JPH044127A - Manufacture of pipe joint having different diameter - Google Patents

Abstract

PURPOSE:To manufacture easily and inexpensively a pipe joint which is light in weight, superior in strength and has different diameters, by a method wherein an end part of a tubular body is softened by heating the same, the diameter of the softened part is contracted, the tubular body where a large-diameter part and tapered part are shaped is inserted into an outer mold and then the inner mold is inserted forcibly into the tubular body. CONSTITUTION:The tip of a tubular body 4 made of heated rigid polyvinyl chloride is inserted forcibly into the inside of the first outer mold 1 until it collides with the top 5 of a plate body and a tapered part 41 is formed. In a cross-sectional form of the tip part of the tapered part 41, it is depressed patly inward in the radial direction and a corrugated state is indicated. Then the tubular body 4 is taken out of the first outer mold 1, charged into the inside of the second outer mold 2, further an inner mold 3 is inserted forcibly into the inside of the tubular body 4 in succession and the tip of the tapered part 41 is expanded outward. A large-diameter part 43 and a pipe joint having different diameters are completed by forming a small-diameter part 42 and finishing even the inside of the tubular body 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a pipe joint of different diameters used for connecting pipes of different diameters in piping work.

(Prior Art) Conventionally, a method called a welding process as shown in FIGS. 5 and 6, for example, is known as a method for manufacturing this type of pipe joint with different diameters.

In this welding process, first, three short pipes are processed and formed into parts of a large diameter part a, a taper part A, and a small diameter part C, respectively, and then each of these parts a, b1. C is joined by welding d and processed into a pipe joint with different diameters.

In addition, in order to reinforce the welded part of the molded product in this way, an uncured fiber-reinforced synthetic resin (FR, P) layer is formed on the outer peripheral surface of a certain range of dimensions with the welded part in the center, A method of curing this by heating is also known.

On the other hand, in addition to the above-mentioned manufacturing method, an injection molding method is also known in which a desired shape is molded.

(Problem to be Solved by the Invention) However, in the conventional welding method described above, it is necessary to form three parts in advance, the large diameter part a, the tapered part b, and the small diameter part C. Since they have to be joined one by one, there is a problem in that manufacturing takes time and effort. In addition, since three parts are joined by welding,
The obtained different diameter pipe joint has problems such as its overall length is long, it is difficult to connect to the pipe material during piping, and its mechanical strength and dimensional accuracy are poor.In addition, the strength of the welded part is poor. When FRP is applied from the outside for reinforcement, there is a problem in that the weight increases and the manufacturing cost increases.

On the other hand, while the injection molding method does not have the above-mentioned problems that the welding method has, the cost of the mold required for molding is high, and different-diameter pipe fittings are generally produced in small quantities in a wide variety of products, especially in accordance with the standard. This tendency is strong in external products, and there is a problem in that the manufacturing cost per unit becomes extremely high.

The present invention has been made with the object of solving the above-mentioned drawbacks and providing a method of manufacturing a pipe joint of different diameters that is lightweight and has excellent strength and can be manufactured easily and at low cost.

(Means for Solving the Problems) The gist of the present invention is to heat and soften the end of the pipe body, thereby shaping the large diameter part of the pipe joint and the tapered part consisting of a funnel-shaped inclined surface. After the tube is forcibly inserted into a first outer mold having a mold surface, the tube is taken out and the end thereof is reheated (with or without reheating), and the shape is substantially the same as the outside shape of the pipe joint. The pipe fitting is charged into a second outer mold having an inner surface shape of The problem lies in the manufacturing method of pipe fittings.

In the manufacturing method of the present invention, as a means for heating and softening the end of the tube, for example, glycerin is used as a heating medium, and the end of the tube is immersed for a certain period of time in a heating tank filled with the heated glycerin. It is best to heat it.

In the manufacturing method of the present invention, the inclination angle of the tapered portion consisting of the funnel-shaped inclined surface of the first outer mold is preferably about 10 to 20 degrees, more preferably about 13 to 20 degrees. If the angle is smaller than 10 degrees, the total length of the pipe joint will be longer than necessary, and if the angle is larger than 20 degrees, the softened portion will tend to buckle during molding.

In the manufacturing method of the present invention, the operation of forcibly inserting the tubular body into the first outer mold, or inserting the inner mold after inserting it into the second outer mold, is as follows: For example, as shown in FIGS. 1 to 3, it is preferable to carry out the process with the mold standing upright on the plate 5 with the large-diameter mold surface facing upward.

In the manufacturing method of the present invention, when the heated end of the tubular body is inserted into the first outer mold until the tip abuts against the upper surface of the plate, the diameter-reduced tip portion has an annular shape. Instead, a portion may be recessed inward in the radial direction and have a wavy shape.

In the manufacturing method of the present invention, first, a large diameter portion and a tapered portion of a pipe joint are shaped using a first outer mold, and then a small diameter portion is shaped using a second outer mold and an inner mold. is the standard method, but the first
The large diameter part and the tapered part are preformed to a size smaller than the desired size of the pipe fitting using the outer mold. When inserting the inner mold, which has an outer shape that is approximately the same as the inner surface shape of the pipe fitting, into the pipe body, the tip of the tapered part, which has been reduced in diameter into a funnel shape, is inserted outward. In addition to expanding to form a small diameter part, the front cylindrical part, that is, the large diameter part or tapered part, may be expanded in diameter from the original shape and shaped to the final size. For example, if the ratio of the large diameter part and the small diameter part is 2=1
It can also be done to a certain extent.

