JPH0233285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of integrally molding annular protrusions or annular grooves at appropriate locations on the inner circumference of a fiber-reinforced resin pipe using centrifugal force. In order to strengthen the bonding force when embedding the pipe into the pipe, or to stably lock the sealing gasket when joining the socket pipe and the spigot pipe with a rubber gasket, the inside of the joint of the fiber-reinforced resin pipe is The present invention relates to a method of integrally molding an annular projection or an annular groove on a peripheral surface.

In conventional centrifugal force forming, it has been difficult to integrally form an annular projection or an annular groove on the inner circumferential surface of a tubular body. The present inventors have been conducting various studies on forming tubular bodies using centrifugal force. As a result, the joints of the joints are buried in the outer periphery of concrete pipes, such as joints for propulsion hume pipes. If an annular projection or annular groove is formed on the inner circumference of the side, the joint and the concrete pipe will be firmly fixed together by the annular projection or annular groove. If a sealing gasket locking part is formed on the inner circumference of the sealing gasket, it will prevent the sealing gasket from shifting or twisting when connecting the socket pipe to the socket pipe or when connecting the socket pipe to the collar type fitting. I found out that it can be prevented.

The present invention proposes a manufacturing method in which an annular projection or annular groove is integrally installed at a suitable position on the inner circumference of a fibrous resin pipe using centrifugal force. An annular piece attached to the inner circumferential wall is arranged, and the fibrous reinforcing material and the synthetic resin binding material are respectively supplied to the inside of the mold while rotating. At the same time, the centrifugal force generated by the rotation of the mold is used to defoam. It is compacted into a tubular body, and then demolded and molded by removing the cap attached to the annular piece.

In the present invention, the reason why air bubbles are removed by centrifugal force is because when a mixture of fiber reinforced reinforcing material and synthetic resin binding material is cured and made into a product, air bubbles become voids and significantly deteriorate the mechanical properties. These air bubbles must be eliminated in order to produce fiber-reinforced resin products with excellent performance. The magnitude of the centrifugal force that eliminates air bubbles is much smaller than the centrifugal force used in conventional manufacturing of reinforced concrete, etc., and a gravitational acceleration of 3 to 15 g is sufficient.
At such a low speed, air bubbles can be eliminated and compaction can be performed at the same time in a short time.

The fibrous reinforcing materials used as raw materials include glass fibers, carbon fibers, asbestos, synthetic polymer fibers, and the like, and these fibers may be used alone or in combination of two or more. There are also fibers such as roving chop, cloth, and pine.
One or more types can be used.

In addition, the synthetic resin binder serving as a raw material includes unsaturated polyester resin, epoxy resin, polyurethane resin, phenolic resin, furan resin, and the like. These resins are used according to the characteristics of the product, and catalysts, curing accelerators, inhibitors, etc. that match the characteristics of the resin are proportioned and used according to the molding conditions and environmental conditions in the manufacturing process. can do.

The amount of fibrous reinforcing material mixed in in the present invention is preferably 10 to 60% by weight based on the synthetic resin binder. The range of the amount of fibrous reinforcement mixed in is determined by the moldability of the product and the required mechanical properties; if the amount added is less than 10% by weight, the mechanical properties of the product will not improve much; If it is more than 60% by weight, molding problems occur, the surface finish is poor, mechanical properties are deteriorated, and it is also economically unfavorable.

When using glass hops as the fibrous reinforcing material, the fiber length of the glass fibers is preferably 10 to 100 mm.

In the present invention, the annular protrusion or annular groove formed on the inner periphery of the fiber-reinforced resin pipe is constituted by an annular piece or the like disposed in advance on the inner periphery of the rotating form. It is preferably made of a fibrous reinforcing material and a synthetic resin binding material, and is made of the same material as the fibrous reinforced resin pipe in which the annular piece is disposed.

The present invention will be explained in more detail below with reference to the illustrated embodiments.

FIG. 1 is an example of a longitudinal section of a manufacturing apparatus for carrying out the manufacturing method according to the present invention, and FIG. 2 is a cross-sectional view thereof.

In FIGS. 1 and 2, a plurality of annular pieces 2 are arranged at appropriate positions on the inner circumference of a tubular formwork 1, and spacer rings 3 are arranged in the longitudinal direction when it is necessary to regulate the length of the product. Ru. This formwork is driven by rotation of a rotating wheel 4 connected to a drive motor (not shown). At that time, the annular piece 2 has a cap 2'
Insert it. Details of the cap 2' will be described later.

On the other hand, the resin spout 5 and the roving cutter 6 are
It is fixed to an arm 7 that reciprocates in a direction parallel to the rotation axis of the formwork 1, and this arm is fixed to a trolley 8 driven by power (not shown). A device 10 and a glass bobbin 11 are loaded. By the reciprocating motion of the cart 8 to which this arm is attached, the resin spout 5 and the roving cutter 6 can reciprocate in the longitudinal direction of the mold.

First, the formwork 1 is rotated by the rotating wheel 4,
When a predetermined rotational speed is reached, the resin is sent from the resin tank 9 to the resin injection port 5 through the pipe 12 by the resin transport device 10, and is supplied into a mold in which a plurality of annular pieces are arranged. On the other hand, the glass fiber is bobbin 11
The resin is guided from the roving cutter 6 to the roving cutter 6 and supplied into the mold like resin. Resin 13 and glass chops 14 are supplied simultaneously or alternately to the inner surface of mold 1 to form the deposited glass fiber/resin mixture 15.

