JP3332052B2 - Method of manufacturing spiral heat transfer tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a spiral heat transfer tube constituting a heat transfer section of a spiral tube heat exchanger.

[0002]

2. Description of the Related Art In a spiral tube type heat exchanger, a heat transfer section is constituted by a spiral heat transfer tube, that is, a plurality of spiral heat transfer tubes which are closely arranged in a row. Heat exchange and heat recovery between both fluids by flowing in a spiral fluid passage formed between spiral layers of the group and flowing a second fluid having a temperature difference from the first fluid in each heat transfer tube. Is performed.

[0003] Generally, such a spiral heat transfer tube is formed by forming a plurality of copper heat transfer tubes one by one into a spiral shape, and then bundling them in close horizontal rows. Normal.

[0004]

However, with such a manufacturing method, it is difficult to accurately form the heat transfer tubes into a spiral shape with a constant pitch, and furthermore, since the heat transfer tubes are formed one by one, It is extremely difficult to obtain a spiral heat transfer tube having the same shape, as well as extremely low efficiency. As a result, when a plurality of heat transfer tubes are bundled and arranged in the casing, it is difficult for the cross-sectional shape of the fluid passage formed along the heat transfer tube group to be constant. Therefore, in a heat exchanger in which a spiral heat transfer tube manufactured by a conventional method is incorporated as a heat transfer portion, a fluid does not flow smoothly, and a predetermined heat exchanger function cannot be expected. Further, when the shape of the spiral heat transfer tube is corrected after the molding, the production efficiency is further reduced, and the heat transfer tube may be deformed into an irregular shape at the time of the correction. In any case, depending on the conventional method, it is not possible to efficiently manufacture a high-precision spiral heat transfer tube with a constant cross-sectional shape of the fluid passage.

The present invention has been made in view of the above points, and provides a method of manufacturing a spiral heat transfer tube that can efficiently and easily form a plurality of heat transfer tubes into the same spiral shape with high precision. It is intended to do so.

[0006]

In order to solve the above-mentioned problems, a method of manufacturing a spiral heat transfer tube according to the present invention comprises a plurality of metal heat transfer tubes arranged in a row and a metal having a thickness in a vertical direction larger than a diameter of the heat transfer tubes. At least two dummy pipes made of a rod, the two dummy pipes are arranged on both sides of the heat transfer tube group, connected inseparably by welding, and a row tube group consisting of these heat transfer tubes and the dummy pipes, It is proposed to sequentially wind the dummy tube around the drum peripheral surface in such a manner that only the dummy tube comes into contact with the peripheral surface of the forming drum and is closely overlapped in a spiral shape.

In such a manufacturing method, the heat transfer tube and the dummy tube are preferably made of stainless steel, and each heat transfer tube and the heat transfer tube or the dummy tube adjacent thereto are connected by spot welding. Is preferred.

In addition, the forming drum is a cylindrical body, and its peripheral surface is formed into a spiral shape surface having a step between the start end and the end which corresponds to the vertical thickness of the row tube group. And an axial engagement groove formed between the start end and the end of the spiral peripheral surface so as to penetrate into the drum and insert and engage the end of the row tube group. It is preferable to keep it. In the case of using such a forming drum, it is preferable to wind the row tube group around the drum peripheral surface after fixing the front end portion to the engaging groove. Further, it is preferable that the row tube group is wound around the drum peripheral surface by rotating the forming drum. Further, a header tube is welded to the end of the row tube group in a communicating manner, and this header tube is inserted into the drum, and the end portion of the row tube group is engaged with the engaging groove. Is preferably wound around the drum peripheral surface.

Each of the dummy tubes is divided into a dummy tube portion made of a round bar having substantially the same diameter as the heat transfer tube and a passage forming portion made of a square bar, and the dummy tube portion is placed on a horizontal surface of the heat transfer tube. In this state, the passage-forming portion is welded only at the tip side of the row tube group, and the passage tube portion is brought into contact with the drum peripheral surface and the dummy tube is formed. It is preferable to wind the portion around the drum in a state where the portion is spirally adhered and polymerized on the portion.

