JP2006317046A - Heat exchanger tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat exchanger effectiveness of a heat exchanger tube by improving a heat exchange area with a fluid inside and outside the tube. <P>SOLUTION: A tube wall is formed with circumferentially long projected strip parts 2 and recessed groove parts 3 alternately in a tube axis direction, and a fin 4 is joined to the outer peripheral surface of either one of each projected strip part 2 and each recessed groove part 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat transfer tube having an excellent heat exchange rate.

As this type of heat transfer tube, as shown in Patent Document 1, a tube used in a double tube type liquefied natural gas vaporizer, in which fins extending spirally are provided on the inner and outer peripheral surfaces of the tube, is known. It has been.
On the other hand, Patent Document 2 discloses one in which inner grooves and convex portions are formed on the inner peripheral surface of the pipe.
JP-A-8-183971 Japanese Patent Laid-Open No. 10-115495

In the heat transfer tubes of Patent Documents 1 and 2, the heat transfer tube is processed to improve the heat exchange area such as fins or protrusions, and only the fins are provided or the protrusions are formed. The heat exchange rate cannot be increased sufficiently.
An object of this invention is to provide the heat exchanger tube which can solve such a problem.
The present invention forms convex ridges and concave ridges alternately in the tube axis direction, and joins fins to the outer peripheral surface to improve the heat exchange area with the fluid inside and outside the tube, thereby improving the heat exchange rate. It is an object of the present invention to provide a heat transfer tube that can be made to flow.

In order to achieve the above object, the present invention takes the following measures. That is,
On the tube wall, long ridges 2 and concave ridges 3 that are long in the circumferential direction are formed alternately in the tube axis direction, and fins 4 are joined to the outer peripheral surface of either the ridges 2 or the ridges 3. Has been.
Thereby, the heat exchange area with the fluid inside and outside the pipe can be improved, and the heat exchange rate can be improved.
Fins 4 that are long in the circumferential direction are formed in the pipe wall at intervals in the pipe axis direction, and a long protruding strip 2 or a concave strip 3 is provided in the pipe wall between the fins 4 in the circumferential direction. .

Thereby, the heat exchange area with the fluid inside and outside the pipe can be improved, and the heat exchange rate can be improved.
In the tube wall, long ridges 2 and concave ridges 3 that are long in the circumferential direction are formed alternately in the tube axis direction, and the tube wall before and after the ridges 2 is folded in two to fold the folds 5 in the circumferential direction. The fin 4 is joined to the tip of the folded portion 5.
Thereby, the heat exchange area with the fluid inside and outside the pipe can be improved, and the heat exchange rate can be improved. In addition, since the folded portions 5 can be formed densely in the tube axis direction, the heat exchange area can be expanded to further improve the heat exchange rate.

The ridge portion 2 has a ring shape or a spiral shape.
This facilitates the bonding of the fins 4.

  According to the present invention, the heat exchange area with the fluid inside and outside the pipe can be improved, and the heat exchange rate can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The heat transfer tube 1 of the first embodiment is used in a heat exchanger such as a boiler as a metal heat transfer tube that exchanges heat of fluid inside and outside the tube.
As shown in FIG. 1, the tube wall protrudes spirally in the tube axis direction to form a single ridge portion 2 and a concave ridge portion 3, and fins 4 are formed along the outer peripheral surface of the concave ridge portion 3. It is constructed by joining.
The ridge portion 2 is a portion in which the tube wall protrudes in a drum shape in the radially outward direction adjacent to a straight tubular tube end portion 6 provided at an end portion in the tube axis direction. It is formed in the direction with an interval corresponding to the length of the concave strip 3 (spiral pitch).

The concave strip portion 3 is formed between the convex strip portions 2 adjacent in the tube axis direction and has substantially the same diameter as the tube end portion 6.
The fin 4 is joined to the outer peripheral surface of the valley bottom of the concave strip portion 3 by a joining method that hardly hinders heat transfer such as brazing and welding while spirally turning around the base plate side. Yes.
The inner groove 7 on the inner peripheral surface of the heat transfer tube 1 increases the heat transfer area of the inner peripheral surface of the tube and improves the heat exchange rate. The inner groove 7 is composed of two types of grooves having different inclination angles with respect to the tube axis direction, and an inner groove boundary line 8 is provided at the boundary between the two types of inner grooves 7, respectively, in the vicinity of the inner groove boundary line 8. The fluids in the pipes that have moved along the inner groove 7 collide with each other to generate turbulent flow, thereby improving the heat exchange rate.

