JPH02251311A - Manufacture of interior worked heat transfer tube - Google Patents

Abstract

PURPOSE:To continuously carry out manufacture of tube stock and inside processing thereof by inserting a rod from a part where a metallic band plate is formed in a tubular shape, holding a plug having grooves on the peripheral surface and pressuring the outer periphery of a position of the tube stock into which the plug is inserted with rollers revolving round the axis of the tube stock in the shape of a planet. CONSTITUTION:The metallic band plate 1 is formed by forming rolls 10-13 in the shape of a tube and both sides are welded by a welding means 2 to make the tube stock (a) and it is formed by squeeze rolls 14. A support arm 40 is hung from the upper part to fix the rod 4 and the plug 41 round which grooves are formed is held freely rotatably on the rod 4. A spindle 31 is provided in the housing 30 of an interior working device 3 through bearings 32, a roller holder 33 is equipped on the tip of the spindle and several rollers 34 are set in the roller holder. The spindle 31 is rotated by a belt 35, each roller 34 is revolved in the shape of a planet, the tube stock (a) is pressurized by the rollers 34 to the plug 41 to continuously manufacture the heat transfer tube C having grooves C1 on the inside surface.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method of manufacturing an internally processed heat exchanger tube having grooves in a certain direction on the inside thereof.

"Prior art" This type of heat exchanger tube manufacturing method includes, for example, Japanese Patent Application Laid-Open No. 54-37
As disclosed in Publication No. 059, while applying axial feed to the raw pipe by drawing, a plug having a predetermined groove is inserted into the raw pipe prior to the drawing, and the outer periphery of the raw pipe is A method of compressing using a plurality of planetary rotating rollers has been proposed.

In addition, 1, for example, as disclosed in JP-A No. 55-43360, a metal strip of a constant width is continuously fed out, and the metal strip is sandwiched between a grooved roll and a rolling roll. There is a method in which grooves are formed on the surface of the metal strip, the grooves are formed on the inner surface, the metal strip is formed into a tubular shape using a group of forming rolls, and the opposing sides are welded.

"Problem to be solved by the invention" Recently, due to the demand for smaller and lighter heat exchangers, even for heat exchanger tubes with internal processing, small diameter tubes with an outer diameter of 10 mm or less and a wall thickness of 0.31 mm or less are required. There is a demand for thin-walled tubes, but when manufacturing such thin-walled and small-diameter heat transfer tubes using the former method among the conventional manufacturing methods described above, it is necessary to draw a large-diameter, thick-walled tube many times to reduce the small-diameter and thin-walled tubes. The problem is that the manufacturing cost of the raw tube increases. In addition, according to this method, since the tube is pulled out while reducing the diameter and making grooves in the tube at the same time, the pulling force increases significantly.
When manufacturing small-diameter, thin-walled heat transfer tubes, the tubes tend to break, and it is difficult to form deep and sharp grooves.

On the other hand, when using the latter of the conventional methods, there is no problem as described above, but the grooves on the inner surface become discontinuous due to the beats that occur in the welded part, which tends to cause directionality in the heat transfer performance of the heat transfer tube. When incorporating it into an exchanger, it becomes necessary to consider this directionality. Furthermore, when assembling a heat exchanger tube into a heat exchanger, the relevant part of the heat exchanger tube is expanded through a hole in the tube sheet and fixed to the tube sheet, but during this tube expansion, the beats peel off and the metal powder is inside the tube. Attach to. Furthermore, this manufacturing method has a problem in that when the grooves or protrusions are formed and then formed into a tubular shape by a group of forming rolls, the grooves or protrusions on the surface may be crushed or deformed due to the pressure of the forming rolls.

An object of the present invention is to provide a method for manufacturing an internally processed heat exchanger tube that eliminates the above-mentioned problems.

"Means for Solving the Problem" In order to achieve the above object, one of the methods of the present invention is to form a continuously fed metal strip into a tubular shape, and then weld the opposing sides to produce a blank pipe. A rod is inserted into the raw pipe from the part where the metal band plate is being formed into a tubular shape, and a plug having a predetermined groove on the circumferential surface is held in the part of the rod located in the raw pipe, and the rod is formed into a tubular shape. While moving the tube in the same direction as the feeding direction of the metal strip, the outer periphery of the plug insertion position of the blank tube is pressurized by several rollers or balls that rotate planetarily around the axis of the blank tube. It was adopted.