[0010]

By wrapping the row tube group around the drum peripheral surface, all the heat transfer tubes are simultaneously formed into the same spiral shape.

At this time, since the thickness of the dummy tube in the vertical direction, that is, the thickness in the direction orthogonal to the parallel direction of the heat transfer tubes is larger than the diameter of the heat transfer tubes, the drums acting on the row tube groups at the time of winding around the drum peripheral surface. The pressing force from the peripheral surface and the pressing force between the spiral layers act only on the dummy tube and do not act on the heat transfer tube. That is, the heat transfer tube group is wound around with a gap having a size corresponding to the difference between the vertical thickness of the dummy tube and the diameter of the heat transfer tube between the drum peripheral surface and the spiral layer. . Therefore, even when the heat transfer tube is a thin-walled tube that is easily deformed, the heat transfer tube is not dented by being wound around the drum peripheral surface, and a plurality of heat transfer tubes can be collectively formed into a good and identical spiral shape. .

Further, the spiral gap formed between the spiral layers of the heat transfer tube group, that is, the cross-sectional shape of the fluid passage is determined by the vertical thickness of the dummy tube as described above, and does not change. That is, a fluid passage having a constant cross-sectional shape can be formed. The cross-sectional shape of the fluid passage is maintained by the spiral layers of the dummy tubes located at least on both sides of the heat transfer tube group even after molding.

By the way, in a multi-tube cylindrical heat exchanger, a stainless steel tube having high corrosion resistance is often used as a heat transfer tube. However, in a conventional spiral tube heat exchanger, the heat transfer tube has a spiral shape. Because of the necessity of being molded, a copper tube having high moldability is used. Therefore, when a corrosive fluid is handled, the spiral tube heat exchanger is difficult to use because the copper tube has poor corrosion resistance.

However, according to the method of the present invention, as described above, even if the heat transfer tube is easily deformable, the heat transfer tube can be formed into a spiral shape, so that a thin stainless steel tube can be used as the heat transfer tube. it can. Therefore, compared to the conventional spiral tube heat exchanger using the copper heat transfer tube, a spiral tube heat exchanger that can be used for an extremely wide range of applications can be provided.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be specifically described below with reference to the embodiments shown in FIGS.

First, as shown in FIG. 3, a plurality of metal heat transfer tubes 11 arranged in a row and two metal bars each having a vertical thickness H (see FIG. 5) larger than the diameter D of the heat transfer tubes. The dummy tubes 12 and 12 are connected to each other, and the dummy tubes 12 and 12 are connected to the heat transfer tube group 11.
Are connected inseparably by welding (FIG. 3A), and the heat transfer tubes 11.
12 is connected to the first header tube 2.
3 and is welded in a communicating manner (FIG. 2B).

The heat transfer tube 11 has an outer diameter of 6.35 mm.
The dummy tube 12 is made of stainless steel and has a diameter substantially equal to the diameter D of the heat transfer tube (6 m).
m), a dummy tube portion 12a made of a round bar having a uniform cross section and a passage forming portion 12b made of a square bar (5 mm × 5 mm) having a uniform cross section. The heat transfer tubes 11... And the dummy tube portions 12a, 12a are closely arranged in a row on the same plane, and the space between each dummy tube portion 12a and the heat transfer tube 11 adjacent thereto and between the adjacent heat transfer tubes 11, 11a. The spaces are connected by spot welding at predetermined intervals in the axial direction. Each passage forming portion 12
b is in contact with the lower surface of the dummy tube portion 12a,
Dummy tube portion 12a only on the tip side of row tube group 10
To the peripheral surface of the first header tube 23. The distal end of the row tube group 10 excluding the passage forming portions 12b, 12b is welded in a state of being fitted into an elongated hole 23a formed in the header tube 23 (see FIG. 3).

