JP2000292088A - Heat transfer tube with internal grooves and method and apparatus for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve further the heat transfer performance of a heat transfer tube having V-shaped internal grooves. SOLUTION: A plurality of lines of V-shaped thread grooves 3 are provided in the inner peripheral surface 2 of a tube main body 1a so that they are symmetric in the direction of the tube axis, while secondary grooves 6 of a prescribed depth are formed in part in projecting thread portions formed between the thread grooves, so that a pressure loss be reduced. On the other hand, the widths in the circumferential direction of the V-shaped thread grooves 3 are made unequal so as to generate rotating components in the helical direction. As a result, the flow of a refrigerant in the tube is made controllable even when the flow rate of the refrigerant is small, and thus the heat transfer performance is improved as much as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an inner grooved heat transfer tube having a groove on an inner peripheral surface of a tube main body.

[0002]

2. Description of the Related Art Heat transfer tubes of heat exchangers such as evaporators and condensers for air conditioners have been disclosed in, for example, JP-A-9-42881 from the viewpoint of improving the heat transfer coefficient. So that a spiral groove is provided on the inner peripheral surface of the pipe,
What adopted the thing which increased the stirring effect by enlarging the heat transfer area and making the refrigerant | coolant which flows through a pipe circularly flow is employ | adopted.

However, in the case of the heat transfer tube having the above structure, when the condensation action progresses to a certain extent, the liquid film portion becomes substantially uniformly distributed in the tube, and the thickness gradually increases. The diffusion resistance increases and the heat transfer performance decreases.

To cope with such a problem, the inner peripheral surface of the tube is divided into a plurality of regions in the circumferential direction as shown in, for example, Japanese Patent Application Laid-Open No. 9-42880. A plurality of rows of V-shaped grooves that are symmetrical in the direction and are equal in width in the circumferential direction are provided.

[0005] In this configuration, the heat transfer tube having the spiral groove is symmetrical in the tube axis direction provided on the inner peripheral surface of the tube, and
Due to the merging or branching action of the V-shaped grooves in a plurality of rows having the same width in the circumferential direction, the distribution of the refrigerant flowing in the pipe in the pipe circumferential direction can be made non-uniform. Then, a high heat transfer coefficient is realized in the thinned region of the liquid refrigerant, so that the heat transfer coefficient at the time of condensation is improved.

[0006]

However, in the case of a heat transfer tube having a V-shaped groove which is symmetric in the tube axis direction and has the same width in the circumferential direction on the inner circumferential surface of the tube as described above, Because the flow of the refrigerant collides and joins by the V-shaped groove,
When the flow resistance is large and, for example, it is used as a heat transfer tube for an evaporator, the effect of a high pressure loss is exerted, and a sufficient heat transfer performance improving effect cannot always be obtained.

[0007] 2. In a region where the flow velocity of the refrigerant is low (a region where the amount of circulating refrigerant is small), the effect of making the distribution of the refrigerant uneven by the V-shaped groove is small. In particular, when used as, for example, a heat transfer tube for an evaporator due to the structure of the groove, the liquid refrigerant cannot be supplied sufficiently in the circumferential direction of the tube, so that the heat transfer performance promoting effect cannot be obtained. That is, the ability cannot be expected to be improved depending on the use area.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is intended to reduce the pressure loss and to more appropriately control the flow of the refrigerant in the pipe even when the flow rate of the refrigerant is small. It is an object of the present invention to provide a heat transfer tube with an inner groove having improved heat transfer performance as much as possible, a method of manufacturing the same, and a manufacturing apparatus.

[0009]

Means for Solving the Problems In order to achieve the above objects, the present invention has the following means for solving the problems.

(1) The heat transfer tube with an inner surface groove according to the invention of the first aspect of the present invention comprises a plurality of rows of V-shaped grooves 3 symmetrical in the tube axis direction on the inner peripheral surface 2 of the tube main body 1a.
Are provided, and the plurality of rows of V-shaped grooves 3, 3,.
Is characterized in that the width in the circumferential direction is irregular.

