JP3903888B2 - Heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat exchanger used for cooling a gas such as an evaporator of a refrigeration apparatus.
[0002]
[Prior art]
In an air conditioner such as an automobile, a heat exchanger in which corrugated fins are joined between parallel tubes is used as an evaporator for cooling. In order to increase the efficiency of heat exchange with the airflow, the corrugated fin is provided with a cut and raised row (louver) in a direction intersecting with the airflow. In the cutting and raising, linear cuts in the direction intersecting the air flow are arranged in parallel at equal intervals on the fins, and press-molded so that the entire width of the cuts has a substantially constant inclination.
[0003]
In recent years, in order to improve the heat exchange performance, there is a tendency to reduce the peak height and fin pitch of the corrugated fins, but this causes a decrease in drainage and an increase in water splash. Condensation caused by moisture in the airflow on the surface of the heat exchanger is important to increase the heat exchange efficiency and prevent water splashing by quickly flowing down and discharging. For this reason, the thing which opened the drainage hole in the intermediate part and the bending part of a corrugated fin is proposed (refer patent document 1), and the thing which opened the drainage hole in the non-molding part of a louver is known (refer patent document 2). .
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 61-128578 (FIGS. 5 and 6).
[Patent Document 2]
Japanese Utility Model Publication No. 62-34675 (FIG. 1).
[0005]
[Problems to be solved by the invention]
Both of these require drilling in the corrugated fins, complicating the corrugated fin formation process, and generating scrap when drilling, which necessitates scrap processing and reduces productivity. Moreover, since the junction area of a corrugated fin and a tube reduces, the heat transfer from a corrugated fin to a tube is prevented and the problem that heat exchange efficiency (cooling performance) falls arises.
[0006]
An object of the present invention is to provide a heat exchanger provided with fins with louvers that do not require scrap processing, can obtain high heat exchange efficiency, can improve drainage, and can reduce water splash.
[0007]
[Means for Solving the Problems]
The present invention relates to a heat exchanger in which fins having cut-and-raised rows are joined between parallel tubes in a direction intersecting the air flow, and the cut-and-raised rows constituting the cut-and-raised rows are inclined at the entire width , The cut-and-raised angle is set to be larger than the cut-and-raised angle of the intermediate portion, and a fluoroscopic opening is created in the vertical direction at the corner . For this reason, the condensed water flows smoothly downward from the corner with a large angle of cut and rise, so that water splash can be reduced and heat transfer from the fin to the tube is performed smoothly. It is desirable to provide corners with a large cut and raised angle on both sides of the cut and raised. The fin of the present invention is generally a corrugated fin, but can also be applied to a plate fin.
[0008]
In addition, the corner of the cut and raised portion has a lower airflow speed than the middle part and is close to the side of the tube, which is the main source of condensation, so that the occurrence of water splash can be reliably prevented and the It is effective for drainage. Furthermore, a cut-and-raised row (louver) having a larger corner-raised angle can be easily formed only by press molding. For this reason, the complexity of processing and the cost of scrap generation, which are causes of cost increase, do not occur.
[0009]
Furthermore, it is desirable to set the cut-and-raised angle α at both corners to be 1.5 to 2.5 times the cut-and-raised angle β of the intermediate portion. In a conventional corrugated fin heat exchanger for an evaporator, the cut-and-raised angle α is generally about 35 degrees. In the present invention, the cut-and-raised angle α at both corners is preferably in the range of 70 ° ± 10 ° from the viewpoint of drainage, and the width w of the portion of the cut-and-raised angle α is 20% to 40% of the total width W of the cut and raised. A range of% is suitable.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a heat exchanger 1 installed in an air conditioner of an automobile and used as an evaporator of a refrigeration apparatus. The heat exchanger 1 includes a flat tube 2 that is bent in a meandering manner and through which a refrigerant flows, and corrugated fins 3 brazed to both side surfaces 22 and 22 of a straight portion 21 of the flat tube 2. In this embodiment, the flat tube 2 has a substantially W shape, and an inlet pipe 23 and an outlet pipe 24 are provided at both ends.
