JP4246983B2 - Pipe fitting - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe joint for connecting a resin pipe or a composite pipe of resin and metal, wherein a pipe body connecting metal nipple is provided on one surface of the pipe joint body, and a metal thin core is provided on the outer surface of the nipple. After the tube end is inserted between the nipple and the thin core, the thin core is compressed by compressing the outer peripheral surface of the thin core with a compression jig (hereinafter referred to as caulking). The present invention relates to a pipe joint (hereinafter referred to as a caulking joint or a caulking joint) having a structure in which the pipe body is fixed to the joint by pressing against the outer surface of the pipe.
[0002]
[Prior art]
A conventional caulking joint for connecting a resin pipe or a resin-metal composite pipe is provided with a metal nipple for connecting a pipe body on one surface of the caulking joint body, and a thin metal core on the outer surface of the nipple. After the tube body end is inserted between the nipple and the thin core, the outer surface of the thin core is compressed with a compression jig, and the thin core is pressed against the outer surface of the tube to join the tube It is set as the structure fixed to. These joints are usually composed of a joint body, a pipe connecting nipple, a water-stopping packing, a thin core, and if necessary, a pipe retaining protrusion. In addition, the water stop packing is attached to a concave groove provided along the circumferential direction on the nipple outer peripheral surface.
[0003]
For example, when connecting a composite pipe in which a metal layer is laminated between synthetic resin layers, this caulking joint has a plurality of compression dies provided on a compression die of the compression jig when the compression jig is compressed and reduced in diameter. The ridge compresses the water-stopping packing installed in the groove and deforms it. Water-stopping due to the deformation of the water-stopping packing and water-stopping due to the inner peripheral surface of the tube coming into contact with the nipple outer peripheral surface It is designed so that the water stop is completed with both effects (referred to as Patent Document 1, for example).
[0004]
In this caulking joint, if the amount of protrusion of the water-stopping packing from the groove is increased, the water-stopping packing will be removed from the groove when the tube end is inserted into the nipple. Has been. Accordingly, the amount of compressive deformation of the water stop packing is small.
[0005]
[Patent Document 1]
Patent DE-29814047-U1
[0006]
[Problems to be solved by the invention]
However, in the method of Patent Document 1, the axial positioning of the compression packing is insufficient, and the ridge position provided on the compression die may not always coincide with the position of the groove. In this case, the amount of compressive deformation of the water-stopping packing becomes smaller in addition to the originally designed amount of deformation of the water-stopping packing being small.
[0007]
When connecting pipes using such joints, even if a normal water pressure test (internal pressure creep test) was performed on the connected pipe line, the hard seal effect was effective and no water leakage was observed. In a repeated test (a test in which hot water at 95 ° C. and normal temperature water was repeatedly passed through a pipe), water leakage was observed. This is because when the hot water flows, the entire pipe line expands and becomes large, and then when normal temperature water flows, the pipe inner surface is cold, the joint outer surface is hot, a temperature gradient is created, and the linear expansion difference is significantly increased. This is because water cannot be stopped with the seal, and water cannot be stopped because the amount of deformation is small even with the water sealing.
[0008]
The present invention solves the problems of the above-mentioned conventional crimping joints, the groove of the water-stopping packing does not slip when the pipe is inserted, and after the caulking, the amount of compressive deformation of the water-stopping packing becomes large, even during repeated cooling and heating. It was made for the purpose of providing a pipe joint that does not leak.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention , a nipple for connecting a tubular body is integrally projected from one end surface of a metal joint body, and a concave groove is provided along the circumferential direction on the outer peripheral surface of the nipple. The groove is provided with a water-stopping packing that is in close contact with the inner peripheral surface of the pipe body, and an annular groove is provided concentrically with the nipple on one end face of the joint body projecting from the nipple. The metal thin core is disposed along the outer peripheral surface of the nipple by fitting the tip of the metal thin core, and the end of the tubular body connected between the thin core and the nipple is inserted. And a pipe joint for fixing and connecting the nipple and the pipe body by compressing the outer peripheral surface of the thin core with a compression jig and reducing the diameter, and the inner peripheral surface of the compression die of the compression jig A plurality of ridges are provided on one of the ridges, and one of the ridges is provided on one side of the compression die in the width direction of the joint body When in contact with the end surface, a pipe joint, characterized in that provided in the groove with the opposite position of the nipple.
