JPH10166088A - Plate fin tube type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a concurrent phenomenon and to eliminate lowering of heat exchange performance in a plate fin tube type heat exchanger by forming a bent forming part, which extends in the direction crossing the longitudinal direction of a plate fin, in the manner in which the part is positioned between adjacent flares. SOLUTION: A plate fin 11 is formed with an upward projecting bent forming part 15 that extends in the direction orthogonally crossing the longitudinal direction of the fin 11 so that the part is situated between adjacent flares 13. Accordingly, the plate fin 11 is bent by the out-of-plane deformation of the bent forming part 15, in the manner in which its chevron shape forms an acute angle, by means of the moment generating at the time of the tube expanding operation and a compressive stress generating longitudinally in the plane of the plate fin 11. This deformation is always larger than the deformation by the moment; hence, the plate fin 11 is deformed all in the same direction, preventing the generation of irregular deformation known as the concurrent phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate-fin tube type heat exchanger suitable for a condenser or an evaporator of an air conditioner or a refrigerator.

[0002]

2. Description of the Related Art FIG. 3 shows an example of such a conventional plate-fin tube type heat exchanger. A large number of strip-shaped plate fins 11 made of thin plates of aluminum or the like arranged in parallel with each other at a predetermined gap are fixed with a plurality of tubes 20 made of copper or the like penetrating therethrough and spaced apart from each other in parallel with each other. It is growing.

[0003] The refrigerant flowing through the tube 20 condenses or evaporates by exchanging heat with the air A flowing through the gaps between the plate fins 11.

As shown in FIG. 4, each plate fin 11 is formed with a flare 13 surrounding the tube hole 12 at a predetermined interval along the longitudinal direction thereof, and has longitudinal rigidity on both side edges. In order to improve the performance, a bead 14 having a sectional shape is formed.

When assembling this heat exchanger, FIG.
As shown in the figure, a number of plate fins 11 are arranged in parallel with a predetermined gap,
After penetrating the tube 20 whose outer diameter is slightly smaller than its inner diameter into 12, the plug 31 whose outer diameter is slightly larger than its inner diameter is pushed into the tube 20 in the direction of the arrow, and the tube 20 is expanded by its tapered portion 32. By expanding the flare 13, the tube 20 and the plate fin 11 are brought into close contact with each other.

At this time, since the longitudinal direction of the plate fin 11 is restrained, the flare 13 is pushed and expanded, so that a compressive stress is generated in the plane of the plate fin 11 in the longitudinal direction. Deforms in the out-of-plane direction.

That is, as shown in FIG. 6 (A), since the pressing force Fr acting on the flare 13 and the center of the plate thickness of the plate fin 11 are eccentric, a moment Mr is generated.
As a result, the plate fins 11 are flare 13
Turn to the opposite side.

Further, when the plug 31 is pushed into the tube 20, the tube 20 shrinks in the axial direction thereof, and the flares 13 are pressed against each other as shown in FIG. Is subjected to an axial load Fz.
The plate fin 11 bends toward the flare 13 as shown by a broken line by a moment Mz generated based on the axial load Fz. As shown in FIG. 7, the axial load Fz increases in accordance with the moving distance of the plug 31 from the expansion start point and saturates at a certain value.

[0009]

During the pipe expansion operation, the plug 31
Irrespective of the moving distance of, the moment Mr is constant, but the moment Mz changes according to the change of the axial load Fz,
The plate fin is determined by the relative relationship between the moments Mr and Mz.
In FIG. 11, a phenomenon called the Abbe phenomenon occurs, as shown in FIG. This results in a plate fin
Since the gap between the elevens is not constant, the heat exchange performance of the plate-fin tube type heat exchanger may be reduced.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the first invention is that a number of strip-shaped plate fins are separated by a predetermined gap. The tubes are passed through a plurality of flares formed at predetermined intervals along the longitudinal direction of the plate fins, and the tubes are expanded. In the plate fin tube type heat exchanger, a plate fin tube type heat exchanger is characterized in that the plate fin is formed with a bent formed portion extending in a direction intersecting the longitudinal direction thereof so as to be located between the adjacent flares. In the heat exchanger.

Another feature is that the bent portion is formed so as to extend in a direction perpendicular to the longitudinal direction of the plate fin.

