JP4687931B2 - Complex pipe manufacturing equipment - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a composite pipe manufacturing facility in which an outer pipe and an inner pipe are integrally coupled.
[0002]
[Prior art]
Steel pipes are used to transport various liquids such as water, hot water, and chemicals, gases such as gas, and particulate matter in a wide range of industries such as industry and industry.
However, since steel pipes are rusted and corrode when used for a long time, they are treated for rust prevention and corrosion resistance. For example, a coating surface is formed in the steel pipe by galvanizing or painting to protect the metal surface, but it is difficult to form a uniform coating surface without generating bubbles in the steel pipe. It is. Furthermore, the coating surface may be peeled off due to the flow pressure of the liquid or the flow friction of the granular material, and the metal material will corrode from this peeled surface, so it has an excellent effect on long-term rust prevention and corrosion resistance. It did not have, and it required a lot of expenses for maintenance and management.
[0003]
As described above, rusted and corroded steel pipes are not suitable for transfer because they contaminate the circulating liquid and cause liquid leakage. In the food, pharmaceutical, and chemical industries, various types of granular materials are used as raw materials for products. However, the use of corroded steel pipes for transportation is extremely inappropriate from the standpoint of hygiene and product management. is there. In the case of a gas such as gas, there is a risk of causing gas leakage from small holes formed by corrosion.
[0004]
Therefore, a composite pipe is provided in which a metal pipe (inner pipe) of another material having rust prevention and corrosion resistance is tightly inserted into the steel pipe (outer pipe), and the outer pipe and the inner pipe are integrally joined. Yes.
Conventionally, an adhesive is generally used as a means for connecting the outer tube and the inner tube, and means for using an insert material such as a plating layer is provided. In addition, there is provided means for wrapping and joining the inner tube within the outer tube by mechanical processing means.
[0005]
[Problems to be solved by the invention]
When connecting the outer tube and the inner tube with an adhesive, first, the adhesive is poured into the outer tube from the upper end opening while rotating the outer tube in an inclined state in the circumferential direction. The inner tube is fitted into the outer tube in the applied state. However, in this case, prior work for polishing and cleaning the joint surfaces such as the inner surface of the outer tube and the outer surface of the inner tube is required.
[0006]
In addition, when the inner tube is fitted into the outer tube in a state where there is not much dimensional difference between the inner diameter of the outer tube and the outer diameter of the inner tube, that is, in the case of a dimensional difference in which the inner tube can be forcibly fitted into the outer tube. The tip edge of the inner tube peeled off the adhesive applied to the outer tube, and the bonding and bonding were not perfect.
[0007]
Therefore, the inner diameter of the outer tube is made slightly larger than the outer diameter of the inner tube to make it easier to fit the inner tube into the outer tube, and after the adhesive has been applied to the outer tube as described above, the inner tube is fitted. The outer tube is drawn and reduced by a drawing mill, the entire outer tube is reduced in diameter in the circumferential direction, and the outer tube and the inner tube are bonded and bonded together in a pressure contact state.
[0008]
However, if the outer tube is not evenly rolled with respect to the inner tube, the concentric position of the outer tube and the inner tube is shifted, resulting in a gap between the outer tube and the inner tube and insufficient adhesion. It was happening. Furthermore, the bonding with the adhesive generally has a risk that the adhesive deteriorates due to a change with time, and the outer tube and the inner tube are peeled off.
[0009]
When an insert material such as a plating layer is interposed between the outer tube and the inner tube, they are joined by hot extrusion or hot working, but a metal material with poor hot workability is used as the inner tube. When this occurs, the inner pipe is cracked, or the outer pipe and the inner pipe are in a state in which they cannot be completely joined due to the difference in deformation resistance.
[0010]
For example, Japanese Patent Laid-Open No. 4-59141 is provided as a technique for joining an outer tube and an inner tube by a mechanical processing means. This known technique is to form a steel tube gradually in a cylindrical shape in the process of transferring a room temperature steel strip from a plurality of horizontal axis roll groups 1 to a vertical axis roll 5. Then, in this steel pipe forming process, that is, the inner pipe is introduced into the steel pipe from the opening in a state where the steel pipe is not completely formed yet and the upper surface is opened along the length direction, and the inner pipe and the steel pipe are connected. The steel pipe is elastically pressed by the longitudinal axis roll 5 while being transferred at the same time, thereby closing the upper opening 12 of the steel pipe and finally forming a composite pipe in which the inner pipe is inserted into the outer pipe. This composite pipe is reduced in size by drawing, and after the steel pipe and the inner pipe are physically fixed, the seam of the steel pipe is welded.
