JPS5954013B2 - Method for installing film on the inner surface of uncured pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing a film on the inner surface of 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 bent pipe using the centrifugal forming method,
First, an unhardened straight pipe was centrifugally formed, and this unhardened straight pipe was 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 is drooping,
The shape will not be stable. 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 the film tubes are all inflated at once, an air layer will be created between the uncured straight pipes and the film tube, especially in the longitudinal middle part of the uncured straight pipes. This disturbs the inner surface and some of it enters the uncured straight pipe as air bubbles. Furthermore, the method of supplying fluid into the film tube to inflate the film tube complicates the structure and operation. Therefore, the present invention provides a method for installing a film on the inner surface of an uncured tube, which 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 J, and can be rotated around a horizontal axis 4 via a plurality of rolls 3, and the rotational force 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. A solvent-resistant film tube 6 is inserted into the film tube supply pipe 5 in a compressed manner. The tip of the film tube supply pipe 5 is formed into an outwardly opening part 7, and the outer surface of this outwardly opening part 7, which is continuous with the inside of the film tube supply pipe 5, is formed as a film tube guide surface 7a, and an inner surface which is continuous with the outer surface is formed. The side surface is formed into a spring receiving surface 7b. A coil spring 8 whose outer side is received by the spring receiving surface 7b is disposed around the outer periphery of the tip of the film tube supply pipe 5, and an annular coil spring pressing plate 9 which receives the inner side of the coil spring 8 is fitted onto the outside. Ru. The outer surface of the coil spring pressing plate 9 is formed as a coil spring pressing surface 9a, and the inner surface has an annular bracket 10 erected from the outer peripheral surface of the film tube supply pipe 5.
The tips of a plurality of bolts 11 that are screwed together are in contact with each other.
The coil spring 8 is made of stainless steel or spring steel, and its coil diameter d is the inner diameter D of the molded unhardened tube 2.
5 (1/5 to 1/10) D: d, and the coil diameter d to wire diameter d''. (1/5 to 1/20
)d. Furthermore, as shown in FIG.
While the rotary mold is stopped, the tip of the film tube supply pipe 5 is brought sufficiently close to the rotary mold 1. And a drawer. After fixing the end of the film tube 6 to the entrance of the rotary mold 1, the coil spring 8 is inserted into the entrance. Next, the coil spring pressing plate 9 is moved by operating the bolt 11, and the coil spring 8 is deformed so that its outer diameter becomes larger by bringing the coil spring pressing surface 9a closer to the spring receiving surface 7b. As a result, the film tube 6 is connected to the uncured tube 2 via the deformed coil spring 8.
Press it onto the inner circumferential surface of the By inserting the film tube supply pipe 5 in this state, the film tube 6 is gradually taken out from the film tube supply pipe 5 and placed on the inner circumferential surface of the uncured tube 2, as shown in FIGS. Supplied under pressure. Since the pressure contact position via the coil spring 8 moves sequentially from the inlet side to the outlet side as the film tube supply tube 5 is inserted, there is an air gap between the film tube 6 and the uncured tube 2. This does not occur at all, and a pressure-squeezing action occurs, promoting defoaming of the uncured tube 2. During this operation, the coil spring 8 rotates around the annular axis 12, and this becomes a roll compaction state, which promotes defoaming of the uncured tube 2 and at the same time suppresses the inner surface irregularities. The entire film tube 6 is taken out from the film tube supply pipe 5,
Then, the bolt 11 is pressed against the entire inner surface of the unhardened tube 2.
After loosening and deforming the outer diameter of the coil spring 8 to a small value, the film tube supply pipe 5 is extracted from the rotary mold 1. Next, the rotary mold 1 is lowered from the roll 3, the rotary mold 1 is dismantled, and the uncured tube 2 is taken out from the rotary mold 1 together with the film tube 8. The uncured tube 2 taken out is subjected to secondary plastic processing and then heated and hardened, and the film tube 6 is removed and reused. As described above, according to the present invention, the film tube is pressed against the inner surface of the uncured tube while the pressure contact position is sequentially moved in the axial direction of the uncured tube. It is possible to completely eliminate the formation of an air layer between the
Further, when the pressure contact position is sequentially moved, a squeezing action is generated to promote defoaming of the uncured pipe.

Furthermore, since the film tube is pressed against the film tube via a coil spring, the structure and operation can be simplified compared to, for example, a method using compressed air.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 and 2 are vertical side views showing the operating state, respectively, and FIG. 3 is a vertical front view of FIG. 2. DESCRIPTION OF SYMBOLS 1... Rotating type, 2... Uncured tube, 5... Film tube supply pipe, 6... Film tube, 8...
Coil spring, 9... Coil spring pressing plate, 10... Annular bracket, 11... Bolt.

Claims (1)

[Claims] 1. A method of installing a film tube on the inner surface of an uncured tube centrifugally formed on the inner peripheral surface of a rotary mold, in which the film tube supply tube is movable on a horizontal axis, which is the rotation axis of the rotary mold. A coil spring rotatable around an annular axis centered on the film tube supply pipe axis is wound and fitted on the outer periphery of the distal end, and a shrunken film tube is contained within the film tube supply pipe, After centrifugally molding the uncured tube, first fix the end of the film tube to the inlet of the rotary mold, then insert the film tube supply tube into the uncured tube from the inlet of the rotary mold, and then insert the film tube from the inlet of the rotary mold. An inner surface of an uncured tube characterized in that the film tube is taken out and, at that time, the film tube is brought into pressure contact with the inner circumferential surface of the uncured tube via a rotatable coil spring on the outer circumferential surface of the distal end of the film tube supply tube. Film interior method.