The gist of the second invention is that a number of strip-shaped plate fins are arranged parallel to each other with a predetermined gap therebetween, and each of these plate fins is spaced at a predetermined interval along the longitudinal direction thereof. In a plate fin tube type heat exchanger in which a tube is penetrated through a plurality of formed flares and then expanded by expanding the tube, an annular bead is formed around each flare of the plate fin. The plate fin tube type heat exchanger is characterized in that:

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. Flare 13 adjacent to plate fin 11
An upwardly convex bent-formed portion 15 extending in a direction orthogonal to the longitudinal direction of the plate fin 11 is formed so as to be located therebetween. Note that the bent portion 15 may be slightly inclined with respect to the longitudinal direction of the plate fin 11. Other configurations are the same as the conventional one shown in FIG. 3 and FIG.
Corresponding members have the same reference characters allotted, and description thereof will not be repeated.

However, the plate fins 11 are out-of-plane so that the angle of the plate fins 11 becomes acute at the bent portion 15 by the moment Mr generated during the pipe expanding operation and the compressive stress generated in the plane of the plate fins 11 in the longitudinal direction. It is bent by being deformed. The amount of deformation is moment
Since the amount of deformation is always larger than the amount of deformation due to Mz, the plate fins 11 are all deformed in the same direction, and the occurrence of the so-called Abeck phenomenon, which is irregularly deformed like the conventional one shown in FIG. 8, can be prevented.

A second embodiment of the present invention is shown in FIG. In this embodiment, an annular bead 16 is formed around each flare 13 concentrically therewith. In addition,
This bead 16 may be plural. The other configuration is the same as that of the conventional one shown in FIGS. 3 and 4, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

However, the plate fin 11 is deformed out of the plane toward the flare 13 at the bead portion 16 by the moment Mr generated during the pipe expanding operation and the compressive stress generated in the plane of the plate fin 11 in the longitudinal direction. Since the deformation amount is larger than the deformation amount due to the moment Mz, all the plate fins 11 are deformed in the same direction,
Therefore, the occurrence of the Abeck phenomenon can be prevented.

[0017]

According to the first aspect of the present invention,
The plate fin is formed with a bent portion extending in a direction intersecting the longitudinal direction thereof so as to be located between the adjacent flares, so that the occurrence of the Abeck phenomenon can be prevented, and therefore, the heat of the plate fin tube type heat exchanger can be prevented. The exchange performance can be prevented from deteriorating.

If the bent portion is formed so as to extend in a direction perpendicular to the longitudinal direction of the plate fin, the Abeck phenomenon can be effectively prevented.

According to the second aspect of the present invention, since an annular bead is formed around each flare of the plate fin, the occurrence of the Abeck phenomenon can be prevented,
Therefore, it is possible to prevent the heat exchange performance of the plate fin tube type heat exchanger from deteriorating.

[Brief description of the drawings]

FIG. 1 is a perspective view of a plate fin illustrating a first embodiment of the present invention.

FIG. 2 is a perspective view of a plate fin according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a conventional plate-fin heat exchanger.

FIG. 4 is a perspective view of a plate fin of a conventional plate fin type heat exchanger.

FIG. 5 is a longitudinal sectional view showing an assembling procedure of a conventional plate fin type heat exchanger.

6A and 6B are explanatory diagrams of deformation of a plate fin during a pipe expanding operation, in which FIG. 6A shows a result by a pressing force, and FIG. 6B shows a result by an axial load.

FIG. 7 is a diagram showing a relationship between a moving distance of a plug and an axial load.

FIG. 8 is a longitudinal sectional view showing an Abeck phenomenon occurring in a conventional plate-fin type heat exchanger.

[Explanation of symbols]

 11 Plate fin 12 Tube hole 13 Flare 14 Bead 15 Bend part

Claims (3)

[Claims] 1. A large number of strip-shaped plate fins are arranged in parallel with a predetermined gap therebetween, and tubes are mounted on a plurality of flares formed at predetermined intervals along the longitudinal direction of each plate fin. In the plate fin tube type heat exchanger, which is in close contact with the plate fin by expanding the tube after penetrating, the bent portion extending in the direction intersecting with the longitudinal direction of the plate fin is formed adjacent to the flare. A plate fin tube type heat exchanger formed so as to be located between them. 2. The plate fin tube type heat exchanger according to claim 1, wherein said bent portion is formed so as to extend in a direction perpendicular to a longitudinal direction of said plate fin. 3. A large number of strip-shaped plate fins are arranged parallel to each other with a predetermined gap therebetween, and tubes are formed on a plurality of flares formed at predetermined intervals along the longitudinal direction of each plate fin. A plate fin tube type heat exchanger in which the tube is expanded and then brought into close contact with the plate fin, wherein an annular bead is formed around each flare of the plate fin. Fin tube type heat exchanger.