[0011]
In the case of such a mechanical work, a plurality of horizontal axis rolls are required to form the steel strip into a cylindrical shape, and both are combined while putting the inner tube into a cylindrical body whose upper surface is opened, and A means for narrowing down, a welding means, and the like are required, the apparatus becomes large, and a skillful technique is required to maintain the roundness, and maintenance of the entire apparatus is difficult.
[0012]
In view of the above-described conventional composite pipe manufacturing methods and manufacturing techniques, the present invention expands the inner pipe after fitting the inner pipe reduced in diameter into the outer pipe and presses the inner pipe against the outer pipe. An object of the present invention is to provide a facility capable of easily manufacturing a composite pipe without using an adhesive or an insert material.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the composite pipe manufacturing facility of the present invention has a rotation holding unit 2, a rotation support unit 3 and a reciprocating movement unit 4 arranged in a straight line on a base 1, and the rotation holding unit 2 is The base 10 of the outer tube 8 having the inner tube 20 with a reduced diameter is fixed to hold the outer tube 8 in a horizontal state, and the support 10b can be opened and closed on the support 10a fixed on the base 1 so as to be movable. The support 10 that can be connected to a shaft to form an annular body includes a rotation support portion 3 in which a plurality of arms 12 provided with a support roll 13 that can be rotated at the tip are provided obliquely toward the center of the annular body. The outer tube 8 and the inner tube 20 are rotatably supported between the rotation holding portion 2 and the rotation support portion 3 by supporting the intermediate portion and / or the distal end portion of the outer tube 8, and can be reciprocated toward the rotation holding portion 2. The movable body 17 of the reciprocating moving unit 4 has a length that extends horizontally toward the rotation holding unit 2. A base fixed to Do support arm 18, and the apparatus for manufacturing a composite pipe where the pressure can be the pressure member 19 to the inner peripheral surface of the inner tube 20 is provided at the distal end of the support arm 18, a long form extended in the horizontal direction soy in the longitudinal direction of the inner tube 20 by the pressure roll 28 and 29 pivotally attached to the distal end of the support arm 26, 27 of the bottom a pair above and a plurality of reduced diameter contouring groove 25 toward the radially It consists of a diameter-reducing device that can be formed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a state in which the entire manufacturing apparatus of a composite pipe used in the manufacturing facility of the present invention is viewed from the side, and a rotation holding portion 2, a rotation support portion 3 and a reciprocating movement portion 4 are provided on a base 1. It is installed in a line in a straight line.
[0015]
The composite tube is composed of an outer tube and an inner tube fitted in the outer tube, and the rotation holding unit 2 provides the rotation supporting unit 3 and the reciprocating unit 4 with the inner tube fitted in the outer tube and the outer tube. The outer tube and the inner tube are rotated in the circumferential direction, and a holder 5 projects from the front portion of the rotation holding unit 2.
[0016]
As shown in FIGS. 2 and 3, the holder 5 is provided with a fitting hole 6 in the center of the front surface and a fastening tool 7 in the radial direction adjacent to the fitting hole 6. The base portion of the outer tube 8 forming the composite tube can be fitted into the joint hole 6.
[0017]
By placing the outer tube 8 in a horizontal state and fitting the base portion into the fitting hole 6 and tightening the outer tube 8 from around with a fastener 7, the base portion of the outer tube 8 is fixed and held in a horizontal state. Become. The holder 5 is directly connected to the drive shaft of the drive motor 9 installed in the rotation holding unit 2, and is externally held in a horizontal state by rotating the holder 5 in the circumferential direction by the drive motor 9. The tube 8 will also rotate at the same time.
[0018]
As the fastener 7, for example, a chuck used in a conventional machine tool can be used as it is, and the outer tube 8 is attached by press-contacting a plurality of chuck tips provided in the radial direction around the outer tube 8. Can be tightened and fixed. Alternatively, a plurality of bolts provided in the radial direction can be used.
[0019]
That is, a plurality of bolts may be screwed into the holder 5 in the radial direction in the vicinity of the fitting hole 6, and the tip of the bolt may be pressed against the peripheral surface of the outer tube 8. After all, as long as the outer tube 8 is held horizontally and can be rotated, the fixing means of the outer tube 8 is not questioned.
