JPH0493A - Plastic joint - 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> The present invention is widely used in plastic piping for fluid transfer in various industrial fields.

<Prior art and its problems> Many types of joints have been used in the field of use for which this invention is intended, and with the exception of joints that can be used with adhesives such as vinyl chloride pipes, polyethylene <PE>
For fittings of thermoplastic resin pipes, polypropylene <PP> pipes, polybutene <PB> Sugagasa adhesives cannot be used, there is a method of using metal screws in a small portion of small diameter pipes, but other than this method, heating The butt-welding of pipe end faces by melting (0-join υ-butt welding), and the plug-in joining (nogat welding) by simultaneous heating and melting before joining the pipe and socket are used.

In addition, in the part of the large-diameter PP pipe, insert mold a nichrome wire on the inner surface, insert the PP pipe to be joined, heat the nichrome wire by applying electricity, and melt the joint.
However, this method requires strict dimensional accuracy of the gap between the socket and the tube, which is less than 0.7% of the tube diameter.
Furthermore, when the socket is heated, the internal diameter expands due to thermal expansion, reducing the pressure applied to the adhesive surface and causing adhesion failure. To prevent this, it is necessary to tighten a metal fixing band around the outer periphery of the socket.

However, with this method, in the case of a resin pipe with low rigidity such as a PB pipe, relief deformation due to so-called sagging occurs also on the inner diameter side, so there is a great risk of poor bonding due to insufficient adhesive pressure.

Furthermore, the above two methods of welding require centering and pressurization of the joint, and holding the weld in place for a certain period of time (curing period), which requires special machinery. It becomes. However, this is difficult to use in narrow spaces or at high places, which is a factor that greatly reduces work efficiency.
It has also become.

In particular, resins such as PI3 pipes, which have a unique crystal transformation from a molten state to cooling and solidification (complete assimilation takes about two weeks at room temperature), require at least 30 minutes of curing time, which greatly affects workability.

<Means for Solving the Problem> This invention uses a joint construction that uses both the mechanical bonding force method using screws and the fusion bonding method, so that it can be directly joined during piping as in the conventional joints described above. Problem 1 was solved by displacing the functional elements of centering, pressurization, and curing from the joint mechanism itself, which eliminates the need to install large-scale equipment at each location.

<Example> The present invention will be described below with reference to the drawings, using a PB pipe as an example.

1) is the insertion part of the present invention, which is joined to 2) (butt welding) by a thick actual at part (welded part, hereinafter referred to as t) shown in 2a) on one end surface of the PB pipe of 2). It is inserted into the socket of 3), and the tip part? Collected screws Ia)i
So, 3a) below? This screws together.

Of course, 1) and 2) may be joined by socket welding as in the eighth lkl. The inner surface of tube 3) is gently tapered, and a wall of tube 3a) is provided at the inner part of the tube, and a wall of abutment section 3b) is provided at the center of the tube. 1
) is formed with a flange part /I), and when the above 1a) and 31) are screwed together, the end face 3 of the socket 3)
The nichrome wire 5) is embedded (insert) in contact with c), and 5a) is its lead wire. 3C
) 4G) indicates the welding part, and 5a is connected from a power source (not shown).
>, the heat generated in 5) melts the part 4c) and the part 3c) in contact with it, and when the core reaches a state suitable for welding, tighten the screw 1a) and apply the necessary additions to the melted part 27. Apply pressure to complete welding. At this time, by tightening the screws, axial centering, position fixing, and post-curing functions will also be generated at the same time. (If you tighten the screws smoothly and firmly, you can omit further screw tightening during welding.) When tightening the screws during welding, be sure to tighten 3) and l) before welding. It is necessary to determine the relative dimensions of 3) and 1) so that there is a slight gap (tightening margin) between the tip of 13) and the surface 3b) when joined.

This is between 1) and 3) due to the pressure applied during welding, that is, 3
c) This is to ensure that when a part of 4c) becomes a bead and protrudes to the outside, this gap disappears and a strong bond is obtained.

6) is a rubber O-ring as an auxiliary means for sealing, which can be omitted.

The other side of 3) (on the left side of the drawing) shows that the part 2b) is inserted and joined by the conventional socket welding method.

Figure 28 shows that it is located in a part of the i-pa of the ink mark 5) in Figure 1 [7 square or 1].
As mentioned above, straight PB pipes tend to deform due to stress in the soft parts when heated and softened, but in the case of this figure, the tapered part can pressurize the melted part by moving it forward, making it possible to obtain a strong weld. .

