A parallel flow type heat in which a plurality of flat tubes are arranged between a plurality of header pipes so that a plurality of refrigerant passages in the flat tubes communicate with the inside of the header pipe, and fins such as corrugated fins are arranged between the flat tubes. Exchangers are widely used in outdoor units of car air conditioners and building air conditioners.

  The basic structure of a side flow parallel flow heat exchanger is shown in FIG. In FIG. 7, the upper side of the paper is the upper side of the heat exchanger, and the lower side of the paper is the lower side of the heat exchanger. The heat exchanger 1 includes two header pipes 2 and 3 and a plurality of flat tubes 4 arranged therebetween. In FIG. 7, the header pipes 2 and 3 extend in the vertical direction and are arranged in parallel in the horizontal direction at intervals, and the flat tubes 4 extend in the horizontal direction and are arranged at a predetermined pitch in the vertical direction. Since the heat exchanger 1 is installed at various angles according to design requirements at the stage of actually mounting on equipment, the “vertical direction” and “horizontal direction” in this specification should not be strictly interpreted. It should be understood as a mere measure of direction.

  The flat tube 4 is an elongated molded product obtained by extruding a metal, and a refrigerant passage 5 through which a refrigerant flows is formed. Since the flat tube 4 is disposed so that the extrusion direction, which is the longitudinal direction, is horizontal, the refrigerant flow direction of the refrigerant passage 5 is also horizontal. A plurality of refrigerant passages 5 having the same cross-sectional shape and cross-sectional area are arranged in the depth direction of FIG. 7, so that the vertical cross section of the flat tube 4 has a harmonica shape as shown in FIG. 8. Each refrigerant passage 5 communicates with the inside of the header pipes 2 and 3. Fins 6 are arranged between adjacent flat tubes 4. Here, corrugated fins are used as the fins 6, but plate fins may be used.

  Outer flat corrugated fins 6a are arranged on the flat surfaces facing the outer side of the flat tubes 4 located on the outermost side among the flat tubes 4 in which a plurality of tubes are arranged in parallel. A side plate 10 is disposed outside the outermost corrugated fin 6a.

  The header pipes 2 and 3, the flat tube 4, the corrugated fin 6, the outermost corrugated fin 6 a, and the side plate 10 are all made of a metal having good heat conductivity such as aluminum, and the flat tube 4 is The corrugated fin 6 and the outermost corrugated fin 6a are fixed to the flat tube 4 and the side plate 10 is fixed to the outermost corrugated fin 6a by brazing or welding.

  In the heat exchanger 1 of FIG. 7, the refrigerant inlets and outlets 7 and 8 are provided only on the header pipe 3 side. Two partition plates 9a and 9c are provided in the header pipe 3 at intervals in the vertical direction. Inside the header pipe 2, the partition plates are located at a height intermediate between the partition plates 9a and 9c. 9b is provided.

  When the heat exchanger 1 is used as an evaporator, the refrigerant flows from the lower refrigerant inlet / outlet 7 as indicated by solid line arrows in FIG. The refrigerant entering from the refrigerant inlet / outlet 7 is blocked by the partition plate 9 a and travels toward the header pipe 2 via the flat tube 4. This refrigerant flow is represented by a left-pointing block arrow. The refrigerant that has entered the header pipe 2 is blocked by the partition plate 9 b and travels to the header pipe 3 via another flat tube 4. This refrigerant flow is represented by a right-pointing block arrow. The refrigerant that has entered the header pipe 3 is dammed up by the partition plate 9 c, and further travels toward the header pipe 2 via another flat tube 4. This refrigerant flow is represented by a left-pointing block arrow. The refrigerant that has entered the header pipe 2 is folded back and travels again to the header pipe 3 via another flat tube 4. This refrigerant flow is represented by a right-pointing block arrow. The refrigerant that has entered the header pipe 3 flows out from the refrigerant inlet / outlet 8. In this way, the refrigerant follows the zigzag path and flows from the bottom to the top. Although the case where the number of partition plates is 3 is shown here, this is only an example, and the number of partition plates and the number of times the resulting refrigerant flow may be folded may be set as desired. it can.

