JP5042927B2 - Heat exchanger - Google Patents

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 equipment is widely used in outdoor units of car air conditioners and building air conditioners.

An example of a conventional parallel flow type heat exchanger 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. 6 , 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 the same cross-sectional area are arranged in the depth direction of the figure, so that 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 or brazing. 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. The positional relationship between the refrigerant inlet 7 and the refrigerant outlet 8 shown here is an example, and the present invention is not limited to this. For example, the structure which has the refrigerant | coolant outflow port 8 in two places is also possible.

  When a parallel flow type heat exchanger is used as an evaporator, a low-temperature refrigerant flows through the refrigerant passage 5 and the surface temperature of the flat tubes 4 and the corrugated fins 6 decreases. Thereby, the phenomenon (frosting phenomenon) that the water | moisture content in air adheres as a frost on the surface of the flat tube 4 or the corrugated fin 6 occurs. When frost formation occurs, the transfer of cold heat from the flat tube 4 and the corrugated fins 6 to air deteriorates, and the gaps between the corrugated fins 6 are narrowed by frost, making it difficult for the air to flow. To do. For this reason, the defrosting operation which reverses the roles of the evaporator and the condenser is sometimes performed to melt the frost.

  If the frost-melted water, that is, defrosted water remains attached to the flat tubes 4 and the corrugated fins 6, it will freeze when returning from the defrosting operation to the normal operation, thereby reducing the heat exchange efficiency. . Therefore, it is necessary to drain defrost water promptly.

  Further, in the indoor unit of the air conditioner, condensation occurs in the heat exchanger due to heat exchange with room air during the cooling operation. In the outdoor unit of the air conditioner, condensation occurs in the heat exchanger due to heat exchange with outdoor air during heating operation. Condensed water also reduces the heat exchange performance by narrowing the cross-sectional area of the air flow passage, so it must be drained quickly.

  In order to quickly drain defrost water and condensed water, configurations of Patent Document 1 and Patent Document 2 are proposed.

  In the heat exchanger described in Patent Document 1, corrugated fin corrugated valleys and ridges are inclined in the depth direction of the heat exchanger, and the defrost water flows to the fin lower end surface along the inclined fin surface. It is supposed to flow down along the tube.

In the heat exchanger described in Patent Document 2, a through hole is provided in a joint portion between the corrugated fin and the flat tube so that defrost water passes through the through hole and flows down along the flat tube.
JP 2004-177040 A JP 2005-24187 A

  When defrosting is performed with a parallel flow heat exchanger, a bridge phenomenon (water film is stretched) due to the surface tension of water becomes a problem. When a bridging phenomenon occurs in the through hole of Patent Document 2, water does not easily flow down from the through hole. The bridging phenomenon also occurs between the corrugated fins, and even when water hangs down to the end of the corrugated fins, a situation occurs in which the film is merely stretched there and not dripped. The same can be said for dew condensation water as well as dew condensation water.

  In order to overcome the above situation, for example, if the diameter of the through hole is increased, the contact area between the flat tube and the corrugated fin is reduced, and the heat exchange performance is lowered. If the pitch between the corrugated fins is increased, the heat radiation area of the corrugated fins is reduced, and this leads to a decrease in heat exchange performance.

  The present invention has been made in view of the above points, and an object of the present invention is to allow the defrost water and condensed water to be smoothly drained by improving the shape of the corrugated fin in the parallel flow type heat exchanger. And

In order to achieve the above object, the present invention provides a plurality of header pipes arranged in parallel at intervals, and a plurality of refrigerant pipes arranged between the plurality of header pipes, and having refrigerant passages provided inside the header pipes. In the heat exchanger comprising a flat tube communicated with the corrugated fin and a corrugated fin disposed between the flat tubes, the corrugated fin has a slope in which the windward side of the airflow passing therethrough is high and the leeward side is low. A slit continuous in a direction parallel to the longitudinal direction of the flat tube is formed at an end corresponding to the leeward side , the depth of the slit is less than the depth of the corrugated fin, and the portion of the slit is most depressed. It is said.

  In the heat exchanger having the above configuration, it is preferable that the slit is opened after the corrugated fin is fixed to the flat tube.

According to the present invention, since the corrugated fin has a slope in which the windward side of the airflow passing through the corrugated fin is high and the leeward side is low, the defrost water generated on the surface of the corrugated fin is leeward even if there is no wind by the blower. Water droplets that gather on the side, grow, and grow on both sides of the slit meet at the slit, break together with each other by breaking the surface tension, and flow down without causing a bridging phenomenon. There is no decrease in heat exchange performance due to the cross-sectional area of the air flow passage being narrowed by water. Since the depth of the slit is less than the depth of the corrugated fin, the strength of the corrugated fin is not significantly reduced. In addition, since the corrugated fins are most depressed at the slits, the water droplets fall to the slits, and the water droplets easily meet at the slits, so that the drainage is performed more smoothly .

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 is a diagram schematically showing a combination of a parallel flow heat exchanger and a blower, FIG. 2 is a vertical sectional view of the heat exchanger, and FIG. 3 is a partial front view of the heat exchanger as viewed from the leeward side. Note that the same reference numerals as are used in FIG. 6 to common elements with functionally heat exchanger of the conventional structure shown FIG. 6, description will be omitted.

  In FIG. 1, the heat exchanger 1 is shown in a horizontal cross section, and the blower 10 is symbolized by the shape of a propeller fan. The blower 10 is installed at a position facing the heat exchanger 1. When the blower 10 is driven, the airflow generated thereby passes through the heat exchanger 1, and heat exchange is performed between the refrigerant flowing through the heat exchanger 1 and the airflow.

