JP2001082655A - Electrically insulated pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrically insulated pipe joint capable of connecting a lining steel pipe by preventing occurrence of water leakage and red water regardless of quality of construction and solving a problem of corrosion due to contact of dissimilar metals in spite of connecting it in a short period of time without requiring screw thread cutting work, etc. SOLUTION: This electrically insulated pipe joint is constituted of a metal made socket 2 main body, a metal made box nut 10, a metal made lock ring 40, a synthetic resin made ring cover 50 with glass fiber and a synthetic resin made integral type packing 20. A part between a lining steel pipe RP and the socket main body 2 is sealed and electrically insulated by interposing the integral type packing 20 between the socket main body 2 and the lining steel pipe RP. The ring cover 50 is interposed between the box nut 10 and the lock ring 40 installed on the lining steel pipe RP, fastening force of the box nut is transmitted to the lock ring 40 trough this ring cover 50, and the box nut 10 and the lock ring 40 are electrically insulated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a socket body made of a metal, which is previously mounted on a first pipe, and a cap nut also made of metal, which is screwed to the socket body. When an insulating and sealing member made of synthetic resin, a metal lock ring, and the like are attached between the cap nut and the second lining steel pipe to be connected, and the cap nut is tightened to the socket body, the first Second in the tube
The present invention relates to an insulated pipe joint in which the lining steel pipe is electrically connected in an insulated state.

[0002]

2. Description of the Related Art As a water supply pipe, a galvanized lining steel pipe is used together with a lining steel pipe whose inner and outer surfaces are coated with a synthetic resin. This lining steel pipe is cut to an appropriate length in the same manner as a conventional water pipe, and is connected and connected by a pipe joint. Various methods are used to connect such lining steel pipes,
Generally, the outer periphery of the lining steel pipe is threaded,
A method of applying or filling a seal material to a joint to cut off contact with water is adopted. According to this method, since the sealing material is applied, the problem of rust has been solved temporarily, but the outer periphery of the lining steel pipe must be threaded at the site, and there is a drawback that the construction time becomes longer. .
Further, according to the construction method of applying the sealing material, it takes time to dry the sealing material, and the construction time is further lengthened. In addition, even if a sealing material is applied after threading, there is a disadvantage that rust remains depending on the quality of construction.

Therefore, a corrosion-resistant pipe joint that does not require threading is disclosed in, for example, Japanese Patent Application Laid-Open No.
No. 28298, for example. JP-A-7-110
The mechanical pipe joint described in No. 084 includes a joint body, a nut, a packing, and a ridged rubber packing. Therefore, when the packing and the ridged rubber packing are mounted and the nut is screwed into the joint body, the resin-coated tube, that is, the lining steel tube is connected. Once connected,
Water leakage is prevented by the packing, and generation of red water caused by rust at the cut end of the lining steel pipe is suppressed by the ridged rubber packing. In addition, actual opening Hei 7-28298
The No. 1 anticorrosion cap has a packing in addition to the anticorrosion cap. Therefore, generation of red water as well as water leakage is prevented.

As described above, since the conventional anticorrosive pipe joint is also provided with the ridged rubber packing or the anticorrosive cap, the cut end surface of the lining steel pipe is corroded by water, and red water due to rust is mixed into tap water. It is temporarily prevented. In addition, since the nut is screwed into the joint body, there is an effect that it is not necessary to perform thread cutting on the outer periphery of the lining steel pipe to be connected at the construction site. However, the conventional anti-corrosion pipe joint requires two packings, one for preventing water leakage and one for preventing red water, that is, the number of parts is large, so connection construction on site may take time. . Also, since there are many parts, there is a problem in management. Further, these packings are generally formed by a mold, but two expensive molds are required, which also increases the cost. Also,
The conventional anticorrosion cap has a structure in which water leakage is prevented only when the cut end face of the lining steel pipe abuts airtightly.Therefore, the cut end face of the lining steel pipe may not come into contact with the anticorrosion cap due to construction. However, there is also a problem that it depends on construction conditions.