  When the heat exchanger 1 is used as a condenser, the refrigerant flow is reversed. That is, the refrigerant enters the header pipe 3 from the refrigerant inlet / outlet 8 as shown by the dotted arrow in FIG. 7, is dammed by the partition plate 9c and goes to the header pipe 2 via the flat tube 4, and is dammed by the partition plate 9b in the header pipe 2. It heads to the header pipe 3 via another flat tube 4, and the header pipe 3 is dammed by a partition plate 9 a, then goes to the header pipe 2 again via another flat tube 4, and is folded back by the header pipe 2 to make another flat It flows from the top to the bottom following the zigzag path in which it goes to the header pipe 3 again via the tube 4 and flows out from the refrigerant inlet / outlet 7 as indicated by the dotted line arrow.

  The heat exchanger 1 can be mounted on an outdoor unit or an indoor unit of a separate type air conditioner, or both. First, a basic configuration of a separate type air conditioner will be described with reference to FIG.

  The separate air conditioner includes an outdoor unit 20 and an indoor unit 40. The outdoor unit 20 houses a compressor 22, a four-way valve 23, an outdoor heat exchanger 24, an expansion valve 25, an outdoor blower 26 and the like inside a housing 21. The indoor unit 40 houses an indoor side heat exchanger 42, an indoor side blower 43, and the like inside a housing 41. The outdoor heat exchanger 24 functions as an evaporator during heating operation and functions as a condenser during cooling operation. The indoor heat exchanger 42 functions as a condenser during heating operation and functions as an evaporator during cooling operation.

  The compressor 22, the four-way valve 23, the outdoor heat exchanger 24, the expansion valve 25, and the indoor heat exchanger 42 are connected in a loop shape by a refrigerant pipe to constitute a heat pump cycle.

  The outdoor blower 26 combined with the outdoor heat exchanger 24 includes a propeller fan 26a for forming a blown airflow. The indoor air blower 43 combined with the indoor heat exchanger 42 includes a cross flow fan 43a for forming an air flow. The cross flow fan 43a is arranged below the indoor heat exchanger 42 with the axis line horizontal.

  The heat exchanger 1 can be used as the outdoor heat exchanger 24. Moreover, the heat exchanger 1 can also be used as a component of the indoor side heat exchanger 42. The indoor heat exchanger 42 is a combination of three heat exchangers 42A, 42B, 42C like a roof that covers the indoor blower 43, and any or all of the heat exchangers 42A, 42B, 42C are combined. The heat exchanger 1 can be obtained.

  FIG. 9 shows a state during heating operation. At this time, the high-temperature and high-pressure refrigerant discharged from the compressor 22 enters the indoor heat exchanger 42 where it dissipates heat and condenses. The refrigerant exiting the indoor heat exchanger 42 enters the outdoor heat exchanger 24 from the expansion valve 25 and expands there, takes heat from the outdoor air, and returns to the compressor 22. The air flow generated by the indoor blower 43 promotes heat dissipation from the indoor heat exchanger 42, and the air flow generated by the outdoor blower 26 promotes heat absorption of the outdoor heat exchanger 24.

  FIG. 10 shows a state during cooling operation or defrosting operation. At this time, the four-way valve 23 is switched, and the refrigerant flow is reversed from that during the heating operation. That is, the high-temperature and high-pressure refrigerant discharged from the compressor 22 enters the outdoor heat exchanger 24 where it dissipates heat and condenses. The refrigerant exiting the outdoor heat exchanger 24 enters the indoor heat exchanger 42 from the expansion valve 25 and expands there, takes heat from the indoor air, and returns to the compressor 22. The airflow generated by the outdoor fan 26 promotes heat dissipation from the outdoor heat exchanger 24, and the airflow generated by the indoor fan 43 promotes heat absorption of the indoor heat exchanger 42.

  FIG. 11 shows the structure of the outdoor unit 20 more substantively. The casing 21 of the outdoor unit 20 is made of sheet metal, and is drawn in a substantially rectangular shape in FIG. The casing 21 has a long side as a front surface 21F and a back surface 21B, and a short side as a left side surface 21L and a right side surface 21R. An exhaust port 27 is formed on the front surface 21F, a rear air intake port 28 is formed on the rear surface 21B, and a side air intake port 29 is formed on the left side surface 21L. The exhaust port 27 is composed of a set of a plurality of horizontal slit-shaped openings, and the rear intake port 28 and the side intake port 29 are composed of lattice-shaped openings. A top plate and a bottom plate not shown in FIG. 11 are added to the four sheet metal members of the front surface 21F, the rear surface 21B, the left side surface 21L, and the right side surface 21R, thereby forming a hexahedral-shaped casing 21.