As described above, a plurality of rows of V-shaped grooves 3, 3 are provided.
Are arranged side by side in the circumferential direction with unequal widths, and the refrigerant liquid flowing in a non-uniform state in the pipe axis direction while repeating merging and branching at the V-shaped grooves 3, 3... Is generated, and an annular flow generating action close to that obtained by combining the spiral grooves can be obtained. Further, the stirring effect is realized and the heat transfer performance is improved.

(2) The invention of claim 2 The heat transfer tube with an inner surface groove according to the invention of claim 2 of the present invention is the above-mentioned claim 1.
In the configuration of the described invention, a plurality of rows of V-shaped grooves 3,
, And at least a portion of the ridges 5, 5 formed between the grooves 3, 3,... Has a predetermined depth from the top 5a side to the base 5b side. Next groove 6,6 ...
Is formed.

As described above, a plurality of rows of V-shaped grooves 3, 3 are provided.
, Each of the grooves 3, 3,.
Are formed in at least a part of them from the top 5a side to the bottom 5b side with a predetermined depth, and the secondary grooves 6, 6,. The flow resistance of the refrigerant flowing through is reduced and the pressure loss is reduced,
Even when the flow rate of the refrigerant is small, the heat transfer performance is effectively improved.

(3) Invention of Claim 3 The heat transfer tube with an inner groove according to the invention of claim 3 of the present invention is the above-mentioned claim 2.
In the configuration of the described invention, the secondary grooves 6, 6,... Are notched grooves in the spiral direction.

In this case, the flow resistance of the refrigerant flowing through the pipe is effectively reduced by the secondary grooves 6, 6,... Formed by the notched grooves in the spiral direction, and the spiral component in the spiral direction is further increased. As a result, the heat transfer performance is further improved.

(4) The invention of claim 4 The heat transfer tube with an inner groove according to the invention of claim 5 of the present invention is the above-described claim 1.
In the configuration of the described invention, a plurality of rows of V-shaped grooves 3,
, And at least a part of the ridges 5, 5,... Formed between the grooves 3, 3,. .. Are formed.

Thus, a plurality of rows of V-shaped grooves 3, 3
, Each of the grooves 3, 3,.
Are formed in at least a part of the outer peripheral surface thereof at a predetermined depth, the flow resistance of the refrigerant flowing in the pipe is formed by the secondary grooves 7, 7,. And the pressure loss is reduced, and the heat transfer performance is effectively improved even when the flow rate of the refrigerant is small.

(5) Invention of Claim 5 The heat transfer tube with an inner surface groove according to the invention of claim 5 of the present invention is the above-described claim 4.
.. Are characterized in that the secondary grooves 7, 7... Are fine grooves extending from one side surface to the other side surface of the convex ridge portions 5, 5,.

In this case, the secondary grooves 7, 7,... Formed by fine grooves extending from one side of the convex ridges 5, 5,.
The flow resistance of the refrigerant flowing in the pipe is effectively reduced, and the heat transfer performance is improved. In addition, even when the tube is expanded, the fine grooves on the side portions are not collapsed, and the heat transfer performance is not reduced.

(6) The sixth aspect of the present invention is directed to a method of manufacturing a heat transfer tube with an inner surface groove according to the sixth aspect of the present invention, wherein a plurality of rows of V-shaped grooves 3, 3.
.. And a plurality of V-shaped grooves 3, 3... Formed in the plurality of rows, and convex ridges 5, 5. Using a second marking roll 12 for marking the secondary grooves 7, 7... At least in a part of the heat transfer tube material and a roll forming device 17 for forming the flat heat transfer tube material 13 into a cylindrical tube. The first and second engraving rolls 11,
12 and a plurality of rows of V-shaped grooves 3, 3.
Are successively stamped and then roll-formed by the roll-forming device 17 to form a cylindrical tube.

In the method for manufacturing a heat transfer tube with an inner surface groove, the first and second marking rolls 11 and 12 are combined in the moving direction of the heat transfer tube material 13 in a flat state and are successively stamped in two stages. The heat transfer tube with the inner surface groove having the configuration of the invention according to claim 1, 4 or 5 can be easily manufactured only by using the heat transfer tube.

