JPH0335832A - Manufacture of metallic tube having internal and external fins - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method of manufacturing a metal tube with internal and external fins used in a heat exchanger.

PRIOR ART AND PRIOR ART PROBLEM TO BE SOLVED BY THE INVENTION It is widely known that a metal tube with external fins, in which spiral fins are integrally formed on the outer peripheral surface by rolling, is used in a heat exchanger. BACKGROUND Metal pipes have conventionally been manufactured by inserting a mandrel for preventing pipe deformation into the metal pipe and rolling the outer circumferential surface of the metal pipe.

However, in order to further improve the heat exchange performance of the heat exchanger, grooves are formed on the inner surface of the external finned metal tube.
It is considered to increase the heat transfer area. Since it is impossible to form grooves on the inner surface of a metal tube with external fins after forming spiral fins, grooves are formed in the raw tube and rolling processing is performed on the outer peripheral surface of this tube. to form a spiral fin.

However, this method has the problem that the grooves are crushed by the external pressure applied to the raw tube during the rolling process, and when this is used in a heat exchanger, the expected heat exchange performance cannot be obtained.

An object of the present invention is to provide a method for manufacturing a metal tube having both inner and outer fins, which solves the above-mentioned problems.

Means for Solving the Problems The method for manufacturing a metal tube with inner and outer fins according to the present invention provides an interior having three or more radial walls that are formed integrally with each other and whose tips are brought into close contact with the inner surface of the metal tube. A method for manufacturing a metal tube in which fins are provided and spiral fins are integrally formed on the outer peripheral surface by rolling, the method comprising three or more radial walls integrally formed within the metal tube. In this state, the outer circumferential surface of the metal tube is rolled to form a spiral fin, and the metal tube is deformed radially inward to form inner fins on its inner surface and radial wall. This is characterized by the fact that the inner fin material is fixed to the base pipe by bringing the tip into close contact with the inner fin material.

Example Embodiments of the invention will be described below with reference to the drawings.

In the following explanation, the word "aluminum" refers to
In addition to pure aluminum, aluminum alloys are included.

FIG. 4 shows an aluminum tube with internal and external fins manufactured by the method of the present invention. An internal fin (2) having three or more radial walls (2a) integrally formed with each other is provided inside the internal and external finned aluminum tube (1). Spiral fins (3) are integrally formed on the outer peripheral surface of the aluminum tube (1) by rolling.

The radial wall (2a) of the internal fin (2) is integrally formed with a cylindrical base (2b) located on the axis of the aluminum tube (1), and its tip end is connected to the aluminum tube (1).
) Close to the inner world.

The above-mentioned inner and outer finned aluminum tube (1) is manufactured as follows.

First, an aluminum tube (11) as shown in Figure 1
and an internal fin material (12) made of an extruded aluminum material in which three or more radial walls (12a) are integrally formed on a cylindrical base (12b) as shown in FIG. Material (12) is made of aluminum tube (1
1) Insert it inside. Thereafter, as shown in FIG. 3, the outer circumferential surface of the raw tube (11) is rolled using a rolling round die (13) to form spiral fins (3). At this time, the raw pipe (11) is deformed radially inward by the external pressure, and its inner surface and the radial wall (1
The tips of 2a) are brought into close contact with each other, and the internal fin material (12) is fixed to the raw tube <lI). In this way, an aluminum tube (1) with internal and external fins is manufactured.

In the above, a groove may be formed in the inner circumferential surface of the aluminum tube (11) to increase the heat transfer area. In this case, the grooves are not crushed even when the spiral fins (3) are formed by rolling, and the effect of increasing the heat transfer area due to the presence of the grooves is maintained. In addition, in the above, the metal tube (11) and the internal fin material (12)
Although a material made of aluminum is used as a material, it is not limited to this.

Effects of the Invention According to the method of the present invention, when forming the external spiral fin by rolling, the internal fin material is fixed to the metal tube, so both the internal and external fins can be formed in one process. You can do it and it will make your work easier. Furthermore, since a mandrel for rolling is not required, equipment costs are reduced.

In addition, since the internal and external finned metal tubes manufactured by the method of the present invention have an increased internal heat transfer area due to the presence of internal fins, when this is used in a heat exchanger, the heat exchanger's heat exchange Performance is dramatically improved compared to conventional external spiral finned metal tubes.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a perspective view of a metal tube used in carrying out the method of the present invention, Fig. 2 is a perspective view of an internal fin material used in carrying out the method of this invention, and Fig. 3 is a perspective view of the internal fin material. FIG. 4 is a perspective view showing a state in which a fin material is inserted into a blank pipe and then subjected to a rolling process. FIG. 4 is a perspective view of a metal pipe with inner and outer fins manufactured by the method of the present invention. (1)...Aluminum tube with inner and outer fins, (2>・
... Internal fin, (2a) ... Radial wall, (3) ...
・Spiral fin, (II)...Aluminum tube, (12>...Internal fin material, (12a)...
radial wall. that's all

Claims (1)

[Claims] Internal fins having three or more radial walls that are integrally formed with each other and whose tips are brought into close contact with the inner surface of the metal tube are provided inside, and a spiral fin is integrally formed on the outer peripheral surface by rolling. A method of manufacturing a metal tube, which involves inserting an internal fin material having three or more integrally formed radial walls into a metal tube, and rolling the outer peripheral surface of the metal tube in this state. is applied to form a spiral fin, and the metal tube is deformed radially inward to bring the inner surface of the tube into close contact with the tip of the radial wall, thereby fixing the internal fin material to the tube. Method for manufacturing finned metal tubes.