JP2009068742A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat exchange efficiency by not making a big difference in a flow rate of a refrigerant in a flat tube regardless of a position to a refrigerant outflow port in a parallel flow-type heat exchanger. <P>SOLUTION: The heat exchanger 1 includes two header pipes 2 disposed spaced apart in parallel with each other, the plurality of flat tubes 4 disposed between the header pipes 2, 3 at prescribed pitches and communicating refrigerant passages 5 vertically disposed thereto with the inside of the header pipes, and corrugated fins 6 disposed among the flat tubes 4. A refrigerant inflow port 7 is formed at one end of the header pipe 3, and the refrigerant outflow port 8 is formed at one end of the header pipe 2. The internal flow channel resistance of the flat tubes 4 near the refrigerant outflow port 8 is relatively more than that of the flat tubes 4 far from the refrigerant outflow port 9. The difference in the internal flow channel resistances of the flat tubes 4 is made by changing a cross-sectional area of the refrigerant passages 5 or changing the number of refrigerant passages 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a parallel flow type heat exchanger.

  A parallel flow type heat exchange in which a plurality of flat tubes are arranged between two header pipes so that a refrigerant passage inside the flat tubes communicates with the header pipe, and fins such as corrugated fins are arranged between the flat tubes. The instrument is widely used for car air conditioners. Examples thereof can be seen in Patent Documents 1 and 2.

  An example of a conventional parallel flow heat exchanger is shown in FIG. In the heat exchanger 1, two horizontal header pipes 2 and 3 are arranged in parallel with an interval in the vertical direction, and a plurality of vertical flat tubes 4 are arranged between the header pipes 2 and 3 at a predetermined pitch. The flat tube 4 is an elongated molded product obtained by extruding a metal having good heat conductivity such as aluminum, and a refrigerant passage 5 through which a refrigerant flows is formed inside. Since the flat tube 4 is disposed so that the extrusion molding direction is vertical, the refrigerant flow direction of the refrigerant passage 5 is also vertical. Each refrigerant passage 5 communicates with the inside of the header pipes 2 and 3. In FIG. 14, the upper side of the paper is the upper side in the vertical direction, the lower side of the paper is the lower side in the vertical direction, and a plurality of flat tubes 4 are vertically arranged between the upper header pipe 2 and the lower header pipe 3. The configuration is arranged at a predetermined pitch.

  The header pipes 2 and 3 and the flat tube 4 are fixed by welding. A plurality of refrigerant passages 5 having the same cross-sectional shape and cross-sectional area are arranged in the depth direction of the drawing, and therefore the flat tube 4 has a cross section like a harmonica. Corrugated fins 6 are disposed between the flat tubes 4. The flat tube 4 and the corrugated fin 6 are fixed by welding. In addition to the flat tube 4, the header pipes 2 and 3 and the corrugated fin 6 are also made of a metal having good heat conduction.

Since many flat tubes 4 are provided between the header pipes 2 and 3 and corrugated fins 6 are provided between the flat tubes 4, the heat exchanger 1 has a large heat radiation (heat absorption) area, and efficiently exchanges heat. It can be performed. A refrigerant inlet 7 is provided at one end of the lower header pipe (sometimes referred to as a lower header pipe), and a refrigerant flow is provided at one end of the upper header pipe (sometimes referred to as an upper header pipe) 2. A refrigerant outlet 8 is provided at a position diagonal to the inlet 7.
JP 2005-37054 A JP 2001-59689 A

  The shaded figure in FIG. 14 symbolizes and shows the amount of refrigerant flowing through each flat tube 4 when the heat exchanger 1 is used as an evaporator. As shown therein, a large amount of refrigerant flows through the flat tube 4 closer to the refrigerant outlet 8, and the refrigerant flow rate tends to decrease as the distance from the refrigerant outlet 8 increases. That is, there is a tendency for the refrigerant to drift. There is a large difference in the amount of heat exchange between the flat tube 4 with a high refrigerant flow rate and the flat tube 4 with a low refrigerant flow rate. Therefore, when a drift occurs, the heat exchange efficiency is significantly higher than when the refrigerant flows evenly without a drift. Will fall. The same applies to the case where the refrigerant inlet 7 and the refrigerant outlet 8 are on the same side as shown in FIG.