[0010]
In the present invention according to claim 2, when the end portion of the thin core on the side into which the tube is inserted is expanded outwardly, and one surface in the width direction of the compression die is brought into contact with one end surface of the joint body, The pipe joint according to claim 1, wherein a length from the taper surface start point of the thin core to one end surface of the joint body is set to be larger than the width of the compression die.
[0011]
According to the third aspect of the present invention, protrusions for preventing the tube from coming off are provided on both sides of the groove provided on the outer peripheral surface of the nipple, and the shape of the protrusions is asymmetrical with respect to the groove. And the positions of the two protrusions are positions where the protrusions can be engaged with the inner peripheral surface of the end of the tube when the end of the tube is fitted between the nipple and the thin core. The pipe joint according to claim 1 or 2, wherein the pipe joint is provided.
[0012]
The pipe targeted by the present invention is a synthetic resin pipe such as polyethylene, cross-linked polyethylene, modified polyethylene, polypropylene, polybutene; synthetic resin layers on the inner layer side and outer layer side are polyolefin-based such as polyethylene, cross-linked polyethylene, modified polyethylene, polypropylene, polybutene A metal composite tube or the like which is a synthetic resin and whose intermediate layer metal is aluminum , aluminum alloy, iron, steel, stainless steel or the like.
[0013]
The joint body and the thin core are not particularly limited as long as they are made of metal . However, in consideration of the case where the metal composite pipe is applied as a pipe body, an excessive force is applied when the composite pipe is inserted into the joint during connection of the composite pipe, and the tip of the composite pipe is deformed. Since the synthetic resin of the composite pipe may deteriorate due to secular change, or the metal of the joint body may oxidize, the metal of the joint body and the metal of the composite pipe may come into contact with each other. It is desirable to use a metal having a small equilibrium electrode potential (a metal nobler than aluminum), and in particular, a casting such as copper, copper alloy, stainless steel, iron or steel is preferable.
[0014]
(Function)
In the pipe joint according to the first aspect of the present invention, a plurality of protrusions are provided on the inner peripheral surface of the compression die of the compression jig, and one of the protrusions has one surface in the width direction of the compression die. when the one end surface in contact with, Runode provided in the concave groove that faces the position of the nipple, when reduced in diameter by compressing the compression die, ridges pushes the tubular body, the inner peripheral surface (nipple Push the concave contact part of the contact side into the groove. Therefore, the waterproof gasket installed in the concave groove is always compressed more reliably than the nipple surface compared to the case where the compression occurs to the inside of the groove and only the nipple surface in the case of a conventional pipe joint occurs. Since the amount of deformation increases, the pipe joint does not leak during repeated cooling and heating.
[0015]
In the pipe joint of the present invention according to claim 2, the end portion of the thin core on the side into which the pipe body is inserted is expanded outwardly, and one surface in the width direction of the compression die is brought into contact with one end surface of the joint body Since the length from the diameter expansion start point of the thin core to one end surface of the joint body is larger than the width of the compression die, the compression die of the compression jig is accurately placed on the outer periphery of the thin core. It can be applied to the surface, and the position of the ridge and the position of the groove are hardly shifted.
[0016]
According to a third aspect of the present invention, there is provided a pipe joint according to the present invention, wherein protrusions are provided on both sides of the concave groove provided on the outer peripheral surface of the nipple to prevent the tubular body from coming off. It is asymmetrical, and the positions of both protrusions may cause the protrusions to bite into the inner peripheral surface of the end of the tube when the end of the tube is fitted between the nipple and the thin core. Since it is provided at a possible position , the tube body position does not move on the nipple after the tube body is inserted into the nipple, so that the water-stopping packing does not come off or twist in the groove.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an example of implementation of the pipe joint of the present invention.
