JPH1052714A - Heat transfer tube with groove on inner surface and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat transfer tube with grooves on the inner surface acting uniform tube expanding force in the peripheral direction at the time of expanding the tube by positioning the top parts of projecting lines and the inner surface side top parts of welded bead part on a virtual complete roudness. SOLUTION: At the time of welding a flat plate stock 1' formed as groove patterns to a tube state in the welded part to manufacture the heat transfer tube with the grooves in the inner surface, the bead is formed at the joined part. The bead on the outer peripheral part is cut off in a following work but the bead on the inner peripheral part remains because of the impossibility of working. Since the remaining bead is formed on the pre-formed build-up welded part 13, on the inner surface side of the weld-joined part in the heat conduction tube with the grooves in the inner surface, the top parts of the projecting lines 11, 11... and the inner surface side top part of the welded based part are position on the virtual complete roudness. In order to form the welded bead part having such shape, it is necessary to set so that the difference (h) between the projecting line 11 and the height of the build-up part 13 is equalized to the bead thickness at the time of welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer tube having an inner groove and a method for manufacturing the same.

[0002]

2. Description of the Related Art For the purpose of improving the heat transfer coefficient on the inner surface side of a heat transfer tube used in a cross fin coil type heat exchanger for an air conditioner, a number of convexes are formed on the inner surface. An inner grooved heat transfer tube having a groove formed between strips has been developed.

[0003] As a method for manufacturing the above-mentioned heat transfer tube with an inner groove, a longitudinal end of a plate-like material having a large number of ridges formed on one side is welded with the surface having the ridges formed inside. The method has been well known (for example, see Japanese Patent Publication No. 2-48350).

[0004]

When a cross fin coil type heat exchanger is manufactured, a method of mechanically expanding the heat transfer tube is often employed in order to bring the fin and the heat transfer tube into close contact.

[0005] This pipe expansion is performed by pushing a pipe expansion head into the heat transfer pipe to apply a uniform force in the centrifugal direction. In such a case, the following problems may occur.

That is, when a welded tube is used as the heat transfer tube, as shown in FIG. 7, the height of the weld bead portion 14 is lower than the height of the ridges 11, 11,. The pipe expanding force of the welding head hardly acts on the weld bead portion 14. As a result, the heat transfer tube after the expansion has a ridge 1
Although the portion where 1, 11,... Are formed is sufficiently expanded, the expansion of the weld bead portion 14 becomes insufficient and the heat transfer tube becomes flat. Then, the adhesion between the heat transfer tube 1 and the fins F is insufficient at the portion, and in an extreme case, there is a possibility that a gap S may be generated, and heat transfer from the heat transfer tube 1 to the fins F is hindered. It greatly affects the performance of the heat exchanger.

[0007] In order to eliminate the above problems,
It is conceivable to increase the tube expanding force. In this case, however, a problem may occur in which the ridge is deformed when the ridge is high or the ridge has a sharp top.

The present invention has been made in view of the above points, and has as its object to provide an internally grooved heat transfer tube in which a pipe expanding force can uniformly act in a circumferential direction.

[0009]

According to a first basic configuration of the present invention, as a means for solving the above-mentioned problems, a flat material 1 'having a large number of ridges 11, 11 on one surface side is provided. Are welded with their longitudinal ends welded with the surface on which the ridges 11, 11... Are formed inward, and the top of the ridges 11, 11,. 14 is positioned on the virtual perfect circle P so that a uniform pipe expanding force can be applied in the circumferential direction when the pipe is expanded.

In the first basic configuration of the present invention, if the heights of the ridges 11, 11,... And the weld bead portion 14 are the same, the ridges 11, 11,.
Is preferred in that the formation of.

The height of the ridges 11, 11,...
When the height of the weld bead portion 14 is set so as to gradually increase toward the portion facing the weld bead portion 14 with reference to the inner surface height of the weld bead portion 14, the shape of the weld bead portion 14 can be made conventional. Is preferred.

