JPH07269755A - Anticorrosive coupling for heterogeneous metal pipe connection - Google Patents

Abstract

PURPOSE:To prevent draft of a tubular body due to screwed torque of a piping material by inserting this tubular body provided with an internal thread into a coupling body via an insulating resin layer, and installing an almost tubular engaged member provided with an engaged projection strip lying along each end face of the coupling body and the insulating resin layer. CONSTITUTION:In a pipe coupling A formed two thread parts 11 and 12 on each inner circumferential surface at both ends of an iron coupling body 1, a first thread part 11 is made up of directly threaded, while a second thread part 12 is installed by way of inserting a copper tubular body 15 with an internal thread on the inner surface at a time when an insulating resin layer 14 being integral with a resin core 13 as one body is formed by means of injection molding. In addition, a tubular engaged member 17 is attached to a peripheral surface at the side of the second thread part 12 tightly by means of thread connection, and an engaged projection strip 17a projectingly installed toward the inside from an end edge of this engaged member 17 is engaged with each end face of the insulating resin layer 14 and the tubular body 15. Subsequently an elastic sealant 18 is filled up in space between the engaged projection strip 17a, the insulating resin layer 14 and the tubular body 15, whereby sealability is secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to two metal tubes, in particular
The present invention relates to an anticorrosion joint for connecting dissimilar metal pipes, which is used to connect metal pipes made of materials having different natural potentials.

[0002]

2. Description of the Related Art Generally, piping materials made of copper or copper alloy are used in a hot water supply line such as a water heater for heating and supplying water at home. On the other hand, a steel pipe or a resin-lined steel pipe is used for a water supply line for supplying tap water or the like to the copper or copper alloy piping material.

The water supply line and the hot water supply line are connected to each other via a joint made of the same material as one of the pipe materials, for example, a pipe joint (socket), a nipple, a valve, or the like. Therefore, the joint and one of the piping materials,
It is made of a different metal material.

However, when exposed to an electrolyte such as water, the portion where such a foreign metal material is contacted with is exposed to an electrolyte such as water, in the case of a base metal having a natural potential (corrosion potential), steel and copper or a copper alloy, The steel side causes corrosion of dissimilar metals and causes red water in the piping. Therefore, in order to solve such a problem, an anti-corrosion joint for connecting dissimilar metal pipes as disclosed in Japanese Utility Model Publication No. 4-111983 has already been proposed.

That is, as shown in FIG. 4, this anti-corrosion joint 100 for connecting a foreign metal pipe has a tubular body 103 made of steel with an insulating resin layer 102 inside a joint body 101 made of iron.
And a tubular body 104 made of copper are inserted. Then, on the inner peripheral surface of each cylindrical body 103, 104, screws 103a,
104a is provided so that the lining steel pipe 105 is screwed to the screw 103a and the copper pipe 106 is screwed to the other screw 104a.

Further, inside the joint body 101, a resin core 107 is provided integrally with the insulating resin layer 102.
The resin core 107 includes a seal portion 107a that is watertightly pressed against the inner peripheral surface of the lining steel pipe 105 when the lining steel pipe 105 is screwed to the screw 103a.
That is, the anti-corrosion joint 100 for connecting a dissimilar metal pipe is configured such that the screw 103a, 104a made of the same material is provided at each screw connection portion of the lining steel pipe 105 and the copper pipe 106.
And the screws 103a and 104a are insulated from each other, so that corrosion of dissimilar metal contact does not occur. Moreover, the lining steel pipe 105
Although the steel pipe portion is exposed at the end, since the seal portion 107a of the resin core 107 is water-tightly pressed against the inner peripheral surface of the lining steel pipe 105, the end of the lining steel pipe 105 is also not exposed to water. , The generation of red water can be completely suppressed.

[0007]

However, the dissimilar metal pipe connecting joint 100 has the following problems. That is, the fitting between the tubular body 103 (104) inserted by the screwing torque of the lining steel pipe 105 or the copper pipe 106 and the insulating resin layer 102 becomes weak, and the tubular body 10 is pressed by the water pressure in the pipe and the weight of the pipe.
3 (104) could easily slip out.

In this way, once the escape occurs,
The watertight performance between the outer surface of the tubular body 103 (104) and the insulating resin layer 102 is easily deteriorated, and water in the pipe may leak from the gap between the outer surface of the tubular body 103 (104) and the insulating resin layer 102. In view of such circumstances, the present invention has an object to provide a joint for connecting dissimilar metal pipes, which can completely prevent corrosive corrosion of dissimilar metals and is excellent in strength and connection workability. I am trying.

