JPS589099Y2 - Finch tube for heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved structure of a fin tube mainly used in a heat exchanger.

Conventionally, as this type of fin tube structure, those shown in FIGS. 4 to 6 are known.

The fin tube 10 is composed of a tube 11 through which a heat medium, for example, water, flows, and fins 12 arranged in multiple rows at predetermined intervals in the longitudinal direction.

As shown in FIG. 4, the fins 12 are usually divided into left and right halves, with a required gap formed between them.

When manufacturing such a fin tube 10, conventionally, the fin body 13 and 13, which are divided into left and right halves, are each provided with a curvature that matches the outer diameter of the tube 11, as shown in FIG. A circular arc notch 14° 14 is cut out, and both fin bodies 13, 13 are welded to the tube 11 by RI electric resistance welding.

The fin bodies 13, 13 were moved from both the left and right sides around the tube 11, and were brought into pressure contact with the tube 11, thereby welding them together.

However, the fin tube 10 manufactured by such a method had poor heat transfer efficiency even though the fin bodies 13, 13 were welded to the outer periphery of the tube 11.

So, when we elucidated the cause, we found that the fin body 13.13
It was found that the welded portion between the tube 11 and the tube 11 was not uniformly welded over the entire contact surface.

First, although they were welded by electric resistance welding, there were often cases where they were partially welded.

In such a state, no matter how well the fin bodies 13, 13 having relatively large areas receive heat, the heat transfer path in the heat medium 1 inside the tube is interrupted.
This results in poor heat exchange efficiency.

In the past, there was no problem with finned tubes like this, but nowadays, there is a growing demand for effective use of energy, and there are changes from the overall structure of heat exchangers to the details such as finned tubes. Every trench has been thoroughly examined and improvements have been requested.

This invention was devised in order to solve the above-mentioned problems, and its main purpose is to completely weld the inner part and the tube, and maintain a predetermined heat exchange efficiency. To provide a finned tube for a heat exchanger that can be used without any problems.

Another purpose of this invention is to improve equipment such as automatic resistance welding machines that have been used conventionally. To provide a fin tube for a heat exchanger that can be manufactured without the need for special equipment, equipment, or equipment, and which enables complete welding of fins and tubes.

Still another object of the present invention is to form a circular notch in the fin body constituting the fin, and an end surface that abuts against the outer circumference of the fin.
In addition to creating a continuous uneven shape, the end corner of the circular notch is cut out so that it does not touch the outer periphery of the tube, and the entire range of the circular notch and the continuous uneven part excluding the cut out part is the outer circumference of the tube. To provide a fin tube for a heat exchanger which is uniformly welded to the fin tube and which is prevented from excessive welding and welding distortion due to the presence of the cut portion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, details of an embodiment of the present invention will be explained based on the drawings, especially FIGS. 1 to 3.

As shown in FIGS. 1 and 2, a finned tube 1 for a heat exchanger according to the present invention includes a cylindrical tube 2 through which a heat medium such as water flows, and a cylindrical tube 2 through which heat of mainly high-temperature gases such as exhaust gas and steam flows. A large number of fins 3 are arranged at predetermined intervals in the longitudinal direction of the tube 2.

The fin 3 is made of a thin plate, and in this embodiment is divided into left and right halves, with a predetermined gap formed between them.

Arc-shaped notches 5, 5 corresponding to the outer diameter of the tube 2 are cut in the tube-side ends of the left and right fin bodies 4, 4.

In the present invention, this arcuate notch 5 is replaced by a continuous uneven portion 6.
and cutout portions 7, 7 on both ends thereof.

The cutout portions 7, 7 are located at the terminal corners of the arcuate notch 5, are shaped with rounded corners, and are stopped within a relatively small area.

The continuous concavo-convex portion 6 is formed over a relatively wide area except for the cut-out portions 7, 7, and in this embodiment, it is serrated and has rounded tips and bottoms. .

Of course, the shape is not limited to a sawtooth shape, and it is also possible to have a comb shape, a gear tooth shape, etc.