[0011]
The corrugated fin 3 is formed by bending a metal strip in a meandering manner, and includes a semi-cylindrical curved portion 4 and a flat plate portion 5. The flat plate portion 5 is provided with cut-and-raised columns 6 to form cut-and-raised rows (louvers) 60. The bending portion 4 is brazed with the tip abutting against the side surface 22. The tips of the outer curved portions 4 of the corrugated fins 3A and 3B on the left and right sides are brazed to the inner surface of the side plate 11 fixed to the outer surface of the flat tube 2 (see FIG. 2). Since there is no missing portion that reduces the contact area between the corrugated fin 3 and the flat tube 2 at the tip of the curved portion 4, heat conduction from the corrugated fin 3 to the flat tube 2 is performed smoothly and is high. Cooling performance can be obtained.
[0012]
As shown in FIG. 3, the cut and raised 6 is plastic so that a large number of cuts A are linearly formed parallel to the plate width direction of the corrugated fins 3, and both sides of the cut A are cut and raised 6 in the upside down direction. Deform. By press forming, the cut and raised portions 6 constituting the louver 60 can be formed at a time, and no scrap is generated as in the case of drilling the corrugated fins 3. The cut-and-raised portion 6 constituting the louver 60 is substantially in the center and the cut-and-raised direction is reversed.
[0013]
In this embodiment, the cut-and-raised part 6 is set such that both corners 61 and 61 are cut and raised at an angle α = 60 degrees, and the intermediate part 62 is set at a raised and raised angle β = 30 degrees. The ratio of the width w of the portion (both corner portions 61, 61) where the cut-and-raised angle α = 60 degrees with respect to the entire width W is 20%. Thereby, at both corners 61, 61, a transparent opening 63 is formed in the vertical direction as shown in the plan view of FIG. 3A, and the water droplets quickly flow downward as indicated by the arrow Y in FIG. The residence time attached to the corrugated fin 3 is shortened.
[0014]
In the evaporator, since the refrigerant is vaporized in the heat exchanger 1, dew condensation is likely to occur on the surfaces of the flat tube 2 and the corrugated fins 3. The condensed water droplets flow down along the side surface 22 and quickly fall downward through the corners 61 and 61 located at a close distance from the side surface 22. In the vicinity of the side surface 22, the flow speed of the conditioned air is slower than the intermediate portion between the straight portions 21 and 21. For this reason, it is possible to reliably prevent the occurrence of so-called water splash, in which water droplets are blown into the air-conditioned air flow and adhere to the heater core or air mix door installed downstream or enter the vehicle compartment from various air outlets.
[0015]
[Modification]
The corners 61 and 61 having a large cut and raised angle α are preferably provided on both sides of the cut and raised 6 as in this embodiment, but may be provided on only one side in the corrugated fins 3A and 3B on the left and right sides.
[Brief description of the drawings]
FIG. 1 is a front view of a heat exchanger according to the present invention.
FIG. 2 is an enlarged perspective view of a main part of FIG.
FIG. 3 is a plan view and a front cross-sectional view of a cut and raised row.
FIG. 4 is a side sectional view of a cut and raised row.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Flat tube 3 Corrugated fin 4 Curved part 5 Flat plate part 6 Cut and raised 60 Cut and raised row (louver)
61 Corner 62 Middle
63 Perspective opening

Claims (1)

In a heat exchanger in which fins having rows cut and raised in a direction intersecting the airflow are joined between parallel tubes,
The cut-and-raised row constituting the cut-and-raised row is inclined in its entire width, and the cut-and-raised angle of the corner is set to be larger than the cut-and-raised angle of the intermediate portion, and a transparent opening is formed in the vertical direction in the corner. A heat exchanger characterized by

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