JPH04319019A - Manufacture of heat transfer tube having inside grooves - Google Patents

Abstract

PURPOSE:To simultaneously manufacture plural tubes having inside grooves by grooving a metallic plate bar with a rolling method, forming it in the shape of a tube, welding both edges and making the directions of groove leads same. CONSTITUTION:Grooving is performed to a soft copper plate here, etc., by grooved rolls 3a, 3b at the same time so that the grooves provided on the front surface and rear are symmetrical horizontally about the center viewing from one plane direction of a metallic bar such as a soft copper plate bar, the metallic bar is cut and separated at the centerof the boundary having grooves different in the direction. After the separated metallic bars are formed in a tubular form so that the grooves-formed surface comes to the inner side, the butted surfaces of the tubular material are joined. In this way, a tube having an inside grooves excellent in dimentional accuracy can be manufactured efficiently.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a process in which an internally grooved tube used in a heat exchanger such as an air conditioner or a refrigerator is grooved on a metal plate strip using a roll forming method, and then formed into a tube shape and welded. , relates to a method for simultaneously manufacturing a plurality of internally grooved tubes having groove leads in the same direction.

0002

[Prior Art] Various methods have been proposed for producing internally grooved tubes with lead angles from metal sheet strips. A thrust force acts in a direction perpendicular to the groove, causing lateral displacement of the metal strip during grooving. In order to solve this problem, in Japanese Unexamined Patent Publication No. 2-108411, grooves are formed on one side of a metal strip at the same time in opposite directions across the longitudinal centerline, and A method has been proposed in which a plurality of internally grooved tubes are simultaneously manufactured by cutting along the center line, forming the tube into a tube shape, and welding the tube.

0003

[Problems to be Solved by the Invention] However, although the above-mentioned conventional method can prevent the metal strip from shifting laterally during the grooving process, the internally grooved tube obtained by this method always has the leads in opposite directions. The problem was that they were manufactured in the same number. The present invention has been made in view of the above-mentioned problems of the prior art, and is intended to prevent lateral displacement of a metal strip when grooving the metal strip with a groove roll, and to prevent inner surfaces having the same lead direction. It is an object of the present invention to provide a method for manufacturing a plurality of grooved tubes at the same time.

0004

SUMMARY OF THE INVENTION The above object is achieved by a method for manufacturing an internally grooved heat exchanger tube as set forth in the claims. That is, a groove formed on the front surface and a groove formed on the back surface of a metal strip such as a soft copper plate strip when viewed from one plane direction from the front and back surfaces of the metal strip using a grooved roll having a lead angle. Grooving was performed at the same time so that the left and right sides were symmetrical, and then the grooved metal strip was cut and separated from the center of the boundary between the grooves in different directions when viewed from one plane. An inner surface that simultaneously manufactures a plurality of inner-grooved tubes with the same groove direction by forming a metal strip into a tube shape with the groove forming surface facing the inner surface and joining the abutting surfaces of the formed tubes. This is a method for manufacturing a grooved heat exchanger tube.

In the above method, the number of internally grooved tubes to be manufactured at the same time is an even number of 2×n (n: an integer of 2 or more) or an odd number of 3 or more. Furthermore, in the above method, in-line or in a separate process, a step is created in the metal strip that is larger than the average wall thickness after completion of the grooved tube to be manufactured and less than the groove depth. This is a method for manufacturing an internally grooved heat exchanger tube in which steps are formed in advance on the front and back sides of the strips so that they are formed alternately on the front and back sides.

[0006]

[Example] Figures 1 to 5 show examples of the present invention. Figure 1 is an overall perspective view of an apparatus for manufacturing an internally grooved heat exchanger tube based on the present invention, and Figure 2 is an arrow indicated by the arrows a and a in Figure 1. A cross-sectional view, FIG. 3 is a partial perspective view of the grooved roll and slitter when simultaneously manufacturing four internally grooved tubes with the same groove direction, and FIG. 4 is a cross-sectional view of a stepped metal strip. FIG. 5 is a front view of a stepped roll that performs stepped processing. Each figure except FIG. 3 shows the case where two inner grooved tubes having the same groove direction are manufactured at the same time.

1 to 5, 1 is an unprocessed metal strip such as soft copper, 2 is a payoff reel, 3a and 3b are rolls with half grooves on one side, 4 is a grooved metal strip, 5 is a slitter, 6a and 6b are metal strips cut in half, 7 is a roll former, 8a and 8b are tubular bodies, 9 is a welding machine, 10a and 10b are internally grooved tubes with groove leads in the same direction, and 11 is a stepped tube. The processed metal strips 12a and 12b are stepped rolls.