[0009]

In order to achieve such an object, a joint for connecting dissimilar metal pipes according to the present invention is provided with a metal-made substantially tubular joint main body, and the joint main body has one inner side It has a metal threaded part on its peripheral surface and a threaded part made of a different material from the threaded part on the inner peripheral surface or outer peripheral surface of the other side, and one of the threaded parts is the same as the joint body A heterogeneous material that is made of a material and has a threaded portion provided on at least one inner peripheral surface that is integrated with the joint body by inserting a tubular body with a threaded inner surface through an insulating resin layer. In a metal pipe connecting anticorrosion joint, a substantially tubular locking member having locking projections along the end faces of the joint body and the insulating resin layer on the inner peripheral surface is the side on which the tubular body of the joint body is inserted. Is fixed so as to surround the outer surface of the Elastic sealing member has a configuration that is filled between the end face of the body and the insulating resin layer.

In the above structure, the joint for connecting dissimilar metal pipes (hereinafter referred to as "joint" only) means not only a pipe joint (socket) for a straight pipe but also a pipe for connecting pipes, that is, , Elbows, cheese, bulbs, etc. are also included. The material of the joint body is not limited to any particular value, but castings such as white-heart malleable cast iron, black-heart malleable cast iron, and ductile cast iron are most suitable.

The thickness of the elastic sealing material is not particularly limited as long as the sealing property is sufficiently secured, but it is preferably about 2 mm. The locking member may be fixed to the joint body by press fitting, but it is preferably fixed by screw connection or welding. The resin forming the insulating resin layer is not particularly limited, but for example, when used for water supply, a hard vinyl chloride resin, a general-purpose resin such as polyethylene resin, and when used for hot water supply, a heat-resistant hard vinyl chloride resin. , Thermoplastic resins such as crosslinkable polyethylene resin and polybutene resin. Then, the tubular body can be inserted at the same time when the insulating resin layer is injection-molded.

Further, a resin core having a seal portion that is watertightly pressed against the inner peripheral surface of the lining steel pipe may be provided at the same time when the insulating resin layer is provided by injection molding. Further, in the above structure, it is preferable to form a recess into which the insulating resin layer partially enters, or to provide an adhesive layer between the cylindrical body and the insulating resin layer, on the outer peripheral surface of the cylindrical body.

The recesses are not particularly limited, but they may be provided at several radial positions on the same circumference, or may be annular grooves. Further, in the case of the annular groove, it is preferable to provide a plurality of grooves at a predetermined pitch. The adhesive forming the adhesive layer is preferably one that remains as a film after drying with an emulsion, and examples thereof include those obtained by emulsifying vinyl acetate as a main component with an organic solvent.

[0014]

According to the above construction, even if the tubular body is about to come out due to the screwing torque of the pipe material, the end portion of the tubular body is locked by the locking projection of the locking member, so that the tubular body is prevented from coming out. . Moreover, since the elastic sealing material is filled between the locking ridges and the end faces of the joint body and the insulating resin layer, even if water in the pipe seeps into the gap between the insulating resin layer and the joint body,
Water that has exuded into the gap between the insulating resin layer and the joint body is completely sealed by the elastic sealing material.

Further, if a concave portion is provided on the outer surface of the cylindrical body and a part of the insulating resin layer is inserted into this concave portion, a part of the insulating resin layer locks the cylindrical body. . On the other hand, if the adhesive layer is provided between the insulating resin layer and the tubular body, the insulating resin layer and the tubular body are more firmly integrated, and the adhesive layer also functions as a seal material. To do.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 shows a pipe joint as a first embodiment of the joint according to the present invention. As shown in the figure, in the pipe joint A, a first threaded portion 11 is provided on one side inner peripheral surface of the iron joint body 1 and a second threaded portion 12 is provided on the other side inner peripheral surface.

The first threaded portion 11 is directly threaded on the inner peripheral surface of the joint body 1. On the other hand, the second screw part 1
2 is an insulating resin layer 14 provided integrally with the resin core 13.
When it is provided by injection molding, it is provided integrally with the joint main body 1 by inserting a copper tubular body 15 having a thread previously cut into the inner surface. On the outer peripheral surface of the tubular body 15, three grooves 15a are annularly provided at substantially equal pitches, and a part of the insulating resin layer 14 is inserted into the grooves 15a.

Moreover, the tubular body 15 and the insulating resin layer 14 are bonded and integrated via the adhesive layer 16. A tubular locking member 17 is fixed to the other side of the joint body 1, that is, the outer peripheral surface on the side of the second screw portion 12 by screw connection. The locking member 17 has a locking projection 17a protruding inward from the end edge, and the end surfaces of the insulating resin layer 14 and the tubular body 15 can be locked by the locking projection 17a. ing.

An elastic sealing material 18 is filled between the locking projection 17a and the end surfaces of the insulating resin layer 14 and the tubular body 15. Further, the resin core 13 is provided so that a seal portion 13 a that is watertightly pressed against the inner peripheral surface of the resin-lined steel pipe 2 that is screw-connected faces the first screw portion 11.

