JPH07323480A - How to connect pipes - Google Patents

Abstract

(57) [Summary] [Structure] A connection method for heating the inner peripheral surface 11 of the pipe joint 1 and the outer peripheral surface 21 of the end portion of the pipe body 2 to melt the surfaces, and thereafter connecting the two. The diameter of the inlet of the inner peripheral surface 11 of the joint 1 is large, and the diameter is gradually reduced to two or more steps toward the inner side, and the end outer peripheral surface 21 of the pipe body 2 is the inner peripheral surface of the pipe joint 1. Expanded to fit. [Effect] Since the diameter of the tip of the pipe body 2 is small and the diameter of the inlet of the pipe joint is large, it is easy to insert the tip of the pipe body 2 from the inlet of the pipe joint 1 even if there are variations in dimensions. Further, since the inner diameter of the pipe joint 1 is gradually reduced and the outer diameter of the pipe body 2 is gradually increased, there is no gap when the pipe body 2 is inserted into the pipe joint 1. Both sides are in close contact. Therefore, even if there are variations in the dimensions, they can be closely adhered as a surface and firmly adhered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting pipes.

[0002]

2. Description of the Related Art Conventionally, there are various methods for connecting pipes, but as described in Japanese Patent Publication No. 42340/1990, the inner surface of the pipe joint and the outer peripheral surface of the end of the pipe are heated to melt the surfaces. After this, the pipe connecting method is often used in which the end of the pipe is inserted into this pipe joint and the inner peripheral surface of the pipe joint and the outer peripheral surface of the end of the pipe are fusion-bonded. .

[0003]

However, the conventional method of connecting pipes is good because of variations in dimensions due to differences in pipe joint and pipe manufacturing conditions, and variations in construction such as cutting of the end of the pipe. May not be able to connect to. This will be described with reference to FIGS. 4 and 5. As shown in FIG.
The inner peripheral surface 101 of the pipe joint 100 is a substantially parallel surface or a tapered (1 ° to 3 °) surface that slightly expands outward. Further, the pipe body 200 to be connected is ground so that the outer peripheral surface 201 of the end portion fits the pipe joint, and is made into a substantially parallel surface or a slightly tapered surface (1 ° to 3 °). Then, after heating and melting the both surfaces, the end portion of the pipe is inserted into the pipe joint.

Then, the outer diameter of the pipe body and the inner diameter of the pipe joint are different from a predetermined size due to variations in dimensions and variations in construction such as cutting, and the taper angle is different so that the inner surface of the pipe joint and the end portion of the pipe are different. There may be a gap between it and the outer surface, or it may not be possible to insert it. Furthermore, if the end portion of the pipe body is forcibly inserted into the pipe joint that is difficult to insert, as shown in FIG.
A protrusion 300 called a bead is generated. As a result, the liquid passing through the inside may leak or the flow may deteriorate, and the bead may protrude from the outer peripheral surface to deteriorate the appearance. Therefore, an object of the present invention is to provide a pipe body that allows easy insertion of the tip end portion of the pipe body into the pipe joint even if there are variations in dimensions or variations in construction such as cutting, and that enables good connection. It is to provide a connection method of.

[0005]

The present invention has been made to solve the above problems and achieve the above objects.
After heating the inner peripheral surface of the pipe joint and the outer peripheral surface of the end portion of the pipe body to melt the surfaces, the end portion of the pipe body is inserted into this pipe joint to insert the inner peripheral surface of the pipe joint body and the pipe body. In the method of connecting a pipe body by fusion-splicing with the outer peripheral surface of the end portion of the pipe body, the inner peripheral surface of the pipe joint has a large inlet diameter, and the diameter is gradually reduced to two or more stages as it goes deeper. The outer peripheral surface of the end portion has a small diameter at the tip end and is gradually increased in diameter toward the root in two or more steps so as to fit the inner peripheral surface of the pipe joint.