  In FIG. 2, the left side is the windward and the right side is the leeward. The corrugated fin 6 is inclined so that the windward side becomes higher and the leeward side becomes lower. The flat tubes 4 need not be arranged at an equal pitch, and may be arranged at different pitches.

  A slit 9 is formed on the leeward edge of the corrugated fin 6 at a central position when viewed from the leeward side. The slit 9 extends in the direction along the airflow, and the depth thereof is less than the depth of the corrugated fin 6. In the drawing, the depth of the slit 9 is a ratio of one third to one half of the depth of the corrugated fin 6, but is not limited to this. As seen in FIG. 3, each slit 9 is continuous in the vertical direction, that is, the direction parallel to the longitudinal direction of the flat tube 4.

  When the defrosting operation of the heat exchanger 1 is performed while driving the blower 10, the defrost water generated on the surface of the corrugated fin 6 is blown toward the leeward side by the wind from the blower 10. When water droplets that have grown on both sides of the slit 9 meet at the slit 9, the surface tensions of each other break up and merge together, and flow down without causing a bridging phenomenon. A series of slits 9 becomes a drainage channel (water guide channel), and water sequentially flows down. Since the defrost water flows down smoothly, when returning from the defrost operation to the normal operation, there is little risk that water drops remaining without being drained will freeze and impair the heat exchange performance. Condensed water flows down in the same way as defrost water.

The dimension of each part of the heat exchanger 1 is good to determine an appropriate value through experiment. As an example, the interval between the flat tubes 4 is 5.5 mm, the thickness of the flat tubes 4 is 1.3 mm, the horizontal length of the corrugated fins 6 in the air flow direction is 18 mm, and the peak-valley pitch of the corrugated fins 6 is 2 mm. Numerical values such as ˜3 mm and the maximum width of the slit 9 can be 1 mm. Needless to say, these numerical values are merely examples and do not limit the content of the invention.

  A specification that the blower 10 is not driven during the defrosting operation is also possible. Since the corrugated fins 6 are inclined so that the leeward side becomes higher and the leeward side becomes lower, the defrost water generated on the surface of the corrugated fins 6 gathers and grows on the leeward side even if there is no wind by the blower 10. To do. The water droplets grown on both sides of the slit 9 eventually meet at the slit 9, break the surface tension with each other and coalesce, and flow down through the series of slits 9 without causing a bridging phenomenon.

  In the example shown in FIGS. 1 to 3, the slit 9 is formed at the center of the corrugated fin 6 on the leeward side as viewed from the leeward side. However, the present invention is not limited to this configuration. It is also possible to add a slit at the center of the corrugated fin 6 on the windward side as viewed from the windward side. In this way, the water droplets of defrost water and dew condensation water generated on the windward side of the corrugated fin 6 meet and coalesce at the slit on the windward side before moving to the leeward side, and the wind does not occur without causing a bridge phenomenon. Since it flows down through a series of upper slits, defrost water and dew condensation water generated on the windward side of the corrugated fin 6 can be quickly drained. In addition, by extending the slit 9 on the leeward side to the vicinity of the edge on the leeward side of the corrugated fin 6, it can be used instead of the slit on the leeward side. Conversely, by extending the slit on the leeward side to the vicinity of the edge on the leeward side of the corrugated fin 6, it can be used as a substitute for the leeward side slit.

Although the slit 9 is depicted as being located at the center of the interval between the flat tubes 4, this position is not absolute. It may be biased to either the left or right as viewed from the leeward side. A staggered arrangement may be adopted in which the corrugated fins 6 are deviated to the left or to the right every one or several steps. Further, the slits 9 can be formed only in the upper half of the corrugated fins 6, or in the lower half of the corrugated fins 6.

The slit 9 can be formed as follows . After fixing the corrugated fin 6 to the flat tube 4, as shown in FIG. 4 , the blade 20 is moved from the top to the bottom to open the slit 9. Thereby, the slit 9 can be formed easily.

As shown in FIG. 4 , when the blade 20 is moved from top to bottom and the slit 9 is cut open, as shown in FIG. 5 , the corrugated fin 6 is depressed most at the position of the slit 9. With such a shape, the water droplets on the surface of the corrugated fins 6 go down to the slits 9, so that the water droplets easily meet at the slits 9, and the drainage is performed more smoothly.

  In the corrugated fin 6, the slit 9 is depressed most, in addition to the above-described method of forming depression along with the cutting with the blade, and after forming a slit having no depression by a rotary blade or laser processing, press processing is performed separately. It is also possible to adopt a technique such as forming a depression by bending.

  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.

The figure which shows typically the combination of the heat exchanger and air blower which concern on embodiment. Vertical sectional view of a heat exchanger according to an embodiment The partial front view which looked at the heat exchanger which concerns on embodiment from the leeward side Illustration of slit forming method The partial front view which looked at the heat exchanger which formed the slit by the method of FIG. 4 from the leeward side Vertical sectional view showing the schematic structure of a 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 Slit 10 Blower 20 Blade

Claims (2)

A plurality of header pipes arranged in parallel at intervals, a plurality of flat tubes arranged between the plurality of header pipes and having refrigerant passages provided therein communicated with the inside of the header pipes, and the flat tubes In a heat exchanger with corrugated fins arranged between,
The corrugated fin has a high windward side of the air flow passing through it, with the leeward side becomes lower slope, the end corresponding to the downstream side, a slit continuous in a direction parallel to the longitudinal direction of the flat tubes, the slits The depth is less than the depth of the corrugated fin,
A heat exchanger characterized by the most depressed slit . 2. The heat exchanger according to claim 1, wherein the slit is formed by cutting the corrugated fin after fixing the corrugated fin to the flat tube .

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