JPH05164481A - Heat exchanger - Google Patents

Abstract

PURPOSE:To enhance corrosion resistant and heat transfer properties by providing a corrugated fin between fins, since it is difficult to expect an improvement of a cross fin tube type heat exchanger adopted in the field of air conditioner heat exchangers due to their corrosion problems. CONSTITUTION:Corrugated fins 4 are mounted between a large number of plate fins 1 having a louver part laid out in parallel to each other with a span so as to reduce the load of the louver part in the plate fins 1 and increase their heat transfer areas. This construction makes it possible to enhance their corrosion resistant and heat transfer properties so that the heat exchangers may be used for a long time in a stabilized manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger suitable for exchanging heat with air, such as an air conditioner, a refrigerator or a dehumidifier.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to a cross fin tube type heat exchanger. In the conventional cross fin tube type heat exchanger, a plurality of holes for inserting a copper heat transfer tube are opened in a fin formed of an aluminum plate or the like having an appropriate area, and the fins are arranged in parallel at a pitch of several mm. , A plurality of heat transfer tubes are arranged in this parallel fin so as to pass through this hole, the heat transfer tube and the fin are formed in close contact with each other by means such as expansion, and the end of the heat transfer tube is connected by a U-shaped vent tube. However, a suitable number of heat transfer passages extending in a meandering shape are formed. A large number of louvers, called louvers, are provided on the upper surface of the fins to improve the performance by exposing the fins to fresh air as much as possible. In general, the fin surface is treated with a surface treatment agent to consider drainage and corrosion resistance.However, in the cross fin tube type heat exchanger, aluminum fins and copper heat transfer tubes are contacted with different metals with large potential difference. As a result, the fin collar is corroded and the fins fall off.
Further, the fins disclosed in JP-A-1-208698 and JP-A-2-37293 increase the louver occupying area to improve the heat transfer coefficient. It doesn't hit. In this way, as the performance of heat exchangers has improved, the fins have become thinner and the louvers have become finer, so corrosion from the cut-and-raised cross section that has not been surface-treated affects the durability of the heat exchanger. Is occurring. Moreover, in order to improve the performance of the heat exchanger in the future,
Further, it is shown that as the fins become finer, it is becoming difficult to improve the performance of the conventional cross fin tube type heat exchanger in terms of corrosion resistance.

[0003]

In the above-mentioned prior art, in the corrosion of the cross-fin tube type heat exchanger, by ensuring a sufficient distance between the copper heat transfer tube and the slit root of the fin, the life until the fin falls off during the corrosion. However, in consideration of the corrosion of the miniaturized louvers, and in recent years, the heat exchangers are required to have higher performance as they become smaller and lighter. Corrosion due to miniaturization has become a problem.
Conventionally, in heat exchangers, fins are provided with a surface treatment agent in preparation for corrosion, but since a plurality of louvers are cut and raised by press molding, a cut and raised cross section without the surface treatment agent is produced.
With the miniaturization of the louver, the area of the cut and raised cross section of the fin increases, which affects the corrosion resistance of the fin, which is an obstacle to higher performance.

An object of the present invention is to provide a corrugated fin between plate fins to reduce the load of the louvers on the plate fins, improve the corrosion resistance of the fins, and achieve high performance of the heat exchanger. ..

[0005]

SUMMARY OF THE INVENTION The above object is to provide a heat exchanger having a plurality of heat transfer tubes which are formed by stacking plate fins in a direction intersecting the flow direction in a direction of shearing a fluid flow and penetrating the plate fins. This is achieved by providing corrugated fins in the upstream and downstream portions of the heat transfer tube in the flow direction.

[0006]

