JPS622089A - Method of integrally molding collar to pipe made of long-sized crosslinking polyolefin having collar and end section of pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION FIELD 1 The present invention relates to a long crosslinked polyolefin pipe having a flange at least at one end, and a method for integrally molding the flange to the end of the pipe.

r Conventional technology and its problems 1 Long steel pipes were generally used when constructing pipelines for transporting hot bodies, but such steel pipes have problems with corrosion resistance and chemical resistance. Therefore, the inner circumferential surface of the steel pipe is lined with polyethylene, polyvinyl chloride, or the like, or coated with a coating or the like.

However, the cost of the lined or coached steel pipe is extremely high.

Recently, polyolefin-based pipes, typified by long polyethylene lengths of 100 mm, have been adopted as pipes for transporting fluids that satisfy corrosion resistance, chemical resistance, heat resistance, low cost, and the like.

Among the above-mentioned polyolefin pipes, non-crosslinked ones made of polyethylene, for example, can be welded by known butt welding means or sleeve welding means as shown in Fig. 6.
A connecting portion is formed by welding a flange member to the end of the pipe a.

By the way, in the case of cross-linked polyolefin pipes that have further improved physical properties such as heat resistance by cross-linking molecules, when the gel fraction indicating the degree of cross-linking is as low as 0 to 15%, the properties are similar to ordinary polyethylene. Therefore, heat welding can be performed in the same way as conventional polyethylene pipes, but heat welding is impossible with high gel fraction materials that have sufficient heat resistance.In such cases, both ends of pipe a are The so-called mechanical joint method C, which connects pipes by interposing a metal core on the inner periphery of the part, was used.

However, this mechanical joint method also exposes the metal parts inside the pipe through which the liquid flows, so if a corrosive liquid or chemical is passed through it, the connection part will corrode, which is a fatal flaw. there were.

In addition, even if it is a cross-linked pipe, if it is a short pipe, it is possible to make one with a connecting collar integrally formed at the end of the pipe using molding, etc., but this method cannot be applied to long pipes. This would require extensive equipment, which is extremely impractical.

In view of the above-mentioned problems, the present invention provides a long cross-linked oriolefin pipe with a flange at the end of the pipe that allows for strong connection between the pipes, and a flange on the end of the pipe that is simple and rational without forming defects. The purpose of this invention is to provide a method that allows for precise molding.

Means for Solving Problems J The long cross-linked polyolefin pipe according to the present invention is characterized in that a flange formed by thermoforming is integrally formed on the outer periphery of the end of the long cross-linked polyolefin pipe. It is said that

On the other hand, the method of forming a flange at the end of a pipe according to the present invention is as follows:
In a method of integrally molding a collar by thermoforming on the outer periphery of the end of a cross-linked polyolefin pipe, a core having an outer circumferential surface that can be fitted relatively to the inner circumferential surface of the pipe is placed inside the end of a predetermined cross-linked polyolefin pipe. Then, on the outer periphery of the end of the pipe, a large diameter cylindrical part having an inner diameter larger than the outer diameter of the pipe and a small diameter cylindrical part having an inner diameter approximately equal to the outer diameter of the pipe are attached in the length direction. The tubular molded female fittings formed concentrically are attached via the small diameter cylindrical part so that the edge of the large diameter cylindrical part almost coincides with the edge of the crosslinked polyolefin pipe. After that, the part is heated to a predetermined molding temperature, and then a core storage part for storing the core is provided at the tip in the large diameter cylindrical part of the molding female tool, and the size of the molding female tool is adjusted. A molded male tool having a cylindrical portion of a predetermined length with an outer diameter smaller than the inner diameter of the cylindrical portion is pushed in, and the end of the crosslinked polyolefin pipe is pressurized and deformed by the pushing pressure at this time to form a pipe end. It is characterized by the formation of a tsuba around the outer periphery.

r Effect 1 The long crosslinked polyolefin pipe according to the present invention has a collar integrally molded at the end of the pipe.

