JPS59158233A - Preparation of slit pipe - Google Patents

Abstract

PURPOSE:To prepare a slit pipe in good efficiency, by press bonding adjacent pipe base material by uniformly pressing the same to the inside at every predetermined length while forming a group comprising pipe base materials successively arranged in a peripheral direction in a cylindrical form so as to leave slit intervals therebetween by extrusion molding. CONSTITUTION:A thermoplastic resin thrown in an extrusion molding machine 1 is extruded through a mold to mold a pipe base material group 7 comprising pipe base materials 71 arranged in a peripheral direction in a cylindrical form so as to leave slit intervals S each corresponding to a partition width 21. In the next step, the pipe base material group 7 is sent to a heating apparatus 3 and high temp. gas is injected toward the slit intervals S from radially arranged jet nozzles 31 to melt the side parts of each pipe base material and, thereafter, introduced between the molding rolls 41, which can be separated and contacted, of a molding machine 4 and, when the closing control of the rolls 41 is performed, the base materials 71 are uniformly pressed to the inside by the semi- circular molding surfaces 41a of the rolls 41 to be press bonded while the formed slit free cylinder part is cooled and hadened by a cooling apparatus 5 and cut by a constant length cutter 6.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a slit tube.

When manufacturing slit pipes that have many holes in the surrounding wall and are used for purposes such as underdrain drainage pipes and rainwater and permeable pipes, conventional pipes were extruded, cooled, and then cut to a certain length and then machined. Since the slits are formed by the method, there is a drawback that as the number of required slits increases, the number of man-hours increases and the manufacturing cost increases.

The present invention was made in order to eliminate the above-mentioned drawbacks, and while extruding a group of tube materials lined up in a cylindrical shape with sequentially spaced slits in the circumferential direction, each tube material is evenly spaced inward for each predetermined length. It is an object of the present invention to provide a method for manufacturing a slit tube that can improve manufacturing efficiency and reduce manufacturing costs compared to the conventional method by pressing the adjacent tube materials together.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an extrusion molding machine.

The mold 2 mounted thereon has cavities 22 partitioned by partitions 21 at predetermined intervals in the circumferential direction, as shown in FIG. 3 is a heating device, 4 is a molding machine, 5 is a cooling device, 6
is a cutting machine.

A thermoplastic synthetic resin is charged into an extrusion molding machine 1, and the thermoplastic synthetic resin is molded into a tube material group 7 through a mold 2. As shown in FIG. 3, the tube material group 7 is made up of cylindrical tube materials 71, 71 arranged in the circumferential direction with a gap S (hereinafter referred to as the gap) corresponding to the width of the partition 21.
Consisting of The tube material group 7 extruded from the mold 2 is sent to a heating device 32 and then to a molding machine 4. The heating device 3 has six high-temperature gas injection nozzles 31 as shown in FIG. It is placed toward the S part and injects high-temperature gas. While each of the tube materials 71, 71, . The molding machine 4 has a molding space whose opening and closing are controlled, and in this embodiment, the molding space is formed by forming semicircular arc surfaces of two molding rolls 41 and 41 as shown in FIGS. 41a.

The forming rolls 41 and 41 are arranged so that they can be separated from each other and come into contact with each other across the running path of the tube material group 7 above and below, and when they are in contact with each other, that is, during the closing control, the slits are formed from the circumferential length of the tube material group 7. A molding space P having a circumference equal to or less than the equivalent of the distance S is formed. At the time of opening control, an interval larger than the diameter of the circumscribed circle is extended. The opening/closing control of the molding machine 4 is repeated at regular intervals for a certain period of time as shown in FIG. 5(b).

Therefore, when the above-mentioned closing control of the forming machine 4 is performed on the traveling tube material group 7, each tube material 71, 71, etc. is equally displaced by receiving the inward pushing force, Adjacent tube materials are crimped together to form a slit-free cylindrical portion A. Since the portion of the tube material group 7 that passes through the forming machine 4 during the opening control of the forming machine 4 is not subjected to any pressing force, it becomes a slit cylinder portion B having a plurality of spacings S in the circumferential direction. In this way, a slit tube having slits at predetermined intervals in the tube axis direction is formed.

After the slit tube is cooled and hardened in the cooling device 5.

It is cut into a predetermined length by a regular length cutter 6.

When manufacturing an egg-shaped slit tube, a mold 2 having an egg-shaped cavity with a partition similar to the partition 21 is used to form an envelope shape as shown in FIGS. 6(a) and 6(b). A forming roll 51 is used to extrude the oval-shaped tube material group 8, and the forming surface of the forming space P is similar in size to the above-mentioned envelope outline.
51 may be used.

As described above, according to the present invention, while extruding a plurality of tube materials into a cylindrical arrangement, it is sufficient to cool the tube materials by passing them through a heating device and then a molding machine. Compared to the case.

Manufacturing efficiency can be increased and manufacturing costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a flowchart of an embodiment of the slit pipe manufacturing method according to the present invention, Fig. 2 is a cross-sectional view of the cavity in the above embodiment, Fig. 3 is a cross-sectional view taken along the line ■-■ of Fig. 1, and Fig. 4 is the above-described cross-sectional view. A layout diagram of the high-temperature gas injection nozzle of the heating device in the embodiment, FIGS. It is an explanatory diagram of operation of a molding machine of another example. ■...Extrusion molding machine 2...Mold 4...Molding machine 41.51...Molding roll P...Molding space Patent applicant Representative of Sekisui Chemical Co., Ltd. Mototoshi Fujinuma

Claims (1)

[Claims] 1. Extrude thermoplastic synthetic resin through a mold with cavities partitioned at predetermined intervals in the circumferential direction. 2. Open and close the group of tube materials extruded in a cylindrical arrangement with slit intervals in the circumferential direction at predetermined intervals. A method for manufacturing a slit tube, characterized in that adjacent tube materials are fused together by passing through a controlled forming space whose forming surface when closed is similar in diameter to the envelope surface of the group of tube materials.