First, the specific content of the present invention will be explained based on FIG. ■ Metal strip 1 made of soft copper etc. is placed on payoff reel 2
Let it roll out. ■ The strip 1 is attached to a half-grooved reel 3a on one side.
, 3b, and grooves are formed on each half of the front and back sides of the strip 1 across the center line. ■ The center line of the grooved metal strip 4 is cut in half in the longitudinal direction using a slitter 5. (2) The halved metal strips 6a and 6b are formed into a tubular shape using a roll former 7 with the grooved surface facing the inner surface. ■ The abutting surfaces of the molded tubular bodies 8a and 8b are welded using a welding machine 9 such as a high-frequency induction heating machine to form an inner grooved tube 10a with the leads in the same direction.
, 10b are obtained. In this case, the welding is resistance welding or TI
It may be performed by a method such as G welding. ■ After this, annealing is performed continuously or off-line as necessary.

FIG. 1 shows a method for manufacturing two internally grooved tubes at the same time, but by configuring the apparatus as shown in FIG. 3, it is possible to simultaneously manufacture 2×n internally grooved tubes. becomes possible.

[0010] In the method based on the present invention, when an odd number of three or more metal strips are manufactured at the same time, measures are taken such as forcibly restraining the lateral deviation of the metal strip during grooving by applying tension or the like. This makes it possible to manufacture an odd number of pieces.

In order to further facilitate the production of internally grooved tubes by the above method, as shown in FIG. In order to form large steps smaller than the groove depth alternately on the front and back sides of the metal strip, it is preferable to carry out the step processing in one pass or two passes using a step roll as shown in FIG. 5.

In this case, if the step is less than the average wall thickness of the grooved tube to be manufactured, the metal of the metal strip will not completely enter the groove of the roll when grooved. The step must have a dimension exceeding the average wall thickness.

Further, if the step is made larger than the groove depth, the thickness of the metal strip escapes in the longitudinal direction of the rolling direction and does not contribute to the formation of the groove, resulting in a decrease in efficiency, so it is sufficient that the step is less than the groove depth.

The above-mentioned step processing may be incorporated into the internally grooved tube manufacturing line shown in FIGS. 1 and 3, or may be carried out off-line.

[0015]

[Effects of the Invention] According to the present invention, as described in the above embodiments, the following effects are achieved.

[0016] By making the lead direction of the grooves symmetrical and simultaneously grooving a plurality of grooves, it is possible to prevent horizontal displacement of the metal strip that occurs during processing and efficiently manufacture pipes with excellent dimensional accuracy. At the same time, by simultaneously manufacturing a plurality of internally grooved tubes having the same lead direction, only the necessary internally grooved tubes are manufactured, thereby enabling rational production.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of an apparatus for manufacturing an internally grooved heat exchanger tube according to the present invention.

FIG. 2 is a sectional view taken along the line a-a in FIG. 1;

FIG. 3 is a partial perspective view of the vicinity of a grooved roll and a slitter when four internally grooved tubes with grooves in the same direction are manufactured at the same time.

FIG. 4 is a cross-sectional view of a stepped metal strip.

FIG. 5 is a front view of a stepped roll that performs stepped processing.

[Explanation of symbols]

1 Unprocessed metal strip 2 Payoff reel 3a Half-grooved roll on one side 3b Half-grooved roll on one side 4 Grooved metal strip 5 Slitter 6a Half-split metal strip 6b Half-split metal strip 7 Roll former 8a Tubular body 8b Tubular body 9 Welding machine 10a Internally grooved tube 10 with groove leads in the same direction
b Internally grooved tube 11 with groove leads in the same direction
Stepped metal strip 12a Stepped roll 12b Stepped roll

Claims (4)

[Claims] [Claim 1] A metal strip such as a soft copper plate strip is formed by using a grooved roll having a lead angle to form grooves on the front and back surfaces of the metal strip when viewed from one plane direction. Grooving is performed at the same time so that the grooves are symmetrical, and then the grooved metal strip is cut and separated from the center of the boundary between the grooves that are oriented in different directions when viewed from one plane. By forming each separated metal strip into a tube shape with the groove forming surface facing the inner surface, and joining the abutting surfaces of the formed tubes, multiple inner grooved tubes with grooves in the same direction can be made at the same time. 1. A method for manufacturing an internally grooved heat exchanger tube. 2. The method for manufacturing an internally grooved heat exchanger tube according to claim 1, wherein the number of internally grooved tubes manufactured at the same time is two or an even multiple thereof. 3. The method for manufacturing an internally grooved heat exchanger tube according to claim 1, wherein an odd number of internally grooved tubes of three or more are manufactured at the same time. 4. Before the metal strip is grooved, the surface of the metal strip is processed in-line or in a separate process to a thickness that is larger than the average wall thickness of the finished grooved pipe and less than the groove depth. The internal groove according to claim 1, 2 or 3, wherein the stepped metal strip is alternately stepped and grooved on the higher side of the stepped metal strip. Method for manufacturing heat exchanger tubes.