Next, the distal end portion of the row tube group 10 is detachably attached to the forming drum 30 (FIG. 1A).

That is, as shown in FIG. 4, the forming drum 30 includes a cylindrical main body 31, a disk-shaped first guide 32 integrally formed at one end of the main body 31, and a first guide 32.
A mounting shaft 34 having a center hole 34a at the center of the end face thereof; a chucking portion 33 formed integrally with the header tube 2;
3 and a disc-shaped second guide 35 formed with insertion holes 35a and 35b of the mounting shaft 34. The chucking portion 33 is mounted on an appropriate rotating device (not shown), and By holding the hole 34a with a rolling center or the like in the chucking portion 33 direction, that is, in the axial direction of the mounting shaft 34, the hole 34a can be rotated in a fixed direction about the mounting shaft 34. The peripheral surface 36 of the main body 31 is formed in a spiral shape having a step between the start end 36a and the end 36b corresponding to the vertical thickness H of the row tube group 10, and the spiral is formed. An axial engagement groove 37 is formed between the start end 36a and the end 36a of the peripheral surface 36 so as to penetrate into the main body 31 and to insert and engage the distal end portion 10a of the row tube group 10. I have. The spiral shape of the drum peripheral surface 36 is such that the radius gradually increases from the start end 36a to the end 36b. The axes of the chucking portion 33 and the mounting shaft 34 are coincident with each other, and pass through substantially the center of the spiral forming the drum peripheral surface 36.

Therefore, as shown in FIGS. 1A and 4, the end of the row tube group 10 is inserted into the engagement groove 37 for engagement with the first header, as shown in FIGS. After inserting the tube 23 into the main body 31, the header tube 23 and the end of the mounting shaft 34 are inserted through the insertion holes 35 a and 35 b of the second guide 35, and the nut 3 is inserted into the mounting shaft 34.
8 can be easily attached by screwing the second guide 35 to the main body 31. At this time,
The row tube group 10 is inserted into the engagement groove 37 so that the passage forming portions 12b and 12b face the start end 36a of the drum peripheral surface 36 (see FIG. 1A). In addition, row tube group 1
The reference numeral 0 is located between the guides 32 and 35, and the interval between the guides 32 and 35 is approximately equal to the width of the row tube group 10. Although not shown in the first guide 32,
Header tube 23 corresponding to insertion hole 35a of second guide 35
Is formed so that the header tube 23 can be fixedly held in a state parallel to the mounting shaft 34 by inserting both ends of the header tube 23 into the insertion holes of the guides 32 and 35. .

Next, as shown in FIG. 1 and FIG. 2, the forming drum 30 is rotated by the above-mentioned rotating device in the anti-swirl direction of the drum peripheral surface 36, that is, in the direction of the start end portion 36a (A direction), and the row tube group 10 is moved. While the revolving around the drum 30 is prevented by the guide roller 39 provided in the vicinity of the drum 30, the drum is gradually wound around the drum peripheral surface 36 from the start end 36a to the end 36b.

That is, with the rotation of the forming drum 30, the row tube group 10 first moves to the starting end 36 of the drum peripheral surface 36.
(a) (FIG. 1 (B)), and then bends along the drum peripheral surface 36 from the start end 36a to the end 36b (FIG. 1 (C)). At this time, the dummy tube portion 12a and the passage forming portion 12b constituting each of the dummy tubes 12 come into close contact with the pressing force from the drum peripheral surface 36 while the passage forming portion 12b is in pressure contact with the drum peripheral surface 36. In this state, it is curved along the drum peripheral surface 36, while
Since the heat transfer tube group 11 has a gap 14 corresponding to the thickness of the passage forming portion 12b between the heat transfer tube group 11 and the drum circumferential surface 36, the heat transfer tube group 11 does not directly receive the pressing force from the drum circumferential surface 36 (FIG. C), FIG. 5). However, since the heat transfer tubes 11 are welded and connected to each other, and the dummy tube portions 12a, 12a are welded and connected on both sides of the heat transfer tube groups 11, the heat transfer tube groups 11 are connected to the dummy tube portions 12a. , 1
With the curvature of 2a, it is curved and deformed to the same shape. Therefore, the heat transfer tubes 11 are not dented by the pressing force from the drum peripheral surface 36. Each of the dummy tubes 12 is separated into a dummy tube portion 12a and a passage forming portion 12b. However, only the dummy tube portion 12a is connected to the heat transfer tube group 11, and the passage forming portion 12b starts to be wound. Since only the portion is connected to the dummy tube portion 12a, the heat transfer tube group 11 is not deformed by the difference in the radius of curvature generated between the two portions 12a and 12b.