  The present invention has been made in view of the above points, and in a parallel flow type heat exchanger, regardless of the position with respect to the refrigerant outlet, so as not to make a large difference in the flow rate of the refrigerant in the flat tube, The purpose is to improve the heat exchange efficiency.

  In order to achieve the above object, the present invention includes two header pipes arranged in parallel at a distance, and a plurality of flat tubes arranged at a predetermined pitch between the two header pipes, The flat tube has a refrigerant passage for allowing the refrigerant to circulate in the vertical direction, and a refrigerant outlet is provided in one of the two header pipes in a heat exchanger in which the refrigerant passage communicates with the inside of the header pipe. In addition, the flat tube has a relatively large internal flow resistance near the refrigerant outlet in the flat tube compared to the internal flow resistance of the flat tube far from the refrigerant outlet. It is characterized in that the refrigerant flow rate difference between them is reduced.

  According to this configuration, the flow of the refrigerant is not biased toward the refrigerant outlet of the heat exchanger, and the flow rate of the refrigerant is uniform over the entire heat exchanger. Therefore, the entire heat exchanger is involved in heat dissipation (heat absorption) without unevenness. , Heat exchange efficiency is improved.

  In the heat exchanger having the above-described configuration, it is preferable that the cross-sectional area of the refrigerant passage in the flat tube is changed to cause a difference in internal flow resistance.

  With such a configuration, the internal channel resistance can be accurately varied.

  In the heat exchanger having the above configuration, it is preferable that the flat tube is plastically deformed to change the cross-sectional area of the refrigerant passage.

  With such a configuration, the refrigerant passage cross-sectional area of the flat tube can be easily changed.

  In the heat exchanger having the above configuration, the flat tube has a plurality of refrigerant passages therein, and it is preferable to change the number of the refrigerant passages to cause a difference in the internal flow passage resistance.

  With such a configuration, a difference in internal flow path resistance can be easily obtained.

  In the heat exchanger configured as described above, it is preferable that a selected one of the plurality of refrigerant passages is closed with a plug to change the number of refrigerant passages.

  With this configuration, the number of refrigerant passages can be easily changed.

  According to the present invention, in the parallel flow type heat exchanger, the heat exchange efficiency of the heat exchanger is improved by equalizing the refrigerant flow rate in each flat tube, regardless of the position of the refrigerant outlet. be able to.

  A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a vertical sectional view showing a schematic structure of a heat exchanger, and FIG. 2 is a horizontal sectional view of a flat tube. Elements that are functionally common to the heat exchanger having the conventional structure shown in FIGS. 14 and 15 are denoted by the same reference numerals as those used in FIGS. The same applies to the second and following embodiments.

  As in the case of FIG. 14, the heat exchanger 1 has a refrigerant outlet 8 at a position diagonal to the refrigerant inlet 7. In the flat tube 4, the internal flow resistance of the flat tube 4 close to the refrigerant outlet 8 is relatively large compared to the internal flow resistance of the flat tube 4 far from the refrigerant outlet 8. Therefore, as can be seen from the shaded figure in FIG. 1, the refrigerant flow rate of the flat tube 4 located away from the refrigerant outlet 8 increases, and the difference between the refrigerant flow rate of the flat tube 4 close to the refrigerant outlet 8 is small. It has become. As a result, the refrigerant flow is not biased toward the refrigerant outlet 8 side of the heat exchanger 1 and the refrigerant flow rate is made uniform over the entire heat exchanger 1, so that the entire heat exchanger 1 is involved in heat dissipation (heat absorption) without unevenness. As a result, the heat exchange efficiency is improved.