Is it melting at the taper part? Although the weld is shown in the figure, it may be short in some cases, so that the threaded part can sufficiently cope with the pull-out stress of the pipe, and in this case the weld part simply serves as a fluid sole. This means that you are doing the following.

Normally, in the present invention, the weld strength and the mechanical strength of the screw have a complementary relationship with respect to the pull-out stress applied to the pipe joint, and the screw design and weld length are determined based on this. decide.

In Figure B, as an example, the nichrome wire of 5) is inserted into the deformed flange surface as shown in the drawing, which can increase the welding area and increase the adhesive strength.

For the third six prongs, the screws Ia) and 3a) are located at flange 4.
) or at the end of socket 3). The welded part and its strength are the same as in Figure 1 and are used to join thin-walled pipes.

In Figure B, a ring-shaped glue knob 7) is provided on the abutting end surface of 1). 6) has the same effect.

In the 46th session, the nichrome wire 5) of the heating element in Figure 2A is made of a substance that generates heat due to high-frequency induced current, such as metal powder, ferrite powder, carboxylic powder, or short fibers of these in FB at 10-50%. As shown in Figures 6A and B, this is molded into a thin-walled shape and insert-molded in the area to be melted, or melted. An adhesive (f, hotmelt) is sandwiched and fixed at the location to be welded, and the second Welding is carried out as explained in the figure.

In Figure B, 5) in Figure 1 is replaced with the heating element 8) in Figure A. Explanation will be omitted.

Figure 5 shows the case where conventional butt welding is used to heat and melt the joint surface of the 36th prong, using an external hot plate heating element with a built-in heater, or a hot plate]0) (halved ring shape). ). Ia) at this time
3a) The screws should preferably have multiple threads with a large pitch, and the desired spacing required for attaching and detaching the screws in step 10) should be obtained by turning 1) by 1 to 3 turns or less. In any case, the thinner the item 10), the better.

Figures 6A and 6B show substances that are induction heated by high frequency current as described above, such as powders of ferrite, carphone, etc.
Alternatively, a melt-bonded part (hot melt) 12) formed into a thin wall using FB blended with 10-50% (but not limited to) of these short fibers 11) is shown.

Figure C shows the nichrome wire from 5) in Figure 1 molded into a thin PB disk plate from 12) and insert-molded as a heating element.It is used by placing it in this position in the same way as 5) in Figure 1. . However, the shape of the nichrome wire is free, and this figure is just an example.

Figure 7 shows the application of the present invention to the double pipe joint of Japanese Patent Application No. H1-221809 by the present inventor. There are no walls. 13) is a thin-walled tube made of 4-fluorocarbon resin. Explanation will be omitted.

FIG. 8 shows a state in which 1) and 2) are joined by socket welding, which is used in the same way as butt welding. Explanation will be omitted.

(Effects of the Invention) As described above, the present invention has the advantage that the conventional welding and joining methods of thermoplastic pipes are limited to butt welding and socket welding, and that centering, pressurization, and fixation during joining are not required for specific machines. Although it requires equipment and skill, it is possible to easily and reliably achieve the desired purpose without requiring any equipment or skill.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view when the present invention is implemented. Figures 2, 3, 4, and 5 are partial cross-sectional views when the present invention is implemented. Figure 6 A and B are actual states of the heat generating plate. Figures 7 and 8 are a front view of the disc-shaped fully heated plate, and Figures 7 and 8 are partial cross-sectional views of the present invention. In the drawing, 1)...insertion part, la)...screw,
2)...Pipe, 2a), 2b)...Welded part,
3)...Socket, 3a)...Screw, 3b)...
・Abutting wall, 3c)...Welded part, 4)...Flange, 4c)...Welded part, 5) Nichrome wire, 5a)
・・Lead wire, 6)・・O ring, 7)・・Ripknoll, 8)・・High frequency heating element, 9)
High frequency coil, 10)...Heat plate 11)...High frequency heating element 12)...FB plate, Note that the thick solid line indicates the welded part.

Claims (1)

[Claims] In a joint structure consisting of a socket (receptacle) etc. for connecting plastic pipes and an insert part that is joined to the pipe at one end, a flange is formed near the base of the insert part, Furthermore, a threaded portion is formed on the entire length or part of the straight or tapered portion of the front body,
A joint connection that is screwed together by a screw formed in at least one socket of the socket, the outer circumferential surface of the body on the insertion side, the inner circumferential surface of the socket, the flange end surface,
Alternatively, insert molding stripes of a substance that generates heat by electric current or high-frequency current on the flange surface that butts against this surface, or blend powder or short fibers of the exothermic substance into the same material as the joint and form it into a thin plate. The structure of a plastic joint is made by combining molded heating elements.