JPH116588A - Pipe made of composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily fix a flange body to an end part and stand large shaft force. SOLUTION: This pipe is a pipe body 1 made of a composite material in which a metallic short pipe 2 is arranged at the end part and a fiber layer is formed by covering the surface of the short pipe 2. In the short pipe 2, a large diameter part 2a is formed at the center part and a first contracted part 2b and a second reduced part 2c are formed at both side thereof. The first contracted part 2b is formed on the surface contracted from the large diameter part 2a toward the end part of the short pipe 2. The pipe body 1 is constituted so that the pipe body 1 may bear shaft force generated in the pipe body 1 by converting the force into radial force and is constituted by further fixing a flange body 6 to the short pipe 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite pipe, and more particularly, to a fiber reinforced plastic pipe having an improved joint.

[0002]

2. Description of the Related Art In general, composite pipes (hereinafter referred to as FRP pipes), which are plastics reinforced with high-strength fibers such as glass fibers and carbon fibers, are used when joined to other structures. In this case, a plastic or metal flange is bonded and fixed to the end of the FRP pipe, and a bolt is tightened between the flange and the structure. The flanges are bolted together to join the FRP pipes.

[0003] Further, a method has been practiced in which the inner diameter of the end of the FRP pipe is expanded in accordance with the outer diameter of the pipe to be joined, which is fitted to the pipe and joined with an adhesive.

[0004]

In the method of bonding the flange to the end of the FRP pipe as described above, since the fiber layer cannot be provided up to the flange portion, the joining strength between the FRP pipe and the flange is not so high. In order to increase the joining strength, a special structure having a short pipe portion to be joined to the pipe portion on the flange must be used. However, even if such a flange is used, it cannot sufficiently counter the tension acting in the axial direction of the pipe.

On the other hand, when the end of the FRP pipe is enlarged in accordance with the pipe to be joined, the FRP
It is necessary to enlarge the end of the RP pipe, which makes it difficult to form a pipe section of accurate dimensions, increases the manufacturing cost, and has a problem in product management.

In recent years, marine development in relatively deep sea areas has been active, and one of them is oil drilling using riser pipes. This riser pipe may have a length of up to 2000 m, and when the riser pipe is a metal pipe, its weight is large, and thus a large axial tension (axial force) is generated. There is a problem that must be used. Therefore, a method of using an FRP pipe to reduce the generation of the large axial force has been studied.

[0007] Since the FRP pipe is lighter in weight than the metal pipe, it is possible to greatly reduce the axial force as compared with the metal pipe. However, there is a problem in the structure of the joint, and the strength is reduced. There is a problem that must be improved. An object of the present invention is to provide an FRP pipe in which a flange, particularly a metal flange, can be easily attached to an end.

[0008]

[Means for Solving the Problems]

A) The present invention has been made to solve the above-mentioned problems of the prior art, and a metal short tube is arranged at at least one end, and a fiber layer is covered over the surface of the short tube. In the formed composite pipe body, the short pipe has a large-diameter portion at a central portion, and a first reduced portion and a second reduced portion formed on both sides thereof, and the first reduced portion is The pipe is formed on a surface reduced from the large diameter portion toward the end of the short pipe, and the first reduced portion converts an axial force generated in the pipe body into a radial force and bears the same. Further, a flange body is fixed to the short pipe.

B) A screw portion is formed on the inner surface of the first reduced portion of the metal short tube, and the screw portion formed on the short tube portion of the flange body is screwed and fixed to the screw portion. doing. Further, the first reduced portion of the metal short tube is formed on a surface whose cross section is reduced in an arc shape toward the end of the short tube. C) The first reduced portion of the metal short tube is formed on a surface whose cross section is conically reduced toward the end of the short tube.

D) A composite pipe body in which a short pipe made of metal is disposed at at least one end and a fiber layer is formed so as to cover the surface of the short pipe, and the short pipe is formed in a central portion. A first reduced portion and a second reduced portion are formed on both sides of the large diameter portion, and the first reduced portion has a surface reduced from the large diameter portion toward the end of the short pipe. The first reduced portion is configured to convert the axial force generated in the pipe body into a radial force and bear the same, and at least the first reduced portion is provided with the tubular portion at the fiber layer. The flange body is extended so as to protrude outward, and a flange body is fixed to the extended portion.

