JPS62255794A - Heat transfer pipe with fin and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve heat exchange performance as a pressure loss of a flow in a pipe is prevented from occurring, by a method wherein a number of pyramidform projections are uniformly formed on the inner wall of a heat transfer pipe, and a helical continuous fin, bent in one-way, is formed to the outer wall of the heat transfer pipe. CONSTITUTION:An unprocessed pipe 2 is inserted through a dice 3 to draw it in a direction A, and by means of a first grooved plug 7 and a compacting roller 9, a first groove 10 is formed in an inner wall, and by means of a second grooved plug 12 and a press disc 15, a second groove crossing the groove 10 at right angles is engraved to form a pyramidform crossing groove 1b. Simultaneously, the pipe is gathered up to form a continuous spiral fin 19 on an outer wall as the press disc 15 is rotated, and the fin is bent leftward by means of a bending processing disc 27 to form a curved fin 1a. This constitution reduces incurring of a pressure loss of a flow in a pipe, and enables easy manufacture of a heat transfer pipe with a fin having high heat exchange performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a finned transmission which is used in liquid-liquid type or gas-liquid type heat exchangers, and is particularly suitable for shell and tube type heat exchangers. The present invention relates to a heat tube and a method of manufacturing the finned heat exchanger tube.

[Prior art]

Conventionally, a heat exchanger tube used in a liquid-liquid heat exchanger and a method of manufacturing the heat exchanger tube 41 are shown in FIGS. 7 and 8 (
The one shown in USP 3,768,291 is known.

As shown in FIG. 7, a wavy loaf-in 41a is formed on the outer wall of the heat exchanger tube 41, and the heat exchanger tube 4
Convex ribs 41b are formed on the inner wall of 1 at predetermined intervals.

Here, let us consider a case where water is allowed to flow on the inner surface of the heat transfer tube 41 and a Freon medium, which is a low boiling point organic medium, is passed outside the tube. In this case, when the water in the heat exchanger tube 41 crosses over the ribs 41b, turbulent flow occurs, especially in the vicinity of the inner wall of the heat exchanger tube 41. Therefore, heat exchange between the inner wall of the heat exchanger tube 41 and the water is not carried out. Can be done. At this time, the temperature of the water in the heat transfer tube 41 is usually 10 to 20 degrees Celsius higher than the temperature of the Freon medium.
(referred to as the medium temperature difference range), so the conventional heat exchanger tube 41 described above
Good heat exchange can be carried out even in this case. However, in recent years, as energy-saving technology and high-efficiency heat exchange technology have been required, the difference between the refrigerant temperature outside the heat exchanger tube and the countercurrent temperature inside the heat exchanger tube tends to become smaller (for example,
Even in this small temperature difference region, there is a need to maintain and improve heat exchange performance without reducing heat transfer between the inside and outside of the tube. .

In response to such requests, the conventional heat exchanger tube 41 has the following features:
Although the heat exchange performance was good in the above-mentioned medium temperature difference range, the heat exchange performance in the small temperature difference range was insufficient because the surface area within the heat transfer tube 41 was small. In addition, since the ribs 41b were formed high, there were problems such as a large loss of power for conveying water.

Further, the heat exchanger tube 41 was manufactured by the method shown in FIG.

That is, the mandrel 43, which has grooves 43a formed at predetermined intervals on its tip, is inserted into the tube 46, and the outer wall of the tube 46 is squeezed by the aperture disk 44.
... is pressurized by a rolling pressure unit 45 provided on the outer periphery. Then, with the mandrel 43 fixed, the pipe material 46 is
By rotating the rolling unit 45 in the direction B without rotating it, and rotating the rolling pressure unit 45, ribs 41b are formed in a spiral shape on the inner wall of the tube material 46, and loaf-in 41a...・It was intended to form a

However, in the above conventional method, (1) Since the pipe material 46 was rotated, it was easy to cause blurring over the entire length of the pipe material 46 (and the work could not be performed at high speed rotation. Therefore, productivity This was leading to a worsening of the situation.

(2) Since it is a fixed mandrel method, it is suitable for processing straight pipes, but it is suitable for processing pipe materials with a length of about 3 to 4 m.
I was only able to process 6. Therefore, it is not possible to process a long coiled pipe material (having a length of several corridors), which is required in recent years. In addition, this method cannot be applied to a system that automatically manufactures fixed-length tubes using a combined machine by continuously processing the original coil tube, resulting in decreased productivity and increased costs.