In addition, in order to achieve the above-mentioned object, another method of the present invention is to form a continuously fed metal strip into a tubular shape, and then weld both sides of the metal strip to produce a blank pipe. While moving the raw tube in the same direction as the feeding direction of the metal strip,
The metal strip is passed through a die to reduce its diameter, and a rod is inserted into the reduced-diameter tube from the portion where the metal strip is being formed into a tubular shape, and a predetermined groove is formed on the circumferential surface of the portion of the rod located within the reduced-diameter tube. A structure is adopted in which the plug is held and the outer periphery of the diameter-reduced tube at the plug insertion position is pressed by several rollers or balls that rotate planetarily around the axis of the tube.

When the groove of the plug is formed in a spiral shape with respect to the central axis, the plug is rotatably held on the rod.

``Function'' In the process of manufacturing raw pipes, by selecting metal strips with the desired wall thickness and width, raw pipes with the desired wall thickness and diameter can be easily and continuously manufactured, making it easy to manufacture raw pipes and process the inner surface. By continuing the above steps, the work of supplying raw tubes can be omitted.

"Example" Hereinafter, preferred embodiments of the method of the present invention will be explained with reference to the drawings.

From an uncoiler (not shown), metal strips l made of copper, aluminum, alloys thereof, or other metals are continuously fed out in a constant direction at a constant speed as shown in FIG. 1 by appropriate means.

In this example, a metal strip 1 made of copper with a wall thickness of 0.3 mm and a width of 2 B mm is fed out at a speed of 50 m/7 minutes, and a metal strip 1 is rolled by forming roll groups 10 to 13.
is rolled in the width direction and gradually formed into a tubular shape, and the butted sides are welded using a welding induction coil, TIG, or other suitable welding means 2 to form a continuous raw tube a with an outer diameter of approximately 9 mm. The blank tube a is continuously manufactured and shaped by squeeze rolls 14, 14, and continuously supplied to the next inner surface processing device 3.

A support arm 40 is suspended from above at a suitable position in the region where the metal band plate 1 is to be formed into a tubular shape, and a rod 4 to be inserted into the inside of the raw pipe a manufactured as described above is fixed to this support arm 40. Along with that.

As shown in FIG. 2, a plug 41 having a groove formed on its circumferential surface is rotatably held in the rod 4 so as to be located inside the portion of the raw pipe a that reaches the inner surface processing device 3.

Before supplying the raw tube a to the inner surface processing device 3, it is preferable that the beats on the outer surface caused by welding are removed using a beat cutter 5, and that it is cooled to room temperature by passing through a suitable cooling device 6.

As shown in FIG. 2, the inner surface processing device R3 includes a housing 30.
A spindle 31 is provided inside via a bearing ring 32, and a roller holder 33 is attached to the tip of the spindle 31. Attach the opening to the rear 34.

The spindle 31 is rotated in a fixed direction via a belt 35 by a drive device (not shown), and each roller 34 is rotated planetarily around the axis of the raw tube a, and the rollers 34 move the raw tube a to the inner plug 41. is applied, and the raw tube a is pulled and moved in the same direction as the feeding direction of the metal strip l, thereby continuously manufacturing a heat exchanger tube C having grooves cl on the inner surface.

This heat exchanger tube C is passed through a forming die (preferably provided continuously in the inner surface processing device 3), not shown, to adjust the outer diameter.
Outer diameter 7.94mm, wall thickness at the bottom of cl groove 0.2mm
Finish it into a heat transfer tube and wind it into a coil or cut it to an appropriate size.

FIG. 3 shows an example of an inner surface processing device for explaining another embodiment of the method of the present invention, which is located at the front of the housing 30 and in front of the grooved plug 41 and the roller 34. A die holder 36 is provided, and the die 37 for empty drawing is held in the die holder 36, and the raw tube a manufactured in the same manner as described above and continuously supplied is passed through the die 37 and is compressed. After manufacturing a diameter-reduced tube, the inner surface of the diameter-reduced tube is processed using a plug 41 and a roller 34 to manufacture a heat exchanger tube C having a groove c1 on the inner surface.