E) The cross-sectional shape of the first reduced portion may be deformed into an arc shape or a conical shape, or a similar shape in some cases. In the present invention, the pipe member is formed by the first reduced portion. It is characterized in that the axial force generated in the above is converted into a radial force to bear it.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a cross-sectional view of an end portion of a composite pipe according to the present invention, showing a pipe section 1 of a composite pipe P made of high-strength fibers such as carbon fiber, glass fiber, or aramid fiber and plastic. A short pipe 2 made of metal is embedded in the inner diameter of the end, and a joining portion 4 formed by a thick portion 3 made of a fiber layer is formed surrounding the short pipe 2.

The short tube 2 has a large diameter portion 2a at an intermediate portion,
An arc-shaped first reduced portion 2b having a small cross section is provided on one end portion of one of the pipe portions 1 of the large-diameter portion 2a, and a conical second reduced portion 2c is provided on a main portion of the pipe portion 1. Are formed, and the inner diameter of the short pipe 2 matches the inner diameter of the pipe portion 1.

The operation of each section of the short pipe 2 will be described. The first reduced section 2b formed at the end of the pipe section 1 is generated in the pipe section 1 via the thick section 3 formed of a fiber layer. This axial force is converted into a force in the radial direction to act to compress the first reduced portion 2b, and is a portion that distributes and bears the axial force, and plays an important role.

Therefore, when an axial force acts, the braided or arranged fiber layers are caught and spread on the first reduced portion 2b, and the fiber layer is bonded to the first reduced portion 2b. Even if the strength is not so large, it can withstand a large axial force.

In this embodiment, the second reduced portion 2c for reducing the diameter from the large diameter portion 2a to the inner diameter portion of the pipe portion 1 has a gentle conical surface. The radial force converted by the portion 2c is converted into an axial force directed toward the pipe portion 1 at this portion. In this sense, the second reduced portion 2c smoothly moves from the large diameter portion 2a to the pipe portion 1. It is good to adopt an external shape that generates force.

As shown in FIG. 1, the second reduced portion 2c may be a conical shape or an arc-shaped cross section slightly bulging to the outer surface. Further, the thick portion 3 is a portion composed of a fiber layer formed so as to surround the outer peripheral portion of the short pipe 2, and at the end of the pipe portion 1, in the radial direction due to the action of the portion of the first reduced portion 2 b. The converted axial force is borne by adjusting the thickness thereof, so that the joint 4 can be formed short by adjusting the thickness. In FIG. 1, the outer shape of the thick portion 3 is formed by a columnar portion and a conical portion, but this portion has a gentle curved surface extending from the columnar portion to the pipe portion 1. You may do it.

A thread 5 is formed on the inner diameter of the short tube 2 on the first reduced portion 2b side, and a flange 6 composed of a flange 6a and a short tube 6b is formed on the short tube 6b. A screw portion 6c formed on the outer peripheral surface is screwed into the screw portion 5 to fix the flange body 6 to the end of the joint portion 4. The flange body 6 faces the flange body of a pipe (not shown) to be connected, and the two are connected by bolting.

Next, the manufacturing process of the composite pipe P will be described with reference to FIGS. As shown in FIG.
The short pipes 2A and 2B made of metal are fitted to both ends of the mandrel 10. As shown in FIG. 3, while attaching and rotating the mandrel 10 to a spindle of a filament winding device (not shown), the short fibers 2A and 2B and the glass fiber are formed on the peripheral surface of the mandrel 10 therebetween by the filament winding method. Fiber 11 such as carbon fiber
Is wound while being traversed as indicated by an arrow through a traverse device 11a to form a fiber layer 11a having a predetermined thickness.
To form

Next, the unreacted plastic material surrounding the fiber layer 11a through the filament winding step shown in FIG. 3 is polymerized by heating or the like according to a conventional method, and as shown in FIG. To produce a prototype.

Next, the mandrel 10 arranged at the center of the original model of the pipe P is extracted to produce a composite pipe P of a predetermined length. When the preparatory step shown in FIG. 2 is completed, a layer of a release agent or a layer of a sheet material or the like having the same effect as above is formed so that plastic does not adhere to the outer surfaces of the mandrel 10 and the short tubes 2A and 2B. Keep it.

In FIG. 4, when the mandrel 10 is pulled out from the composite pipe P to obtain the state shown in FIG. 5, short pipes 2A and 2B are built in both ends of the pipe P as shown in FIG. Then, the screw portion 6c of the short tube portion 6b of the flange body 6 is screwed and fixed to the screw portion 5 of the short tube 2A, 2B, and the flange portion 6a is fixed to both ends of the pipe P.

FIG. 6 shows a cross section of a joint 4 of a composite pipe P showing another embodiment of the present invention. A large diameter portion 20a is formed at the center of a short pipe 20. The first reduced portion 20b and the second reduced portion 2 having an arc-shaped cross section on both sides of the
0c is formed gently, and the ends of the first and second reduced portions 20b and 20c are further formed into tubular portions 20d and 20e.
Have been extended.