(3) Rib 41b: Since the height was larger than the thickness of the heat exchanger tube 41, it was not possible to wind the heat exchanger tube 41 into a coil after forming the heat exchanger tube 41.

(4) Since short straight pipes are processed, the pipes and pipe ends must be cut off for each straight pipe, which involves unsteady processing, resulting in a decrease in yield.

(5) Since the tube material 46 rotates, the surface of the heat exchanger tube 41 is easily scratched on the outlet table or the like.

It had the following problems.

In addition, as a method for manufacturing heat exchanger tubes, see Figure 9 (Japanese Patent Publication No. 1973
15469) is also conventionally known.

That is, the blank pipe 53 is inserted into two rotatable dies 50 and 51 arranged in series by forming multiple diagonal grooves with opposite angles on the inner circumferential surface, and Inside the blank tube 53, two floating plugs 54 and 55 are arranged in series, each having a multi-striped diagonal groove formed on its outer circumferential surface at an angle opposite to the diagonal groove in each of the dies with respect to the plug axis. When drawing the tube by pulling out the raw tube 53 from the dies 50 and 51, these dies are 50/51!11 mutual and floating plug 54/5
5 are rotated in forward and reverse directions to form multiple diagonal ribs that cross each other on both the inner and outer surfaces of the tube by one tube elongation.

However, the above conventional method has the following problems.

(1) Mandrel 56 is floating plug 54/5
By pressing 5, the floating plug 54.
55 was pushed between dice 50 and 51, so 4~
It can only be applied to straight pipes with a length of 5 m. Furthermore, if the floating plugs 54 and 55 bite into the pipe wall, processing cannot be interrupted until the pipe has finished passing through, so it is impossible to provide a land part in the middle of the pipe material.

(2) Since grooves were formed in the approach portions of the floating plugs 54 and 55 and the approach portions of the inner surfaces of the dies 50 and 51, pipe breakage occurs when processing thin-walled pipes. In addition, grooves are carved on the inner surfaces of the dies 50 and 51, and by pressing and rotating the dies 50 and 51 against the outer wall of the tube, a protrusion is attached to the outer wall of the tube. Since the drawing process and the protrusion forming process are performed at the same time, the resistance to pulling out the tube becomes extremely large, and if the tube is thin, it will not be able to withstand the pullout resistance, and as a result, A pipe break had occurred. For these reasons, in the above conventional method,
Only thick-walled pipes could be applied.

(3) Since the outer wall of the tube is pressed and deformed, when the process is performed at high speed rotation, a large amount of heat is generated and the temperature of the tube rises. Therefore, in order to maintain good surface quality (for example, to prevent seizure due to heat generation), it is necessary to perform processing at low speed rotation and to perform drawing at low speed, which reduces productivity.

(4) Since it is necessary to process straight and short pipe materials, a date section for chuck gripping must be provided for each tube material, and the mouth part is set after the process and the pipe is processed. Since a step of cutting out the part is required, productivity is lowered, and the yield is also lowered.

Conventionally, as a method for manufacturing heat exchanger tubes, the method shown in FIGS. 10 and 11 (Australian FAT No. 1
11528) is also known.

That is, as shown in FIG.
2, the fins 64 are formed on the tube by the rotation and pressing of the fin erecting roll 63 provided near the outer periphery of the mandrel 62°. This fin 6
4... is formed is slid along the outer peripheral surface of the mandrel 62 in the direction of the mandrel base 65.

(2) With the end of the tube gripped by the gripper 61,
The mandrel 62 is moved inside the tube in the direction of the griffper 61, and the fin stand roll 63 is moved in the tube axis direction while pressing the outside of the tube. In this case as well, fin 6
4... is formed on the tube slides along the outer peripheral surface of the mandrel 62.

A pipe is processed by the above (1) or (2).

Here, as shown in FIG. 11, if it is a 40-type fin stand roll, the fin stand rolls 63 can be synchronously moved toward and away from the pipe, thereby making it possible to move the fin stand rolls 63 . A tube with sections can be made.

However, when forming relatively large ribs on the inner wall of heat transfer tubes, especially thin-walled and small-diameter heat transfer tubes, to improve heat transfer through turbulent flow, the quality of the curved tube portion deteriorates, and even worse. , can cause duct blockage.

Therefore, in order to prevent deterioration of the quality of the curved pipe portion, a thick walled pipe had to be used.