Accordingly, the applicant of the present invention disclosed in Japanese Patent Laid-Open No. 10-781.
No. 81, a substantially cylindrical joint body, a cap nut screwed to an end of the joint body, a sealing member mounted between a lining steel pipe connected to the joint body, and a seal And a core member for pressing the member toward the lining steel pipe side, wherein the sealing member is
When the cap nut is attached to a lining steel pipe and screwed into a screw formed at an end of the joint body, a first bulge pressed against an inner peripheral surface of the joint body and an outer peripheral surface of the lining steel pipe. Portion, a first cylindrical portion located between the inner peripheral surface of the joint body and the outer peripheral surface of the lining steel pipe, a bottom portion facing the cutting end surface of the lining steel pipe, and a first cylindrical portion located on the inner peripheral surface side of the lining steel pipe. A second tubular portion that seals in contact with the second tubular portion. The second tubular portion is provided with a second bulging portion, and the first bulging portion and the first bulging portion. Of the cylinder,
The bottom portion, the second cylindrical portion, and the second bulging portion provided an anticorrosion joint integrally formed of an elastic material such as rubber or synthetic resin.

[0006]

According to the anticorrosion pipe joint proposed by the present applicant, a seal member is attached to a lining steel pipe, a core member is inserted, and a cap nut is screwed into a screw of the joint body. Just connect the lining steel pipe. Therefore, it is possible to obtain an effect that the lining steel pipe can be connected while preventing the generation of red water and the leakage of water regardless of the quality of construction. In addition, the first bulging portion and the first cylindrical portion, which can be connected in a short time without requiring a thread cutting process and the like, constitute a sealing member,
Since the bottom portion, the second cylindrical portion, and the second bulging portion are integrally formed from an elastic material such as rubber or synthetic resin, the number of parts is small, and for example, a mold for forming a seal member. Also, the effect that only one surface is required can be obtained. However, since the problem of corrosion due to the contact of dissimilar metals has not been solved, when the pipe body and the socket body or the cap nut forming the joint come into metallic contact, the pipe body and the socket body are generally made of different metals. Therefore, those with a low ionization tendency are corroded. As a result, water leakage occurs, and the corroded metal dissolves in tap water, causing water pollution. Therefore, the present invention can connect the lining steel pipe regardless of the quality of the construction, preventing the generation of red water together with water leakage and connecting the pipes in a short time without the need for threading or the like. It is an object of the present invention to provide an insulated pipe joint which has solved the problem of corrosion due to contact of dissimilar metals in spite of low cost and low cost.

[0007]