The other configurations of this manufacturing method are the same as the example explained in FIG. 2, so the explanation will be omitted.

In each manufacturing method according to the present invention, as shown in FIG.
By fixing a ball holder 38 to the spindle 31 instead of the roller 34, holding a plurality of freely rotating balls 39 in the holder 38, and rotating the spindle 31 in a fixed direction in the same manner as in each of the above methods, ball 3
It can also be implemented by configuring the blank pipe a or the diameter-reduced pipe to pressurize the grooved plug 41 while rotating the pipe 9 planetarily.

In each of the above embodiments, the plug 41 is connected to the rod 4.
However, if the groove on the surface of the plug 41 is a straight line parallel to its central axis, the plug 41
It can also be implemented by fixing it to the rod 4.

Furthermore, in each of the above methods, grooved plugs 41 are provided at two locations in the front and rear in the drawing direction, and rollers 34 or balls 39 are provided at two locations in the front and back corresponding to the respective plugs,
It is also possible to press the blank pipe or the diameter-reduced pipe to the plug using these rollers or balls.

"Effects of the Invention" The method for manufacturing an internally processed heat exchanger tube according to the present invention does not require drawing at the stage of manufacturing the raw tube, so the drawing force is reduced and a thinner heat exchanger tube with a smaller diameter can be easily manufactured. , the rod of the plug is passed from the forming part of the metal strip into the raw tube or diameter-reduced tube that is being manufactured, so that the raw tube manufacturing and the inner surface processing are continuous, and the raw tube supply is continuous at the same time as the raw tube manufacturing. This eliminates the need for repeating the supply of raw tubes, thereby further reducing manufacturing costs.

Furthermore, since the grooves or protrusions are processed after the raw pipe is formed, the grooves or protrusions are not crushed or deformed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of an apparatus for the manufacturing process of a blank pipe in the method of the present invention, FIG. 2 is a sectional view showing an example of an apparatus for the inner surface processing process, and FIG. FIG. 4 is a sectional view illustrating an example of an apparatus for the inner surface processing process, and FIG. 4 is a partial sectional view illustrating another apparatus for carrying out each manufacturing method according to the present invention. Explanation of main symbols in the figure 1 is a metal strip, 10 to 13 are forming roll groups, 2 is a welding means, 3 is an inner surface processing device, 31 is a spindle 33 is a roller holder, 34 is a roller, 38 is a ball holder, 3
9 is a ball, 4 is a rod 40 is a support arm, 5 is a beat cutter, a is a blank tube, b is a reduced diameter tube, C is a heat exchanger tube, and C is a groove or protrusion on the inner surface. Patent applicant agent Patent attorney Shigeru Kawano Daido
Patent Attorney Kama 1) Hisao l is a heat exchanger tube.

Claims (3)

[Claims] (1) After forming a metal strip that is continuously fed out into a tubular shape, welding the abutted sides on both sides to produce a blank pipe, and starting from the part where the metal strip is being formed into a tubular shape, inside the blank pipe. A rod is inserted into the base tube, a plug having a predetermined groove on the circumferential surface is held in the part of the rod located inside the base pipe, and while the base pipe is moved in the same direction as the direction in which the metal strip is fed out, A method for producing an internally processed heat exchanger tube, which comprises pressurizing the outer periphery of a raw tube at a plug insertion position using several rollers or balls that rotate planetarily around the axis of the raw tube. (2) After forming the metal strip that is continuously fed out into a tubular shape, welding the butted sides together to produce a blank tube, and moving this blank tube in the same direction as the feeding direction of the metal strip. while passing through a die to reduce the diameter, and inserting a rod into the reduced diameter tube from the part where the metal band plate is being formed into a tubular shape,
A plug having a predetermined groove on the circumferential surface is held in the portion of the rod located inside the diameter-reducing tube, and the outer periphery of the plug insertion position of the diameter-reducing tube is covered with several plugs that rotate planetarily around the axis of the tube. A method for manufacturing an internally processed heat exchanger tube, characterized by applying pressure using rollers or balls. (3) The method for manufacturing an internally processed heat exchanger tube according to claim 1 or 2, wherein the plug is rotatably held by the rod, and a groove on the circumferential surface of the plug is formed in a spiral shape.