In addition, if the tube is rotated when forming the grooves on the inner wall and the fins 64, the surface of the tube is likely to be hit or scratched, and the diameter of the mandrel 62 (
Since φ1) is smaller than the diameter between the machined inner ribs (φ2), a gap is created between the inner wall of the tube and the outer wall of the mandrel 62, which causes the tube to vibrate and reduce machining accuracy. He was inviting me. On the other hand, when the tube does not rotate and the mandrel 62 rotates, although the vibration is reduced, the entire relatively long mandrel 62 rotates, so the machining part rotates around the revolution of the fin stand roll 63. In combination with this, core deviation occurs, resulting in problems such as deterioration of processing accuracy.

[Purpose of the invention]

The finned heat exchanger tube of the first invention has been made in consideration of the above conventional problems, and is capable of sufficient heat exchange even when the temperature difference between the temperature of the refrigerant and the flow inside the tube is small. The object of the present invention is to provide a finned heat exchanger tube that can significantly reduce energy loss.

The method for manufacturing a finned heat exchanger tube according to the second and third inventions has been made in consideration of the above-mentioned conventional problems, and is capable of processing a long coiled tube with a thin wall thickness and a small diameter at high speed. The purpose of the present invention is to provide a method for manufacturing a finned heat exchanger tube that can improve productivity by making it possible to do this, and can manufacture high quality finned heat exchanger tubes by reducing vibrations, scratches, etc. That is.

[Structure of the invention]

In order to achieve the above-mentioned object, the finned heat exchanger tube according to the first invention has a large number of pyramid-shaped protrusions uniformly formed on the inner wall of the heat exchanger tube that performs heat exchange, and a number of pyramid-shaped projections are uniformly formed on the outer wall of the heat exchanger tube. , characterized by forming continuous spiral fins that are bent in one direction, and configured to improve heat exchange performance while minimizing loss of power for conveying the flow inside the pipe. It is.

In order to achieve the above object, the method for manufacturing a finned heat exchanger tube according to the second aspect of the present invention uses a first grooved plug and a compaction roll that revolves around the first grooved plug and the tube in a predetermined direction while moving the tube. by carving a first groove in the inner wall of the tube, and then by means of a compression disk and a second grooved plug rotating around the tube of the second grooved plug in a direction opposite to the compaction roll, A plurality of pyramid-shaped protrusions are formed uniformly by carving a second groove intersecting the first groove on the inner wall of the tube having the first groove carved therein, and
A spirally continuous fin is formed that protrudes from the outer wall of the tube at right angles to the tube axis, and then the second groove and the fin are formed around the tube in the same direction as the compression disk. The fins are continuously curved in one direction by a rotating bending disk, so that a long coiled tube with a thin wall thickness and a small diameter can be processed at high speed, and processing efficiency can be improved. It is something to do.

In order to achieve the above object, the method for manufacturing a finned heat exchanger tube according to the third invention reduces the diameter and wall thickness of the original tube using a die and a floating plug while moving the tube. A first groove is carved in the inner wall of the pipe using a first grooved plug and a rolling pressure roll that revolves around the pipe in a predetermined direction, and then a first groove is carved around the pipe of the second grooved plug. A compression disk rotating in the opposite direction to the roll and a second grooved plug form a plurality of pyramid-shaped grooves by carving second grooves intersecting with the first grooves on the inner wall of the tube in which the first grooves have been carved. While forming the protrusions uniformly, continuous spiral fins perpendicular to the tube axis are formed on the outer wall of the tube, and then the circumference of the tube in which the second groove and fins are formed is the same as the compression disk. The fin is characterized in that the fin is continuously curved in one direction by a curved disk that rotates in one direction.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 to 6.

As shown in FIGS. 1 and 6, on the outer wall of the heat exchanger tube 1,
A spiral curved fin 1a curved in one direction is formed, and as shown in FIG. 22... is engraved. The first grooves 10 and the second grooves 22 constitute an intersecting groove 1b, and a pyramid-shaped projection 30 is formed by the intersecting groove 1b.

Therefore, in the finned heat exchanger tube of the present invention, (1) the height of the protrusions 30 formed by the intersecting grooves 1b is smaller than that of the conventional tube, and the surface area inside the heat exchanger tube 1 is uniformly reduced compared to the conventional tube. Since the surface area of the pipe can be increased by at least 50% or more (usually twice or more), the heat exchange performance can be improved while suppressing the loss of power for conveying the flow inside the pipe.