In order to achieve the above object, the present invention provides a metal socket body previously mounted on a first pipe, and a metal socket body which is screwed to the socket body. A synthetic resin insulating and sealing member, a metal lock ring, and the like are mounted between the socket body and the cap nut and the second lining steel pipe to be connected. Is an insulated pipe joint in which the second lining steel pipe is electrically connected to the first pipe in an electrically insulated state when tightened to the socket body, wherein the insulating and sealing member is made of synthetic resin. of,
A ring cover and an integral packing, wherein the integral packing is attached to a distal end of a second lining steel pipe, and when the cap nut is tightened to the socket body, the inner peripheral surface of the socket body and the lining steel pipe A bulging portion pressed against both surfaces of an outer peripheral surface of the lining steel tube, a first cylindrical portion located between an inner peripheral surface of the socket body and an outer peripheral surface of the lining steel pipe, and an abutting contact of a tip end surface of the lining steel pipe. Department and
From the second cylindrical portion, which is located on the inner peripheral surface side of the lining steel pipe and seals in contact with the same, is formed continuously and integrally;
Accordingly, the socket body and the second lining steel pipe are sealed and electrically insulated from each other, and the ring cover has a substantially tapered tubular shape, and is provided with the lock ring attached to the second lining steel pipe. While being interposed between the cap nut and transmitting the tightening force for tightening the cap nut to the socket body to the lock ring, the gap between them is maintained at a predetermined interval in an electrically insulated state. Be composed. The invention according to claim 2 is a method in which the first
A metal socket main body attached to the pipe, and a similarly metal cap nut screwed into the socket main body. The socket body and the cap nut are connected to a second lining steel pipe. When an insulating / sealing member made of synthetic resin, a metal lock ring, and the like are attached between them and the cap nut is tightened to the socket body, the second lining steel pipe is electrically insulated from the first pipe. An insulated pipe joint adapted to be connected by, wherein the insulating and sealing member is made of synthetic resin, a ring cover, and a core,
An integral packing, wherein the integral packing is attached to a distal end of a second lining steel pipe, and when the cap nut is tightened to the socket main body, an inner peripheral surface of the socket main body and an outer peripheral surface of the lining steel pipe are formed. A bulging portion pressed against both surfaces, a first cylindrical portion located between an inner peripheral surface of the socket body and an outer peripheral surface of the lining steel pipe, a contact portion with which a tip end surface of the lining steel pipe comes into contact, A second cylindrical portion which is located on the inner peripheral surface side of the steel pipe and is in contact with and seals with the steel pipe, and is continuously and integrally formed, whereby a seal is formed between the socket body and the second lining steel pipe. And the core is electrically insulated, and the core has a tubular portion having a function of pushing a second tubular portion of the integrated packing attached to the second lining steel pipe outward in a radial direction. Integrated package The ring cover is formed integrally with a flange-shaped stopper portion abutting on the abutting portion of the ring, the ring cover has a substantially tapered tubular shape, and is formed by the lock ring and the cap nut mounted on a second lining steel pipe. It is interposed between the lock ring and the lock ring to transmit a tightening force for tightening the cap nut to the socket body to the lock ring, and to maintain a predetermined gap therebetween in an electrically insulated state. According to a third aspect of the present invention, the ring cover according to the first or second aspect is formed of a synthetic resin containing glass fiber.

[0008]

An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, an insulated pipe joint 1 according to the present embodiment generally includes a metal socket body 2 fixed near a joint end of one pipe K, Similarly, a metal cap nut 10 screwed to the outer peripheral portion of the main body 2, a synthetic resin integrated packing 20 and a core 30 attached to the tip of the other lining steel pipe RP, and pressed against the lining steel pipe RP when connected. A metal lock ring 40, a synthetic resin ring cover 50 mounted between the inner peripheral surface of the cap nut 10 and the outer peripheral surface of the lock ring 40, and the rear ends of the lock ring 40 and the ring cover 50. It is composed of a cover 60 made of synthetic resin and the like mounted between the front end of the socket body 2 and the like.

The socket body 2 has a straight pipe portion 3, an enlarged straight pipe portion 4 having a diameter larger than that of the straight pipe portion 3, and a tapered shape which is tapered from the expanded straight pipe portion 4 toward the tip end. Tapered pipe part 5
And a maximum diameter straight pipe part 6 having the same diameter as the maximum diameter of the tapered pipe part 3. And the maximum diameter straight pipe part 6
A male screw 7 with which the female screw of the cap nut 10 is screwed is formed on the outer peripheral surface of the nut. The socket body 2 configured as described above is liquid-tight in the straight pipe portion 3 of the pipe K by the flow swelling method proposed by the present applicant and disclosed in, for example, JP-A-8-261371. Is fixed.

The cap nut 10 has a conventionally well-known shape formed by a nut portion 11 having an outer peripheral portion in the shape of a nut and a tapered portion 12 having a rear portion of the inner peripheral surface, that is, a tapered portion on the left side in FIG. It is configured. And nut part 1
A female screw that is screwed to the male screw 7 of the socket body 2 is formed on the inner peripheral surface of the socket body 1. Therefore, as will be described in detail later, when the cap nut 10 is screwed into the male screw 7 of the socket body 2 by mounting the integral packing 50 or the like inside the maximum diameter straight pipe portion 6 of the socket body 2, the taper of the cap nut 10 is increased. Part 1
2, the integral packing 50 is pressed in the axial direction via the cover 60 to be sealed. The cap nut 10 is connected to the lining steel pipe RP via the lock ring 40.
And integrated.