  In order to make a difference in the internal flow path resistance of the flat tube 4, in the first embodiment, a method of changing the cross-sectional area of the refrigerant passage 5 in the flat tube 4 is adopted. In FIG. 2, the left side of the figure is the refrigerant inlet 7 side, and the right side of the figure is the refrigerant outlet 8 side, but six refrigerant passages 5 are arranged in a row in the flat tubes 4 arranged in the left-right direction. (Six is merely an example, and an arbitrary number of refrigerant passages can be provided). The cross-sectional area of the refrigerant passage 5 is relatively smaller than that provided in the flat tube 4 close to the refrigerant outlet 8 than that provided in the flat tube 4 far from the refrigerant outlet 8. In other words, when the total cross-sectional area of the refrigerant passage 5 formed in one flat tube 4 (in this embodiment, the total cross-sectional area of the six refrigerant passages 5) is compared, the flat tube far from the refrigerant outlet 8 Compared to 4, the flat tube 4 close to the refrigerant outlet 8 is relatively small.

  Accordingly, the flat tube 4 close to the refrigerant outlet 8 has a relatively large internal flow resistance, and the flat tube 4 far from the refrigerant outlet 8 has a relatively small internal flow resistance, so that the refrigerant between the flat tubes 4 can be reduced. The flow rate difference is reduced. It is better to determine how to obtain the cross-sectional area ratio through experiments. It is possible to change the cross-sectional area of the refrigerant passage 5 by replacing the extrusion mold of the flat tube 4.

  In FIG. 2, the sectional area of the refrigerant passage 5 is reduced for each of the flat tubes 4 from the flat tube 4 closest to the refrigerant inlet 7 to the flat tube 4 closest to the refrigerant outlet 8. Is not absolute. The configuration may be such that after an arbitrary number of flat tubes 4 having the same refrigerant passage cross-sectional area are continued, an arbitrary number of flat tubes 4 whose refrigerant passage cross-sectional area is further reduced are continued.

  A second embodiment of the present invention is shown in FIG. FIG. 3 is a horizontal sectional view of the flat tube. In FIG. 3, the left side of the figure is the refrigerant inlet 7 side, and the right side of the figure is the refrigerant outlet 8 side.

  In the second embodiment, the sectional areas of the refrigerant passages 5 of the individual flat tubes 4 are the same, but the number of the refrigerant passages 5 is different for each flat tube 4. That is, the flat tube 4 farthest from the refrigerant outlet 8 has six refrigerant passages 5, whereas the flat tube 4 closest to the refrigerant outlet 8 has only two refrigerant passages 5. The intermediate flat tube 4 has five, four, and three refrigerant passages 5 such that the number of refrigerant passages 5 decreases as the refrigerant outlet port 8 is approached. The number of refrigerant passages 5 can be changed by replacing the extrusion mold of the flat tube 4.

  By configuring as described above, the flat tube 4 close to the refrigerant outlet 8 has a relatively large internal channel resistance, and the flat tube 4 far from the refrigerant outlet 8 has a relatively small internal channel resistance, The refrigerant flow rate becomes uniform throughout the heat exchanger 1. As a result, the entire heat exchanger 1 is involved in heat dissipation (heat absorption) without unevenness, and heat exchange efficiency is improved.

  In FIG. 3, the number of refrigerant passages 5 is reduced for each of the flat tubes 4 from the flat tube 4 closest to the refrigerant inlet 7 to the flat tube 4 closest to the refrigerant outlet 8. It is not absolute. The configuration may be such that after an arbitrary number of flat tubes 4 having the same number of refrigerant passages 5 are made continuous, an arbitrary number of flat tubes 4 having the number of refrigerant passages 5 further reduced are made continuous.