In the second basic configuration of the present invention, as a means for solving the above-mentioned problems, a pattern forming step of forming a large number of ridges 11, 11,... The longitudinal ends of the flat material 1 ′ are
And a welding step of welding with the surface on which 11... Are formed inward, and sequentially performing a welding process.
In the pattern forming step, the cladding portions 13 extending in the longitudinal direction and slightly lower than the ridges 11, 11,... Later, the height of the weld bead portion 14 is made equal to the height of the ridges 11, 11,.
By simply adding the simple step of forming the pipe 3, a heat transfer tube with an inner surface groove capable of applying a uniform expanding force in the circumferential direction at the time of expanding the tube can be obtained.

According to a third basic structure of the present invention, as a means for solving the above-mentioned problems, a pattern forming step of forming a large number of ridges 11, 11,... The longitudinal ends of the flat material 1 ′ are
And a welding step of welding with the surface on which 11... Are formed inward, and sequentially performing a welding process.
In the pattern forming step, the heights of the ridges 11 are formed so as to gradually increase from both longitudinal ends of the flat material 1 'toward the center in the width direction, and after the welding step. A simple process of making the tops of the ridges 11, 11,... And the inner side top of the weld bead portion 14 positioned on the virtual perfect circle P, and devising the height of the ridges 11, 11,. By simply adding, an inner grooved heat transfer tube capable of exerting a uniform expanding force in the circumferential direction at the time of expanding the tube is obtained.

According to a fourth basic structure of the present invention, as a means for solving the above-mentioned problems, a pattern forming step of forming a number of ridges 11, 11,... The longitudinal ends of the flat material 1 ′ are
And a welding step of welding with the surface on which 11... Are formed inward, and sequentially performing a welding process.
By adjusting the pressure at which the longitudinal ends of the flat material 1 'are butted in the welding step, the ridges 11, 11 are adjusted.
.. only the simple step of adjusting the abutting force during welding so that the top of the welding bead 14 and the inner side top of the welding bead portion 14 are positioned on the virtual perfect circle P,
An inner grooved heat transfer tube capable of exerting a uniform expanding force in the circumferential direction at the time of expanding the tube is obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

First Embodiment FIGS. 1 to 4 show a method of manufacturing an inner grooved heat transfer tube according to a first embodiment of the present invention and an inner grooved heat transfer tube manufactured by the manufacturing method. It is shown.

This heat transfer tube with an inner groove is manufactured by using a welding pipe forming apparatus as shown in FIG.

The welding pipe forming apparatus comprises a pattern forming section 2 for forming a groove pattern composed of a large number of ridges on one surface of a metal flat plate material 1 'having a predetermined width, and supplying the flat plate material 1'. And a feed adjusting portion 3 for smoothing the plate-shaped material 1 ′ and a tube having a slit-shaped seam in the longitudinal direction with the surface on which the groove pattern is formed in the pattern forming portion 2 inside. And a welder section 5 that performs electric resistance welding while pressing both edges of the joint formed into a tubular shape in the forming section 4 with a squeeze roll 6. ing. It should be noted that the illustration of the process sections after the welder section 5 (for example, the heating softening section and the cutting section) is omitted.

In this embodiment, as shown in FIGS. 2 and 3, the groove pattern formed in the pattern forming section 2 has a large number of convex portions having a predetermined inclination angle with respect to the longitudinal direction. Articles 11 and 11 and these ridges 1
A large number of concave grooves 12, 12, ... formed between 1, 11, ...
And a built-up portion 13 formed on a groove-shaped molding surface at both longitudinal ends of the flat plate-shaped material 1 ′ and having a predetermined dimension h smaller than the ridges 11.

When the flat material 1 'having the groove pattern as described above is tubularly welded at the welder portion 5 to manufacture the heat transfer tube 1 with the inner surface groove, a bead is formed at the joint.
And the bead on the outer peripheral side is cut off by post-processing,
The inner bead is left as it cannot be machined.
As shown in FIG. 4, the remaining bead is formed on the built-up portion 13 formed in advance, and on the inner surface side of the welded joint 1 a in the inner grooved heat transfer tube 1, as shown in FIG.
The weld bead portions 14 having the same height as 1, 11,... Are formed. That is, the tops of the ridges 11, 11,... And the top on the inner surface side of the weld bead portion 14 are positioned on the imaginary perfect circle P. In order to form the weld bead portion 14 having such a shape, it is necessary to set the height difference h between the ridge 11 and the build-up portion 13 to be the same as the thickness of the bead formed at the time of welding. Of course.