In addition, the holder 5 from which the magnitude | size of the fitting hole 6 differs according to the outer diameter of the outer tube | pipe 8 can be used.
[0020]
The rotation support part 3 rotatably supports the intermediate part and the tip part of the outer tube 8 held horizontally by the holder 5 as described above, and is positioned concentrically with the fitting hole 6. It has a plurality of support rolls. That is, as shown in FIG. 4, a pair of support tools 10 that can form an annular body as a whole are rotatably connected at one end to a shaft 11, and one support tool 10 a is movable on the base 1. The other support tool 10b can be opened and closed with respect to the support tool 10a about the shaft 11.
[0021]
Two arms 12 are provided in the support tool 10a symmetrically in an oblique state toward the center of the annular body formed by the support tool 10a and the support tool 10b. A possible support roll 13 is provided. A support roll 13 is also provided at the tip of the arm 12 provided at the center of the support 10b.
[0022]
When the support 10b in the released state in FIG. 4 is closed and the ends of the support 10a and the support 10b are connected and fixed to form an annular support 10, the three pieces positioned in the radial direction are provided. The support roll 12 is positioned concentrically with the fitting hole 6 of the holder 5. Therefore, the outer tube 8 is supported horizontally and linearly between the holder 5 and the rotation support portion 3.
[0023]
In order to fix the support tool 10a and the support tool 10b to the annular body, for example, the U-shaped flange 14 provided at the tip of the support tool 10b, and the fixing tool 15 provided at the tip of the support tool 10a Can be done. One end of this fixing tool 15 is screwed into a fixing screw 16 provided at the tip of the support tool 10a so as to be rotatable in the vertical direction, and the screw 15 is fitted with the ends of the support tool 10a and the support tool 10b being aligned. 16 is inserted into a U-shaped groove (not shown) of the flange 14, and the fixture 15 is tightened along the screw 16. The lower end of the fixture 15 abuts against the upper surface of the flange 14, and both supports 10a. Both end portions of 10b are fixed (see FIG. 13 described later). Alternatively, a known appropriate instrument may be used as a fixing means for the support tool 10a and the support tool 10b.
[0024]
The rotation support part 3 can change the stationary position according to the length of the outer tube 8 by making it movable on the base 1 toward the holder 5. Further, a plurality of rotation support portions 3 may be installed according to the length of the outer tube 8. Furthermore, each arm 12 can determine the protruding position of each support roll 13 in accordance with the outer diameter of the outer tube 8 by changing the inward protruding length to be fixed to the supporting tools 10a and 10b. .
[0025]
The reciprocating unit 4 includes a moving body 17 that can reciprocate on the base 1 with respect to the holder 5 and a long support arm 18 that extends horizontally toward the holder 5. A pressure member 19 is provided at the tip of the support arm 18 whose base is fixed on the body 17. As the pressure member 19, a rolling roller that can rotate around the support arm 18 can be used.
[0026]
The support arm 18 and the pressurizing member 19 are located at substantially the same height as the outer tube 8, and the pressurizing member 19 is inserted into the inner tube fitted into the outer tube 8, and pressure is applied to the inner surface of the inner tube. Is to give. Therefore, as shown in FIG. 5, the support arm 18 is inclined with respect to the linear direction of the outer tube 18 and the inner tube 20, and the distal end is obtained by inserting the support arm 18 into the inner tube 20. The pressure member 19 is pressed against the inner surface of the inner tube 20. The tilt direction of the support arm 18 is not limited to the horizontal direction with respect to the inner tube 20 as shown in the figure, but may be tilted in any direction.
[0027]
In order to reciprocate the moving body 17, for example, a known rotation guide member 21 such as a ball screw or a ball screw can be used. That is, as shown in FIGS. 1 and 5, a rotation guide member 21 is provided horizontally on the side surface of the base 1, and one end of the rotation guide member 21 screwed into the movable body 17 is rotatably held on the base 1. At the same time, the other end of the rotation guide member 21 is directly connected to a drive shaft of a drive motor 22 that can be reversed and installed in the rotation holding unit 2.
[0028]
When the rotation guide member 21 is rotated in one direction by the drive motor 22 and the moving body 17 is advanced in the direction of the holder 5, the pressure member 19 enters deep inside the inner tube 20. Further, when the rotation guide member 21 is rotated in the other direction, the moving body 17 moves backward, so that the pressure member 19 is pulled out while being pressed against the inner surface of the inner tube 20.