(7) Invention of claim 7 The apparatus for manufacturing a heat transfer tube with an inner surface groove according to the invention of claim 7 of the present invention provides a heat transfer tube material 13 in a flat state in which a plurality of rows of V-shaped grooves 3, 3 are provided.
, And the raised ridges 5, 5 formed between the plurality of rows of the V-shaped ridges 3, 3,... , And a roll forming device 17 for forming the heat transfer tube material 13 in a flat state into a cylindrical tube. Heat transfer tube material 1 in state
3, the first and second engraving rolls 1
, And the secondary grooves 7, 7,... Are successively engraved in two stages by the roll forming device 17 and then roll-formed by the roll forming device 17 to form a cylindrical pipe. It is characterized in that it is formed.

In the apparatus for manufacturing a heat transfer tube with an inner groove, the first and second marking rolls 11 and 12 are combined in the moving direction of the heat transfer tube material 13 in a flat plate state and are sequentially marked in two stages. It is possible to easily manufacture the heat transfer tube with the inner surface groove having the structure according to the first, fourth or fifth aspect of the present invention.

[0024]

As described above, according to the heat transfer tube with an inner groove and the method and apparatus for manufacturing the same according to the invention of the present application, even when the heat exchanger is configured as either a condenser or an evaporator,
Further, even when the heat exchanger is configured as an evaporator and the refrigerant flow rate is small, the heat loss in the heat loss and the pressure loss in the heat transfer tube is reduced, and a heat exchanger with sufficiently high heat transfer performance is provided. Can be provided.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS.
1 shows a structure of an inner grooved heat transfer tube according to Embodiment 1 of the present invention.

First, an inner grooved heat transfer tube 1 according to the present embodiment is formed on an inner peripheral surface 2 of an electric resistance welded tube main body 1a as shown in FIGS. In order to promote the turbulence of the flowing refrigerant liquid and to form a dense portion by branching or merging with the flow of the refrigerant liquid to promote the thinning of the refrigerant liquid, the main groove is symmetrical in the pipe axis direction. , A relatively sharp V-shaped groove with unequal width in the circumferential direction
The first to fifth plurality of rows of groove groups A to E are arranged in the circumferential direction with different lead angles θ.

Numeral 5 in FIG. 3 denotes a convex ridge formed between the V-shaped grooves 3, 3..., 5a denotes its top, and 5b denotes its base. I have.

As described above, the first to fifth rows of the groove groups A to E each having the V-shaped grooves 3, 3... Having different lead angles θ are arranged in the circumferential direction at unequal widths. When set, each V
The refrigerant liquid flowing non-uniformly in the circumferential direction while repeating branching and merging at the U-shaped grooves 3, 3... It is possible to obtain an annular flow generating action close to that obtained by combining the spiral grooves, and an effective stirring effect is realized, and the heat transfer performance is improved.

The first to fifth plural rows of groove groups A to
Each of the V-shaped grooves 3, 3... E has a predetermined lead angle θ and a predetermined depth H, so that the flow resistance of the grooves is reduced as much as possible to reduce the pressure loss. It is formed with a predetermined number N of lines. Therefore, even when used as a heat transfer tube for an evaporator and the flow rate of the refrigerant is small, the pressure loss is effectively reduced and the heat transfer performance is improved. The lead angle θ, the groove depth H, and the number N of the V-shaped grooves 3, 3... Of the first to fifth groove groups A to E are:
According to the experimental results of the present inventors, for example, the outer diameter φ = 7 m
m, H = 5 to 15 °, H = 0.2 to
In the case of 0.3 mm and N = 45 to 55, the flow resistance was the smallest, and the pressure loss was effectively reduced.

As described above, according to the configuration of the heat transfer tube with the inner surface groove of the present embodiment, first, the V angles having different lead angles θ are different from each other.
.. A plurality of rows of groove groups A to E composed of letter-shaped grooves 3, 3,...
Is set to be unequal width instead of equal width in the circumferential direction,
The refrigerant in the pipe has a swirling flow component like a conventional spiral groove pipe. Thus, even when the flow velocity of the refrigerant is low, the refrigerant is effectively supplied in the pipe circumferential direction, so that the heat transfer promoting effect is not impaired.