  Since the technical contents of the first embodiment and the second embodiment are not exclusive or alternative, both may be performed simultaneously.

  A third embodiment of the present invention is shown in FIGS. 4 is an enlarged cross-sectional view of a connection portion between the header pipe and the flat tube, and FIG. 5 is a horizontal cross-sectional view of the flat tube.

  As in the first embodiment, the third embodiment changes the cross-sectional area of the refrigerant passage 5 to cause a difference in the internal flow resistance. The cross-sectional area of the refrigerant passage 5 is changed as follows. That is, the coolant passage 5 is sandwiched with a tool (not shown), and a plastic deformation portion 9 is formed as shown in FIG. 5 to reduce the cross-sectional area of the coolant passage 5. Here, of the six refrigerant passages 5, two cross-sectional areas are reduced. By doing so, the total sectional area of the refrigerant passages 5 provided in one flat tube 4 (the total sectional area of the six refrigerant passages 5 in FIG. 5) is reduced. By appropriately setting the plastic deformation amount of the plastic deformation portion 9 and the number of refrigerant passages 5 to be plastically deformed, the internal flow path resistance can be increased by a desired amount.

  The plastic deformation of the refrigerant passage 5 is performed by selecting a portion of the flat tube 4 protruding into the header pipe 2 or 3 that does not affect the welding with the header pipe. It is not preferable to select a portion that goes out of the header pipe 2 or 3 because it may adversely affect the welding of the flat tube 4 and the corrugated fin 6.

  A fourth embodiment of the present invention is shown in FIGS. FIG. 6 is an enlarged cross-sectional view of the connection portion between the header pipe and the flat tube, and FIG. 7 is a horizontal cross-sectional view of the flat tube.

  As in the first embodiment, the fourth embodiment changes the cross-sectional area of the refrigerant passage 5 to cause a difference in the internal flow resistance. The cross-sectional area of the refrigerant passage 5 is changed as follows. That is, the plug 10 having a predetermined cross section is pushed into the refrigerant passage 5 to reduce the cross-sectional area of the refrigerant passage 5. By doing so, the total sectional area of the refrigerant passages 5 provided in one flat tube 4 (the total sectional area of the six refrigerant passages 5 in FIG. 5) is reduced. Here, a plug 10 having an X cross section is pushed into the refrigerant passage 4 having a square cross section. By appropriately setting the cross-sectional shape of the plug 10 and the number of refrigerant passages 5 into which the plug 10 is pushed, the internal flow resistance can be increased by a desired amount.

  A fifth embodiment of the present invention is shown in FIGS. FIG. 8 is an enlarged cross-sectional view of the connection portion between the header pipe and the flat tube, and FIG. 9 is a horizontal cross-sectional view of the flat tube.

  In the fifth embodiment, as in the second embodiment, the number of refrigerant passages 5 is changed to cause a difference in internal flow path resistance. The number of refrigerant passages 5 is changed as follows. That is, a U-shaped plug 11 is inserted into two adjacent refrigerant passages 5 to close the two refrigerant passages 5. If the number of plugs 11 is increased, the number of refrigerant passages 5 to be blocked can be increased. In the drawing, the cross section of the plug 11 is circular. However, if the cross section is a square cross section that matches the shape of the refrigerant passage 5, the degree of blockage is further improved.

  A sixth embodiment of the present invention is shown in FIGS. FIG. 10 is an enlarged cross-sectional view of the connection portion between the header pipe and the flat tube, and FIG. 11 is a horizontal cross-sectional view of the flat tube.

  In the sixth embodiment, as in the fifth embodiment, the number of refrigerant passages 5 is reduced by plugs. The plug 12 used here has a rectangular cross section adapted to the shape of the refrigerant passage 5, and has a flange 12a at one end. If this plug 12 is used, the refrigerant passages 5 can be closed one by one.

  The plugs 10, 11, and 12 from the fourth embodiment to the sixth embodiment can be made of metal, synthetic resin, or ceramic.