[0029]
Reference numeral 23 denotes a movement guide member provided in parallel with the rotation guide member 21. The movement guide member 23 penetrates through the movable body 17 and both ends are fixed to the base 1, and the movable body 17 can reciprocate stably along the movement guide member 23. Alternatively, instead of the rotation guide member 23, the moving body 17 may be fitted into a moving groove provided on the upper surface of the base 1, and moved along the groove.
[0030]
Although the case where the support arm 18 is disposed in an inclined manner with respect to the outer tube 8 and the inner tube 20 has been described, the present invention is not limited to this. For example, as shown in FIG. 6, the support member 18 is parallel to the inner tube 20 and is offset from the inner tube 20 so that the pressurizing member 19 is pressed to the inner surface of the inner tube 20. Can do.
[0031]
Further, when the support arm 18 is inclined with respect to the inner tube 20 or is eccentric in parallel, the base portion of the support arm 18 is pivoted horizontally above the movable body 17 as shown in FIG. The pressure member 19 can be brought into pressure contact with the inner surface of the inner tube 20 by connecting the support arm 18 and imparting a pressing behavior in one direction by the tensile force or extension elasticity of the elastic body 24 such as a spring.
[0032]
In the above description, the case where the rotation guide member 21 such as a ball screw or a ball screw is used to reciprocate the moving body 17 is described. However, the present invention is not limited to this. For example, a circulatable chain is used. Can do. In other words, the chain is attached to the sprockets provided at both ends of the side surface of the base 1, one sprocket is directly connected to a reversible drive motor, and the chain and the moving body 17 are connected, and the chain circulates in one direction. Thus, the moving body 17 can be moved forward toward the holder 5, and the moving body 17 can be moved backward by circulating the chain in the reverse direction. Furthermore, it is also possible to reciprocate the moving body 17 by a cylinder, and it is possible to freely select what kind of mechanism the moving guide member is used.
[0033]
The composite pipe manufacturing apparatus is configured as described above. Next, the outer pipe 8 and the inner pipe 20 forming the composite pipe will be described.
In the present invention, the inner tube 20 having a large outer diameter of about 0.1 to 0.4 mm is normally used with respect to the inner diameter of the outer tube 8. Therefore, the inner tube 20 cannot be inserted into the outer tube 8 as it is. Therefore, the inner tube 20 is reduced in diameter in the circumferential direction to the extent that the inner tube 20 can be inserted into the outer tube 8, and the reduced inner tube 20 is placed in the outer tube 8, By forcibly expanding the diameter of the tube 20, the outer tube 8 and the inner tube 20 can be tightly coupled. A steel pipe is used as the outer pipe 8, and a material such as rust prevention, corrosion resistance, and chemical resistance, for example, a stainless pipe is used as the inner pipe 20.
[0034]
In order to reduce the diameter of the inner tube 20, as shown in FIG. 8, a plurality of diameter-reducing grooves 25 formed along the length direction of the inner tube 20 are provided along the circumferential direction of the inner tube 20. The diameter of the inner tube 20 decreases on average by the formation of the diameter-reducing groove 25, and the inner tube 20 that cannot be normally fitted into the outer tube 8 is inserted into the outer tube 8 as described above. It will be able to fit inside. And in order to form this diameter reduction groove | channel 25, the diameter reduction apparatus which consists of a pair of upper and lower pressure rolls is used.
[0035]
As shown in FIGS. 9 and 10, this diameter reducing device can rotate pressure rolls 28 and 29 to the tips of a pair of long upper and lower support arms 26 and 27 that are fixed in the horizontal direction with the base fixed. One of the pressure rolls, for example, the circumferential pressure surface 28a of the upper pressure roll 28 is formed so as to enter the circumferential pressure groove 29a of the lower pressure roll 29.
[0036]
More specifically, as shown in FIG. 11 and FIG. 12, when the inner tube 20 is pushed horizontally between the upper and lower pressure rolls 28 and 29 from the tip side, the pressure surface 28a of the pressure roll 28 and By the pressure groove 29a of the pressure roll 29, the diameter-reducing groove 25 is formed in the lengthwise direction of the inner tube 20 so as to be recessed in the radial direction.
[0037]
After forming the diameter-reducing grooves 25 over the entire length of the inner tube 20, a plurality of grooves 26 may be formed in the circumferential direction in the same manner. The width, depth, number, and the like of the reduced diameter grooves 25 to be formed can be selected as necessary as long as the inner tube 20 can be fitted into the outer tube 8. The width, depth, number, etc. of the diameter-reducing grooves 25 can also be selected according to the size of the outer diameter and the plate thickness.