The lead angle θ, groove depth H, and number N of V-shaped grooves 3, 3... Of a plurality of rows of groove groups A to E provided on the inner peripheral surface 2 of the pipe are determined. Are set to values corresponding to the above-described experimental results in which the flow resistance is the smallest. Accordingly, the flow resistance can be reduced as much as possible to reduce the pressure loss, so that a heat transfer tube for a heat exchanger having sufficiently high performance can be obtained even when used as an evaporator.

(Embodiment 2) FIGS. 4 to 6 show the structure of a heat transfer tube with an inner surface groove according to Embodiment 2 of the present invention.

First, the heat transfer tube 1 with the inner surface groove according to the present embodiment is arranged such that the turbulence of the refrigerant liquid flowing in the tube body 1a is formed on the inner peripheral surface 2 of the tube body 1a having the same electric resistance welded tube structure as described above. The main groove is symmetrical in the pipe axis direction and has an irregular width in the circumferential direction, in order to promote fluidization and to form a dense portion by branching or merging with the refrigerant liquid to promote thinning of the refrigerant liquid. 1 to 5 comprising V-shaped grooves 3, 3... Having a relatively sharp shape
Are arranged in the circumferential direction with different lead angles θ.

Reference numeral 5 in FIGS. 5 and 6 denotes a convex portion formed between the V-shaped grooves 3, 3..., 5a denotes a top portion, and 5b denotes a base portion. Each is shown. In the case of this embodiment, the top 5a
Are formed in the direction from the base 5b to the base 5b. The secondary grooves 6, 6,... Are formed of spiral notches having a predetermined depth d, so that the flow resistance of the refrigerant is reduced and the turning direction is further reduced. Is increased.

As described above, the first to fifth rows of the groove groups A to E each having the V-shaped grooves 3, 3... Having different lead angles θ are arranged in the circumferential direction at unequal widths. When set, each V
The refrigerant liquid flowing non-uniformly in the circumferential direction while repeating branching and merging at the U-shaped grooves 3, 3... It is possible to obtain an annular flow generating action close to that obtained by combining the spiral grooves, and an effective stirring effect is realized, and the heat transfer performance is improved.

Each V of the first to fifth groove groups A to E
Each of the groove-shaped grooves 3, 3... Is formed by a spiral notched groove (slit groove) as described above so that the flow resistance of the groove portion is reduced as much as possible to reduce the pressure loss. .., And have a predetermined lead angle θ, a predetermined depth H, and a predetermined number of steps N similar to those in the first embodiment. Therefore, even when used as a heat transfer tube for an evaporator and the flow rate of the refrigerant is small, the pressure loss is effectively reduced and the heat transfer performance is improved.

The lead angle θ, the groove depth H, and the number N of the V-shaped grooves 3, 3... Of the first to fifth groove groups A to E are as described above. According to the experimental results of the inventors, for example, in the case of a heat transfer tube having an outer diameter φ = 7 mm, θ = 5
15 °, H = 0.2-0.3 mm, N = 45-55, 2
Next groove depth d / H = 0.25 to 0.75
The flow resistance was the smallest, and the pressure loss was effectively reduced.

As described above, according to the configuration of the heat transfer tube with inner grooves according to the present embodiment, as described above, first, as described above, a plurality of rows of V-shaped grooves 3, 3... Since the circumferential widths of the groove groups A to E are set to be unequal widths rather than equal widths, the refrigerant in the pipes has a swirling flow component like a conventional spiral grooved pipe. Thus, even when the flow rate of the refrigerant is small and the flow velocity of the refrigerant is low, the refrigerant is effectively supplied in the pipe circumferential direction, so that the heat transfer promoting effect is not impaired.

