JP2545852Y2 - Fins for heat exchangers - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fin for a heat exchanger mainly used as an inner fin inserted into a tube, which is obtained by bending a thin metal plate into a trapezoidal or rectangular wave shape.

[0002]

2. Description of the Related Art In a fin formed by bending a thin metal plate to form a trapezoidal or rectangular wave, the heat exchange medium is agitated to improve the heat transfer property. Some have a rectangular hole formed in the surface and allow the heat exchange medium to flow along the wave ridge direction, that is, along the longitudinal direction of the top or bottom of the rectangular wave. In addition,
The rectangular hole was formed so as to rise at right angles to the flow of the heat exchange medium.

[0003]

The above-mentioned conventional fins for heat exchangers are characterized by relatively low fluid resistance, but prevent sufficient agitation of the heat exchange medium and development of a boundary layer on the fin surface. There was a drawback that the effect was relatively small.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention has a small fluid resistance, a large leading edge effect by a slit, and
In particular, an object of the present invention is to provide a heat exchanger fin capable of improving heat conductivity by causing agitation in which a helical rotation is given to a heat exchange medium. In order to achieve the object, the following configuration is adopted.
A thin metal plate is bent in a trapezoidal or rectangular wave shape, and in the heat exchanger fins through which the heat exchange medium 9 flows in the ridge direction of each wave, the opening edge is inclined so as not to be orthogonal to the longitudinal direction of the side surface of the wave. The slit 1 is formed on the rising surface 2 and the falling surface 3 of the wave, which are both side surfaces of each of the waves, so that the inclination directions are opposite to each other.

[0005]

According to the heat exchanger fin of the present invention, the heat exchange medium 9 develops when flowing along the wall surface of the fin due to the opening edge of the slit 1 inclined with respect to the flow direction of the heat exchange medium 9. The boundary layer is effectively separated by the slit 1 and its development is prevented. That is, as the leading edge of the slit 1 becomes longer, the leading edge effect on the fluid is increased, and the fluid flowing through each part is agitated, so that the heat conductivity is improved. Moreover,
Since the inclinations of the slits formed on the opposite side walls are opposite to each other, a spiral rotational force is applied to the heat exchange medium flowing in the direction of the ridge line of the wave as shown in FIG. This is based on the fact that a portion where the forced flow in the oblique direction is fast occurs at every slit interval. Further, since the inclinations of the slits on both sides are different, the flow flowing through each slit is more effectively and uniformly stirred.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a heat exchanger fin according to the present invention; FIG. 1 is a perspective view of a main part of the heat exchanger fin, and FIG. 3 is a perspective view of the heat exchanger fin provided inside a flat tube 6. The fin of this embodiment is formed by bending a thin metal plate as shown in FIG. 1 to form a rectangular wave. The amplitude of this rectangular wave, that is, the height and top 4 and bottom 5 of the rising surface 2 and the falling surface 3
The width and the ratio can be appropriately changed depending on the purpose of use and the like. For example, rising surface 2, falling surface 3
Can be several times the width of the top 4 and bottom 5. As the metal plate, a copper plate, an aluminum plate, a stainless steel plate, a brass plate, or the like having good heat conductivity is used, and a plate having a thickness of about 0.02 to 0.5 mm is often used. A slit 1 is formed in the rising surface 2 and the falling surface 3. The slit 1 is provided to be inclined so as not to be orthogonal to the longitudinal direction of the rising surface 2 and the falling surface 3. Further, the slits 1 on the rising surface 2 and the slits 1 on the falling surface 3 are inclined in opposite directions. That is, on the rising surface 2, the slit 1 is inclined forward and downward with respect to the flow of the heat exchange medium 9,
With respect to the falling surface 3, it is inclined in a rising direction. This makes it possible to further improve the stirring effect.

In order to manufacture such a fin, a large number of slits 1 are previously drilled in a flat state at portions corresponding to the rising surface 2 and the falling surface 3, and then each slit 1 is formed with a wave. The metal plate may be bent so as to be located on the side wall. Further, in this embodiment, the shape of the wave is formed in a rectangular wave shape. Even if it is formed in the shape of a trapezoidal wave, the same effect as the rectangular wave can be obtained. As shown in FIG. 3, the fin thus formed is provided inside the flat tube 6 as an example, and its top and bottom are brazed or soldered to the inner surface of the flat tube 6. The heat exchange medium 9 flows in the longitudinal direction of the flat tube 6. In addition, the fin 8 for heat exchangers of the present invention can be provided in a stacked heat exchanger.

[0008]

The heat exchanger fin of the present invention is formed by bending a thin metal plate into a trapezoidal wave or a rectangular wave, and forming a slit 1 on the rising surface 2 and the falling surface 3 of the wave. The slit 1 is characterized in that the opening edge is formed so as to be inclined so as not to be orthogonal to the longitudinal direction of the side surface of the wave, and the slits on both side surfaces are inclined in opposite directions. Therefore, with respect to the heat exchange medium 9 flowing in the direction of the ridge line of the wave, the length of the opening edge for separating the development of the boundary layer is increased, and the heat transfer property is improved. At the same time, as shown in FIG.
Are opened in opposite directions, a helical rotational force is applied to the heat exchange medium 9 flowing in the direction of the ridge line of the wave, and the stirring effect is dramatically improved.

That is, the heat exchange medium 9 is divided at the slit 1 where the slow-flow boundary layer in contact with the side wall surface is formed obliquely, and a fast-flow portion along the slit is generated.
The fast part of the flow has an obliquely upward vector on one side wall and an obliquely downward vector on the other side wall. As a result, the fluid sandwiched between the side walls causes a helical twist, and a rotating force is applied to increase the stirring effect, thereby improving the heat transfer. In FIG. 2, the twisting directions of the heat exchange medium flowing through the portion A surrounded by the top of the rectangular wave and the heat exchange medium flowing through the portion B surrounded by the valley of the rectangular wave are opposite to each other. The twist directions of the matching heat exchange media will reinforce each other. Further, uniform stirring is secured as a whole, and there is an effect that the heat transfer of each part of the fin is improved. Moreover, the fluid resistance is hardly increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a heat exchanger fin according to the present invention.

FIG. 2 is an explanatory view showing the flow of the heat exchange medium inside the fin of the present invention.

FIG. 3 is a schematic perspective view of a flat tube provided with the heat exchanger fin of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slit 2 Rising surface 3 Falling surface 4 Top 5 Bottom 6 Flat tube 7 Ridge line 8 Fin for heat exchanger 9 Heat exchange medium

Claims (1)

(57) [Scope of request for utility model registration] 1. A fin for a heat exchanger in which a thin metal plate is bent into a trapezoidal wave or a rectangular wave, and a heat exchange medium flows in a ridge direction of each wave, and an opening edge is not perpendicular to a longitudinal direction of a side surface of the wave. The slits (1) inclined as described above are formed on the rising surface (2) and the falling surface (3) of the wave, which are both side surfaces of each of the waves, so that the inclination directions are opposite to each other. Heat exchanger fins.