When modeling a continuous uneven portion 6 as shown in FIG. 3, for example, the diameter (pitch circle diameter) passing between the tooth tip and the tooth bottom (dental membrane)
If D' is made equal to the outer diameter of the tube 2, during electric resistance welding, the tip of the tooth will melt and face the bottom of the tooth, and in the final stage, the outer circumference of the tube 2 will extend over its entire range. Welded uniformly.

Of course, the curvature of the continuous concavo-convex portion 6 is not limited as described above, and can be appropriately set in consideration of the welding state of the rounded portion and the final welding finish state.

The point is that the contact area with the tube 2 is small at the beginning of welding and gradually increases, and this is done evenly at equal intervals over the entire joint surface between the tube 2 and the fin body 4. It is sufficient to set various conditions such as the shape, pitch, height, curvature, etc. of the continuous uneven portion 6 as much as possible.

In addition, in the present invention, the terminal corner of the arcuate notch 5 is cut out to form the cutout part 7.

Conventionally, as shown in FIGS. 4 and 6, this has not been done in order to increase the joint area with the tube and enhance the heat exchange effect.

However, when constructed as in the past, the same part was welded more tightly than other parts, which caused a problem in that local welding distortion occurred.

Therefore, in the present invention, as shown in FIGS. 1 and 3, this corner is cut off from the beginning to prevent it from coming into contact with the tube 2 and being welded.

In this way, although the heat transfer coefficient is slightly lowered, the above-mentioned excessive welding and local welding distortion can be completely eliminated.

The cutout portion 7 is not limited to a straight line as in this embodiment, but may be arcuate or the like.

In this embodiment, a structure in which the fin 3 is divided into two parts horizontally is described, but the present invention can also be applied to, for example, a fin 3 which is divided into four parts horizontally and vertically.

The method of division is arbitrary as long as there are two or more. Since each fin body 4 is formed by punching out a plate material by press working to form an arcuate notch 5 having continuous uneven portions 6 and cut-out portions 7, mass production is possible with great ease and accuracy.

The material of the tube 2 and the fin 3 may be general steel, special steel such as stainless steel or corrosion-resistant steel, or any other material that can be resistance welded, and can be appropriately adopted depending on the purpose.

As described above, according to the present invention, the fins and tubes are completely welded together, and a predetermined heat exchange efficiency can be achieved without interruption.

It can be manufactured using existing equipment, and there is no need to invest in new equipment, and it can be implemented immediately.

Since the arc-shaped notch in the fin body is made into a continuous uneven shape and has a cutout, the contact area with the tube gradually increases from the initial welding stage to the final welding process. This is done in each location to ensure complete melting and welding.

Therefore, after welding, the entire range of the continuous uneven portions is bonded without interruption, resulting in a good heat transfer coefficient, which brings about various effects such as significantly increasing the heat exchange efficiency.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a fin tube according to the present invention. FIG. 2 is a side view of the same part shown in longitudinal section. FIG. 3 is an enlarged front view of the main part showing the shape of the arcuate notch. FIG. 4 is a longitudinal sectional view showing the structure of a conventional fin tube. FIG. 5 is a side view of FIG. 4, partially shown in longitudinal section. FIG. 6 is a longitudinal sectional view showing the disassembled state of the fin and tube. 1... Fin tube for heat exchanger, 2...
...Tube, 3...Fin, 4...
Fin body, 5... Arc-shaped notch, 6...
・Continuous uneven portion, 7...Removed portion.

Claims (1)

[Scope of utility model registration request] It comprises a cylindrical tube 2 and an appropriate number of fins 3 arranged at appropriate intervals on the outer periphery of the tube in the longitudinal direction, and the fins 3 are divided at least left and right so that each fin body 4 has a tube abutting end. An arcuate cutout 5 is formed in the tube 2.
In the fin tube that is welded by electrical resistance welding by press-welding the fin body 4, the arc-shaped notch 5 formed in the fin body 4 is formed on one continuous concavo-convex portion 6 over a relatively wide range, and on both sides of the circular notch 5. A finned tube for a heat exchanger, characterized in that the finned tube for a heat exchanger is constituted by two relatively narrow cutout portions I obtained by cutting off the terminal corners of an arcuate cutout 5.