  Inside the housing 21, a planar L-shaped outdoor heat exchanger 24 is disposed immediately inside the rear air inlet 28 and the side air inlet 29. In order to force heat exchange between the outdoor heat exchanger 24 and the outdoor air, an outdoor fan 26 is disposed between the outdoor heat exchanger 24 and the exhaust port 27. The blower 26 is a combination of a propeller fan 26a and an electric motor 26b. A bell mouth 30 surrounding the propeller fan 26a is attached to the inner surface of the front surface 21F of the housing 21 in order to improve the blowing efficiency. The space inside the right side surface 21 </ b> R of the housing 21 is isolated by the partition wall 31 from the air flow flowing from the rear intake port 28 to the exhaust port 27, and the compressor 22 is accommodated in this space.

  When the heat exchanger 1 is used as the outdoor heat exchanger 24, high-temperature and high-pressure compressed refrigerant is sent from the compressor 22 to the heat exchanger 1 during the cooling operation. At this time, the driving sound of the compressor 22 and the pressure pulsation caused by the compression / release of the refrigerant are transmitted through the refrigerant pipe through the heat exchanger 1 and the three-way valve (the refrigerant pipe is connected and disconnected, and the refrigerant flows out of the outdoor unit 20). Are transmitted for the purpose of shutting down, and are not shown in the figure), and are emitted to the outside as noise.

  In order to prevent noise originating from the driving of the compressor from being released from the heat exchanger, various ideas have been made so far. An example of this can be seen in US Pat.

  Patent Document 1 describes a parallel flow type vehicle heat exchanger. In this heat exchanger, a muffler is provided on the inlet side of the inlet header pipe. The inlet header pipe and the muffler are integrally formed by expanding or narrowing.

Japanese Utility Model Publication No. 2-69287

  In order to reduce the propagation of the pressure pulsation, generally, a muffler such as 36 in FIG. 1 is inserted into a pipe which is a propagation path. However, the muffler has a silencing characteristic, and noise with a specific frequency component cannot be reduced when the cross-sectional area is increased. When the compressor is driven, the muffler may vibrate like a pendulum at a specific number of revolutions. However, if the muffler has a large cross-sectional area, the vibration may increase excessively and may cause fatigue damage to the piping.

  In the heat exchanger described in Patent Document 1, a muffler is integrally formed on the inlet header pipe, and the muffler is placed outside the heat exchanger. However, if the cross-sectional area of the muffler is increased, installation restrictions increase, Design becomes difficult. Further, like the muffler, noise with a specific frequency component cannot be reduced.

  The present invention has been made in view of the above points, and the muffler structure formed on the header pipe of the parallel flow type heat exchanger can effectively reduce noise and reduce the risk of fatigue failure. Objective.

  The parallel flow heat exchanger according to the present invention includes a plurality of header pipes arranged in parallel at intervals, and a plurality of header pipes arranged between the plurality of header pipes, and a refrigerant passage provided therein is provided in the header pipe. A flat tube connected to the inside, and at least one of the header pipes is provided with a muffler projecting in the side surface direction of the header pipe at a position separated in the axial direction of the header pipe in the same internal space of the header pipe. A plurality of refrigerant pipes are connected to the muffler to flow refrigerant into the header pipe, and the refrigerant pipe is divided into one refrigerant pipe at a branch portion and distributed to the plurality of mufflers. The path length from the branch portion to the location where the muffler opens into the internal space of the header pipe is different for each muffler.

  In the parallel flow heat exchanger configured as described above, two adjacent mufflers among the plurality of mufflers are such that sound waves flowing from there into the internal space of the header pipe are shifted by a half wavelength in the internal space. It is preferable that the path length is met.

  The present invention is also characterized in that the device includes the parallel flow heat exchanger.

  According to the present invention, since the muffler is integrated with the header portion of the heat exchanger, the muffler does not vibrate like a pendulum as described above, and the risk of fatigue failure is reduced. Further, by branching the refrigerant pipe connected to the header, the sectional area of the refrigerant pipe after branching is reduced, so that it is formed in the header pipe necessary for obtaining the same noise reduction effect as the muffler. In the muffler shape, the size of the diameter can be reduced as compared with the muffler. Furthermore, a path difference is provided in the route of the refrigerant pipe after branching for noise having a frequency at which the muffler cannot obtain a silencing effect, and the noise is canceled within the header pipe after passing through the muffler. If adjusted and set, a silencing effect can be obtained in a wider frequency band than the muffler.