When a heat exchanger of the cross fin coil type is manufactured using the heat transfer tube 1 with the inner surface groove obtained as described above, the expanding force of the expanding head is located on the imaginary perfect circle P. , 11 and... And the weld bead portion 14. Therefore, the inner grooved heat transfer tubes 1 are uniformly expanded, and good adhesion to the fins can be secured.

Second Embodiment FIG. 5 shows a cross section of a heat transfer tube with an inner surface groove according to a second embodiment of the present invention.

In this case, the flat material 1 'includes
Only the grooves 1, 12,... And the concave grooves 12, 12,... Are not formed, but the overlay portion 13 in the first embodiment is not formed. The height of the ridges 11, 11,... Is set so as to gradually increase toward the portion facing the weld bead portion 14 with reference to the inner surface side height of the weld bead portion 14. In this manner, the top of the weld bead 14 and the top of the ridges 11, 11,... Are located on the virtual perfect circle P slightly eccentric from the center of the inner grooved heat transfer tube 1 toward the weld bead 14. Becomes As shown in FIG. 6, the height of the ridge 11 at the longitudinal ends of the flat material 1 'is the same as the height of the weld bead portion 14, and the height increases from the ends toward the center in the width direction. Is formed to be high.

When a heat exchanger of the cross fin coil type is manufactured using the heat transfer tube 1 with the inner surface groove obtained as described above, the expanding force of the expanding head is located on the imaginary perfect circle P. , 11 and... And the weld bead portion 14. Therefore, the inner grooved heat transfer tubes 1 are uniformly expanded, and good adhesion to the fins can be secured.

Third Embodiment In this case, at the time of welding, the height of the weld bead portion 14 is adjusted by adjusting the butting force for abutting the longitudinal ends of the flat plate-shaped material 1 '. The height is set to be the same. The adjustment of the butting force is performed by the squeeze roll 6 in the welding pipe forming apparatus.
By doing so, the top of the weld bead portion 14 and the tops of the ridges 11, 11,... Are located on the imaginary perfect circle P only by adjusting the butting force.

In each of the above embodiments, an example is described in which the ridges and grooves are continuous in the longitudinal direction.
The shapes of the ridges and grooves are not limited to these, but may be various shapes.

[0027]

According to the heat transfer tube with an inner groove of the present invention, the longitudinal ends of a flat material 1 'having a large number of ridges 11, 11,... Formed on one side are connected to the ridges 11, 11,. In the heat transfer tube with an inner groove formed by welding with the surface on which is formed inward, the tops of the ridges 11, 11,... And the inner side top of the weld bead portion 14 are on a virtual perfect circle P. , It is possible to exert a uniform pipe expanding force in the circumferential direction at the time of expanding the pipe, and there is an excellent effect that the heat transfer pipe is optimally used for a cross-fin coil type heat exchanger.

According to the method of manufacturing a heat transfer tube with an inner surface groove according to the present invention, a large number of ridges 11, 11 are provided on one surface side of the flat material 1 '.
.. and a welding step of sequentially welding longitudinal ends of the flat material 1 'with the surfaces on which the ridges 11, 11,... Are formed inward. In the method of manufacturing a heat transfer tube, in the pattern forming step, the cladding portions 13 extending in the longitudinal direction and slightly lower than the protruding strips 11, 11,... After the welding step, the height of the weld bead portion 14 is the same as the height of the ridges 11, 11,... Or in the pattern forming step, the height of the ridges 11, 11,. Are formed so as to gradually increase from both longitudinal ends of the flat material 1 ′ toward the center in the width direction, and after the welding process, the tops of the ridges 11, 11. Inner surface top is on virtual perfect circle P It said By so caused to position, or to adjust the pressure to match the longitudinal ends of the flat material 1 'in the welding process ridges 1
Since the tops of 1, 11,... And the top on the inner surface side of the weld bead portion 14 are positioned on the virtual perfect circle P, a simple process of forming the overlay 13 is added.
Alternatively, a simple step of devising the height of the ridges 11, 11... Or a simple step of adjusting the butting force at the time of welding is added, so that a uniform process is achieved in the circumferential direction during pipe expansion. There is an excellent effect that an inner grooved heat transfer tube capable of exerting a pipe expanding force can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a welded pipe forming apparatus used for manufacturing a heat transfer tube with an inner surface groove according to an embodiment of the present invention.