Further, with the rotation of the forming drum 30, the row of tube groups 10 is spirally curved around the drum peripheral surface 36 while the respective dummy tubes 12 are spirally intimately polymerized (FIG. 2). (D)). At this time, the dummy tube portion 12a and the passage forming portion 12b constituting each dummy tube 12 are formed into a spiral shape while the passage forming portion 12b is pressed against the already curved dummy tube portion 12a. But
Each heat transfer tube 11 is spirally curved in the same form as the dummy tube portions 12a, 12a while forming a gap 15 corresponding to the thickness of the passage forming portion 12b between the heat transfer tubes 11 already curved. (See FIG. 5). Therefore,
For each dummy tube 12, the pressing force acts between the spiral layers, but for each heat transfer tube 11, the mutual pressing force does not act at all between the spiral layers, and there is no possibility that the heat transfer tube 11 is dented.

When the base end of the row tube group 10 reaches the position of the guide roller 39, the rotation of the forming drum 30 is stopped to form the row tube group 10 into a complete spiral shape. (FIG. 2E).

The thus obtained spiral row tube group, that is, the spiral heat transfer tube 10 ′ can be easily removed from the forming drum 31 by removing the second guide 35.

As shown in FIGS. 6 and 7, the spiral heat transfer tube 10 'has a second header tube 24 at its base end.
Are welded in a communicating manner, and then assembled into the casing 21 while being sandwiched between the side wall surfaces 21a, 21a, whereby the heat transfer section of the spiral tube heat exchanger 20 is completed.

A spiral tube heat exchanger 2 having such a heat transfer section
6, the spiral heat transfer tube body 10 ′ has a spiral-shaped heat transfer tube body 10 ′ in which the inner peripheral region 25 a and the outer peripheral region 25 b are formed between the spiral layers of the heat transfer tube group 11. Each of the regions 25a, 25b is communicated with each other through the fluid passages 15.
The supply and discharge pipes 26 and 27 provided in the casing 21 are opened to allow the first fluid 28 to flow from the supply pipe 26 to the inner peripheral region 2.
By flowing the second fluid 29 having a temperature difference from the first fluid 28 into the heat transfer tubes 11 from the second header tube 24, heat exchange and heat recovery between the two fluids 28 and 29 are effective. It is done on a regular basis.