It is a perspective view which shows a part of outdoor unit of the air conditioner carrying the parallel flow type heat exchanger which concerns on this invention. It is a front view which shows embodiment of the parallel flow type heat exchanger which concerns on this invention. It is a fragmentary sectional view of the parallel flow type heat exchanger of FIG. It is a schematic diagram which shows the structure of a muffler. It is a schematic diagram explaining the dimensional condition of a muffler. It is a graph which shows the noise reduction characteristic of a muffler. It is a schematic block diagram of the parallel flow type heat exchanger of a side flow system. It is sectional drawing which makes the VIII-VIII line of FIG. 7 a cross-sectional location. It is a schematic block diagram of the air conditioner carrying the parallel flow type heat exchanger which concerns on this invention, and shows the state at the time of heating operation. It is a schematic block diagram of the air conditioner carrying the parallel flow type heat exchanger which concerns on this invention, and shows the state at the time of air_conditionaing | cooling operation. It is a horizontal sectional view showing a schematic structure of an outdoor unit of an air conditioner equipped with a parallel flow type heat exchanger according to the present invention.

An embodiment of the present invention will be described with reference to FIGS. 1 to 6. In addition, the code | symbol used until now is attached as it is to the component which is functionally common with the conventional structure demonstrated so far,
Description is omitted.

  FIG. 1 shows an outdoor heat exchanger 24. The outdoor heat exchanger 24 is configured by a side flow parallel flow heat exchanger 1. The outdoor heat exchanger 24 is bent into a planar L shape, and is installed on the bottom plate 32 of the casing together with the compressor 22.

  The header pipe 3 of the heat exchanger 1 is provided with two mufflers at positions separated in the axial direction of the header pipe 3, that is, at positions separated in the vertical direction. The upper one is the muffler 33U, and the lower one is the muffler 33D. The mufflers 33U and 33D protrude in the side surface direction of the header pipe 3. In the illustrated embodiment, the mufflers 33 </ b> U and 33 </ b> D protrude in a direction perpendicular to the axis of the header pipe 3, that is, in a horizontal direction and in a direction opposite to the flat tube 4.

The basic shape of the mufflers 33U and 33D is a hollow cylinder with both ends closed, and is formed of a metal of the same type as the material of the header pipe 3. The diameter (outer diameter) of the mufflers 33U and 33D is smaller than the diameter (outer diameter) of the header pipe 3. The header pipes 33U and 33D are fixed to the header pipe 3 by brazing or welding. Since the diameters of the mufflers 33U and 33D are small, the outdoor heat exchanger 24 can be easily incorporated into the outdoor unit 20.

  As shown in FIG. 3, an internal space 34 is partitioned by the partition plate 9 at the top of the header pipe 3. One ends of the mufflers 33U and 33D enter the internal space 34, and openings 33Ua and 33Da that open toward the internal space 34 are formed on the end surfaces. The mufflers 33U and 33D serve as the refrigerant inlet / outlet 8 in the heat exchanger 1 of FIG.

  Refrigerant piping 35 is connected to the mufflers 33U and 33D to allow the refrigerant to flow into and out of the mufflers 33U and 33D. The refrigerant pipe 35 is branched into two pipes, a refrigerant pipe branch pipe 35b and a refrigerant pipe branch pipe 35c, at the branch portion 35a. The refrigerant pipe branch pipe 35b is distributed to the muffler 33U, and the refrigerant pipe branch pipe 35c is distributed to the muffler 33D. Then, the refrigerant pipe branch pipe and the muffler are connected.

  The refrigerant pipe branch pipes 35b and 35c are inserted into the mufflers 33U and 33D at a predetermined depth from the end face opposite to the end face where the openings 33Ua and 33Da are formed. The refrigerant piping branch pipes 35b and 35c are inserted horizontally at the centers of the end faces of the mufflers 33U and 33D, and are concentric with the mufflers 33U and 33D. The refrigerant piping branch pipes 35b and 35c are fixed to the mufflers 33U and 33D by brazing or welding.