[0038]
Next, a case where a composite pipe is formed by the outer pipe 8 and the inner pipe 20 reduced in diameter so as to be fitted into the outer pipe 8 will be described.
An operator manually inserts the inner tube 20 into the outer tube 8. In this case, the outer tube 8 and the inner tube 20 have the same length, or the inner tube 20 is slightly shorter. In this state, the end portion of the outer tube 8 is fitted into the fitting hole 6 formed in the holder 5 of the rotation holding portion 2 and fixed by the fastening tool 7.
[0039]
If the intermediate portion and / or the tip of the outer tube 8 is placed between the support members 10a and 10b in an open state, and the support member 10b is closed and fixed to the support member 10a, the outer tube 8 supports the holder 5 and the outer tube 8. It is held in a horizontal state between the tools 10a and 10b. Then, the moving body 17 is advanced toward the holder 5, and the pressurizing member 19 and the support arm 18 are inserted into the inner tube 20 until the pressurizing member 19 reaches the inner end of the inner tube 20.
[0040]
Then, when the movable body 17 is moved backward while rotating the holder 5 and the outer tube 8 in the circumferential direction by the drive motor 9, as shown in FIG. 13, the pressurizing member 19 pressed against the inner surface of the inner tube 20 is used. Since the diameter-reducing groove 25 is crushed by the outward pressure, it is flattened, and the inner tube 20 is enlarged in the outer circumferential direction and pressed against the inner surface of the outer tube 8. The
[0041]
By pressurizing all the plurality of grooves 25 formed in the circumferential direction in this way over the entire length, the inner tube 20 is expanded in the outward direction, and the inner peripheral surface of the outer tube 8 and the outer peripheral surface of the inner tube 20 are It becomes a tightly coupled state. In this way, the inner tube 20 is rolled by the pressurizing member 19 over its entire length and cannot be pulled out from the outer tube 8 by mechanical force when the diameter is expanded.
[0042]
The rotational speeds of the outer tube 8 and the inner tube 20 vary depending on the diameter of the outer tube 8 and the inner tube 20 that constitute the composite tube, the plate thickness of the inner tube 20, etc., but are extremely slow according to experiments. It can be selected freely except in the case of rotation or extremely fast high-speed rotation.
The drawing speed of the pressurizing member 19 can be arbitrarily selected according to the rotational speeds of the outer tube 8 and the inner tube 20, but the diameter reducing groove 25 is completely crushed to enlarge the entire peripheral surface of the inner tube 20. It is necessary. The pressurizing member 19 is not limited to the rolling roller, and may be a member fixed to the tip of the support arm 18 without rotating a circular member.
[0043]
Furthermore, although the case where the pressurizing member 19 performs the pressurizing operation while being pulled out from the inner end of the inner tube 20 is described, the pressurizing operation is performed while moving from the inlet end of the inner tube 20 toward the innermost end. You may do it.
[0044]
In the above description, the outer tube 8 and the inner tube 20 are cases where metal tubes are used. However, the outer tube 8 can be made of plastic instead of metal.
If the inner tube 20 is integrally connected to the plastic tube 8, the plastic tube 8 is reinforced and can be used for a long time.
[0045]
Moreover, in the plant which desalinates seawater, the glass fiber pipe | tube is used in order to transfer seawater and freshwater. However, when used for many years, the phenomenon of water oozing out from the minute gaps in the glass fiber is caused by water pressure. For this reason, the thickness of the tube is set to 4, 5 mm, but this makes the entire tube heavy and inconvenient to handle. In such a case, if the inner tube 20 is integrally coupled to the glass fiber tube according to the present invention, the thickness of the glass fiber tube can be reduced and water leakage can be prevented.
[0046]
【The invention's effect】
As described above, according to the present invention described above, the inner tube 20 that cannot be normally fitted in the outer tube 8 can be inserted into the outer tube 8 by reducing the diameter in the circumferential direction. By pressing the pressure member 19 against the inner peripheral surface of the inner tube 20 while rotating the tube 20 in the circumferential direction, the inner tube 20 is expanded in diameter toward the inner peripheral surface of the outer tube 8 by the applied pressure. 8 is tightly joined to the inner tube 20 and is in a fixed state.
Therefore, the outer tube 8 and the inner tube 20 can be integrally coupled without using an adhesive or brazing.