[0018]
The joint body 1 and the nipple 2 are made of 6 types of continuous cast bronze castings (CAC406C) manufactured integrally, and the thin core 3 is made of stainless steel (SUS316L). The nipple 2 is provided so as to project from the one end surface 11 of the joint body 1, and a concave groove 21 is provided along the circumferential direction at the center of the nipple 2 in the length direction. A rubber O-ring is attached to the concave groove 21 as a water-stop packing 22. On both sides of the concave groove 21, projections 23, 23 are provided to prevent the tubular body from coming off. The shape of both protrusions 23 is asymmetrical with respect to the groove 21, and the positions of both protrusions 23 are provided at positions where both protrusions can bite into the inner peripheral surface of the end of the tube. Yes.
[0019]
Note that the outer diameter of the nipple 2 is substantially the same as the inner diameter of the pipe body 4 to be connected, and is slightly smaller. The one end face (nipple projecting face) 11 of the joint body 1 has (the thickness of the pipe body 4 + the thin core). An annular groove 12 is carved with a width of 3). Therefore, the thin core 3 can be fitted into the annular groove 12 in a state where the tubular body 4 is covered.
[0020]
The end of the thin core 3 on the side where the tubular body 4 is inserted is a tapered surface 31 that expands outward, and the taper angle is 30 degrees from the axial direction. It may be in the range of 90 degrees. The inner diameter of the thin core 3 is substantially the same as the outer diameter of the tube body 4 and is slightly larger than the outer diameter of the tubular body 4. The length of the thin core 3 extends from the nipple projecting surface 11 of the joint body 1 when one end of the thin core 3 is inserted into the annular groove 12. The length (X1) to the taper start line 32 is set to be slightly longer than the width (X2) of the compression die 5 of the compression jig.
[0021]
For example, in the case where the pipe body is a polyethylene pipe having a name of 16A, the width (X2) of the compression die is 19.0 mm, so X1 = 19.5 mm.
[0022]
The depth of the concave groove 21 is set to a deformation rate of 8.4% when the water-stop packing 22 is compressed to the surface of the nipple 2 and deformed. The deformation rate is not particularly limited, and may be changed according to the situation as appropriate.
[0023]
The width of the groove 21 is a width obtained by adding (lateral deformation allowance +0.5 to 2 mm) to the width (mm) of the water blocking packing 22. The width is not particularly limited, and may be appropriately changed as long as the ridges 51 provided on the compression die 5 can reliably face the concave grooves 21.
[0024]
On the compression die 5 of the compression jig, three ridges 51 are provided in the circumferential direction. Of these, the central protrusion 51 faces the concave groove 21 provided in the nipple 2 when the compression die 5 is correctly placed on the thin core 3 for the caulking work. At this time, in the case of the tubular body of the above-mentioned name 16A, the deviation between the ridge 51 and the groove 21 is 0.5 mm, but since the margin in the width direction of the groove 21 is large, the ridge is surely formed. 51 compresses the water-stopping packing 22 inserted into the concave groove 21 and further deforms the inner side of the concave groove from the surface of the nipple 2 so that the deformation ratio becomes (8.4 + α)%. However, α does not have a constant value because there is a margin in the width of the concave groove 21 and the water stop packing 22 can move in the axial direction.
[0025]
A procedure for connecting pipe bodies using this pipe joint will be described. First, the end of the pipe body 4 to be connected is chamfered, and at the same time, the flatness of the end face is corrected. At this time, if the chamfering is insufficient, the water stop packing of the pipe joint will be damaged, and if the chamfered residue adheres, it will cause water leakage.