The lead angle θ, the groove depth H, and the number N of the V-shaped grooves 3, 3... Of each of the plurality of rows of grooves A to E provided on the inner peripheral surface 2 of the pipe are determined. , The flow resistance is set to the smallest value, and the V-shaped grooves 3, 3,. , And secondary grooves 6, 6,... Formed by cutout grooves oriented in the spiral direction are provided. Accordingly, the flow resistance can be reduced as much as possible to reduce the pressure loss and the swirl component in the spiral direction can be further increased, so that a heat exchanger tube for a heat exchanger with higher performance can be obtained. .

(Embodiment 3) FIGS. 7 to 9 show the structure of a heat transfer tube with an inner surface groove according to Embodiment 3 of the present invention and the structure of a manufacturing apparatus for implementing the method of manufacturing the heat transfer tube, respectively. I have.

First, in the heat transfer tube 1 with an inner surface groove according to the present embodiment, the turbulence of the refrigerant liquid flowing in the tube body 1a is formed on the inner peripheral surface 2 of the tube body 1a having the same electric resistance welded tube structure as described above. The main groove is symmetrical in the pipe axis direction and has an irregular width in the circumferential direction, in order to promote fluidization and to form a dense portion by branching or merging with the refrigerant liquid to promote thinning of the refrigerant liquid. 1 to 5 comprising V-shaped grooves 3, 3... Having a relatively sharp shape
Are arranged in the circumferential direction.

Reference numeral 5 in FIGS. 7 and 8 denotes a convex portion formed between the V-shaped grooves 3, 3..., 5a denotes a top portion, and 5b denotes a base portion. Each is shown. In the case of the present embodiment, a secondary, e.g., spiral groove having a predetermined depth is formed from one side surface to the other side surface of the outer peripheral surface of the ridges 5, 5,. .. Are provided so as to reduce the flow resistance of the refrigerant and to further increase the component in the swirling direction.

As described above, the first to fifth plural rows of the groove groups A to E composed of the V-shaped groove grooves 3, 3... When set, each V
The refrigerant liquid flowing non-uniformly in the circumferential direction while repeating branching and merging at the U-shaped grooves 3, 3... It is possible to obtain an annular flow generating action close to that obtained by combining the spiral grooves, and an effective stirring effect is realized, and the heat transfer performance is improved.

Each V of the first to fifth groove groups A to E
Are formed so that the flow resistance of the grooves is reduced as much as possible to reduce the pressure loss. Are formed on the outer peripheral surface of each of the secondary grooves 7, 7,...
And a predetermined lead angle θ, a predetermined depth H, and a predetermined number of threads N similar to those of the first embodiment. Therefore, even when used as a heat transfer tube for an evaporator and the flow rate of the refrigerant is small, the pressure loss is effectively reduced and the heat transfer performance is improved. In addition, even when the tube is expanded, the fine grooves on the side portions are not collapsed, and the heat transfer performance is not reduced.

The lead angle θ, the groove depth H, and the number N of the V-shaped grooves 3, 3... Of each of the first to fifth groove groups A to E are as described above. According to the experimental results of the inventors, for example, in the case of a heat transfer tube having an outer diameter φ = 7 mm, θ = 5
Those having a range of 15 °, H = 0.2 to 0.3 mm, and N = 45 to 55 had the smallest flow resistance and effectively reduced the pressure loss.

As described above, according to the configuration of the heat transfer tube with inner grooves according to the present embodiment, as described above, first, a plurality of rows of V-shaped grooves 3, 3... Since the groove groups A to E are set to have an unequal width rather than an equal width, the refrigerant in the pipe has a swirling flow component like a conventional spiral groove pipe. Thus, even when the flow rate of the refrigerant is small and the flow velocity of the refrigerant is low, the refrigerant is effectively supplied in the pipe circumferential direction, so that the heat transfer promoting effect is not impaired.