The path length L ₁ of the path from the branch part 35a to the opening part 33Da is not the same as the path length L ₂ from the branch part 35a to the opening part 33Ua. If the path length L ₂ is longer than the path length L _1. The meaning of this configuration will be described later.

  FIG. 4 shows a general muffler structure. In the structure (a), the pipe for guiding the fluid to the muffler does not enter the muffler, whereas in the structure (b), the pipe for guiding the fluid to the muffler enters the muffler. The mufflers 33U and 33D follow the structure (b).

  FIG. 5 shows the basic structure of the mufflers 33U and 33D. That is, when the length of the mufflers 33U and 33D is M, the insertion depth of the refrigerant pipe branch pipes 35b and 35c is M / 2. Note that the insertion depth of M / 2 is merely an example, and may be M / 3, M / 4, or other insertion depths.

  When the mufflers 33U and 33D are configured as shown in FIG. 5, the noise reduction characteristics are as shown in the graph of FIG. The frequency f of the sound wave is obtained by the equation f = C / 4l (C is the speed of sound). What can be said from the graph of FIG. 6 is that only the muffler structure of FIG. 5 generates a frequency band with a small noise reduction effect at 4f × n (n = 1, 2, 3,...). This point is improved in the present invention as follows.

  When sound waves of noise flow into the internal space 34 from the mufflers 33U and 33D, they meet in the internal space 34. At this time, the sound waves in the frequency band of 4f × n (n = 1, 2, 3...) Meet and cancel each other with a half-wave shift between the one that entered from the muffler 33U and the one that entered from the muffler 33D. Like that.

The above half-wavelength shift occurs in the following cases. That the path length L ₁ of the path from the branch portion 35a is longer path to the opening 33Da, when the path length L ₂ to the opening 33Ua from the branching unit 35a is shorter path satisfies the following equation It is.
4f = C / 2 (L ₁ −L ₂ )
Accordingly, the piping length is designed by calculating the path lengths L ₁ and L ₂ so as to satisfy the above equation.

Thus, since the muffling effect based on the difference between the path lengths L ₁ and L ₂ is used in addition to the muffling effect of the mufflers 33U and 33D itself, noise can be effectively reduced.

In the present embodiment, the number of mufflers is two, but it may be three or more. Also in this case, the refrigerant pipe is branched at the branching portion, distributed to each muffler, and connected.
The path length from the branching portion to the location where the muffler opens into the internal space of the header pipe is different for each muffler, and the sound waves flowing into the internal space of the header pipe from two adjacent mufflers are in the internal space. The path length is designed to meet at a half wavelength shift.

  The scope of application of the present invention is not limited to the side flow type parallel flow heat exchanger. The present invention is also applicable to a downflow parallel flow heat exchanger.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention is widely applicable to parallel flow heat exchangers and devices equipped with the same.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2, 3 Header pipe 4 Flat tube 5 Refrigerant passage 6 Fin 20 Outdoor unit 21 Case 22 Compressor 23 Four-way valve 24 Outdoor heat exchanger 25 Expansion valve 26 Outdoor blower 33U, 33D Muffler 34 Internal space 35 Refrigerant piping 35a Branch part 35b, 35c Refrigerant piping branch pipe 40 Indoor unit 41 Housing 42 Indoor side heat exchanger 43 Indoor side blower

Claims (3)

A parallel provided with a plurality of header pipes arranged in parallel at intervals, and a flat tube arranged between the plurality of header pipes and having a refrigerant passage provided therein communicated with the inside of the header pipe In flow type heat exchanger,
At least one of the header pipes is provided with a plurality of mufflers projecting in the lateral direction of the header pipe at positions separated in the axial direction of the header pipe with respect to the same internal space of the header pipe, and the refrigerant flows into the header pipe The refrigerant pipe to be connected is connected to the muffler, and the refrigerant pipe is one refrigerant pipe branched at a branch portion and distributed to the plurality of mufflers, and the muffler is connected to the header pipe from the branch portion. The parallel flow type heat exchanger is characterized in that the path length to the location opening in the interior space of each of the mufflers is different for each muffler.   The adjacent two mufflers among the plurality of mufflers have a path length in which sound waves flowing from there to the internal space of the header pipe meet each other with a half-wave shift in the internal space. Item 4. The parallel flow heat exchanger according to Item 3.   The apparatus provided with the parallel flow type heat exchanger of Claim 1 or 2.

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