By repeating the reciprocating motion of the cart 8, the glass fiber/resin mixture is deposited to a predetermined thickness, air bubbles are removed from the deposited layer by centrifugal force, and compaction is performed at the same time.

Next, curing is performed using hot air to accelerate hardening, and the mold is removed to obtain a glass fiber reinforced resin circular tube product provided with an annular projection or an annular groove. In FIG. 1, by removing the spacer ring 3, four products as shown in FIG. 3 can be obtained.

4 to 7 show the annular piece 2. FIG. In FIG. 4, 101 indicates an annular projection or annular groove formed on the inner periphery of the fiber-reinforced resin pipe, 102 indicates fibers protruding from the side surface 105 of the annular piece, and 103 indicates the inner circumferential side of the annular piece. 104 indicates the thickness of the fiber-reinforced resin pipe, and 110 indicates a cap made of an elastic body.

The length of the fibers 102 extending from the side surface of the annular piece 2 is preferably 10 to 50 mm. This fiber combines with the supplied resin and serves as an anchor for integrating the annular piece 2 with the supplied fiber/resin mixture layer 15. Also, a cap 110 made of an elastic material
This is to prevent the supplied fibers and resin from covering and hiding the annular piece 2 or filling the groove 103 thereof, and at the same time to save the labor of later finishing.

In this way, the finishing of the annular protrusion or annular groove after demolding is done by checking the inner circumferential groove 10 of the annular piece 2 before molding.
It was very easy to do this by peeling off the cap 110, which is the elastic body fitted in the cap 3. Furthermore, although the glass fiber/resin mixture layer 15 was molded very densely with no air bubbles, the layer on the elastic cap 110 protrudes from the mixture 15, which may result in an extremely coarse structure. It could have been prevented.

The fibrous reinforced resin pipe of the present invention is used, for example, in the following usage mode.

FIG. 8 is a longitudinal sectional view of a state in which a fiber-reinforced resin pipe provided with an annular protrusion according to the present invention is embedded and joined to the outer peripheral end 1A of the propulsion hume pipe. The annular projection 101 engages with the outer circumferential end 1A of the hume tube and is firmly joined. Therefore, even under severe conditions such as friction with the ground or passage through the hume pipe propulsion work, the inconvenience of the fiber-reinforced resin circular pipe joint being pulled out of the hume pipe 1A and impairing watertightness can be prevented. In this example, the other inner circumferential surface of the fiber-reinforced resin circular tube is smooth, and the spigot-side hume tube 1B is fitted with the sealing gasket 1C.
It is configured so that it can be connected to.

FIGS. 9 to 11 illustrate other fibrous reinforced resin circular tubes obtained by the present invention. In FIG. 9, the fiber-reinforced resin circular tube has a socket tube shape 2A, and a sealing gasket locking annular projection 101 is provided on the inner periphery of the end thereof. By attaching the sealing gasket 2C to the annular protrusion, it is possible to prevent an accident in which the gasket 2C is twisted or displaced from a predetermined position, resulting in loss of watertightness, even when connecting to the spigot pipe 2B. In addition, it can also be applied to collar type joints as illustrated in FIGS. 10 to 11.

A feature of the present invention is that a fibrous reinforcing material and a synthetic resin binding material are supplied into a formwork in which annular pieces are arranged, and an annular protrusion or annular groove is integrally formed on the inner periphery of a fibrous reinforced resin pipe using centrifugal force. It lies in the point of molding. Therefore, in the present invention, not only the shape, number, and structure of the annular pieces, but also the mechanism for molding the fiber-reinforced resin circular tube are not limited to those shown in the figures.

The present invention is constructed as described above, and when applied to a joint of a propulsion hume pipe, an annular projection or annular groove for reinforcing the joint force can be easily integrated into the joint of a socket pipe. When applied to a collar type joint, the annular protrusion for locking the sealing gasket can be easily integrated, so its practical value is extremely high.

[Brief explanation of drawings]

Fig. 1 is a diagram conceptually showing an apparatus for carrying out the manufacturing method of the present invention, Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1, and Fig. 3 shows a molded propulsion tube collar. Figures 4 and 5 are enlarged cross-sectional views of the vicinity of the annular piece, Figure 6 is a cross-sectional view taken along line B-B in Figure 4, Figure 7 is a cross-sectional view taken along line C-C in Figure 5, 8
Figures to Figures 11 show how the collar of the present invention is used, Figure 8 is a sectional view of a joint of a propulsion tube, Figure 9 is a sectional view of a socket-type joint, and Figures 10 and 11 are a sectional view of a conventional collar. It is a sectional view of a collar joint.

Claims (1)

[Claims] 1. In a method of molding a joint in which an annular projection or annular groove is provided at an appropriate position on the inner circumference of a fibrous reinforced resin pipe, an annular piece with a cap attached to the inner circumferential wall surface at an appropriate position in a cylindrical formwork is used. The fibrous reinforcing material and the synthetic resin binding material are arranged coaxially and inwardly, and the fibrous reinforcing material and the synthetic resin binding material are respectively supplied inside the formwork while rotating, and the centrifugal force caused by the rotation of the formwork degasses the tubular material at the same time. 1. A method for manufacturing a fiber-reinforced resin product, characterized in that the product is compacted and then molded by removing a cap attached to the annular piece.