JP2001241580A - Slip-on pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slip-on pipe joint which can absorb compression allowances for expansions thereof, without causing any plastic deformation in a pipe or in a joint and any separation of anticorrosion protection layer on the exterior of the pipe in case of pipe elongation due to an effect of an earthquake or a heat. SOLUTION: A absorbing member 5 for compression allowances comprising of a compression coil and a coned disc spring or the like is put on between a mouth 7 and a pipe end stopper section 8 in the joint main body 1. When a compression load is imposed on the absorbing member 5 for compression allowances because of linear expansion of the end section of a pipe P due to the effect of the earthquake or the heat, then the absorbing member 5 for compression allowances is compressed and the compression allowances are absorbed. Therefore, the plastic deformation, in which the diameter of the end section of the pipe P is reduced or the diameter of the joint main body 1 is enlarged, can be prevented, and the separation of the anticorrosion protection layer P2 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug-in type pipe joint for connecting end portions of pipes through which electric power and communication cables are passed.

[0002]

2. Description of the Related Art As this kind of plug-in type pipe joint, for example, the one shown in FIG. 10 is known. Where,
Receptacles 7, 7 into which the ends of the pipe P are inserted are opened at both ends in the axial center direction of the cylindrical joint body 1. The lock ring 3 is provided inside the receptacle 7, and the lock ring 3 is located on the inner side of the lock ring 3. The rubber seal ring 2 disposed therein is incorporated, and a tube end stopper portion 8 is provided in the inner part of the joint main body 1 below the seal ring 2 so as to slightly narrow the inner diameter. At the location where the lock ring 2 is located on the inner peripheral surface of the receiving port 7, an outer constricted tapered pressing surface 11 is formed. When connecting the pipe P, the end of the pipe P is connected to the pipe end stopper 8 through the socket 7.
When the pipe P is pushed into the pipe P, the seal ring 2 comes into close contact with the outer peripheral surface of the pipe P to be hermetically sealed, and when the pipe P moves in the exit direction, the lock ring 3 comes into contact with the tapered pressing face 11. By contacting and reducing the diameter, the outer peripheral surface of the pipe P is strongly bitten, so that the pipe P can be prevented from coming off.

[0003]

However, in the above-mentioned plug-in type pipe joint, when the pipe P linearly expands due to an earthquake, heat, or the like after the pipe P is connected, the end of the pipe P is connected to the pipe P. A compressive load is applied by strongly contacting the end stopper portion 8, and the end of the pipe P tries to forcibly enter the inner diameter of the pipe end stopper portion 8 due to the compressive load. since the anti-corrosion coating layer P ₂ being is peeled off, the end portion of the pipe P by the separation pipe end stopper portion 8
Of the joint body 1 can be prevented from being forcibly inserted into the inner diameter portion and deformed to reduce the diameter. However, this because it is forced at the expense of corrosion coating layer P ₂ of the pipe P is lost or reduced corrosion capability and peeling is not preferable phenomenon.

FIG. 11 shows a construction method for eliminating such plastic deformation in which the ends and joints of the pipes expand and contract in diameter and peeling of the anticorrosion coating layer.
As shown in (1), there is a construction method in which a predetermined gap (compression allowance) A is formed between the end of the pipe P and the pipe end stopper 8 in the joint body 1. At the time of this construction, first, before inserting the end of the pipe P into the joint, a marking line is marked at a predetermined length position from the end of the pipe P with a magic (registered trademark) or the like. By inserting P to the position of the marked line, a predetermined gap (between the end of the pipe P and the pipe end stopper 8 without causing the end of the pipe P to abut against the pipe end stopper 8) The compression allowance) A is formed, but this requires not only a marking line marking work before inserting the pipe P, which is troublesome, but also that the pipe end does not come into contact with the pipe end stopper 8 without being in front of it. Stopping accurately at a predetermined position required skill and was a very difficult task.