By providing the corrugated fins between the plate fins, the number of louvers in the plate fins can be reduced, so that the corrosion resistance of the fins is improved and the performance is deteriorated due to the deformation of the fins during the manufacturing process such as pipe expansion. The impact can be prevented.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a part of a heat exchanger in which fins according to an embodiment of the present invention are stacked, FIG. 2 is a plan view of plate fins used in the heat exchanger, and FIG. 3 is used in the heat exchanger. It is a perspective view of the corrugated fin which is put. In FIG. 2, 1 is a part of the plate fin, 2 is a louver portion, and 3 is a heat transfer tube insertion hole. Further, in FIG. 1, 4 is a corrugated fin shown in FIG. A conventional cross fin tube type heat exchanger is generally composed of a large number of plate fins arranged in parallel at intervals, and a plurality of heat transfer tubes penetrating the fins. It can be said that corrugated fins are provided on the upstream side and the downstream side in the fluid flow direction with the heat transfer tube as a boundary. FIG. 2 shows a part of the plate fins stacked, and the louver part is
It projects within the projected cross-sectional area of the heat transfer tube when viewed from the side of the heat exchanger. In the fin-tube heat exchanger, the deformation of the louver is one of the factors that hinders the performance improvement. It has been found that the deformation becomes large. Also, in order to improve performance,
The louver becomes finer, which increases the area of the cut and raised cross section of the louver that has not been surface-treated, and the performance of the heat exchanger is limited due to the corrosion of the fins. For this reason, by providing corrugated fins between the plate fins, it is possible to reduce the number of louvers in the plate fins, reduce the load on the louvers, and improve the corrosion resistance of the louver portion. Further, the rigidity of the entire heat exchanger is increased, and the deformation of the fins when expanding the pipe can be reduced. As a result, it is possible to prevent the heat transfer performance from being deteriorated due to the fin deformation and to improve the heat transfer performance because the heat transfer area corresponding to the corrugated fins is increased.

FIG. 4 is a part of a heat exchanger in which fins according to another embodiment of the present invention are laminated, and FIG. 5 is a perspective view of a corrugated fin used in the heat exchanger, which is shown in FIG. The fin pitch is larger than that of the corrugated fin of the embodiment. In this embodiment, the corrugated fins in the upstream portion in the fluid flow direction in the embodiment are made larger than the fin pitch of the corrugated fins in the downstream portion, so that the heat transfer area is smaller than that in the embodiment. However, from the viewpoint of frost formation, most frost formation occurs in the upstream part in the flow direction of the fluid, so the thermal resistance increases due to this frost formation, leading to a decrease in air volume due to an increase in ventilation resistance. It is known that heat transfer performance is significantly reduced. Generally, there is a method of increasing the fin pitch of the heat exchanger inlet with a large amount of frost, or a method of changing the air passage as the frost progresses, but the present invention is based on the latter, As shown in FIG. 4, by providing corrugated fins having different fin pitches in the upstream and downstream portions of the air flow direction with the heat transfer tube as a boundary, the air passage is changed to reduce frost formation per area, and defrosting interval is increased. Can be delayed.

Another embodiment of the present invention will be described with reference to FIG. FIG. 6 shows a part of a heat exchanger in which fins are laminated, 5 is a corrugated fin shown in FIG. 5, 6 is a corrugated fin having a louver, and is smaller than the fin pitch of 5 at the upstream portion in the fluid flow direction. It is a thing. As a result, the louver ratio is increased, so that the heat transfer performance is improved, and the same operational effect against frost formation as in the above-described embodiment can be obtained.

Further, an embodiment of the present invention will be described with reference to FIG. FIG. 7 shows a part of a heat exchanger in which fins are stacked,
Is a corrugated fin having a louver, which is larger than the fin pitch of 6 at the downstream portion in the fluid flow direction. As a result, the louver ratio is increased as compared with the embodiment, so that the heat transfer performance is further improved, and it is possible to obtain the same action and effect as the embodiment with respect to frost formation.

In each of the embodiments described above, aluminum is usually used as the fin material and copper is used as the heat transfer tube.
By using copper as the fin material, the plate fins and corrugated fins can be easily joined by soldering, and corrosion caused by contact between dissimilar metals with a large potential difference can be prevented, resulting in a more stable long-term heat exchanger. It can be used.

[0012]

According to the present invention, by providing corrugated fins between the fins of the cross fin tube type heat exchanger, it is possible to improve the corrosion resistance of the heat exchanger and achieve high performance.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a plan view of a fin.

FIG. 3 is a perspective view of a corrugated fin.

FIG. 4 is a perspective view showing an embodiment of the present invention.

FIG. 5 is a perspective view of a corrugated fin.

FIG. 6 is a perspective view showing an embodiment of the present invention.

FIG. 7 is a perspective view showing an embodiment of the present invention.

[Explanation of symbols]

1 ... Plate fin, 2 ... Louver part, 3 ... Heat transfer tube insertion hole, 4-7 ... Corrugated fin.

Claims (1)

[Claims] 1. A plurality of heat transfer tubes penetrating the plate fins, wherein plate fins having a plurality of cut-and-raised strips in a direction of shearing a fluid flow are laminated in a direction intersecting with the fluid flow direction. In the heat exchanger, each of the louvers is a louver that protrudes to one side in the stacking direction and protrudes inside the projected cross-sectional area of the heat transfer tube when viewed from the side surface of the heat exchanger. A heat exchanger having corrugated fins between plate fins.