The lead angle θ, the groove depth H, and the number N of the V-shaped grooves 3, 3... Of each of the plurality of rows of groove groups A to E provided on the inner circumferential surface 2 of the pipe are determined. , Each of which is set to a value that minimizes the flow resistance, and one side surface of the outer peripheral surface of the convex ridges 5, 5,... Between the V-shaped grooves 3, 3,. Are formed from the side to the other side, for example, formed by fine grooves extending in the spiral direction. Accordingly, the flow resistance can be reduced as much as possible to reduce the pressure loss, and the spiral component of the refrigerant flow in the spiral direction can be further increased. A heat transfer tube for the exchanger can be obtained. In addition, even when the tube is expanded, the fine grooves on the side portions are not collapsed, and the heat transfer performance is not reduced.

The heat transfer tube with an inner surface groove having the above-described structure having a plurality of rows of V-shaped groove groups A to E and secondary grooves 7, 7,... And is easily manufactured by the following manufacturing method.

In FIG. 7, reference numeral 11 denotes a plurality of V-shaped groove groups A to E in the first to fifth rows as the above-mentioned main grooves.
The first engraving roll 12 having an engraved surface 11a corresponding to the above is formed between the V-shaped grooves 3, 3... Of the first to fifth plural rows of grooves A to E. Ridges 5,
A second engraving roll having an engraved surface 12a for engraving fine grooves 7, 7 extending from one side surface to the other side surface, for example, in a spiral direction.
13 is a plate-shaped heat transfer tube material, 16 is a heating device for heating and softening the heat transfer tube material 13 during roll forming,
Reference numeral 14 denotes a first pressing roller for pressing the flat heat transfer tube material 13 between the first engraving roll 11 and 15 denotes a flat heat transfer tube between the second engraving roll 12 and the second pressing roll 12. A second pressing roller 17 for pressing the material 13 is connected to the first to fifth plural rows of V-shaped groove groups A to E, 2 through the first and second marking rolls 11 and 12. Next groove 7,7 ...
Is a roll forming apparatus having a roll forming hole 17a for forming the heat transfer tube material 13 which has been formed and heat-softened by the heating device 16 into a circular tube, the first stamping roll 11 and the first The pressure roller 14, the second engraving roller 12 and the second pressure roller 15, the heating device 16, and the roll forming device 17 are respectively arranged at predetermined intervals in the moving direction of the heat transfer tube material 13 (see arrows). Are installed side by side.

Therefore, in the apparatus for manufacturing a heat transfer tube with internal grooves, the first to fifth rows of V-shaped groove groups A to E are provided.
A first marking roll 11 and a first pressure roller 14 for marking the first and fifth plural rows of V-shaped grooves A
To E, the ridges 5, 5 formed between the grooves 3, 3,...
, A second stamping roll 12 and a second pressure roller 15 for stamping the secondary grooves 7, 7,..., And a heating device for forming the heat transfer tube material 13 in a flat state into a cylindrical tube. 16 and the roll forming device 17, the first and second engraving rolls 11 and 12 are sequentially rotated with respect to the heat-transfer-tube material 13 in the flat-plate state, and the first to fifth plural rows of V .. And the above-mentioned secondary grooves 7, 7... Are continuously engraved in two stages.
After the heat transfer tube material 13 is heated and softened by the heating device 16, it can be roll-formed by the roll forming device 17 to form a cylindrical tube.

That is, in the method and the apparatus for manufacturing the heat transfer tube with inner grooves, the first and second marking rolls 11 and 1 are provided.
By simply combining the two in the moving direction of the heat transfer tube material 13 in a flat state and engraving them sequentially in two stages, it is possible to easily manufacture the heat transfer tube with the inner surface groove as shown in FIG. 7 and FIG.

(Other Embodiments) In each of the embodiments described above, an electric resistance welded tube type heat transfer tube has been described as an example. However, the inner surface groove structure of each of the above embodiments is, for example, a seam tube type heat transfer tube. It goes without saying that the same can be applied to the case of a heat tube.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view showing a structure of a tube main body of an internally grooved heat transfer tube according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view of a main part of an inner peripheral surface of the pipe main body.

FIG. 3 is a perspective view of a cut portion of a main part of the inner peripheral surface of the pipe main body.