In such a long cross-linked polyolefin pipe with a flange, the chemical and physical properties of the pipe end and the flange are the same, and the pipe end and the flange, which are separate parts, are bonded together with an adhesive. Or, since there is no lack of strength or deterioration over time of the bonded part that occurs when heat welding is used, high strength and high sealing can be achieved by butting the ends of the pipes with the brim formed against each other and tightly joining these pipe ends. It is possible to realize a pipe connection of 30 degrees, and also to connect adjacent flanges to each other from the outside of the pipe. There will be no corrosion.

In addition, the method of forming a flange at the end of a pipe according to the present invention involves setting a molded female tool and a core at predetermined positions of a long cross-linked polyolefin pipe, and then attaching a molded male tool to the end face of the pipe end maintained at a molding temperature. A desired tsuba can be formed simply by applying the tip end surfaces of the molding female tool and the molding male tool relatively toward each other in the axial direction.

Therefore, the molding work at this time is easy, and the molded female tool,
By deforming only the necessary parts of the end of a cross-linked polyolefin pipe using the king of cores and molding male tools, it is possible to form the desired flange with high precision without molding defects, and the flange formed in this way is able to form the same shape as the pipe end. Since it is integrated, it can become a flanged pipe end that provides the above-mentioned effects.

Embodiment An embodiment of the present invention will be described below with reference to one drawing.

In FIG. 1 showing an example of a pipe end according to the present invention, 1 is a pipe main body (also simply referred to as a pipe) made of crosslinked polyethylene or other crosslinked polyolefin;
2 is a collar integrally formed on the outer periphery of the end of the pipe.

Figures 2 and 3 show an example of how the pipes are connected to each other, and the flanges 2.2 at the ends of the two pipes 1.1 to be connected are butted against each other, and the abutting portion A ready-made pipe joint 3 is provided on the outer periphery of both pipes 1.
1 is connected.

Note that any suitable pipe joint or fastening device can be used at this time, such as a clip type or a tightening type using bolts and nuts. This is a commercially available product (S-type one-touch-1 type) manufactured by Co., Ltd., and a gasket 4 is provided inside the joint 3.

Next, in FIGS. 4 and 5 showing an embodiment of the method of the present invention, 11 is a molded female tool, 12 is a core, and 13 is a molded male tool.

The molded female fitting 11 has a large diameter cylindrical portion 14 having an inner diameter larger than the outer diameter of the pipe 1 on its distal end side, and a large diameter cylindrical portion 14 having an inner diameter larger than the outer diameter of the pipe 1 on its proximal end side. Small-diameter cylindrical portions 15 having approximately equal inner diameters are formed, and these cylindrical portions 14,15 are arranged concentrically in the length direction of the molded female fitting 11.

The core 12 has an outer circumferential surface that can be fitted relatively to the inner circumferential surface of the end of the pipe 1 .

Although the core 12 in the illustrated example is tubular, it may also be shaft-shaped.

The molded male tool 13 includes a cylindrical portion 16 having an outer diameter approximately equal to the inner diameter of the large-diameter cylindrical portion 14, and a core storage portion 17 for storing the core 12, with a flange portion 18 on the outer periphery. It is formed.

Each of the above-mentioned forming jigs 11, 12, and 13 is made of heat-resistant metal, heat-resistant and high-strength ceramic, or the like.

In FIGS. 4 and 5, when forming a collar on the end of a pipe, a core 12 is fitted into the end of the pipe 1, and a female molding tool 12 is placed over the outer periphery of the end of the pipe 1. Due to this setting, a portion of the core 12 protrudes from the end of the pipe, and the leading end of the molded female fitting 11 coincides with the end surface of the pipe.

Next, the tip of the molded male tool 13 is relatively fitted to the core 12, and the tip surface of the molded male tool 13 is abutted against the end surface of the pipe l.

After the six tools are set at the end of the pipe 1, one of the female molding tool 11 and the male molding tool 13 is attached to a fixed part of a pressurizing machine (not shown), and the other is used to move the pressurizing machine. It can be attached to the section.

On the other hand, the end of the pipe is maintained at a forming temperature of about 180 to 300° C. after the above-mentioned setting operation is completed.

