JPS5954012B2 - How to demold uncured tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for demolding uncured pipes such as uncured resin pipes, uncured reinforced resin pipes, uncured mortar pipes, and uncured composite pipes.

The centrifugal molding method cannot mold anything other than axis-symmetrical cylinders.

Therefore, when obtaining a curved pipe using the centrifugal molding method, an unhardened straight pipe is first centrifugally molded, the unhardened straight pipe is subjected to secondary plastic processing, and then heated and hardened. However, according to this method, when removing the centrifugally molded uncured straight pipe from the rotary mold for centrifugal molding, it is not easy to remove it from the mold because it is uncured, and it takes time to remove it from the mold. The upper part of the uncured straight pipe that has stopped rotating is drooping,
This means that the shape cannot be stabilized. Therefore, a solvent-resistant film tube is placed inside the uncured straight pipe, and the inside of this film tube is pressurized to take out the uncured straight pipe from the rotary mold while it is in pressure contact with the inner surface of the uncured straight pipe. is considered. However, in this case, if the film tubes are all inflated at once, an air layer will be formed between the uncured straight tubes and the film tubes, especially in the middle part in the length direction of the uncured straight tubes. This disturbs the inner surface of the straight pipe and a portion of it will enter the uncured straight pipe as air bubbles. Therefore, the present invention provides a method for demolding an uncured tube that can solve the above-mentioned problems, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1 shows a state in which an uncured tube 2 is centrifugally molded on the inner peripheral surface of a rotary mold 1. As shown in FIG.

This rotary mold 1 can be divided into two in the circumferential direction, and can be rotated around a horizontal axis 4 via a plurality of rolls 3, and the rotational power is applied from the roll 3 side. There is. A film tube supply pipe 5 movable on the horizontal axis 4 is disposed outside one end of the rotary mold 1. That is, the film tube supply pipe 5 is supported by a plurality of rolls 6, and can be inserted into and extracted from the rotary mold 1. Reference numeral 7 denotes a flexible cylinder for extrusion made of fiber-reinforced rubber film, the closed end of which is inserted into the film tube supply pipe 5 from the other end, and the end thereof is inserted into the film tube supply pipe 5 from the other end. While being folded back toward the outer circumferential surface side, the cable body 8 attached to the end of the folded portion 7A is led to a winding device (not shown).

Therefore, the film tube supply pipe 5 is supported by the roll 6 via the folded portion 7A of the flexible extrusion cylinder 7. A solvent-resistant film tube 9 is compressed and inserted into the film tube supply pipe 5. One end of the film tube 9 is closed by a tube stopper 10, and an air receiving device 12 is attached to the other end via a tube stopper valve 11. This air receiving device 12 is connectable to a coupler 13 provided outwardly at the other end of the rotary mold 1, and this coupler 13 communicates with an air supply source (not shown). Note that a lubricant such as grease or oil is interposed between the flexible cylinder for extrusion 7 and the outer and inner circumferential surfaces of the film tube supply pipe 5. As shown by the solid line in FIG. 1, an uncured tube 2 is centrifugally formed on the inner circumferential surface of the rotary mold 1, and with the rotary mold 1 stopped, the film tube supply tube 5 is inserted as shown in the phantom line. It is inserted into the rotary mold 1 from one end, and the air receiving device 12 is connected to the coupler 13.