(2) Since the protrusions 30 are formed almost in a straight line toward the inside of the heat exchanger tube 1, a turbulent flow effect can be created near the inner wall of the heat exchanger tube 1, improving heat exchange performance. can be improved.

(3) As shown in FIG. 2(a), when the finned heat exchanger tube of the present invention is actually used, the curved fins 1a...
・Continuous cavities 31... and intermittent openings 32
are formed, or, as shown in FIG. 2(b), continuous cavities 31... and continuous openings 32... are formed. Therefore, when boiling occurs during heat exchange between the outer wall of the heat transfer tube 1 and the refrigerant, vapor bubbles are retained within the cavities 31, and a thin film of refrigerant is formed between the inner wall of the cavities 31 and the vapor bubbles. is formed. The evaporation of this film promotes latent heat transport, so it is 60 to 1
Heat conductivity can be improved by about 50%. Thereby, even when the temperature difference between the temperature of the refrigerant and the flow in the pipe is small, sufficient heat exchange can be performed.

FIG. 6 shows an example in which the tips of the fins 1a are bent with a strong bending force, and the shortest distance σ between any fin 1a and an adjacent fin 1a is set to be shorter than the distance σ2 between the bodies of the fins 1a. By forming it small, heat transfer efficiency can be significantly improved.

Here, the finned heat exchanger tube is manufactured by the method shown below.

The master tube 2 is being pulled in the direction of A in the figure, so at first,
The original tube 2 is sandwiched between a die 3 and a floating plug 4. At this time, the tapered approach portions 3a and 4a of the die 3 and the floating plug 4 and the bearing portions 3b and 4b of both 3 and 4 work together to press the raw tube 2 that is continuously passing from the inside and outside. , the diameter and wall thickness of the original tube 2 are reduced. In this case, depending on the material and wall thickness of the original tube 2,
The die 3 may be of a rotating type or a fixed type. In addition, a thin lubricant film is formed between the floating plug 4 and the inner wall of the original tube 2 by thinly stretching the lubricant previously applied inside the original tube 2, which causes defects such as seizure during this process. is prevented.

Here, since fin raising processing and curving processing, which will be described later, are precision and high-speed processing, it is necessary to use high-quality raw tubes during processing. Therefore, this process is necessary in order to finish the inner and outer walls of the supplied original tube 2 using the die 3 and the floating plug 4 in advance.

In order to further improve the lubrication effect, grooves or holes (not shown) are provided in the outer wall of the floating plug 4 in the tube axis direction.
Lubricating oil may be passed through this groove or hole to supply the lubricating oil to the next grooving process. Further, the inner wall of the die 3 and the outer wall of the floating plug 4 are finished smoothly by precision machining or surface treatment.

A connecting rod 5 is provided on the A direction side of the floating plug 4.
A first grooved plug 7 that grooves the inner wall of the tube 6 after diameter reduction is rotatably connected to the floating plug 4 via the first grooved plug 7 . A plurality of regularly arranged grooves 7a are carved on the outer wall of the first grooved plug 7 at an angle with respect to the tube axis. Further, a donut-shaped compaction roll 9 is placed at a predetermined distance from the outer periphery of the first grooved plug 7 and is strongly pressurized by a hydraulic mechanism (not shown) and can freely rotate.
is provided. The diameter-reduced tube 6 is conveyed into the gap between the compaction roll 9 and the first grooved plug 7, and when passing through the gap, the outer wall of the diameter-reduced tube 6 is pressed by the compaction roll 9. Therefore, the inner wall of the tube 6 after diameter reduction is connected to the first grooved plug 7.
Pressed by As a result, a part of the tube 6 after the diameter reduction is buried in the groove 7a, and as shown in FIG. 3, a first groove 10 is carved in the inner wall of the tube 6 after the diameter reduction. will be established.

Since the first grooved plug 7 is pulled in the direction A, a thrust bearing 8 is provided on the rear side surface of the first grooved plug 7 to support this tensile force. This allows the first grooved plug 7 to rotate at a fixed position. Further, the compaction roll 9 is not limited to a donut shape, and even if spherical compaction balls are used, the same function can be achieved. Furthermore, the rolling pressure rolls 9 press the pipe 6 after the diameter reduction during processing, but when the processing is not in progress or when not being processed, the hydraulic mechanism is operated to press the pipe 6 after the diameter reduction.
can be separated from Further, the grooves 7a formed in the first grooved plug 7 may be formed parallel to the tube axis direction (in this case, the first grooves 7a formed in the tube 6 after diameter reduction) may be formed parallel to the tube axis direction. Groove 1
0... is parallel to the tube axis direction.