The expanded end portion 1B of the pipe portion 1A is formed by the filament winding process shown in FIG. 7 so as to cover the surface of the short tube 20, and this portion corresponds to the joint portion 4 shown in FIG. I have. After extracting the mandrel 10 from the pipe P, the flange body 6A is fitted to the tubular portion 20d side and fixed by the welded portion 6d.

In the embodiment shown in FIG. 6, the first reduced portion 20b and the second reduced portion 20c are formed in an arc-shaped cross section. It may be a composite shape of an arc and a cone.
According to the composite pipe of the present invention, the short pipes 2 and 20 made of metal are built in the end of the pipe P.
The flange members 6 and 6A can be easily fixed by utilizing 0.

Moreover, the short pipes 2 and 20 have large-diameter portions 2a and 20a at the center, first reduced portions 2b and 20b at the end of the pipe P, and second reduced portions 2b and 20b at the pipes 1 and 1A. Reduction part 2 of
c and 20c, respectively, so that these first
Since the axial force acting on the pipe P via the fiber layer as a reinforcing material can be converted into a radial force by the reduced portions 2b and 20b, and the load can be dispersed and loaded, it is possible to withstand a considerably large axial force. it can.

Therefore, the composite pipe according to the present invention can be effectively used for a long riser pipe for oil drilling.

[0028]

According to the present invention, a short pipe made of metal is incorporated at the end of a composite pipe reinforced with a fiber layer, and this short pipe has a reduced portion formed at least at the end of the pipe. A fiber layer is formed so as to cover the short tube. Therefore, the axial force generated in the pipe by the reduced portion is formed so as to be dispersed and supported by converting it into a radial force, and further, a threaded portion formed on the inner surface of the short pipe, or a tubular portion extended from the reduced portion A separate flange body is fixed to the body.

Therefore, according to the present invention, it is possible to easily attach the flange body by using the short pipe built in the end of the composite pipe. The short pipe converts the axial force of the pipe into a radial force by a reduced portion formed on the end side of the pipe and disperses and bears the load. Therefore, the short pipe withstands a large axial force despite being a composite pipe. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a joint at an end of a composite pipe.

FIG. 2 is a perspective view showing a manufacturing process of the composite pipe.

FIG. 3 is a perspective view showing a manufacturing process of a composite pipe.

FIG. 4 is a perspective view showing a manufacturing process of the composite pipe.

FIG. 5 is a perspective view showing a state where a flange body is screwed to both ends of a manufactured composite pipe.

FIG. 6 is a sectional view of an end portion of the composite pipe according to the embodiment.

FIG. 7 is an explanatory diagram of a manufacturing process of the composite pipe shown in FIG. 6;

[Explanation of symbols]

P Composite material pipe 1, 1A Pipe part 2, 2A, 2B Short pipe 2a Large diameter part 2b First reduced part 2c Second reduced part 3 Thick part 4 Joining part 5 Screw part 6, 6A Flange
6a Flange 6b Short pipe 6c Screw 6d Weld

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI F16L 9/16

Claims (5)

[Claims] 1. A composite pipe body in which a short metal tube is disposed at at least one end and a fiber layer is formed so as to cover the surface of the short tube. Forming a first reduced portion and a second reduced portion on both sides of the diameter portion;
The first reduced portion is formed on a surface reduced from the large diameter portion toward the end of the short tube, and converts the axial force generated in the pipe body into a radial force by the first reduced portion. A composite pipe comprising a flange body fixed to the short pipe. 2. A metal short tube having a screw portion formed on an inner surface of a first reduced portion, and a screw portion formed on a short tube portion of a flange body is screwed and fixed to the screw portion. Item 7. A composite pipe according to Item 1. 3. The composite pipe according to claim 1, wherein the first reduced portion of the metal short tube is formed on a surface whose cross section is reduced in an arc shape toward an end of the short tube. 4. The composite pipe according to claim 1, wherein the first reduced portion of the metal short tube is formed on a surface conically reduced toward the end of the short tube. 5. A composite pipe body in which a metal short pipe is arranged at at least one end and a fiber layer is formed so as to cover the surface of the short pipe. Forming a first reduced portion and a second reduced portion on both sides of the diameter portion;
The first reduced portion forms a surface reduced from the large diameter portion toward the end of the short pipe, and converts an axial force generated in the pipe body by the first reduced portion into a radial force. A composite material comprising a tubular portion extending at least in the first reduced portion so as to protrude outside the fiber layer, and a flange body fixed to the extended portion. Pipes.