FIG. 4 is an enlarged view showing a structure of a main part of an inner peripheral surface of a tube main body of an internally grooved heat transfer tube according to a second embodiment of the present invention.

FIG. 5 is an enlarged perspective view of the main part.

FIG. 6 is a perspective view of a cut portion of a main part of the inner peripheral surface of the pipe main body.

FIG. 7 is an enlarged view showing a structure of a main part of an inner peripheral surface of a tube main body of an internally grooved heat transfer tube according to Embodiment 3 of the present invention.

FIG. 8 is an enlarged perspective view of a cut portion of the main part.

FIG. 9 is a perspective view showing a configuration of a method and an apparatus for manufacturing a heat transfer tube with an inner surface groove according to Embodiment 2 of the present invention.

[Explanation of symbols]

1 is a heat transfer tube, 1a is a tube main body, 3 is a V-shaped groove, 5 is a ridge, 5a is a top, 5b is a base, 6, 7 is a secondary groove, 11
Denotes a first stamping roll, 12 denotes a second stamping roll, 16 denotes a heating device, and 17 denotes a roll forming device.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kanji Akai 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries Inside Kanaoka Plant of Sakai Seisakusho Co., Ltd. (72) Inventor Tetsuaki Okamoto 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries, Ltd. Inside the Sakai Plant Kanaoka Plant (72) Inventor Yu Uchimitsu 1304 Kanaokacho, Sakai City, Osaka Daikin Industries Inside the Sakai Plant Kanaoka Plant

Claims (7)

[Claims] 1. A plurality of rows of V-shaped grooves (3), (3),... Symmetrical in the pipe axis direction on an inner peripheral surface (2) of a pipe body (1a).
, And the plurality of rows of V-shaped grooves (3), (3)...
Characterized in that the width in the circumferential direction of the heat transfer tube is unequal. 2. A plurality of rows of V-shaped grooves (3), (3).
.. at least a part of the ridges (5), (5),... Formed between the grooves (3), (3). The heat transfer tube with an inner surface groove according to claim 1, wherein secondary grooves (6) having a predetermined depth are formed toward the 5b) side. 3. The heat transfer tube with an inner surface groove according to claim 2, wherein the secondary grooves (6), (6)... Are cutout grooves in a spiral direction. 4. A plurality of rows of V-shaped grooves (3), (3).
.. at least a part of the ridges (5), (5),... Formed between the grooves (3), (3),. The heat transfer tube with inner grooves according to claim 1, wherein secondary grooves (7) are formed. 5. The secondary grooves (7), (7)... Are fine grooves extending from one side surface to the other side surface of the convex ridge portions (5). The heat transfer tube with an inner surface groove according to claim 4, characterized in that: 6. A first engraving roll (11) for engraving a plurality of rows of V-shaped grooves (3), (3),... At least one of the ridges (5), (5),... Formed between the V-shaped grooves (3), (3),. And a second marking roll (12) for marking secondary grooves (7), (7).
Roll forming device (1) for forming 3) into a cylindrical tube
7), the first and second engraved rolls (11), (1) are sequentially applied to the flat heat transfer tube material (13).
2) The V-shaped grooves (3), (3).
··· and the secondary grooves (7), (7)... Are continuously engraved and then roll-formed by the roll-forming device (17) to form a cylindrical tube. Of manufacturing heat transfer tubes with internal grooves. 7. A first engraving roll (11) for engraving a plurality of rows of V-shaped grooves (3), (3)... In a flat plate-like heat transfer tube material (13). At least one of the ridges (5), (5),... Formed between the V-shaped grooves (3), (3),. And a second marking roll (12) for marking secondary grooves (7), (7).
Roll forming device (1) for forming 3) into a cylindrical tube
7) are sequentially arranged in the moving direction of the flat heat transfer tube material (13), and the first and second marking rolls (1) are arranged in parallel.
The V-shaped grooves (3) and (3) are sequentially formed according to 1) and (12).
.. And the secondary grooves (7), (7),... Are successively engraved, and then roll-formed by the roll-forming device (17) to form a cylindrical tube. For manufacturing heat transfer tubes with internal grooves.