A second grooved plug 12 that can freely rotate via a connecting rod 11 is provided on the A direction side of the first grooved plug 7, and grooves 12a and 12a are provided on the surface of the second grooved plug 12. ... is formed. The grooves 12a... are formed so that the virtual extension lines of the grooves 12a... and the virtual extension lines of the grooves 7a... of the first grooved plug 7 intersect. This results in
Since the intersecting grooves can be formed on the inner wall of the heat exchanger tube, a heat exchanger tube with good heat conductivity, high productivity, and high quality can be obtained. On the side surface of the second grooved plug 12 on the A direction side,
Since the thrust bearing 13 is provided, the second grooved plug 12 can be freely rotated.

Here, in order to prevent the quality and precision of the inner wall of the finned heat exchanger tube from deteriorating even in high-speed machining, it is necessary to separate the core of the floating plug 4, the core of the first grooved plug 7, and the second grooved It is important that the cores of the plug 12 are aligned in a straight line without eccentricity.

Further, a rolling pressure unit 14, which is an example of a fin stand means, is provided at a predetermined distance from the outer peripheral surface of the second grooved plug 12, and this rolling pressure unit 14 actively rotates around the tube axis ( It has a configuration that revolves around the Earth. This compaction unit 14 includes a plurality of doughnut-shaped pressure discs 15...
(for example, provided every 90' on the outer circumference of the second grooved plug 12), a shaft 16 to which the compression disks 15 are concentrically fixed, and a bearing that supports this shaft 16. and a first disk case 17 with a U-shaped cross section that can be freely rotated.

The compression disks 15 are configured to have a small diameter on the upstream side and gradually increase in diameter toward the downstream side (A direction side). Furthermore, the first disk case 17
is slidably fitted into one groove 20a of the inverted W-shaped unit frame 20. It has a structure that allows it to move in the direction of the tube 18 in which one groove is formed.

Further, a second disk case 23 is slidably fitted into the other groove 2ob of the unit frame 2o, and this second disk case 23 is fixed to the upper part of the second disk case 23, It has a structure in which the fins can be moved in the direction of the tube 25 in which the fins are formed by a pressing member 24 that constitutes a part of the contact/separation mechanism. Second disk case 2 above
A bearing is formed at the bottom of 3, and a shaft 26 is rotatably attached to this bearing. This shaft 26
A curved disk 27 whose side in the A direction is curved is fixed to the outer periphery of the fin so that the fins can be bent continuously and sequentially. The curved disk 27 and the pressure disk 15... rotate in the same direction with respect to the pipe, but both disks 27, 15... and the pressure roll 9
The direction of rotation with respect to the tube is opposite. therefore,
It can cancel out the stress caused by tube bruising.

In addition, only the fin-raising process is performed on the tube 18 in which the first groove is formed by the compression disk 15, and the curved disk 2
7 from the fin-formed tube 25 (thereby, a heat exchanger tube with high fins or middle fins can be manufactured).

Here, the compression disc 15... and the second grooved plug 12
When the tube 18 with the first groove formed therein is conveyed into the gap between the first groove and the first groove, the outer wall of the tube 18 with the first groove formed therein is pressed by the compression disks 15 and the tube flesh is squeezed out. ,
Fins 19 are formed on the outer wall of the tube 18. On the other hand, since a portion of the inner wall of the tube 18 is buried in the grooves 12a, second grooves 22 are carved in the inner wall of the tube 18. As a result, the tube 25 in which the fins 19 and the intersecting grooves 1b are formed is manufactured. In addition, the above compression disc 1
5... is a disk with a small diameter on the upstream side, and the diameter gradually increases toward the downstream side, so
As the fins 19 pass through the compression disks 15, they gradually increase in height.

Next, the tube 25 with the fins and intersecting grooves formed thereon is transported in the entry direction, so one side of the fins 19 is pressed by the curved disc 27 whose entry direction side is curved, and the pipe 25 is transported in the entry direction. A curved fin 1a curved toward the direction side is formed. The finned heat exchanger tube 1 on which the curved fins 1a are formed is continuously wound up by a winder (not shown) to form a level-wound coil, or passed through a combined machine and housed as a long straight tube. In the case of the above-mentioned level wound coil, since the curved fins 1a are bent and laid down, the finned heat exchanger tube 1
or become an obstacle when bending the curved fin 1a.
Since it is possible to prevent the material from being crushed, it can be easily wound into a coil shape.

