JPH0226852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a tube having a connecting flange at one end, the tube being formed from a composite material containing a polytetrafluoroethylene layer and a thermosetting fiber-reinforced plastic layer. Regarding.

[Prior art and its problems]

Various components in various chemical plants are
Corrosion resistance against various chemical substances is required, as well as physical strength. In order to meet these demands, in recent years polytetrafluoroethylene (hereinafter sometimes abbreviated as "PTFE"), which has excellent corrosion resistance against chemical substances, and thermosetting fiber-reinforced plastics, which have high physical strength, have been developed. (hereinafter sometimes abbreviated as "FRP") to form various constituent elements from composite materials laminated together has been proposed and is beginning to be put into practical use.

In chemical plants, pipes having a connecting flange at one end, that is, flanged pipes are often used as components thereof. However, such a component has a unique shape due to the flange present at one end thereof, and therefore no suitable manufacturing method has been developed so far. For example, a tube member having a flange at one end is injection molded from polytetrafluoroethylene, and then a thermosetting fiber-reinforced plastic in a softened molten state is applied to the desired outer surface of the injection molded article and then hardened, thus forming a flanged tube. It is conceivable to manufacture However, in order to mold a pipe with a flange at one end by injection molding, a special mold is required, and unless a large number of identical flanged pipes are manufactured, the manufacturing cost becomes extremely high. I end up.

[Problem to be solved by the invention]

The present invention has been made in view of the above facts, and its main objective is to provide a manufacturing method that can form a flanged pipe made of a composite material containing a PTFE layer and an FRP layer at a sufficiently low cost. That is to say.

[Means for solving the invention] As a result of intensive research, the present inventor has developed an appropriate method for welding PTFE parts that cannot be welded together (for example,
36064), and found that the above problem can be achieved by a unique manufacturing method that involves fitting a PTFE annular plate onto one end of a PTFE pipe member and welding the two together. I found it.

That is, according to the present invention, as a method for manufacturing a flanged pipe that achieves the above problems, one end of a preformed polytetrafluoroethylene pipe member is
A preformed annular plate made of polytetrafluoroethylene having an opening with an inner diameter corresponding to the outer diameter of the tube member is fitted so that one end surface of the tube member and one side of the annular plate are substantially aligned; A welding process for welding the pipe member and the annular plate; After the welding process, a thermosetting fiber-reinforced plastic in a softened and molten state is applied to the other surface of the annular plate to form a bonding layer, and the bonding layer is While in a softened and molten state, a pre-formed thermosetting fiber-reinforced plastic annular member is laminated on the bonding layer, and the annular plate and the annular member are pressed together through the bonding layer. a bonding step of thermosetting the layer and thus bonding the annular member to the annular plate via the bonding layer; A method of manufacturing a flanged pipe made of a composite material is provided, which includes the following steps: applying fiber reinforced plastic to form a reinforcing coating layer, and thermosetting the reinforcing coating layer.

[Function and effect of the invention]

The PTFE pipe member used in the manufacturing method of the present invention is obtained by cutting a commercially available PTFE pipe to the required length, and the PTFE annular plate is also made from a commercially available PTFE pipe. It is obtained by cutting a plate into the desired shape, and therefore the manufacturing cost can be kept sufficiently low. In addition, in the present invention, when laminating FRP on the PTFE annular plate constituting the flange, the pre-formed
Due to the unique method of using an FRP annular member, it is important that the flange end face (one side of the PTFE annular plate) be sufficiently precise and flat to achieve the desired connection. Undesirable thermal deformations due to lamination can be reliably avoided. Thus, according to the present invention, flanged pipes made of composite materials of high quality as desired can be manufactured at a sufficiently low cost.

[Preferred embodiment]

Hereinafter, preferred embodiments of the manufacturing method of the present invention will be described in further detail with reference to the accompanying drawings.

FIG. 1 illustrates a flanged tube in which a connecting annular flange 4 is formed at one end of a cylindrical tube 2, manufactured by the manufacturing method of the present invention.