  In the method of processing the heat transfer tube 1, the inner groove 7 is rolled and formed on one surface of a metal plate, and both ends of the metal plate are joined so that the inner groove 7 comes to the inner periphery, thereby forming the metal tube. Next, the metal tube is expanded from the inside of the tube by bulging (hydroforming) to form the spiral ridge 2. Next, the strips are joined along the concave stripes 3 between the convex stripes 2 to form the fins 4. In the heat transfer tube 1, the strips may be spirally joined to the straight tube to form the fins 4, and then the protrusions 2 may be formed by protruding between the fins 4. Further, the fin 4 may be formed along the top of the ridge 2.

In FIG. 2, the heat transfer tube 1 of the second embodiment has a plurality of ring-shaped protruding ridges 2 and protruding ridges 3 protruding alternately in the tube axis direction. Moreover, the fin 4 is formed with a ring, is fitted and joined to the top of the ring-shaped convex strip 2, and protrudes larger than that provided at the bottom of the valley.
The processing method of the heat transfer tube 1 of the second embodiment is that a straight tube is raised at a constant interval in the tube axis direction to form a convex portion 2, and a ring is fitted to all the convex portions 2 and joined. Thus, the fin 4 is formed.

In FIG. 3, the heat transfer tube 1 according to the third embodiment includes a heat transfer tube 1 (corrugated tube) in which convex ridges 2 and concave ridges 3 are alternately formed in the tube axis direction. The tube walls before and after the tube are contracted, and are folded in two by projecting outward in the diameter, and the fold portion 5 is formed with a gap in the tube axis direction. The fins 4 are formed by joining the base ends. The ridges 2 and the fins 4 can be made larger in diameter than the direct bonding to the corrugated tube, and the intervals between the fins 4 can be made closer.
As shown in FIG. 4, the processing method of the heat transfer tube 1 according to the third embodiment is such that the recess forming die 8 is pressed against the circumferential direction of the metal material pipe so that the recesses 9 are spaced apart in the tube axis direction. The provided corrugated tube 10 is formed. If the concave portion 9 is provided in a ring shape in the circumferential direction of the material pipe, it is easy to fix the material pipe in the subsequent contraction process, and therefore, preferably, the material pipe or the recess forming die 8 is processed while rotating in the circumferential direction. .

Next, the sandwiching die 11 is inserted into the concave strips 9 formed at a predetermined interval in the tube axis direction, moved in the tube axial direction to compress the tube wall between the concave strips 9, and the convex strips 2 are formed at the same time. The folding part 5 is formed. The fin 4 is formed by joining so that a ring may be added to the front end side of the folding part 5.
In the present invention, the shape of each member and the positional relationship between the front, rear, left, and right in the embodiment are best configured as shown in FIGS. However, it is not limited to the said embodiment, A member, a structure can be variously deformed, and a combination can also be changed.

In the second and third embodiments, the fins 4 can be joined to the concave strips 3, but welding work is easier when the fins 4 are joined to the tops of the convex strips 2.
The tube wall can also be provided with a smooth and continuous ridge portion 2 and a concave ridge portion 3 so as to have a front view wave shape. Furthermore, an inner groove can be provided on the outer peripheral surface of the tube wall to further improve the heat exchange rate.

It is a partial cross section side view of the heat exchanger tube of 1st Embodiment of this invention. It is a partial cross section side view of the heat exchanger tube of 2nd Embodiment. It is a partial cross section side view of the heat exchanger tube of 3rd Embodiment. It is explanatory drawing of the processing method of the heat exchanger tube of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat-transfer tube 2 Convex part 3 Concave part 4 Fin 5 Folding part 6 Pipe end part 7 Inner groove 8 Inner groove boundary line 9 Concave part 10 Corrugated pipe 11 Clamping type 12 Internal type

Claims (4)

  On the tube wall, long ridges (2) and ridges (3) that are long in the circumferential direction are formed alternately in the tube axis direction, and either one of the ridges (2) or the ridges (3). A heat transfer tube characterized in that fins (4) are joined to the outer peripheral surface of the heat transfer tube.   Fins (4) that are long in the circumferential direction are formed in the tube wall at intervals in the tube axis direction, and convex ribs (2) or concave strips (2) that are long in the circumferential direction are formed on the tube wall between the fins (4). A heat transfer tube characterized in that 3) is provided.   The tube wall is formed with ridges (2) and ridges (3) that are long in the circumferential direction alternately in the tube axis direction, and the tube wall before and after the ridges (2) is folded in two A heat transfer tube, wherein a folded portion (5) is formed in a direction, and a fin (4) is joined to a tip of the folded portion (5).   The heat transfer tube according to any one of claims 1 to 3, wherein the protruding portion (2) has a ring shape or a spiral shape.

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