Therefore, when produced by the method of the present invention, (1)
The curved disk 27 and compression disk 15... rotate in the same direction with respect to the tube, and both disks 27...
15... and the rolling pressure rolls 9 are rotated in opposite directions with respect to the tube, so that stress caused by twisting of the tube can be canceled out. Therefore, since frictional resistance and deformation resistance are minimized, a long coiled tube with a thin wall thickness and a small diameter can be processed at high speed, and processing efficiency can be improved.

(2) By being pressed by the compression disks 15 and squeezing out the tube flesh, the outer wall of the tube 18 has fins 19 and
... is formed, so it is possible to produce not only low fins but also middle fins (height 1 to 311) and high fins (height 3 or more). Heat transfer performance can be improved by about 200%.

(3) By separating the compaction roll, compression disc 15, and disc 27 from the pipe and pulling out the pipe, as shown in Fig. 5(b)
The land portion shown in can be easily formed.

(4) Since the grooved plug can freely rotate with respect to the connecting rod, there will be no pre-alignment or misalignment.

(5) Since the tube material 2 is not rotated, there is less chance of wobbling over the entire length of the tube material 2, and work can be performed at high speed rotation.

(6) Since the structure is such that the tube material 2 is moved, a long coiled tube can be processed.

(7) Since it is not necessary to cut out the pipes and pipe ends for each straight pipe, processing efficiency can be improved.

In addition, the compression disk 15... and the curved disk 27
can be replaced as necessary. Also,
The compression disk 15... and the curved disk 27 are
It is pressed against the tube 18 or 25 when it is being processed, and can be separated from the tube 18 or 25 when it is not being processed. Furthermore, the compression disks 15... have a structure in which they rotate on their own axis due to friction with the tube 18 in which the first groove is formed while revolving around the tube axis.

In addition, it is known that in the process of forming the fins 19 and the intersecting grooves 1b, the inner diameter of the tube 25 is slightly reduced and also slightly elongated in the longitudinal direction, and this elongation in the longitudinal direction is the same as that of the compression disk 15... The distance between the last disk 15 and the curved disk 27 is an important factor. That is, if the pitch between the fins 19 is Ilc, Δl must be selected empirically and L must be determined so that L=n·lC+ΔIl (n=integer).

Further, the curved disk 27 is not limited to being curved on the entry direction side, and may have a shape that allows the fins 19 to be bent linearly, for example.

Further, the rolling unit 14 may be a follower that rolls on the outer wall of the pipe 25, or may be a driver and actively rotate to further improve the throttling effect.

〔Effect of the invention〕

As described above, the finned heat exchanger tube of the first invention has a large number of pyramid-shaped protrusions uniformly formed on the inner wall of the heat exchanger tube that performs heat exchange, and the outer wall of the heat exchanger tube is bent in one direction. It has a structure in which continuous spiral fins are formed.

Thereby, it is possible to improve the heat exchange performance while suppressing the loss of power for conveying the flow inside the pipe. Further, even when the temperature difference between the temperature of the refrigerant and the flow inside the pipe is small, sufficient heat exchange can be performed. As a result, energy loss can be significantly reduced.

As described above, in the method for manufacturing a finned heat exchanger tube of the second invention, while moving the tube, the first grooved plug and the compaction roll revolving around the tube in a predetermined direction are used to form the tube. A first groove is carved in the inner wall, and then the first groove is carved by a compression disk and a second grooved plug rotating around the pipe of the second grooved plug in a direction opposite to the compaction roll. A second groove that intersects the first groove is carved in the inner wall of the provided pipe to uniformly form a large number of pyramid-shaped protrusions, and protrudes from the outer wall of the pipe perpendicular to the pipe axis. The fins are formed in a spiral manner, and then the fins are continuously compressed in one direction by a curved disc that rotates in the same direction as the compression disc around the tube in which the second groove and the fin are formed. Since the coil tube is curved, a long coiled tube with a thin wall thickness and a small diameter can be processed at high speed, thereby improving processing efficiency. Further, the land portion can be easily formed by separating the compaction roll, compression disk, and disk from the tube and pulling out the tube. For these reasons, productivity can be improved, and the cost of the finned heat exchanger tube can be reduced. In addition, since the compaction unit rotates without rotating the pipe, the occurrence of scratches and scratches is drastically reduced.
Effects such as being able to produce high quality finned heat exchanger tubes can be achieved.