That is, the first fluid 28 is applied to the inner peripheral region 2
From 5 a, the fluid passes through the fluid passage 15 to the outer peripheral area 25 b, and is discharged from the discharge pipe 27 to the outside of the casing 21.
At this time, since the both sides of the fluid passage 15 are completely closed by the dummy tubes 12 and 12 which are spirally tightly overlapped, the first fluid 28 is formed between the spiral heat transfer tube 10 'and the casing wall surfaces 21a and 21a. There is no leakage between them. That is, the presence of the dummy tube 12 does not hinder the function of the heat exchanger but rather improves it. In addition, the fluid passage 15
Is maintained in a constant cross-sectional shape by the passage forming portions 12b, 12b, so that there is no need to interpose a spacer or the like that hinders the flow of the first fluid 28 between the spiral layers, and the first fluid 28 is used for the heat transfer tubes 11. Will flow smoothly along. On the other hand, the second fluid 29 flows into the heat transfer tubes 11 from the second header tube 24 and is discharged from the first header tube 23 to the outside of the casing 21 through the heat transfer tubes 11. At this time, since the heat transfer tubes 11 are formed in the same spiral shape without being dented as described above,
The fluid 29 flows smoothly in each heat transfer tube 11 under the same conditions. Therefore, heat exchange and heat recovery between the two fluids 28 and 29 via the heat transfer tubes 11 are extremely and effectively performed. Moreover, since the heat transfer tube 11 is made of stainless steel and has excellent corrosion resistance as compared with a copper tube, even if the first fluid 28 or the second fluid 29 is a corrosive fluid, the heat transfer tube 11 has a high durability. There is no problem in point. Further, since the stainless steel pipe can be made thinner than the copper pipe, the weight of the heat exchanger 20 can be reduced as compared with the case where a thick copper pipe is used.

By the way, the present invention is not limited to the above-described embodiment, and can be appropriately improved and changed without departing from the basic principle of the present invention.

For example, in the above embodiment, the forming drum 30
To rotate the row tube group 10 to the drum peripheral surface 3.
6. However, in the case where the total length of the row tube group 10 is short, the drum 30 is fixed in reverse, and the row tube group 10 is rotated around the drum 30 to rotate the drum group. Face 3
It is also possible to wind around 6. In the above embodiment, one of the header pipes 23 is welded before the row pipe group 10 is formed.
The molding of 0 may be performed in a state where the header tubes 23 and 24 are not mounted, or may be performed after both the header tubes 23 and 24 are mounted.

Further, in the case where the number of the heat transfer tubes 11 is large, it is difficult to form the heat transfer tube groups 11 in a lump by simply providing the dummy tubes 12 on both sides of the heat transfer tube groups 11. If it is difficult to keep the cross-sectional shape of the fluid passage 15 constant, as shown in FIG.
One or more dummy tubes 12 may be provided also in the middle of the heat transfer tube groups 11. Furthermore, each dummy tube 12
As described above, the dummy tube portion 12a and the passage forming portion 12
b and may be an integral structure as shown in FIG. Of course, the shape of the dummy tube 12 (particularly, the shape of the passage forming portion 12b or a portion corresponding thereto) can be arbitrarily set according to the desired cross-sectional shape of the fluid passage 15.

As described above, the method of the present invention is a particularly advantageous manufacturing method when the heat transfer tube 11 is a thin stainless steel tube, but when the heat transfer tube 11 is a copper tube or the like described at the outset. Can naturally be applied. The shape (wall thickness, etc.) and material of the heat transfer tube 11 and the dummy tube 12 can be appropriately selected according to the desired shape of the spiral heat transfer tube body 10 ′ and the fluid conditions (temperature, properties, etc.).

[0033]

As will be easily understood from the above description, according to the present invention, a plurality of heat transfer tubes can be collectively formed into the same spiral shape, and a spiral heat transfer tube body is manufactured. Can be performed very efficiently. Moreover, the spiral fluid passage existing between the spiral layers of the heat transfer tube group can have a constant cross-sectional shape corresponding to the cross-sectional shape of the dummy tube, and the spiral heat transfer tube body manufactured according to the present invention can be transferred. By using it as a heating part, it is possible to provide a spiral tube type heat exchanger capable of exhibiting an extremely good heat exchanger function by a fluid flowing smoothly. Furthermore, it becomes possible to use a stainless steel tube as a heat transfer tube, and the use of the spiral tube heat exchanger can be greatly expanded.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of a method of manufacturing a spiral heat transfer tube according to the present invention, and showing a first half of a manufacturing process.

FIG. 2 is a vertical sectional side view showing a latter half of the manufacturing process.

FIG. 3 is a perspective view showing a row tube group.

FIG. 4 is an exploded perspective view showing a forming drum.