In the manufacturing method of the present invention for manufacturing the flanged tube shown in FIG. 1, a welding step is first performed. In this welding process, as shown in Figure 2-A, one end of the PTFE pipe member 6 is made of PTFE.
An annular plate 8 made of aluminum is fitted, and one end surface of the tube member 6 (lower end surface in FIG. 1 and FIG. 2-A) and one surface of the annular plate 8 (lower surface in FIG. 1 and FIG. 2-A) make them substantially consistent. The tube member 6 can be obtained by cutting a commercially available PTFE cylindrical tube to the required length. In addition, the annular plate 8
can be obtained by cutting a commercially available PTFE plate into annular shapes. Advantageously, the inner diameter of the annular plate 8 is substantially the same as the outer diameter of the tube member 6. As clearly shown in FIG. 2-A, the outer periphery of one end surface of the tube member 6 is cut radially outward and inclined upward, and the inner periphery of one end surface of the annular plate 8 is cut radially inward. The pipe member 6 is cut so as to be inclined upwardly.
It is preferable to form an annular recess in the boundary area between one end surface of the annular plate 8 and one surface of the annular plate 8. Next, a molten welding material 10a is applied to the annular recess, and a molten welding material 10b is also annularly applied to the boundary area between the outer peripheral surface of the tube member 6 and the other surface of the annular plate 8. By curing 10a and 10b, the tube member 6 and the annular plate 8 are welded together. As the welding materials 10a and 10b, perfluoroalkoxyfluorocarbon disclosed in the above-mentioned Japanese Patent Publication No. 56-36064 can be advantageously used.

It is preferable to carry out a current testing process following the welding process. In this current testing step, as shown in FIG. 2-A, the exposed outer surface of the welding material 10b is covered with a conductive material 12, which may be aluminum foil, carbon-containing synthetic resin, or the like. Then, a current test is performed between the welding material 10a and the welding material 10b using a current test device (not shown) which may be of a known type. If the pipe member 6 and the annular plate 8 are sufficiently well welded, there will be no electricity between the welding material 10a and the welding material 10b, but there will be pinholes etc. (therefore, the pipe member 6 and the annular plate If there is a risk of liquid leakage or the like occurring between the welding material 10a and the welding material 10b, electricity will be applied between the welding material 10a and the welding material 10b.

Next, a bonding process is performed. Continuing the explanation with reference to Fig. 2-B, in this joining process, the other surface of the annular plate 8 welded to the pipe member 6 (Fig. 1, Fig. 2-A, and Fig. 2-B) top surface)
A bonding layer 14 is formed thereon by applying thermosetting FRP in a softened and molten state. An example of thermosetting FRP is an unsaturated polyester resin containing a glass fiber layer. Next, bonding layer 1
4 is in a softened and molten state, an annular member 16 previously separately formed from thermosetting FRP is laminated on the bonding layer 14. It is convenient that the inner diameter of the annular member 16 is slightly larger than the outer diameter of the tubular member 6, and that a slight gap exists between the outer circumferential surface of the tubular member 6 and the inner circumferential surface of the annular member 16. Thereafter, the annular member 16 and the annular plate 8 are pressed together with the bonding layer 14 interposed therebetween. Thus, the annular member 16
The thermosetting FRP of the bonding layer 14 pressed between the annular plate 8 and the annular plate 8 enters the gap between the outer circumferential surface of the tube member 6 and the inner circumferential surface of the annular member 16, and fills the gap. do. While pressing the annular member 16 and the annular plate 8 via the bonding layer 14, the bonding layer 14 is heated and hardened in an appropriate manner, and thus the annular member 16 is attached to the annular plate 8 via the bonding layer 14 ( Then, the inner circumferential surface of the annular member 16 is joined to the outer circumferential surface of the tube member 6. The heating of the bonding layer 14 is performed by heating the bonding layer 14.
This can be conveniently accomplished by a well-known catalytic reaction in itself or the like. The annular member 16 and the annular plate 8 are pressed together through the bonding layer 14 by using a receiving metal fitting 20 having a substantially flat receiving surface and an annular pressing tool 22, as schematically illustrated in FIG. 2-B. It is preferable to carry out. In this case, one end surface of the tube member 6 and one surface of the annular plate 8 are brought into contact with the receiving surface of the receiving metal fitting 20, and the pressing tool 22 is brought into contact with the annular member 16.
Position it above and apply pressure in the direction shown by arrow 18. When such a pressing method is adopted, thermal deformation or distortion occurs on the annular plate 8, especially on one side thereof (the lower surface in Fig. 2-B) due to the influence of heat transmitted from the heated bonding layer 14 to the annular plate 8. This can be reliably prevented from occurring. As will be understood by referring to FIG. 1, one side of the annular plate 8 forms the end face of the connecting annular flange 4 and is preferably sufficiently flat for good connection.