An object of the present invention is to solve such a problem. Even when the pipe is linearly expanded due to an earthquake, heat, or the like, the pipe end and the joint are plastically deformed, and the pipe is subjected to anticorrosion coating. It is an object of the present invention to provide a plug-in type pipe joint which can prevent the layers from peeling.

[0006]

According to the present invention, there is provided a cylindrical joint body having openings at both ends in the axial direction into which the ends of the pipes are inserted. In a plug-in type pipe joint provided with a pipe end stopper part where the part abuts,
It is characterized in that a compression-absorbing member that receives a compressive load and compresses when the end of the tube comes into contact with the linear expansion of the tube is mounted between the socket and the tube end stopper portion. Have In this case, a seal ring that is in close contact with the outer peripheral surface of the end of the pipe and a lock ring that bites into and engages with the outer peripheral surface of the end are incorporated between the socket in the joint body and the stopper at the end of the tube. be able to. Also,
The joint body and the pipe are each made of metal, and a metal compression coil or a spring such as a disc spring can be used as the compression allowance absorbing member.

[0007]

When connecting the pipe, insert the end of the pipe through the socket, and if the pipe end hits the compression-absorbing member and feels resistance, a predetermined compression allowance is inserted between the pipe end and the pipe-end stopper. Is obtained, so that the insertion of the tube should be completed at this time.

When the pipe expands linearly due to an earthquake, heat, or the like, a compressive load is applied to the compression allowance absorbing member by the end of the pipe,
The compression allowance absorbing member compresses to absorb the compression allowance. Therefore, the end of the pipe is not deformed in diameter and the joint is not deformed in diameter, and even when the anticorrosion coating layer is formed on the outer surface of the pipe, the anticorrosion coating layer does not peel off. .

[0009] If a metal compression allowance absorbing member is mounted between the socket in the metal joint body and the pipe end stopper to compress the metal pipe when the end of the metal pipe abuts. Since the end of the metal pipe and the inner surface of the metal joint body are always in contact with each other via the metal compression allowance absorbing member, an electrically conductive state can be obtained, so that the metal pipe and the joint body are grounded. Even when buried therein, the sacrificial anode can be used to pass corrosion current through the tube or the joint body to prevent corrosion of the tube and the joint body.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the plug-in type pipe joint in a state where the pipe is completely inserted, and FIG. 2 is a cross-sectional view showing the plug-in type pipe joint in a state where a compression load is applied to a compression allowance absorbing member in the inside. .

1 and 2, this plug-in type pipe joint includes a joint body 1, a rubber seal ring 2, a lock ring 3, a support elastic ring 4, and a compression allowance absorbing member 5. I have.

The joint body 1 is made of metal and is formed in a cylindrical shape, and its outer periphery is integrally covered with an anticorrosion cylindrical body 6 made of resin. The joint body 1 has openings 7 at both ends in the axial direction into which the ends of the pipes P are inserted. The pipe end stopper portion 8 is narrowed to a narrow portion near the center in the axial direction. And both ends 6a in the axial direction of the anticorrosion cylinder 6
6a are formed so as to protrude outward in the axial direction from both ends of the joint main body 1, and a first concave groove 9 is formed in each of inner ends of the axial end portions 6a of the anticorrosion cylinder 6, and the first groove 9 is formed. A second concave groove 10 having a tapered surface 10a is formed on the inner periphery of the portion in such a manner that an intermediate portion between the concave groove 9 and the tube end stopper portion 8 bulges outward.