FIG. 5 is a sectional view taken along line VV in FIG. 2;

FIG. 6 is a vertical sectional front view showing an example of a spiral tube heat exchanger in which a heat transfer section is constituted by a spiral heat transfer tube manufactured according to the present invention.

FIG. 7 is a vertical sectional side view taken along line VII-VII in FIG. 6;

FIG. 8 is a cross-sectional view corresponding to FIG. 5, showing a modified example of the row tube group.

FIG. 9 is a sectional view, corresponding to FIG. 5, showing another modified example of the row tube group.

[Explanation of symbols]

Reference numeral 10: row tube group, 10 ': spiral tube group (coiled heat transfer tube) formed in a spiral shape, 11: heat transfer tube, 12: dummy tube, 12a: dummy tube portion, 12b: passage forming portion, 1
4: gap between heat transfer tube group and drum peripheral surface, 15: fluid passage,
Reference numeral 20 denotes a spiral tube heat exchanger, 21 denotes a casing, 23 denotes a first header tube (a header tube to which the distal end portion of the row tube group is welded), 24 denotes a second header tube, 28 denotes a first fluid, and 29 denotes a first fluid. 2 fluids, 30: forming drum, 36: drum peripheral surface, 36a
... the start end of the spiral peripheral surface, 36b ... the end end of the spiral peripheral surface,
37: engagement groove, H: vertical height of dummy tube, D: heat transfer tube diameter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B21D 53/06 B21D 7/024 B21D 11/07 F28D 7/04

Claims (7)

(57) [Claims] 1. A heat transfer tube group comprising: a plurality of metal heat transfer tubes arranged in a row and at least two dummy tubes made of a metal rod having a vertical thickness greater than the diameter of the heat transfer tubes; Are arranged so that they cannot be separated by welding, and the row tube group consisting of the heat transfer tube and the dummy tube is brought into a state in which only the dummy tube comes into contact with the peripheral surface of the forming drum and is spirally tightly overlapped. A method of manufacturing a spiral heat transfer tube, wherein the spiral heat transfer tube is sequentially wound around a drum peripheral surface. 2. The method of manufacturing a spiral heat transfer tube according to claim 1, wherein the heat transfer tube and the dummy tube are made of stainless steel. 3. The spiral heat transfer tube according to claim 1, wherein each heat transfer tube is connected to a heat transfer tube or a dummy tube adjacent thereto by spot welding. Method. 4. The forming drum is a cylindrical body, the peripheral surface of which is formed in a spiral shape having a step between a start end and an end which corresponds to the vertical thickness of the row tube group. And an axial engagement groove formed between the start end and the end of the spiral peripheral surface so as to penetrate into the drum and insert and engage the end of the row tube group. 4. The method according to claim 1, wherein the row tube group is wound around the drum peripheral surface after its front end portion is fixedly engaged with the engagement groove. The method of manufacturing the spiral heat transfer tube described. 5. By rotating the forming drum,
The method for manufacturing a spiral heat transfer tube according to claim 4, wherein the row tube group is wound around the drum peripheral surface. 6. A header tube is welded to the tip of the row tube group in a communicating manner, the header tube is inserted into the drum, and the tip portion of the row tube group is engaged with the engagement groove. The method for manufacturing a spiral heat transfer tube according to claim 4 or 5, wherein the row tube group is wound around the drum peripheral surface. 7. Each of the dummy tubes is separated into a dummy tube portion made of a round bar having substantially the same diameter as the heat transfer tube and a passage forming portion made of a square bar, and the dummy tube portion is placed on a horizontal surface of the heat transfer tube. In this state, the passage-forming portion is welded only at the tip side of the row tube group, and the passage tube portion is brought into contact with the drum peripheral surface and the dummy tube is formed. In a state where it can be spirally adhered and polymerized on the part,
The method for manufacturing a spiral heat transfer tube according to any one of claims 1, 2, 3, 4, 5, and 6, wherein the spiral heat transfer tube is wound around a drum peripheral surface. .