In order to increase the bonding strength between the annular plate 8 made of PTFE and the bonding layer 14 made of FRP, if desired, before forming the bonding layer 14 by applying thermosetting FRP in a softened and molten state, The other side of plate 8 (second
-The upper surface in Figure B) can be sandblasted to increase its surface roughness.
Alternatively, the other surface of the annular plate 8 may be subjected to a well-known etching process.

Following the bonding process, a coating process is performed. In this coating step, one exposed surface of the annular member 16 (see FIGS. 1 and 2) as well as the outer peripheral surface of the tube member 6 is
A reinforcing coating layer 24 of a required thickness is formed by applying FRP in a softened and molten state to the upper surface in Figure 1-B, and the reinforcing coating layer 24 is thermally hardened. Thus,
A flanged composite tube having the configuration shown in FIG. 1 is manufactured. Since the annular member 16 is present together with the bonding layer 14 between the reinforcing coating layer 24 and the annular plate 8, the reinforcing coating layer 24 is heated.
The heat transferred to the annular plate 8 via the annular member 16 and the bonding layer 14 is relatively small, and such heat causes unacceptable thermal deformation or damage to the annular plate 8, especially one side thereof (the bottom surface in FIG. 1). There is no risk of distortion being generated.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a flanged tube made of composite material manufactured by the manufacturing method of the present invention. 2nd-
Figures A and 2-B are simplified sectional views for explaining a preferred embodiment of the manufacturing method of the present invention for manufacturing the flanged pipe shown in Figure 1. 2...Pipe, 4...Flange, 6...Pipe member, 8
...Annular plate, 10a and 10b...Welding material, 12
... Conductive material, 14 ... Bonding layer, 16 ... Annular member, 20 ... Bracket, 22 ... Pressing tool, 24
...Reinforcement coating layer.

Claims (1)

[Scope of Claims] 1. A pre-formed polytetrafluoroethylene annular plate having an opening with an inner diameter corresponding to the outer diameter of the pipe member is fitted onto one end of a pre-formed polytetrafluoroethylene pipe member. , a welding step of substantially aligning one end surface of the tube member with one side of the annular plate and welding the tube member and the annular plate; and after the welding step, softening and melting the other side of the annular plate. A bonding layer is formed by applying a thermosetting fiber-reinforced plastic in a state of a joining step of thermosetting the joining layer while pressing the annular plate and the annular member through the joining layer, and thus joining the annular member to the annular plate through the joining layer; A composite material comprising: a coating step of forming a reinforcing coating layer by applying thermosetting fiber-reinforced plastic in a softened and molten state on the exposed outer peripheral surface of the member and one exposed surface of the annular member, and thermosetting the reinforcing coating layer. Manufacturing method of flanged pipe. 2. In the joining step, the one end surface of the tubular member and the one surface of the tubular plate are brought into contact with the substantially flat receiving surface of the receiving fitting to press the annular member toward the receiving surface, thus The method for manufacturing a flanged pipe made of a composite material according to claim 1, wherein the annular plate and the annular member are pressed together via the bonding layer. 3. In the welding step, the pipe member and the annular plate are welded by applying a perfluoroalkoxyfluorocarbon welding material between the pipe member and the annular plate, or 2. The method for manufacturing a flanged pipe made of composite material according to item 2. 4. The composite material flange according to claim 3, wherein an annular recess is formed in the boundary area between the one end surface of the tube member and the one surface of the annular plate, and the welding material is applied to the annular recess. Method of manufacturing attached pipes. 5. A patent that includes an inspection step of covering the welding material with a conductive material after the welding step and before the joining step and performing an electrical conduction test of the welding area between the pipe member and the annular plate. A method for manufacturing a flanged pipe made of a composite material according to any one of claims 1 to 4. 6. In the joining step, the other surface of the annular plate is sandblasted before forming the joining layer, and the composite material flange according to any one of claims 1 to 5 Method of manufacturing tubes. 7. A flange made of composite material according to any one of claims 1 to 5, wherein in the joining step, the other surface of the annular plate is etched before forming the joining layer. Method of manufacturing tubes.