The pipe joint A has the above-mentioned structure,
As shown in the figure, the resin-lined steel pipe 2 is connected to the first screw part 11 side and the copper pipe 3 is connected to the second screw part 12 side, but the first screw part 11 and the second screw part 12 are , Is completely insulated through the insulating resin layer 14. Moreover, since the first threaded portion 11 is made of iron and the second threaded portion 12 is made of the same material as the pipe connected to copper, the problem of contact corrosion of dissimilar metals does not occur at all.

Further, even if the tubular body 15 is pulled in the direction of the copper tube 3 by the torque for screwing in the copper tube 3, the second
The cylindrical body 15 and the insulating resin layer 14 inserted as the screw portion 12 have the end faces of the locking projection 17 of the locking member 17.
Since it is locked by a, the cylindrical body 15 and the insulating resin layer 1
The tubular body 15 will not come loose due to water pressure in the pipe or the weight of the pipe itself.

In addition, in this pipe joint A, an annular groove 15a is provided on the outer surface of the tubular body 15, a part of the insulating resin layer 14 is inserted into this groove 15a, and the tubular body 15 and the insulating resin layer 14 are inserted. Since and are fixed by the adhesive layer 16, the tubular body 15 is more firmly integrated with the insulating resin layer 14. Further, even if the fitting between the tubular body 15 and the insulating resin layer 14 becomes loose, an elastic seal is provided between the end faces of the tubular body 15 and the insulating resin layer 14 and the locking projection 17a. Since the material 18 is filled, even if water in the pipe permeates into the gap between the tubular body 15 and the insulating resin layer 14 or the gap between the insulating resin layer 14 and the joint body 1, the water will flow to the outside of the pipe joint A. No water leaks.

Further, this pipe joint A has a first threaded portion 11
When the seal portion 13a is screwed onto the inner wall surface 21 of the steel pipe 2 lined with resin in a watertight manner, the steel pipe portion 22 exposed at the pipe end is not exposed to water in the pipe. Therefore, generation of red water can be completely prevented.

FIG. 2 shows a pipe joint as a second embodiment of the joint according to the present invention. As shown in the figure, the pipe joint B is formed on the outer peripheral surface on one side of the joint body 4 made of gunmetal with the first
The screw portion 41 is provided, and the second screw portion 42 is provided on the inner peripheral surface of the other side. The first threaded portion 41 is provided by directly threading the outer peripheral surface of the joint body 4. On the other hand, the second screw portion 42 is a joint by inserting an iron tubular body 45 having a screw pre-cut on its inner surface when the insulating resin layer 44 integrally formed with the resin core 43 is provided by injection molding. It is provided integrally with the body 4.

On the outer peripheral surface of the cylindrical body 45, three grooves 45a are formed.
Are provided in an annular shape at substantially equal pitches, and a part of the insulating resin layer 44 is inserted into the groove 45a. Moreover, the tubular body 45 and the insulating resin layer 44 are bonded and integrated via the adhesive layer 46. In addition, on the other side of the joint body 1, that is, on the outer peripheral surface on the side of the second screw portion 42, the cylindrical locking member 4 is provided.
7 are fixed by screw connections.

The locking member 47 has a locking projection 47a protruding inward from the end edge, and the end surfaces of the insulating resin layer 44 and the cylindrical body 45 can be locked by the locking projection 47a. It is like this. An elastic seal material 48 is filled between the locking projection 47a and the end surface of the insulating resin layer 44 and the tubular body 45.

Further, the resin core 43 has a second screw portion 42.
A seal portion 43a that is watertightly pressed against the inner peripheral surface of the resin-lined steel pipe 2 that is screw-connected to is provided so as to face the second screw portion 42. Therefore, this pipe joint B also has the same effect as the pipe joint A of the first embodiment.

FIG. 3 shows an elbow as a third embodiment of the joint according to the present invention. As shown in the figure, in the elbow C, a first screw portion 51 is provided on one side inner peripheral surface of the iron elbow body 5, and a second screw portion 52 is provided on the other side inner peripheral surface. The first threaded portion 51 is provided by directly threading the inner peripheral surface of the elbow body 5.

On the other hand, the second screw portion 52 has a gun metal tubular body 55 having an inner surface pre-threaded when the insulating resin layer 54 integrally formed with the resin core 53 is formed by injection molding. By doing so, it is provided integrally with the joint body 5. On the outer peripheral surface of the tubular body 55, three grooves 55a are annularly provided at substantially equal pitches, and a part of the insulating resin layer 54 is inserted into the grooves 55a.