Thereafter, the female molding tool 11 and the male molding tool 13 are moved toward each other in the axial direction, and as a result, the cylindrical portion 16 of the male molding tool 13 is pushed between the outer periphery of the core 12 and the large diameter cylindrical portion 14. Due to the pressing force at this time, the end portion of the pipe at the above-mentioned molding temperature is deformed under pressure, and the collar 2 is integrally molded on the outer periphery of the end portion of the pipe 1.

When the flange 2 is integrally formed on the outer periphery of the end of the pipe 1 in this way, the thickness of the flange 2 (the dimension in the axial direction of the pipe), the height (the height of the raised dimension in the radial direction) of the pipe 1 are the wall thickness of the pipe 1, Although it is determined by the diameter of the large-diameter cylindrical portion 14 in the molded female tool 11, the amount of pushing of the tip of the molded male tool into the molded female tool 11, etc., the above thickness is usually in the range of about 40 mm and the above height is about 10 colic. If it is set within this range, the flange 2 will be sufficiently formed.

Effects of the Invention J As explained above, the present invention is a long crosslinked polyolefin pipe with excellent heat resistance and chemical resistance, in which a collar is integrally molded at the end of the pipe. By using this, a pipe connection with high strength and high sealing degree can be realized, and it can be suitable as a pipe when constructing a pipeline or the like.

On the other hand, according to the method of forming a flange on a pipe end according to the present invention, a molded female tool and a core are set in a predetermined position on a long cross-linked polyolefin or fin pipe end, and the pipe end is held at a molding temperature. A collar of a desired shape can be formed simply by placing the tip of the male molding tool against the end surface of the pipe and moving the female molding tool and male molding tool relatively close to each other in the axial direction. Molding carini is also possible at installation sites, etc.
With the master of female molding, core, and male molding, it is possible to form the desired flange with high precision by deforming only the necessary parts of a long cross-linked polyolefin pipe.

[Brief Description of the Drawings] Fig. 1 is a cross-sectional view showing one embodiment of a flanged crosslinked polyolefin pipe according to the present invention, and Figs. 2 and 3 show how the pipes are connected to each other via the flanges at the ends. FIGS. 4 and 5 are partially cutaway front views showing each of the main steps in an embodiment of the method for forming a collar on the end of a pipe according to the present invention. , FIG. 6 is a cross-sectional view schematically showing a conventional sleeve welding method, and FIG. 7 is a cross-sectional view schematically showing a conventional mechanical joint method. l... Pipe body part 2, collar 11-@, molded female fitting 12... core 13... molded male fitting 14... large diameter cylindrical part 15... small diameter cylindrical part 16...・Cylindrical part 17... Core storage department agent Patent attorney Yoshio Saito TM Figure 3 Figure 2 1I 4 Figure 5

Claims (2)

[Claims] (1) A long cross-linked polyolefin pipe with a cross-linked polyolefin flange, characterized in that a heat-formed flange is integrally formed on the outer periphery of at least one end of the long cross-linked polyolefin pipe. (2) In a method of integrally molding a collar by thermoforming on the outer periphery of the end of a cross-linked polyolefin pipe, the end of a predetermined cross-linked polyolefin pipe has an outer peripheral surface that can be relatively fitted to the inner peripheral surface of the pipe. The core is fitted, and then a large diameter cylindrical portion having an inner diameter larger than the outer diameter of the pipe and a small diameter cylindrical portion having an inner diameter approximately equal to the outer diameter of the pipe are formed on the outer periphery of the end of the pipe. The tubular molded female fittings, which are formed concentrically in the horizontal direction, are attached via the small diameter cylindrical part so that the edge of the large diameter cylindrical part almost coincides with the edge of the crosslinked polyolefin pipe. After the molding, the part is heated to a predetermined molding temperature, and then a core accommodating part for storing the core is provided at the tip in the large diameter cylindrical part of the molding female component, and the molding female component is A molded male tool having a cylindrical part of a predetermined length with an outer diameter smaller than the inner diameter of the large-diameter cylindrical part is pushed in, and the end part of the crosslinked polyolefin pipe is deformed under pressure by the pushing pressure at this time. A method for integrally molding a flange on the end of a crosslinked polyolefin pipe, characterized by forming a flange on the outer periphery of the end.