The material of the pipe body and the pipe joint used in the present invention may be any material as long as it is a thermoplastic resin, but the same material is preferable for the pipe body and the pipe joint. The preferred material is
There are olefin resins such as polyethylene, polypropylene and polybutene, polystyrene, polyvinyl chloride, polycarbonate, polyphenylene sulfide and the like, but ethylene resins are most preferable. The inner peripheral surface of the pipe joint used in the present invention has a large inlet diameter and is gradually reduced in diameter as it goes deeper, but the boundary of this stepwise reduction is from a large diameter to a small diameter. The diameter may be reduced stepwise or may be tapered. Further, the outer peripheral surface of the end portion of the pipe body is gradually increased in diameter as the diameter of the tip is small and increases toward the root, but the boundary of this stepwise expansion is the inner peripheral surface of the pipe joint. The diameter may be increased stepwise from a small diameter to a large diameter or may be increased in a tapered shape so as to fit.

[0007]

The function of connecting the pipes of the present invention is as follows. That is, the inner peripheral surface of the pipe joint used in the present invention has a large inlet diameter and is gradually reduced in diameter toward the inner side by two or more steps. The outer peripheral surface is cut with a jig so that the diameter of the tip is small so as to fit the inner peripheral surface of this pipe joint, and gradually increases toward the root to have a surface having two or more stages in stages. Next, the inner peripheral surface of the pipe joint and the outer peripheral surface of the tip of the pipe are heated to melt the surfaces, and immediately the tip of the pipe body is inserted into the pipe joint. Then, the outer peripheral surface of the distal end portion of the pipe body is welded to the inner peripheral surface of the pipe joint, and if left for a while, it can be cooled and firmly connected.

The pipes are connected in this manner, but the diameter of the tip of the pipe is small and the diameter of the pipe joint is small even if there are variations in dimensions or variations in construction such as cutting the tip of the pipe. Since the diameter of the inlet is large, it is easy to insert the tip of the pipe into the pipe joint, and the pipe joint is gradually reduced in diameter to two or more stages as it goes deeper, and the outer peripheral surface of the pipe is Since the diameter is gradually increased to two or more steps toward the root, the gap between the inner peripheral surface of the pipe joint and the outer peripheral surface of the pipe becomes smaller as the pipe is inserted deeper, and finally, Both are in close contact. As described above, the diameter is gradually reduced or expanded in two or more steps, so that even if there is variation, it can be closely attached to any one of these steps, and good connection can be achieved. Moreover,
Since the connecting surfaces are connected in parallel to each other, they can be firmly connected.

[0009]

EXAMPLES Next, examples of the present invention will be described. 1 and 2 show an embodiment of a method for connecting a pipe body of the present invention, and (a) of FIG. 1 is an explanatory view showing a cross section of a tip end portion of a pipe joint,
(B) is an explanatory view showing a cross section of the tip portion of the tubular body, and FIG. 2 is an explanatory view showing a cross section of the heater. 3A and 3B show another embodiment of the present invention. FIG. 3A is an explanatory view showing a cross section of the tip end portion of the pipe joint, and FIG. 3B is an explanatory view showing a cross section of the tip end portion of the pipe body.

1 and 2, reference numeral 1 denotes a polyethylene pipe joint, and an inner peripheral surface 11 of the pipe joint 1 has a large inlet diameter and a small inner diameter, that is, the inner peripheral surface. Is reduced in two stages as it goes deeper. The boundary between the large diameter portion and the small diameter portion is stepped. 2 is a polyethylene pipe body, and the outer peripheral surface 2 at the end of the pipe body 2
In No. 1, the diameter of the tip is small and the diameter of the tip is larger so as to fit the inner peripheral surface 11 of the pipe joint 1. That is, the outer peripheral surface 21 is expanded in two steps toward the root. The Sakai between the small diameter portion and the large diameter portion has a stepped shape.

Reference numeral 3 denotes a heater used when connecting the pipe joint 1 and the pipe body 2. The heater 3 has a convex portion 31 slightly smaller than the inner diameter of the pipe joint 1 at one end and a pipe body at the other end. A recess 32, which is slightly larger than the outer diameter of 2, is provided. The heating elements 4 and 5 made of nichrome wire are provided near the outer peripheral surface of the convex portion 31 and near the inner peripheral surface of the concave portion 32, respectively.

Next, a method of connecting the pipe joint 1 and the pipe body 2 will be described. First, the outer peripheral surface of the tip portion of the tubular body 2 is cut to make the diameter of the tip small and the surface of the root larger as shown in FIG. Next, the convex portion 31 of the heater 3
Is inserted into the pipe joint 1, the tip of the pipe body 2 is inserted into the recess 32, and an electric current is applied to the heating bodies 4 and 5 to heat them. Then, since the surfaces of the inner peripheral surface of the pipe joint 1 and the outer peripheral surface of the pipe body 2 are melted, the pipe joint 1 and the pipe body 2 are immediately taken out from the heater 3, and the tip portion of the pipe body 2 is attached to the pipe joint 1. Insert inside.