(Function) In the manufacturing method of the present invention, the end of the pipe is heated and softened to form a mold surface that can shape the large diameter part of the pipe joint and the tapered part consisting of a funnel-shaped inclined surface. Since the tubular body is forcibly inserted into the first outer mold, the end of the tube is inserted while rubbing against the inner wall surface of the first outer mold, and the softened portion follows the inner shape of the first outer mold. The large diameter portion and the tapered portion are shaped by being deformed and reduced in diameter.

Next, the tube shaped as described above is taken out and placed into a second outer mold having an inner surface shape that is approximately the same as the outer surface shape of the tube fitting. Since the inner mold having an outer surface shape that is approximately the same as the inner shape is forcibly inserted, the diameter of the most reduced tip portion is smoothly expanded to form a small diameter portion, and not only the small diameter portion, but also Both the large diameter part and the tapered part are precisely finished to the desired dimensions and shape.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 are cross-sectional views showing an embodiment of the present invention divided into molding stages.

Reference numeral 1 designates a first outer mold having a cylindrical large-diameter mold surface 11 with an inner diameter of 222 mm and a tapered mold surface 12 consisting of a funnel-shaped inclined surface with an inclination angle of 13 degrees at its lower end; The outer surface of the pipe joint consists of a small-diameter mold surface 23 with a diameter of 147 m at the lower end of a tapered mold surface 22 consisting of a large-diameter mold surface 21 with the same diameter as the outer mold l and a funnel-shaped inclined surface with the same inclination angle. a second outer mold having an inner surface shape that is substantially the same as the shape; 3 is the second outer mold 2;
Although it has the same shape, each corresponding portion 3132 and 33 has a smaller diameter by 22 mm, and has an inner shape having an outer shape that is approximately the same as the inner shape of the pipe joint. Note that 5 is the upper surface of the plate on which these molds are placed.

Next, in order to carry out the manufacturing method of the present invention using the above three types of molds, first, the tip of the heated hard polyvinyl chloride tube 4 having a diameter of 200 cm is inserted into the inside of the first outer mold 1. Then, as shown in FIG. 1, the tapered portion 41 is formed by forcibly inserting the plate until it abuts against the upper surface 5 of the plate. As shown in FIG. 4, the cross-sectional shape of the tip end of the tapered portion 41 is partially recessed inward in the radial direction and has a wavy shape.

Next, the tubular body 4 is taken out from the first outer mold 1 and inserted into the second outer mold 2 to form the state shown in FIG. 2. Furthermore, the inner mold 3 is forcibly inserted into the inside of the tube body 4, and as shown in FIG. By also finishing the inner surface of the body 4, the pipe joint with different diameters is completed together with the large diameter portion 43.

(Effects of the Invention) The method for manufacturing a pipe joint with different diameters according to the present invention has a configuration similar to the ridges, so an integral structure can be obtained from a single pipe body, and it is possible to obtain an integral structure from a single pipe body. In comparison, the labor and time required for processing can be significantly reduced, and the length of the pipe joint does not become longer than necessary, making it possible to obtain a pipe joint that is convenient for pipe connection work. Also, large diameter part, tapered part,
Since each part of the small diameter part is integrally molded, a product with excellent mechanical strength can be obtained. In addition, since the inner and outer molds are used, products with excellent dimensional accuracy can be obtained, and since the shaping of the tapered part and the small diameter part is done in separate processes, the diameter expansion operation of the small diameter part is especially difficult, and the large It is also possible to obtain a material with a large reduction ratio between the diameter portion and the small diameter portion, thereby expanding the range of applications.

[Brief explanation of drawings]

1 to 3 are cross-sectional views showing an embodiment of the present invention divided into molding stages. Figure 2 is a diagram showing a state in which the tube body has been taken out from the first outer mold and inserted into a second outer mold, Figure 3 is a diagram showing a state in which the inner mold has been further inserted in the same, and Figure 4
This figure is a cross-sectional view showing the cross-sectional shape of the tip of the tapered portion shown in FIG. 1, and FIGS. 5 and 6 are half-sectional views showing a conventional welding process. 1-first outer mold, 2-second outer mold, 3-inner mold, 4-pipe body, 11.21.31...-large diameter mold surface, 12.2
2.32--Tapered part mold surface, 23.33--Small diameter part mold surface, 41-Tapered part, 42--Small diameter part, 43-Large diameter part.

Claims (1)

[Claims] 1. The end of the pipe is heated and softened, and forced into a first outer mold having a mold surface capable of shaping the large diameter part of the pipe joint and the tapered part consisting of a funnel-shaped inclined surface. After the tube is inserted into the fitting, the tube is removed and the end portion thereof is reheated (or not reheated) to form a second tube having an inner surface shape substantially the same as the outer surface shape of the pipe joint.
A method for manufacturing a pipe fitting of different diameters, the method comprising: inserting the tube into an outer mold, and then forcibly inserting an inner mold having an outer shape substantially the same as the inner surface shape of the pipe fitting into the pipe body.