JPS6213165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for demolding a centrifugally formed tube.

The centrifugal molding method is a method in which a cylindrical mold that can be rotated around a horizontal axis is heated, a resin liquid is poured into the cylindrical mold, and a resin tube is heated and centrifugally molded on the inner peripheral surface of the cylindrical mold. be. Conventionally, the resin pipe molded into a cylindrical shape is removed from the mold by naturally cooling the resin pipe to create a gap between the outer surface of the resin pipe and the inner peripheral surface of the cylindrical shape, and then forming the resin pipe into a cylindrical shape. On the other hand, this was done by pulling out the resin tube in the horizontal axis direction. According to such a demolding method, since the cylindrical mold itself is heated, the resin pipe does not cool down easily, and it takes time for a gap to form, resulting in inefficiency. In addition, if pulling is performed without a gap, the frictional resistance due to the surface contact between the inner circumferential surface of the cylinder and the outer circumferential surface of the resin tube is large, so a large pulling force is required, and in some cases it may not be sufficient. This will lead to deformation of the uncured resin pipe.

The present invention aims to solve the above problems.

That is, the present invention is a method for demolding a resin tube that has been heated and centrifugally molded on the inner peripheral surface of a cylindrical shape rotatable around a horizontal axis, in which a fluid is passed into the resin tube to cool the resin tube, and then the resin tube is cooled. The present invention provides a method for removing a centrifugally molded tube by extracting a resin tube from a cylindrical mold. According to this method, the resin tube, which is expanded and molded by heating, is cooled by the fluid in a short time and is contracted, thereby creating a gap between the outer circumferential surface of the resin tube and the inner circumferential surface of the cylindrical shape. The resin tube can be easily extracted without deforming it.

Hereinafter, one embodiment of the present invention will be described based on the drawings. FIG. 1 shows the state of centrifugal molding. i.e. 1
It has a cylindrical shape, and is supported by a plurality of wheels 2 so as to be rotatable around a horizontal axis 3. Said cylinder type 1
An end face jig 4 is attached to both ends of the cylindrical shape 1.
A heating device 5 is disposed outside. The cylindrical mold 1 is heated by the heating device 5, and while the cylindrical mold 1 is rotated around the horizontal axis 3, a resin liquid is supplied into the cylindrical mold 1, and the cylindrical mold 1 is heated between the both end surface jigs 4. A resin tube 6 is heated and centrifugally molded onto the inner peripheral surface of the tube. After that, as shown in FIG. 2, both end surface jigs 4 are removed,
Then, lids 8A and 8B are attached to both ends of the cylindrical shape 1 via fixtures 7A and 7B, respectively. One lid body 8A
is provided with a supply port 9, which communicates with a cooling tower 11 via a pump 10.
Further, the other lid body 8B is provided with a discharge port 12,
This discharge port 12 communicates with the cooling tower 11 . Therefore, after the resin tube 6 is centrifugally molded, the fluid 13 is passed through the resin tube 6 to cool it. By the way, the resin tube 6 expands during hot centrifugal molding, and its expansion coefficient is ten times or more that of the cylindrical mold (mold) 1. Therefore, when cooling through a fluid 13 such as water or air,
The contraction of the resin tube 6 is greater than the contraction of the cylindrical mold 1,
This creates a gap between the outer circumferential surface of the resin tube and the inner circumferential surface of the cylindrical shape. As a result, both lid bodies 8A,
After removing 8B, the resin pipe 6 can be easily extracted. The resin tube 6 is cooled by the fluid 13 at near room temperature. Fluid 13 that became high temperature due to cooling
is lowered to near room temperature in the cooling tower 11.

According to the demolding method for centrifugally molded tubes according to the present invention described above, the resin tube, which has been expanded and molded by heating, can be cooled and contracted in a short time with fluid, and thereby the outer circumferential surface of the resin tube and A gap is created between the resin tube and the inner circumferential surface of the cylinder due to the difference in shrinkage rate, so that the resin tube can be extracted efficiently in a short time and easily without being deformed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal side view during centrifugal molding, and FIG. 2 being a longitudinal side view during cooling. 1...Cylindrical shape, 2...Ring body, 3...Horizontal axis, 4
... End face jig, 5 ... Heating device, 6 ... Resin pipe,
7A, 7B...Fixing tool, 8A, 8B...Lid, 9
... Supply port, 10 ... Pump, 11 ... Cooling tower, 12 ... Discharge port, 13 ... Fluid.

Claims (1)

[Claims] 1 A demolding method for a resin tube that has been heated and centrifugally molded on the inner peripheral surface of a cylindrical shape that can be rotated around a horizontal axis, in which a fluid is passed into the resin tube to cool the resin tube, and then the resin tube is removed from the cylindrical shape. A demolding method for centrifugally molded tubes, which is characterized by extracting the resin tube.