As described above, in the method for manufacturing a finned heat exchanger tube according to the third invention, after reducing the diameter and wall thickness of the original tube using a die and a floating plug while moving the tube, the first grooved plug is A first groove is carved in the inner wall of the pipe by a rolling pressure roll revolving around the pipe in a predetermined direction, and then a first groove is carved around the pipe of the second grooved plug in a direction opposite to the rolling pressure roll. A compression disc that rotates and a second grooved plug are used to uniformly form a large number of pyramid-shaped protrusions by carving a second groove that intersects the first groove on the inner wall of the tube in which the first groove has been carved. and forming a continuous helical fin on the outer wall of the tube perpendicular to the tube axis, and then rotating in the same direction as the compression disk around the tube in which the second groove and the fin were formed. Since the fins are continuously curved in one direction by the processed disk, it is possible to produce an even higher quality finned heat exchanger tube.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the finned heat exchanger tube of the present invention, Fig. 2 is a sectional view showing the finned heat exchanger tube of the present invention;
Figures (a) and (b) are partially enlarged cross-sectional views showing the state of the fins when heat exchange is performed using the finned heat exchanger tube.
The figure is a sectional view showing the structure of the first groove, FIG. 4 is a perspective sectional view showing the state of the inner wall of the finned heat exchanger tube of the present invention, and FIG.
a) and (b) are overall views of the finned heat exchanger tube, and Figure 6 is a partially enlarged cross-sectional view of the fins with their tips strongly curved.
Fig. 7 is a partial sectional view showing a conventional heat transfer tube, Fig. 8 is a partial sectional view showing a method for manufacturing this heat transfer tube, Fig. 9 is a sectional view showing another conventional heat transfer tube manufacturing method, and Fig. 10. and FIG. 11 shows still another conventional method of manufacturing a heat exchanger tube,
FIG. 10 is a partially sectional front view, and FIG. 11 is a side view. 1 is a heat transfer tube, 1a is a curved fin, 1b is a cross groove, 3 is a die, 4 is a floating plug, 7 is a first grooved plug, 7a is a groove, 9 is a compaction roll, 10 is a first groove, 12 is Second grooved plug, 12a is groove, 15 is compression disk, 27
2 is a curved disk, 22 is a second groove, and 30 is a protrusion. Patent applicant: Kobe Steel, Ltd. Figure 6 2-7 Figure 1b Figure 8

Claims (1)

[Claims] 1. A large number of pyramid-shaped projections are uniformly formed on the inner wall of a heat exchanger tube that performs heat exchange, and continuous spiral fins bent in one direction are provided on the outer wall of the heat exchanger tube. A heat exchanger tube with fins. 2. While moving the pipe, a first groove is carved in the inner wall of the pipe using the first grooved plug and a compaction roll revolving around the pipe in a predetermined direction, and then a second grooved plug is carved into the inner wall of the pipe. A second groove is formed in the inner wall of the pipe in which the first groove has been carved, intersecting with the first groove, by a compression disk rotating in a direction opposite to the compaction roll around the tube of the plug and a second grooved plug. A large number of pyramid-shaped protrusions are uniformly formed by carving, and fins are formed that protrude from the outer wall of the tube perpendicularly to the tube axis and continue in a spiral shape, and then a second groove is formed. A method for manufacturing a finned heat exchanger tube, characterized in that the fins are continuously bent in one direction by a bending disk that rotates in the same direction as the compression disk around the tube in which the fins are formed. 3. While moving the pipe, the diameter and wall thickness of the original pipe are reduced using a die and a floating plug, and then the above-mentioned A first groove is carved in the inner wall of the pipe, and then the first groove is formed by a compression disc rotating around the pipe of the second grooved plug in a direction opposite to the compaction roll and a second grooved plug. A second groove that intersects the first groove is carved on the inner wall of the tube to uniformly form a large number of pyramid-shaped protrusions, and a continuous spiral perpendicular to the tube axis is formed on the outer wall of the tube. forming a shaped fin, and then continuously bending the fin in one direction by a bending disk rotating in the same direction as the compression disk around the tube in which the second groove and the fin are formed. A method for manufacturing a heat exchanger tube with fins.