Moreover, the tubular body 55 and the insulating resin layer 54 are bonded and integrated via the adhesive layer 56. Further, a tubular locking member 57 is fixed to the other side of the joint body 5, that is, the outer peripheral surface on the second screw portion 52 side by screw connection. The locking member 57 has a locking projection 57a protruding inward from the end edge, and the end surfaces of the insulating resin layer 54 and the tubular body 55 can be locked by the locking projection 57a. ing.

An elastic seal material 58 is filled between the locking projection 57a and the end surface of the insulating resin layer 54 and the tubular body 55. Further, the resin core 53 is a resin-lined steel pipe (not shown) screwed to the first screw portion 51.
A seal portion 53a that is water-tightly pressed against the inner peripheral surface of is provided so as to face the first screw portion 51.

Therefore, the elbow C also has the same effect as the pipe joints A and B of the first and second embodiments. The joint according to the present invention is not limited to the above embodiment. For example, in each of the above-described embodiments, one screw part is formed by inserting a tubular body, but both screw parts may be formed by inserting tubular bodies made of different materials. It doesn't matter.

[0033]

Since the joint according to the present invention is constructed as described above, even if the tubular body is about to come out due to the screwing torque of the piping material, the tubular body is secured by the locking projection of the locking member. The ends of the are locked to prevent them from coming out. Moreover, since the elastic sealing material is filled between the locking ridges and the end faces of the joint body and the insulating resin layer, even if water in the pipe seeps into the gap between the insulating resin layer and the joint body, the insulating resin Water exuding into the gap between the layer and the joint body is completely sealed by the elastic sealing material.

Therefore, the piping material can always be firmly connected. Of course, there is no problem of corrosion due to contact with dissimilar metals. Further, when a concave portion is provided on the outer surface of the tubular body and a part of the insulating resin layer is inserted into the concave portion, the insulating resin layer is partially locked to the tubular body. Therefore, in addition to the locking by the locking ridge, a part of the insulating resin layer that has entered the recess is more firmly locked to the joint body.

On the other hand, when the adhesive layer is provided between the insulating resin layer and the tubular body, the insulating resin layer and the tubular body are more firmly integrated. Moreover, the adhesive layer also acts as a sealing material that prevents the water in the pipe from entering the gap between the insulating resin layer and the tubular body, and the water in the pipe is removed from the gap between the insulating resin layer and the tubular body. It is possible to more reliably prevent leakage from the pipe.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a pipe joint as a first embodiment of a joint according to the present invention.

FIG. 2 is a half cross-sectional view showing a pipe joint as a second embodiment of the joint according to the present invention.

FIG. 3 is a half sectional view showing an elbow as a third embodiment of the joint according to the present invention.

FIG. 4 is a half sectional view of a known joint.

[Explanation of symbols]

 A pipe joint (anti-corrosion joint for connecting different metal pipes) B pipe joint (anti-corrosion joint for connecting foreign metal pipes) C Elbow (anti-corrosion joint for connecting different metal pipes) 1 joint body 4 joint body 5 joint body 11 1st screw section 12 Second screw part 14 Insulating resin layer 15 Cylindrical body 15a Groove (recess) 16 Adhesive layer 17 Locking member 17a Locking protrusion 18 Elastic seal material 41 First screw part 42 Second screw part 44 Insulating resin layer 45 Cylinder Shaped body 45a Groove (concave) 46 Adhesive layer 47 Locking member 47a Locking ridge 48 Elastic sealing material 51 First screw part 52 Second screw part 54 Insulating resin layer 55 Cylindrical body 55a Groove (concave) 57 Locking Member 57s Locking ridge 58 Elastic seal material

Claims (3)

[Claims] 1. A metal-made substantially tubular joint body, wherein the joint body has a metal threaded portion on one inner peripheral surface and is different from the threaded portion on the other inner peripheral surface or outer peripheral surface. It has a thread part made of a material, one of both thread parts is made of the same material as the joint body, and at least one of the thread parts provided on the inner peripheral surface has a thread on the inner surface. In an anticorrosion joint for connecting dissimilar metal pipes, which is integrated with the joint body by inserting the tubular body through the insulating resin layer, the locking protrusions along the end faces of the joint body and the insulating resin layer are formed on the inner circumference. A substantially cylindrical locking member provided on the surface is fixed so as to surround the outer surface of the joint body on the side where the cylindrical body is inserted, and the locking ridge, the joint body, and the insulating resin layer Dissimilar metal characterized by being filled with an elastic sealing material between the end face Connection for corrosion protection joints. 2. The anticorrosion joint for connecting dissimilar metal pipes according to claim 1, wherein a concave portion into which a part of the insulating resin layer enters is formed on the outer peripheral surface of the tubular body. 3. The corrosion resistant joint for connecting dissimilar metal pipes according to claim 1, wherein an adhesive layer is provided between the tubular body and the insulating resin layer.