The ring cover 50 disposed inside the cap nut 10 has a tapered tubular shape that is short in the axial direction as a whole, as shown in an enlarged manner in FIG. That is, the tapered outer peripheral surface portion 51 pressed against the inner peripheral surface of the tapered portion 12 of the cap nut 10 at the time of mounting, and the tapered inner peripheral surface 52 pressed against the outer peripheral surface of the lock ring 40 to a predetermined thickness. Are formed in a tapered tubular shape as a whole. The ring cover 50 is made of an electrically insulating synthetic resin having a high hardness, for example, a synthetic resin containing glass fiber in the present embodiment.

As shown in FIG. 2B, the metal lock ring 40 has a tapered outer peripheral surface portion which is pushed in the radial center direction from the inner peripheral surface portion 52 of the ring cover 50. 41 and a straight tubular inner peripheral surface portion 42 fixed to the lining steel pipe RP. Although not shown in FIG. 2B, the metal lock ring 40 is partially cut. Accordingly, when the lock ring 40 is inserted into the lining steel pipe RP and tightened with the cap nut 10, the diameter of the lock ring 40 is reduced, and the lock ring 40 is fixed to the lining steel pipe RP.

As shown in FIG. 2C, the integrated packing 20 is mounted on the socket body 2 at the time of mounting.
Bulge 21 mainly located inside the maximum diameter straight pipe 6
And a first cylindrical portion 22 located between the inner peripheral surface of the enlarged diameter straight pipe portion 4 of the socket body 2 and the outer peripheral surface of the lining steel pipe RP.
And the contact part 23 with which the end face of the lining steel pipe RP contacts.
And the lining steel pipe RP
And the second cylindrical portion 24 located on the inner peripheral surface side of the second member is integrally formed of an elastic material such as rubber or synthetic resin.

As shown in FIG. 2D, the core 30 includes a cylindrical portion 31 and a stopper portion 32 extending radially outward from one end of the cylindrical portion 31 in a flange shape. ,
It is formed integrally from an elastic material such as resin or metal material. The stopper portion 32 is a portion that comes into contact with the outer surface of the contact portion 23 of the integrated packing 20 when the cylindrical portion 32 is mounted. The outer peripheral surface of the cylindrical portion 32 is the inner peripheral surface of the second cylindrical portion 24 of the integrated packing 20. And presses the second cylindrical portion 24 against the inner peripheral surface of the lining steel pipe RP. The cover 60 is formed in a donut shape or a ring shape from a synthetic resin to a size arranged between the inside of the nut portion 11 of the cap nut 10 and the outer peripheral portion of the lining steel pipe RP.

Next, a method of using the above embodiment will be described. A cap nut 10 is attached to the end of the lining steel pipe RP.
, The ring cover 50, the lock ring 40, and the cover 60 are inserted in this order. Further, as shown in FIG. 1, the integral packing 20 is attached to the connection end of the lining steel pipe RP such that the contact portion 23 contacts the connection end of the lining steel pipe RP. Next, the core 30 is connected to the cylindrical portion 3.
1 is inserted first until the stopper portion 32 contacts the outer surface of the contact portion 23 of the integrated packing 20. Then, the cylindrical packing 31 of the core 30 allows the integrated packing 20
Is pressed toward the inner peripheral surface side of the lining steel pipe RP. As a result, the inner peripheral surface of the second cylindrical portion 24 comes into close contact with the inner peripheral surface of the lining steel pipe RP. This seals and protects the cut surface of the lining steel pipe RP from corrosion. Although the sealing effect may be slightly reduced, it is apparent that the present invention can be performed without the core 30. In such a case, it is desirable that the second cylindrical portion 24 of the integrated packing 20 be elastic.