Thus, the seal ring 2 is fitted into the first groove 9 of the joint body 1, and the lock ring 3 is received in the second groove 10 by the supporting elastic ring 4 so as to face the tapered surface 10a. It is fitted in a state where it is stopped and supported. Between the pipe end stopper portion 8 and the lock ring 3 in the joint main body 1, a metal compression allowance absorbing member 5 such as a spring for absorbing a compression allowance at an end of the pipe P to be inserted is mounted. .
The shape and size of the compression allowance absorbing member 5 are determined by a necessary compression load and a compression allowance. In the illustrated example, the compression allowance is made of a cylindrical compression coil spring. By compressing the one end 5a of the compression allowance member 5 to the tube end stopper 8 with a conductive adhesive, the compression allowance absorption member 5 is prevented from inadvertently coming out toward the receiving port 7 before the pipe P is inserted. It is preferable to keep it in a fixed position. In addition, as shown in FIG. 3, an inward flange 4a having an inner diameter smaller than the outer diameter of the compression allowance absorbing member 5 is provided on the inner periphery of the supporting elastic ring 4 as a fixed position holding means for the compression allowance absorption member 5. By receiving the other end 5b of the compression allowance absorbing member 5 with the flange 4a, the compression allowance absorption member 5 can be prevented from protruding toward the receiving port 7.

[0014] connecting pipe P obtained by forming an anticorrosive coating layer P ₂ formed of resin bayonet tube outer surface of a steel pipe such as a metal pipe P ₁ by fitting the above-described structure. At the time of this connection, the end of the pipe P is inserted through the socket 7 at one end of the joint body 1, and when the end of the pipe hits the compression allowance absorbing member 5 and feels resistance, the end of the pipe P and the pipe end stopper Since the required compression allowance is obtained between the tube P and the tube 8, the insertion of the pipe P may be terminated at this time. Although not shown, the end of another pipe P is similarly inserted into the socket 7 at the other end of the joint body 1.

As shown in FIG. 2, when the end of the pipe P is inserted into the socket 7 of the joint body 1 until it comes into contact with the compression absorption member 5, the seal ring 2 is compressed on the outer peripheral surface of the end of the pipe P. The seal ring 2 provides an airtight seal between the inner peripheral surface of the receiving port 7 and the outer peripheral surface of the end of the pipe P. At this time, the inner peripheral portion of the lock ring 3 is lightly engaged with the outer peripheral surface of the end of the pipe P. When the pipe P is pulled in the withdrawal direction, the outer peripheral surface of the lock ring 3 that moves in the same direction together with the pipe P comes into contact with the tapered surface 10a of the second concave groove 10, whereby the diameter of the lock ring 3 is reduced. Biting into the outer peripheral surface of the pipe P is increased, and the end of the pipe P can be reliably prevented from falling out of the receiving port 7.

When the pipe P linearly expands and expands due to an earthquake, heat, or the like, a compressive load is applied to the compression allowance member 5 by the end of the pipe P, as shown in FIG. It will compress and absorb the compression allowance. Therefore, at this time, since the end of the pipe P does not undergo a diameter reduction or a plastic deformation such that the diameter of the joint body 1 increases, the pipe P
Can prevent damage to the power and communication cables in the pipe P due to the diameter reduction deformation of the end of the pipe P, and strength reduction due to the diameter expansion deformation of the joint body 1, and also prevent the anticorrosion coating layer P ₂ of the pipe P from peeling off. it can.

When each of the joint body 1 and the pipe P is made of metal, the end portion of the pipe P and the inner surface of the joint body 1 are always in contact with each other via the metal compression allowance absorbing member 5 so that electrical conduction is possible. become. Therefore, even when the pipe P and the joint main body 1 are buried in the ground, a sacrificial anode (not shown) is connected to the joint main body 1 or the pipe P to pass the anticorrosion current, thereby allowing the pipe P and the joint main body 1 to pass through. Corrosion can be suppressed. Zinc, magnesium, or the like is used as a low-potential metal to be a current carrying anode.