Then, since the tip of the pipe body 2 has a small diameter and the outer peripheral surface of the pipe joint 1 is large, it can be easily inserted. When it is gradually inserted into the inner part, the diameter of the pipe body 2 is gradually increased and the outer peripheral surface of the pipe joint is gradually decreased. If left unattended for a while, the surface will solidify and firmly connect together. In this way, since the diameter is gradually reduced or expanded, there is no possibility that it will come into close contact with somewhere and a gap will not be formed or it cannot be inserted. In addition, since it is stepwise, almost parallel surfaces are bonded and the bonding strength is high.

Next, the embodiment shown in FIG. 3 will be described. When the embodiment shown in FIG. 3 is compared with the embodiment shown in FIGS. 1 and 2, the shapes of the inner peripheral surface 11a of the pipe joint 1a and the stepped outer peripheral surface 21a of the pipe body 2a are different. That is, the inner peripheral surface 11a of the pipe joint 1a has the same large diameter at the inlet and the small diameter at the inner side, but the boundary is tapered and the tip of the pipe body 2a is the same. The outer peripheral surface 21a has a small tip diameter and a large root portion as shown in FIG.
2 is the same as that of FIG. 2 except that the boundary is tapered. The other points are the same as those of the embodiment shown in FIGS. 1 and 2, and the description thereof will be omitted.

[0015]

According to the method of connecting pipes of the present invention, the tip of the pipe has a small diameter, and the diameter of the inlet of the pipe joint is large. Therefore, even if there is variation in size, the tip of the pipe is inserted from the inlet of the pipe joint. easy. Further, the inner diameter of the pipe joint is gradually reduced to a smaller diameter by two steps or more as it goes deeper, and the outer diameter of the pipe body is gradually increased to a larger diameter by two steps or more as it goes to the root. Therefore, as the pipe body is inserted into the pipe joint, the gap between the tip outer peripheral surface of the pipe body and the inner peripheral surface of the pipe joint becomes smaller, and finally the inner peripheral surface of the pipe joint and the outer peripheral surface of the pipe body are Stick to each other. In this way, since the diameter is gradually reduced or expanded in two or more steps, the connection can be satisfactorily made even if the tube body or the pipe joint has dimensional variations. Also, since the substantially parallel surfaces are bonded, a strong connection can be achieved.

[Brief description of drawings]

FIG. 1 shows an embodiment of a method for connecting pipes of the present invention, in which (a) is an explanatory view showing a cross section of a tip portion of a pipe joint,
(B) is explanatory drawing which shows the cross section of the front-end | tip part of a pipe body.

FIG. 2 is an explanatory view showing a cross section of a heater.

3A and 3B show another embodiment of the present invention, in which FIG. 3A is an explanatory view showing a cross section of the tip end portion of the pipe joint, and FIG. 3B is an explanatory view showing a cross section of the tip end portion of the pipe body.

FIG. 4 is an explanatory view showing a cross section of a pipe joint and a pipe body used in a conventional pipe body connecting method.

FIG. 5 is an explanatory view showing a cross section of a connecting portion connected by a conventional tube connecting method.

[Explanation of symbols]

 1 Pipe Joint 11 Inner Surface 2 Tube 21 Outer Surface 3 Heater 4,5 Heater (Nichrome Wire)

Claims (1)

[Claims] 1. The inner peripheral surface of the pipe joint and the outer peripheral surface of the end portion of the pipe body are heated to melt the surfaces, and then the end portion of the pipe body is inserted into the pipe joint to make the inner surface of the pipe joint. In a method of connecting a pipe body by fusion-splicing a peripheral surface and an outer peripheral surface of an end portion of the pipe body, the inner peripheral surface of the pipe joint has a large inlet diameter, and the diameter gradually decreases toward the inner side by two or more stages. The outer peripheral surface of the end of the pipe body has a small diameter at the tip end, and the diameter is gradually increased to two or more steps toward the root so as to match the inner peripheral surface of the pipe joint. Characteristic pipe connection method.