As described above, the lining steel pipe RP equipped with the integral packing 20 and the core 30 is connected to the socket body 2.
, And the female screw of the cap nut 10 is screwed into the male screw 7 of the socket body 2. Then, the cap nut 10 is integrated with the socket body 2. When screwing in the cap nut 1
The ring cover 50 is pushed in the axial direction by the zero tapered portion 12. As a result, the ring cover 50 is
0 is reduced in diameter. Thereby, the lock ring 40 is fixed to the lining steel pipe RP. That is, the lining steel pipe RP is connected to the pipe K. By the way, according to the present embodiment, since the ring cover 50 is formed from a synthetic resin containing glass fiber, the ring cover 50 maintains a predetermined thickness without being crushed and maintains an electrical insulation state. Also, when screwed in,
The rear ends of the ring cover 50 and the lock ring 40 push the bulging portion 21 of the integrated packing 20 rearward, that is, rightward in FIG. Then, since the diameter of the tapered tube portion 5 of the socket body 2 is reduced toward the right, the swelling portion 21 is formed on both the inner circumferential surface of the tapered tube portion 5 of the socket body 2 and the outer circumferential surface of the lining steel pipe RP. Adhere to As a result, it is sealed and the intrusion of water from the outside is prevented. Although sealed in this manner, as shown in FIG. 1, an integral packing 20 is provided between the socket body 2 and the lining steel pipe RP, and a ring cover is provided between the cap nut 10 and the lock ring. Since 50 is interposed, the socket body 2 and the cap nut 10 do not make metal contact with the lining steel pipe RP. Therefore, metal corrosion due to the difference in ionization tendency is prevented.

[0017]

As described above, according to the first or second aspect of the present invention, a metal socket body previously attached to the first tube and a metal socket screwed to the socket body are used. A synthetic resin insulating and sealing member, a metal lock ring, and the like are mounted between the socket body and the cap nut and the second lining steel pipe to be connected. An insulated pipe joint in which when a nut is tightened to the socket body, a second lining steel pipe is electrically connected to the first pipe in an electrically insulated state, wherein the insulating and sealing member is made of a synthetic resin. Made of synthetic resin, and an integrated packing made of synthetic resin. The integrated packing is attached to the tip of a second lining steel pipe, and when the cap nut is fastened to the socket body, A bulging portion pressed into contact with both the inner peripheral surface of the socket body and the outer peripheral surface of the lining steel pipe; a first tubular portion located between the inner peripheral surface of the socket body and the outer peripheral surface of the lining steel pipe; A contact portion with which the distal end surface of the steel pipe abuts, and a second cylindrical portion which is located on the inner peripheral surface side of the lining steel pipe and is in contact with and sealed therewith, is formed continuously and integrally, whereby the socket The main body and the second lining steel pipe are sealed and electrically insulated, and when the core is a part of the invention as claimed in claim 2, the core is formed of the second lining steel pipe. A cylindrical portion having a function of pushing and expanding the second cylindrical portion of the integral packing radially outwardly attached to the integral packing, and a flange-shaped stopper portion abutting against a contact portion of the integral packing at the time of attachment. Is formed so that The ring cover has a substantially tapered tubular shape, is interposed between the lock ring attached to the second lining steel pipe and the cap nut, and reduces a tightening force when the cap nut is tightened to the socket body. The lining steel pipe can be connected only by tightening the cap nut to the socket body, since it is transmitted to the lock ring and maintained at a predetermined interval in an electrically insulated state therebetween. Therefore, according to the present invention, the lining steel pipe can be connected while preventing generation of red water together with water leakage, regardless of the quality of construction. In addition, the connection can be made in a short time without the need for threading or the like, and the integrated packing is integrally formed from the bulging portion, the first tube portion, the contact portion, and the second tube portion. Therefore, the number of parts is small, and for example, a mold for molding a seal member can be provided on one surface and can be provided at low cost.
According to the present invention, a number of effects can be obtained, and according to the present invention, the integral packing electrically insulates between the socket body and the lining steel pipe, and a ring between the cap nut and the lock ring and thus the lining steel pipe. Since it is insulated by the cover, the effect unique to the present invention that corrosion due to electrical contact of dissimilar metals is prevented is further obtained. According to the third aspect of the invention, since the ring cover according to the first or second aspect is made of a synthetic resin containing glass fiber, the ring cover has a high hardness and is crushed when the lock ring is tightened with the cap nut. Without transmitting the tightening force of the cap nut to the lock ring,
Further, an effect of reliably maintaining the insulating state can be further obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment of the present invention with a partial cross-section in a state where a lining steel pipe is connected.