  The methods from the first embodiment to the sixth embodiment can be applied to the heat exchanger 1 shown in FIG. 12 where the refrigerant inlet 7 and the refrigerant outlet 8 are on the same side. FIG. 13 shows the heat exchanger 1 having the refrigerant inlet 7 at both ends of the header pipe 3 and the refrigerant outlet 8 at the center of the header pipe 2. The methods from the first embodiment to the sixth embodiment can be applied.

  In 1st Embodiment to 6th Embodiment, it was set as the structure by which the corrugated fin 6 is arrange | positioned between the flat tubes 4, However, The kind of fin is not restricted to a corrugated fin. Other types of fins such as straight fins and slit fins may be arranged. Further, the present invention can be applied to a heat exchanger that includes only a plurality of header pipes (for example, two header pipes including an upper header pipe and a lower header pipe) and a plurality of flat tubes and does not include fins. .

  As mentioned above, although each embodiment of the present invention was described, the scope of the present invention is not limited to this, 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.

Vertical sectional view showing a schematic structure of a heat exchanger according to the first embodiment Horizontal sectional view of the flat tube of the heat exchanger according to the first embodiment Horizontal sectional view of the flat tube of the heat exchanger according to the second embodiment The expanded sectional view of the connection part of the header pipe and flat tube of the heat exchanger which concerns on 3rd Embodiment. Horizontal sectional view of the flat tube of the heat exchanger according to the third embodiment The expanded sectional view of the connection part of the header pipe and flat tube of the heat exchanger which concerns on 4th Embodiment Horizontal sectional view of the flat tube of the heat exchanger according to the fourth embodiment The expanded sectional view of the connection part of the header pipe and flat tube of the heat exchanger which concerns on 5th Embodiment Horizontal sectional view of flat tube of heat exchanger according to fifth embodiment The expanded sectional view of the connection part of the header pipe and flat tube of the heat exchanger which concerns on 6th Embodiment Horizontal sectional view of the flat tube of the heat exchanger according to the sixth embodiment Vertical sectional view showing a schematic structure of a heat exchanger of another embodiment capable of implementing the present invention Vertical sectional view showing a schematic structure of a heat exchanger according to still another embodiment in which the present invention can be implemented. Vertical sectional view showing the schematic structure of a conventional heat exchanger Vertical sectional view showing the schematic structure of another conventional heat exchanger

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2, 3 Header pipe 4 Flat tube 5 Refrigerant passage 6 Corrugated fin 7 Refrigerant inflow port 8 Refrigerant outflow port 9 Plastic deformation part 10, 11, 12 Plug

Claims (5)

A refrigerant comprising two header pipes arranged in parallel at intervals and a plurality of flat tubes arranged at a predetermined pitch between the two header pipes, wherein the flat tubes circulate a refrigerant in a vertical direction. In a heat exchanger having a passage inside and communicating this refrigerant passage with the inside of the header pipe,
A refrigerant outlet is provided in one of the two header pipes, and an inner flow resistance of the flat tube close to the refrigerant outlet in the flat tube is set to an internal flow resistance of the flat tube far from the refrigerant outlet. A heat exchanger characterized in that the refrigerant flow rate difference between the flat tubes is reduced by making it relatively large compared to the above. 2. The heat exchanger according to claim 1, wherein a difference is produced in the internal flow path resistance by changing a cross-sectional area of the refrigerant passage in the flat tube. The heat exchanger according to claim 2, wherein the flat tube is plastically deformed to change a cross-sectional area of the refrigerant passage. 2. The heat exchanger according to claim 1, wherein the flat tube has a plurality of refrigerant passages therein, and the number of the refrigerant passages is changed to cause a difference in internal flow path resistance. The heat exchanger according to claim 4, wherein the number of the refrigerant passages is changed by closing a selected one of the plurality of refrigerant passages with a plug.

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