JPS5954010B2 - 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 formed 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 if it takes time to remove it from the mold, the The upper part of the stopped uncured straight pipe will sag, making it impossible to stabilize its shape. Therefore, it is possible to place a solvent-resistant film tube inside the uncured straight pipe, pressurize the inside of this film tube, and take out the unhardened straight pipe from the rotary mold while it is in pressure contact with the inner surface of the uncured straight pipe. It is considered. However, in this case, if all the film tubes are inflated at once, an air layer will be created between the uncured straight tubes and the film tube, especially in the longitudinal middle part of the uncured straight tubes. This disturbs the inner surface of the pipe and some of it enters 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 given from the roll 3 side. . 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 the film tube supply pipe 5 is supported by a plurality of rolls 6, and rotates in the forward and reverse directions of the driving rubber roll 7.
Therefore, it can be inserted into and extracted from the rotary mold 1. A solvent-resistant film tube 8 is inserted into the film tube supply pipe 5 in a compressed manner. One end of the film tube 8 is closed by a tube stopper 9, and the other end is closed by an air receiving device 11 via a tube stopper valve 10.
is installed. This air receiving device 11 can be connected to a coupler 12 provided outwardly at the other end of the rotary mold 1, and this coupler 12 communicates with an air supply source (not shown). The other end of the film tube supply pipe 5 is formed into an outwardly opening portion 5A, and a rubber seal 13 in the shape of a flap is attached to the tip of this outwardly opening portion 5A. Furthermore, an annular air retention chamber 14 is formed within the outward opening portion 5A, and this air retention chamber 1
A nozzle 15 communicating with the film tube supply pipe 4 is opened within the film tube supply pipe 5 and toward one end side. This nozzle 15 may be of a porous type or a slit type. The air storage chamber 14 opens at one end through an air supply passage 16 formed in the film tube supply pipe 5, and this opening communicates with an air supply source through an air supply pipe 18 having a valve 17. As shown by the solid line in FIG. 1, an uncured tube 2 is centrifugally molded on the inner peripheral surface of the rotary mold 1, and with the rotary mold 1 stopped, the drive rubber roll 7 is driven to form the tube as shown in the phantom line. Then, the film tube supply pipe 5 is inserted into the rotary mold 1 and the air receiving device 11 is connected to the coupler 12. In this state, both valves 10 and 17 are opened to supply air, and the drive rubber roll 7 is reversely driven to gradually extract the film tube supply pipe 5. As a result, the film tube 8 is taken out from the film tube supply pipe 5 while remaining, and the taken out portion is inflated by air supplied from the valve 10 side, so that it becomes uncured as shown in FIG. tube 2
is pressed against the inner surface of the Since this pressure contact range gradually expands from the other end to the one end as the film tube supply tube 5 is pulled out, there is no possibility that an air layer will be formed between the film tube 8 and the uncured tube 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 supply pipe 5 of the film tube 8 is also swollen by the air supplied into the film tube 8, and the pressure resistance causes the film tube 8 to swell. There is a risk that the film tube 8 may not be taken out smoothly or the film tube 8 may be damaged. However, according to this embodiment, air is supplied between the inner surface of the film tube supply pipe 5 and the film tube 8 via the nozzle 15. This air pressure is higher than the pressure inside the film tube 8, so an air layer (air curtain) is created between the inner surface of the film tube supply pipe 5 and the film tube 8, and the film tube 8 has resistance to pressure contact. It can be taken out smoothly without any cracks. A portion of the air from the nozzle 15 tries to escape, but this is prevented because the film tube 8 is in contact with the seal rubber 13. The entire film tube 8 is taken out from the film tube supply pipe 5 and the uncured tube 2 is removed.
Both valves 10 and 17 are closed while the entire inner surfaces of the coupler 12 and the air receiving device 11 are separated from each other.
Then, the rotary mold 1 is lowered from the roll 3, and the rotary mold 1 is dismantled as shown in FIG. The uncured tube 2 and the film tube 8 are taken out from the rotary mold 1. The uncured tube 2 is quickly removed from the rotary mold 1 by the internal pressure applied through the film tube 8 without deforming the uncured tube 2. The uncured tube 2 taken out is subjected to secondary plastic processing and then heated and hardened, and the film tube 8 is reused after the air is removed. As shown in the imaginary line in FIG.
Alternatively, a lid 20 may be attached, in which case a constant pressure can be maintained within the film tube supply pipe 5.

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. Because it is done in a state where
It is possible to completely eliminate the formation of an air layer between the film tube and the uncured tube, and when the pressing action starting position is sequentially moved, a squeezing action is generated to promote defoaming of the uncured tube.

Furthermore, the film tube can be taken out from the film tube supply pipe smoothly without any resistance due to the air layer created between the two, which can minimize damage to the film tube.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an 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... End hardening tube, 5... Film tube supply pipe, 8... Film tube, 9...
・Tube stop, 10...Tube stop valve, 14
...Air storage chamber, 15...Nozzle.

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 film tube supply tube that is cylindrical and has a nozzle opened toward one end on the inner surface of the other end is closed at one end. and an air intake device through a tube stop valve at the other end,
After inserting the uncured tube in a contracted state by evacuation, and centrifugally forming the uncured tube, first insert the film tube supply tube into the uncured tube from one end, and then attach the film tube supply tube to a coupler communicating with an air supply source at the other end. Connect the air intake device, and remove the film tube while pulling out the film tube supply pipe while supplying air into the film tube by opening the valve and blowing air out from the nozzle. The inner circumferential surface of the cured tube is gradually pressed from the other end to the one end, and an air layer is created between the inner surface of the film tube supply tube and the internal film tube by the ejected air, thereby completely removing the uncured tube. An uncured tube characterized in that after a film tube is brought into pressure contact with the inner surface, a valve is closed and an air receiving device is removed, the uncured tube and the film tube are taken out from a rotating mold. How to remove the mold.