(Second Embodiment) In the first embodiment, a compression coil spring constituting the compression allowance absorbing member 5 is formed of a coil having a circular cross section. Instead of this, a rectangular cross section is used as shown in FIG. The compression allowance absorbing member 5 constituted by a compression coil spring composed of the above-mentioned coils can also be used. In this case, as a means for holding the compression allowance member 5 at a fixed position so that the compression allowance absorption member 5 does not inadvertently come out toward the receiving port 7 before the pipe P is inserted, as in the case of the first embodiment, In addition to bonding one end 5a of the member 5 to the tube end stopper 8 with a conductive adhesive or receiving it with the support elastic ring 4, the outer diameter of the compression allowance absorbing member 5 is slightly smaller than the inner diameter of the joint body 1. It is also possible to employ an interference fitting means of increasing the size and pushing it into the joint body 1. In this case, if the coil of the compression allowance absorbing member 5 is powder-coated with a polyolefin resin such as nylon, the compression allowance absorption member 5 smoothly slides on the inner surface of the joint body 1 and expands and contracts. However, the outer surface of the compression allowance absorbing member 5 and the inner surface of the joint body 1 are not rusted and fixed. However, when the compression allowance absorbing member 5 made of a powder-coated metal coil is used, the end of the compression allowance absorbing member 5 that contacts the end of the pipe P and the end that contacts the tube end stopper 8. The metal surface is exposed only on both end surfaces of 5a and comes into contact with the end of the tube P and the tube end stopper 8, respectively. Since other configurations of the second embodiment are the same as those of the first embodiment, the same members are denoted by the same reference numerals and description thereof will be omitted.

(Third Embodiment) FIGS. 5 and 6 show a third embodiment. In this embodiment, the compression between the pipe end stopper 8 in the joint body 1 and the end of the pipe P is performed. When the margin is as short as about 5 mm, one or two or more compression margin absorbing members 5 constituted by disc springs are used. FIG. 6 shows a state in which a compression load is applied to the compression allowance absorbing member 5. In the case of the third embodiment, as a means for holding the compression allowance absorbing member 5 in a fixed position, as shown in FIG. It is possible to employ an interference fitting means in which the outer diameter is made slightly larger than the inner diameter of the joint body 1 and pushed into the joint body 1. As shown in FIG. 8, when an endless disc spring having no broken portion is used as the compression allowance absorbing member 5, the large-diameter end 5 a may be bonded to the tube end stopper 8 with a conductive adhesive. Since other configurations of the third embodiment are the same as those of the first embodiment, the same reference numerals are given to the same members and the description is omitted.

As is clear from the above description, the compression allowance absorbing member 5 can secure the compression allowance only when the pipe P is connected, and when the pipe P expands due to an external action such as an earthquake or heat after construction. Any spring effect can be used as long as the pipe P is compressed by the elongation of the pipe P and then pushes back the pipe P. Therefore, the compression allowance absorbing member 5
Other than the above-mentioned springs, chrysanthemum washers without a push-back spring effect as shown in the front view of FIG. 9A, the side view of FIG. 9B, and the partially enlarged cross-sectional view of FIG. Such a thing may be used.

[0021]

According to the present invention, when the end of the tube is inserted, the end of the tube only needs to be completed by the touch of the end of the tube with the compression allowance absorbing member. The insertion work that can be secured can be facilitated.

When the end of the tube is linearly expanded by an earthquake or heat and a compressive load is applied to the compression allowance member, the compression allowance member compresses and absorbs the compression allowance. This prevents plastic deformation such as reducing the diameter of the pipe or expanding the diameter of the joint, and also prevents the anticorrosion coating layer from being peeled off even when the anticorrosion coating layer is formed on the outer surface of the pipe.

By using the metal compression allowance absorbing member, it is possible to obtain an electrically conductive state in which the end of the metal pipe is always in contact with the inner surface of the joint body. In the case where the pipe and the joint body are buried, the sacrificial anode is connected to the pipe or the joint body to pass the anticorrosion current, so that the pipe and the joint body can be electrically protected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a plug-in type pipe joint according to a first embodiment in a state where pipe insertion is completed.