FIG. 2 is an enlarged view of an embodiment of the present invention, wherein (a) is a ring cover, (b) is a lock ring, (c) is an integrated packing, and (b) )
FIG. 3 is an enlarged cross-sectional view of each embodiment of the core.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Insulated pipe joint 2 Socket body 10 Cap nut 20
Integrated packing 21 Swelling part 22
First cylindrical portion 23 Contact portion 24
2nd cylinder part 30 core 40
Lock ring 50 Ring cover

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[Procedure amendment]

[Submission date] September 22, 1999 (September 9, 1999
2)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

Claims (2)

[Claims] 1. A metal socket main body which is previously attached to a first pipe, and a similarly metal cap nut screwed into the socket main body, and is connected to the socket main body and the cap nut. A synthetic resin insulating and sealing member, a metal lock ring, and the like are attached between the second pipe and the second lining steel pipe, and the cap nut is tightened to the socket body. An insulating pipe joint in which a lining steel pipe is electrically connected in an insulated state, wherein the insulating and sealing member is made of a synthetic resin, a ring cover, and an integral packing, The packing is attached to the tip of the second lining steel pipe, and when the cap nut is tightened to the socket body, is pressed against both the inner peripheral surface of the socket body and the outer peripheral surface of the lining steel pipe. A projecting portion, a first cylindrical portion located between an inner peripheral surface of the socket body and an outer peripheral surface of the lining steel pipe, a contact portion with which a distal end surface of the lining steel pipe abuts, and an inner peripheral surface side of the lining steel pipe And a second cylindrical portion that is in contact with and seals therefrom, and is formed continuously and integrally, whereby the space between the socket body and the second lining steel pipe is sealed and electrically connected. Insulated, the ring cover has a substantially tapered tubular shape, is interposed between the lock ring attached to the second lining steel pipe and the cap nut, and tightens when the cap nut is tightened to the socket body. An insulated pipe joint which transmits a force to the lock ring and maintains a predetermined distance between them in an electrically insulated state. 2. A metal socket body previously attached to a first pipe, and a metal cap nut screwed onto the socket body, and connected to the socket body and the cap nut. A synthetic resin insulating and sealing member, a metal lock ring, and the like are attached between the second pipe and the second lining steel pipe, and the cap nut is tightened to the socket body. An insulating pipe joint in which the lining steel pipe is electrically connected in an insulated state, wherein the insulating and sealing member is made of a synthetic resin, and includes a ring cover, a core, and an integral packing, The integrated packing is attached to the tip of the second lining steel pipe, and when the cap nut is tightened to the socket body, pressure is applied to both the inner peripheral surface of the socket body and the outer peripheral surface of the lining steel pipe. A bulging portion to be formed, a first cylindrical portion located between an inner peripheral surface of the socket body and an outer peripheral surface of the lining steel pipe, a contact portion with which a tip end surface of the lining steel pipe abuts, A second cylindrical portion which is located on the peripheral surface side and seals in contact with the peripheral surface, and is integrally formed continuously, whereby the space between the socket body and the second lining steel pipe is sealed and The core is electrically insulated, and the core has a tubular portion having a function of pushing a second tubular portion of the integrated packing mounted on the second lining steel pipe outward in a radial direction, and the integrated packing at the time of mounting. The ring cover has a substantially tapered tubular shape, and is formed integrally with a flange-shaped stopper portion abutting on the abutting portion of the lock ring and the cap nut mounted on the second lining steel pipe. Interposed in the bag An insulated pipe joint which transmits a tightening force when a nut is tightened to the socket body to the lock ring, and maintains a predetermined interval between them in an electrically insulated state. 2. An insulated pipe joint, wherein the ring cover according to claim 1 is made of a synthetic resin containing glass fiber.