In this state, the folded portion 7A is pulled through the rope body 8 while the valve 11 is opened to supply air. Then, the film tube 9 expands within the film tube supply pipe 5, and is pushed back within the film tube supply pipe 5 by the tension of the folded portion 7A. However, the tube stopper 10 side of the swollen film tube 9 is of the rotary type 1.
Since it does not move toward the side, the above-mentioned tensile force acts on one end of the film tube supply tube 5, and the film tube supply tube 5 is gradually pulled out from the rotary mold. As a result, the film tube 9 is left in the rotary mold 1 and taken out from the film tube supply pipe 5. This removed portion is inflated by air supplied from the valve 11 side, and is then brought into pressure contact with the inner surface of the uncured tube 2, as shown in FIG. Since this pressure contact range gradually expands from the other end to the one end as the film tube supply pipe 5 is pulled out, there is no possibility that an air layer will be formed between the film tube 9 and the uncured pipe 2. In addition, when the pressing action start position is sequentially moved, a pressing and squeezing action occurs, thereby promoting defoaming of the uncured tube 2. During such work, the remaining portion of the film tube 9 inside the film tube supply pipe 5 also swells due to the air supplied into the film tube 9, as described above, and due to the pressure resistance. There is a risk that the relative sliding between the flexible cylinder for extrusion 7 and the film tube supply pipe 5 will not be smooth or that the flexible cylinder for extrusion 7 will be damaged, but this can be solved by the presence of the lubricant. be done. The entire film tube 9 is taken out from the film tube supply pipe 5, and with the entire inner peripheral surface of the uncured tube 2 in pressure contact, the valve 11 is closed and the coupler 13 is removed.
and the air receiving device 12 are separated. Next, the rotary mold 1 is lowered from the roll 3, and as shown in FIG. 3, the rotary mold 1 is dismantled, and the uncured tube 2 and the film tube 9 are taken out from the rotary mold 1. The uncured tube 2 is removed from the rotary mold 1 by internal pressure through the film tube 9.
It is done quickly without deforming the The unhardened tube 2 taken out is subjected to secondary plastic processing and then heat hardened, and the film tube 9 is reused after removing air.
As described above, according to the present invention, the pressure contact of the film tube against the inner surface of the uncured tube is carried out in such a manner that the pressure contact start position is sequentially moved in the axial direction of the uncured tube, that is, the pressure contact range is gradually expanded. Since the process is carried out under such conditions, it is possible to completely eliminate the formation of an air layer between the film tube and the uncured tube, and when the pressure welding start position is sequentially moved, a squeezing action occurs to defoam the uncured tube. can be promoted.

Furthermore, since the film tube is taken out from the film tube supply pipe via the flexible cylinder for extrusion, the sliding contact that occurs during removal is between the flexible cylinder for extrusion and the film tube supply pipe. , the film tube can be sufficiently protected from being damaged.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 to 3 are partially cutaway front views showing the operating state. DESCRIPTION OF SYMBOLS 1... Rotating type, 2... Uncured tube, 4... Horizontal axis, 5... Film tube supply pipe, 7... Flexible cylinder for extrusion, 7A... Folded part, 9...Film tube.

Claims (1)

[Claims] 1. A method for demolding an uncured tube that has been centrifugally molded on the inner peripheral surface of a rotary mold, in which a flexible cylinder for extrusion with a closed end is inserted into a film tube supply tube whose other end is open. is located inside the film tube supply pipe, and after being folded back outward at the other end of the film tube supply pipe, the folded part is positioned outside the film tube supply pipe, and one end is closed and a valve is attached to the other end. The film tube with the air intake device attached thereto is compressed by evacuation, and one end of the film tube is positioned near the tip of the flexible cylinder for extrusion, and the film tube is inserted into the flexible cylinder for extrusion. After centrifugal molding, the film tube supply pipe, the flexible cylinder for extrusion, and the film tube are first inserted into the rotary mold from one end in the above-described arrangement and insertion state, and then air is supplied to the other end. An air receiving device is connected to a coupler communicating with a source, and the film tube supply tube is rotated by pulling the folded part of the flexible cylinder for extrusion toward one end while supplying air into the film tube by opening a valve. The film tube is taken out from the film tube supply pipe while being pulled out from the mold, and at that time, the film tube, which expands due to the supplied air, is gradually pressed against the inner peripheral surface of the uncured tube from the other end to one end, and the uncured tube is The film tube is brought into pressure contact with the entire inner peripheral surface, and after the valve is closed and the air receiving device is removed, the uncured tube and the film tube are taken out from the rotary mold. How to demold uncured tubes.