FIG. 2 is a sectional view showing the plug-in type pipe joint of FIG. 1 in a state where a compressive load is applied to a compression allowance absorbing member inside the pipe joint;

FIG. 3 is a cross-sectional view of a structure in which a part of the plug-in type pipe joint of the first embodiment is modified and shown.

FIG. 4 is a cross-sectional view showing the plug-in type pipe joint according to the second embodiment in a state where pipe insertion is completed.

FIG. 5 is a cross-sectional view showing the plug-in type pipe joint according to the third embodiment in a state where pipe insertion is completed.

FIG. 6 is a cross-sectional view showing the plug-in type pipe joint of FIG. 5 in a state where a compressive load is applied to a compression allowance absorbing member therein.

FIG. 7 is a front view of a compression allowance absorbing member incorporated in the plug-in type pipe joint of FIG. 6;

FIG. 8 is a front view showing another example of the compression allowance absorbing member incorporated in the plug-in type pipe joint of FIG. 6;

9A is a front view showing still another example of the compression allowance absorbing member incorporated in the plug-in type pipe joint shown in FIG. 6, FIG. 9B is a side view thereof, and FIG. 9C is a partially enlarged sectional view. .

FIG. 10 is a partially cutaway sectional view of a conventional plug-in type pipe joint.

FIG. 11 is a partially cutaway sectional view of another conventional plug-in type pipe joint.

[Explanation of symbols]

 P pipe 1 Fitting body 2 Seal ring 3 Lock ring 5 Compression allowance member 7 Receptacle 8 Pipe end stopper

Claims (7)

[Claims] 1. A plug-in type pipe joint comprising a tubular joint body having openings at both ends in the axial direction into which ends of a pipe are inserted, and a pipe end stopper provided at a deep portion inside the socket. In the above, a compression margin absorbing member that receives a compression load and compresses when the end of the pipe comes into contact with the linear expansion of the pipe is mounted between the socket and the pipe end stopper section. Characteristic plug-in type pipe joint. 2. A tubular fitting body is provided with openings at both ends in the axial direction of the tubular joint body into which ends of the pipes are inserted, and a pipe end stopper is provided at an inner part of the receiving bores. A plug-in type pipe joint, in which a seal ring closely in contact with an outer peripheral surface of an end of the pipe and a lock ring which bites into and engages with the outer peripheral face of the end are incorporated between the end stopper and the end of the pipe. A plug-in type pipe joint characterized in that a compression allowance absorbing member is mounted between the stopper and the end of the pipe in contact with the linear expansion of the pipe so as to receive a compression load and compress the pipe. 3. A cylindrical metal joint body is provided with openings at both axial ends thereof into which ends of metal pipes are inserted, and a pipe end stopper is provided at the inner part of the socket. In the plug-in type pipe joint provided integrally with the main body, the end of the pipe comes into contact with the socket due to the linear expansion of the pipe between the receiving port and the pipe end stopper, so that the pipe receives a compressive load and is compressed. A plug-in type pipe joint comprising a metal compression allowance absorbing member. 4. A cylindrical metal joint body is provided with openings at both axial ends thereof into which ends of metal pipes are inserted, and a pipe end stopper is provided at the inner part of the socket. A plug which is provided integrally with the main body, and in which a seal ring which comes into close contact with the outer peripheral surface of the end of the tube and a lock ring which bites into and engages with the outer peripheral surface of the end are incorporated between the socket and the stopper at the end of the tube. In the pipe fitting, a metal compression allowance absorbing member that receives a compressive load and compresses when the end of the pipe comes into contact with the linear expansion of the pipe between the socket and the pipe end stopper portion. A plug-in type pipe fitting characterized by being mounted. 5. The plug-in type pipe joint according to claim 1, wherein said compression allowance absorbing member comprises a spring. 6. The plug-in type pipe joint according to claim 1, wherein said compression allowance absorbing member comprises a compression coil spring. 7. The plug-in type pipe joint according to claim 1, wherein said compression allowance absorbing member comprises a disc spring.