[0047]
On the base 1, the rotation holding unit 2, the rotation support unit 3, and the reciprocation unit 4 are installed in a straight line, and an inner tube 20 is fitted between the rotation holding unit 2 and the rotation support unit 3. A pressure member 19 is provided at the tip of the moving body 17 of the reciprocating unit 4 that holds the outer tube 8 in a horizontal state and can rotate in the circumferential direction and can reciprocate toward the rotation holding unit 2. Since the support arm 18 extends horizontally toward the rotation holding portion 2 and the pressurizing member 19 is movable from the inner end of the inner tube 20 to the inlet end while being pressed against the inner peripheral surface of the inner tube 20, The outer tube 8 and the inner tube 20 are brought into close contact with each other simply by expanding the diameter of the inner tube 20 by the pressure applied by the pressurizing member 19, and are brought into a coupled state.
[0048]
In order to reduce the diameter of the inner tube 20 in the circumferential direction, it is possible to pass the inner tube 20 between a pair of upper and lower pressure rolls 28 and 29 and to form a groove 25 for reducing the diameter of the inner tube 20 along the entire length. Such a diameter reduction operation can be easily performed in a short time by a manual operation by an operator.
[0049]
[Brief description of the drawings]
FIG. 1 is a side view of an entire apparatus used in the present invention.
FIG. 2 is a front view of a rotation holding unit installed on a base.
FIG. 3 is a side view of a rotation holding unit.
FIG. 4 is a front view of a state in which a pair of supports that can open and close the rotation support portion is opened.
FIG. 5 is a plan view, partly in section, showing the positional relationship between the outer tube, the inner tube and a support arm provided with a rolling roll.
FIG. 6 is a plan view of the support arm in an eccentric state with respect to the inner tube.
FIG. 7 is a plan view showing a state in which the support arm is given a pressing behavior in one direction with respect to the inner tube.
FIG. 8 is a front view of the inner tube in a reduced diameter state.
FIG. 9 is a side view of the diameter reducing device.
FIG. 10 is a plan view of the diameter reducing device.
FIG. 11 is an enlarged side view of a main part of the diameter reducing device.
FIG. 12 is a cross-sectional view of a diameter reducing device showing a state of reducing the diameter of an inner tube.
FIG. 13 is a front view of a state in which an inner tube in an outer tube provided between a rotation holding unit and a rotation support unit is rolled by a rolling roller.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base 2 Rotation holding part 3 Rotation support part 4 Reciprocating movement part 5 Holding tool 6 Outer tube fitting hole 7 Outer tube clamping tool 8 Outer tube 9 Drive motor 10 Support tool 11 Connecting shaft 12 Arm 13 Support roll 14 U-shaped flange 15 Fixing tool 16 Fixing screw 17 Moving body 18 Support arm 19 Pressurizing member 20 Inner tube 21 Rotating guide member 22 Drive motor 23 Moving guide member 24 Elastic body 25 Shrinking groove 26 Support arm 27 Support arm 28 Pressure roll 29 Pressure roll

Claims (1)

The rotation holding part 2, the rotation support part 3 and the reciprocating movement part 4 are installed in a line in a straight line on the base 1, and the rotation holding part 2 has a base part of the outer pipe 8 having an inner pipe 20 with a reduced diameter inside. A support 10 that can be fixed to hold the outer tube 8 in a horizontal state and can be axially connected to a support 10 a that is movably placed on the base 1 so that the support 10 b can be opened and closed to form an annular body. The rotation support part 3 provided with a plurality of arms 12 provided with a support roll 13 which can be rotated at the front end obliquely toward the center of the annular body supports the intermediate part and / or the front end part of the outer tube 8 and holds the rotation. The outer tube 8 and the inner tube 20 are rotatably supported between the unit 2 and the rotation support unit 3, and the movable body 17 of the reciprocating unit 4 that can be reciprocated toward the rotation holding unit 2 includes the rotation holding unit 2. The base of the long support arm 18 extended horizontally toward the end is fixed, and the tip of the support arm 18 is fixed. In the press can be pressure member 19 on the inner peripheral surface of the inner tube 20 and the manufacturing apparatus of a composite tube which is provided, pivotably to the tip of the elongated upper and lower pair of support arms 26, 27 extending in the horizontal direction A composite pipe characterized by comprising a diameter reducing device capable of forming a plurality of diameter reducing grooves 25 along the length of the inner pipe 20 by the attached pressure rolls 28 and 29 and extending in the radial direction. Manufacturing equipment.

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