FIG. 2 is a partial plan view of the flat material in the course of manufacturing the heat transfer tube with internal grooves according to the first embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a cross-sectional view of an inner grooved heat transfer tube manufactured by the method for manufacturing an inner grooved heat transfer tube according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of an inner grooved heat transfer tube manufactured by a method for manufacturing an inner grooved heat transfer tube according to a second embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view of a ridge portion of a flat plate material after a groove pattern is formed in a method of manufacturing an internally grooved heat transfer tube according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of a conventional heat transfer tube with internal grooves.

[Description of Signs] 1 is a heat transfer tube with an inner groove, 1 'is a flat plate material, 11 is a ridge,
12 is a concave groove, 13 is a built-up portion, 14 is a weld bead portion, and P is a virtual perfect circle.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B23K 9/025 B23K 9/025 A 9/04 9348-4E 9/04 H F28F 1/40 F28F 1 / 40 D

Claims (6)

[Claims] 1. A plurality of ridges (11), (11) on one surface side.
.. An inner grooved transmission formed by welding both longitudinal ends of the plate-shaped material (1 ') formed with the ridges (11), (11). A heat tube,
An inner grooved heat transfer tube characterized in that the tops of the ridges (11), (11)... And the inner side top of the weld bead (14) are positioned on a virtual perfect circle (P). . 2. The heat transfer tube with an inner surface groove according to claim 1, wherein the heights of the ridges (11), (11)... And the weld bead portion (14) are the same. 3. The height of the ridges (11), (11)... Is directed to a portion facing the weld bead portion (14) with reference to the inner surface height of the weld bead portion (14). 2. The heat transfer tube with an inner surface groove according to claim 1, wherein the heat transfer tube is set so as to sequentially increase in height. 4. A pattern forming step of forming a large number of ridges (11) on one surface side of a flat material (1 ');
The two longitudinal ends of the flat material (1 ') are connected to the ridges (1').
1), (11)... A welding step of welding with the surface on which the (11)... Are formed inward, and a welding step of sequentially performing the welding. ) Are formed in advance on the groove-shaped molding surfaces at both ends in the longitudinal direction and are slightly lower than the ridges (11), (11)... After the welding process. (14) The height of the ridges (11), (11)
.. A method for manufacturing an inner grooved heat transfer tube, wherein the height of the heat transfer tube is the same as the height of the heat transfer tube. 5. A pattern forming step of forming a large number of ridges (11) on one surface side of a flat material (1 ');
The two longitudinal ends of the flat material (1 ') are connected to the ridges (1').
1), a welding step of welding with the surface on which (11)... Are formed inside, and a welding step of sequentially welding the inner grooved heat transfer tube, wherein in the pattern forming step, each of the ridges (1) is formed.
1), (11)... The height of the flat material (1 ')
Are formed so as to gradually increase from both longitudinal ends toward the center in the width direction, and after the welding process, the tops of the ridges (11), (11)... And the weld bead portion (14).
Characterized in that the top of the inner surface is positioned on a virtual perfect circle (P). 6. A pattern forming step of forming a number of ridges (11) on one surface side of a flat material (1 ');
The two longitudinal ends of the flat material (1 ') are connected to the ridges (1').
1), (11) ... a method of manufacturing a heat transfer tube with an inner surface groove, in which a welding process is performed in which the surface on which the formed surface is formed is inward. By adjusting the pressure at which the longitudinal ends are abutted, the tops of the ridges (11), (11).
(4) The method for manufacturing a heat transfer tube with an inner surface groove, wherein the inner side top portion and the inner surface side top are positioned on a virtual perfect circle (P).