[0026]
Next, the pipe end is inserted straight into the gap between the nipple 2 of the pipe joint and the thin core 3 until it hits the back. Forcible insertion such as oblique insertion may cause damage to the water-stop packing 22 and should not be done. It is confirmed that the tubular body is visible from the insertion confirmation hole 33 provided in the thin core.
[0027]
Next, the outer surface of the thin core is compressed with a dedicated compression jig. That is, the compression die 5 of the compression tool is applied to the straight surface (from the taper start line of the thin core to the nipple projecting surface of the joint body) on the outer peripheral surface of the thin core 3 . Since the width of the compression die is substantially the same as the length of the straight portion of the thin core 3 and is slightly smaller, care should be taken not to be applied to the tapered portion. When the compression dies are correctly arranged, the compression dies are compressed, the diameter of the thin core 3 is reduced, and the tube body 4 is deformed to the nipple 2 side and pressed. After compression, the compression die is removed from the joint.
[0028]
Since the three ridges are provided on the compression surface of the compression die, it is confirmed that three compression marks are included in the straight portion of the thin core. Further, it is confirmed that the tubular body 4 is visible from the insertion confirmation hole 33 of the thin core 3 . Through the above operation, the ridges 51 provided on the compression die 5 are surely opposed to the concave grooves 21 provided on the nipple 2 and compress the water-stopping packing 22 attached to the concave grooves 21. 22 is greatly deformed and water stoppage is ensured.
[0029]
Using this pipe joint, when the polyethylene pipe was connected by the above-mentioned method, the water-stopping packing did not come off from the concave groove, and the cold heat repeated test (95 ° C hot water and normal temperature water was repeated once each time 1 As a cycle, 30000 cycles were repeated), but there was no water leakage.
[0030]
【The invention's effect】
As described above, the pipe joint according to the present invention does not disengage the groove of the water-stopping packing when inserting the pipe body, and after crimping, the amount of compressive deformation of the water-stopping packing increases, so that water does not leak even during repeated cooling and heating. It becomes a pipe joint.
[Brief description of the drawings]
FIG. 1 is a half sectional view of an example of an embodiment of a pipe joint of the present invention.
[Explanation of symbols]
1 Joint body 11 Nipple projecting surface (one end surface)
12 Annular groove 2 Nipple 21 Recessed groove 22 Water stop packing
23 Projection 3 Thin core 31 Tapered surface 32 Taper start line 4 Tubing body 5 Compression die 51 Convex ridge

Claims (3)

Metal fitting nipple for pipe connection from a end surface of the body is integrally projected, grooves are provided along the circumferential direction on the outer peripheral surface of the nipple, the inner peripheral surface of the tube to the recessed groove An annular groove is provided concentrically with the nipple on one end face of the joint body on which the waterstop packing is closely attached to the nipple, and the tip of the metal thin core is provided in the annular groove. The metal thin core is disposed along the outer peripheral surface of the nipple by being fitted, and the end of the tubular body connected between the thin core and the nipple is inserted, and the outer peripheral surface of the thin core A pipe joint for fixing and connecting the nipple and the pipe body by compressing them with a compression jig and reducing the diameter ,
A plurality of ridges are provided on the inner peripheral surface of the compression die of the compression jig, and when one of the ridges abuts one surface in the width direction of the compression die against one end surface of the joint body, the nipple A pipe joint provided at a position opposite to the concave groove . When the end of the thin core on the side into which the tube is inserted is expanded outward, and one surface in the width direction of the compression die is brought into contact with one end surface of the joint body, the taper surface start point of the thin core The pipe joint according to claim 1 , wherein a length of the joint body to one end surface is larger than a width of the compression die . Protrusions that prevent the tube from coming off are provided on both sides of the groove provided on the outer peripheral surface of the nipple, and the shape of both protrusions is asymmetrical with respect to the groove, and both the protrusions When the end of the tube is fitted between the nipple and the thin core, the protrusion is provided at a position where both the protrusions can be engaged with the inner peripheral surface of the end of the tube. The pipe joint according to claim 1 or 2.

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