JPH11190489A - Transition joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate corrosion, and to facilitate job site work by arranging a resin coating film layer on the outside surface of a joint main body and a nut, projecting a cylinder body to the end part of a joint main body side resin coating film layer, and sealing/connecting a conduit pipe inserted into the outside surface of a bellows pipe through packing in/to a socket arranged in the end part of a nut side resin coating film layer. SOLUTION: In the connection with a metallic bellows pipe 4, first of all, a joint main body 1 and a nut 3 are set by sandwiching a spacer 5 in a state of being threadedly preengaged in the prescribed length. The bellows pipe 4 is inserted into a joint from the steel end part of the nut 3 by removing an outside surface resin coating film layer 41 of the connecting end part by the length of 4 to 5 crests from the end part. Since a crest 42 on the tip of the bellows pipe 4 pushes a projection 23 of a sleeve, after the sleeve 2 advances up to a locking position with the nut, the sleeve expands/contracts when the projection 23 is pushed by the wave crest of the bellows pipe in the locking position with the nut, so that the tip part of the bellows pipe 4 strikes on packing 13 of the airtight surface in a state of entering a first trough 43 to complete pipe inserting work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buried transition joint for connecting a polyethylene pipe used for a buried pipe for gas, and a metal bellows pipe having flexibility which can be easily piped. The present invention relates to a pipe joint for connecting a resin pipe to a metal bellows pipe, which is connected to a gas meter on the ground by rising pipe from an underground buried portion.

[0002]

2. Description of the Related Art In recent years, flexible polyethylene pipes and metal bellows pipes have been widely used from the viewpoint of pipe workability and earthquake resistance. For this purpose, a polyethylene pipe and a metal bellows pipe are connected. Transition joints are needed.
Conventionally, there is a pipe joint disclosed in Japanese Utility Model Laid-Open No. 6-20987 as a joint for connecting the polyethylene pipe and a metal bellows pipe. In this device, a metal bellows tube and a plastic tube are attached to the inner surface of each end of the joint body, and a metal stiffener is inserted between both attached tubes so that the metal stiffener is inserted between the two tubes. The metal resin pipe and the plastic pipe are connected to each other by crimping on the inner peripheral surface of the joint body by expanding the diameter from the peripheral side.

[0003]

The above polyethylene pipes are mainly used for underground pipes because they deteriorate with ultraviolet rays. Metal bellows pipes are mainly used for aboveground pipes because they have a problem of corrosion when buried in the ground such as macrocell corrosion generated between soil and concrete. Therefore, when a metal bellows tube is used for a buried pipe, it is necessary to provide an insulating joint or take various anticorrosion measures, and it is necessary to periodically perform a security inspection.

In the above conventional pipe joint, since a metal stiffener is expanded in diameter from the inner surfaces of a plastic pipe and a metal bellows pipe mounted on the inner peripheral surface of a joint body, and both pipes are integrally press-fixed and fixed. The process of expanding the stiffener is always factory-produced, and there is a problem that piping work cannot be performed on site. In addition, since it is inevitable that the metal bellows tube comes into contact with the soil because it is connected to the plastic tube used for the buried piping, it is necessary to perform anticorrosion treatment of the metal bellows tube. Also, it was difficult to confirm whether both pipes were securely compressed and fixed with one stiffener. The present invention solves the above problems, there is no problem of corrosion, piping can be easily performed on site, and a connection between a metal bellows tube and a plastic pipe can be made in an underground buried portion, for example, from an underground buried portion. Provided is a transition joint for connecting a resin pipe and a metal bellows pipe, which is suitable for connecting to a gas meter on the ground by starting piping.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a joint for connecting a metal bellows tube with a joint body and a nut screwed to the joint body. Layers, the resin coating layers are brought into sealing contact with each other via packing, and a cylindrical body connected to a resin pipe is provided at an end of the joint body side resin coating layer so as to protrude therefrom, and the nut side resin coating layer is provided. The transition joint is characterized in that a receptacle for a conduit pipe is provided at an end of the pipe, and a conduit pipe inserted into an outer surface of the connected metal bellows pipe is hermetically connected to the receptacle via a packing. Further, in the above description, the pipe joint has a joint body and a nut screwed to the joint body, a sleeve is engaged with the nut, and the end of the metal bellows tube at the end of the sleeve is placed inside the joint body. A transition joint characterized by being connected by crimping. Further, in the above description, the conduit pipe is a transition joint characterized by comprising a bellows pipe made of resin.

[0006]

According to the present invention, since the end portion of the resin coating layer in which the outer surface of the joint body is resin-coated is formed in a cylindrical body having the same outer diameter as the resin pipe to be connected, for example, The resin pipes can be easily connected to each other using the existing electrofusion joints and mechanical joints. The end of the metal bellows tube connected to the joint can be easily connected to a device such as a gas meter installed on the ground, for example, using an existing metal bellows tube connection joint. Also, the outer surfaces of the joint body and the nut of the pipe joint are covered with a resin coating layer, and the resin coating layer of the joint body and the nut are in sealing contact with packing via a packing in a state where a metal bellows tube is connected. The connected metal bellows tube is covered with a resin bellows tube hermetically connected to the end of the resin coating layer on the nut side. For this reason, the metal joint body, nut, and metal bellows tube are both shielded from the external environment. Absent. In addition, since the metal bellows tube and the resin tube are not connected in advance as in the related art, the connection can be easily performed at the piping site by the same connection method of the conventional pipe joint according to the situation of the piping site.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a transition joint 10 according to one embodiment of the present invention, FIG. 2 is an enlarged view showing a portion of the transition joint 10 connected to a bellows tube of this embodiment, and FIG. It is a figure which shows the state which connected the metal bellows pipe 4 from the polyethylene pipe 8 buried underground and connected to the gas meter 9 on the ground. In FIG. 1, reference numeral 1 denotes a joint body made of a copper alloy, in which a coating layer 52 of polyethylene resin is provided on the outer surface by injection molding, and a cylindrical body 53 having the same outer diameter as the polyethylene pipe 8 to be connected is provided at the end of the resin coating layer 52. It is provided to protrude. A rubber packing 54 is interposed between the joint body 1 and the resin coating layer 52 so as to prevent internal fluid from being transmitted, and a projection 55 or the like is provided on the outer surface of the joint body 1 in order to impart adhesion strength and rotational strength to the resin coating layer. Polygon outer surface 56
And a resin coating layer 52 is provided. 18 is the cylinder 5
3 is removed when it is connected to the buried resin pipe with the cap over it.

Reference numeral 3 denotes a nut made of a copper alloy which is screwed to the joint body 1. A plurality of ribs 61 are provided on the outer surface of the nut 3, and a polyethylene resin coating layer 62 is provided by injection molding. 52 and the resin coating layer 62 on the nut side
Are provided with butting portions 57 and 67 which come into contact with each other while the metal bellows tube 4 is connected. A packing 68 is attached to the butt portion so that the bellows tube 4 is connected between the butt portions 57 and 67 to hermetically seal. Note that, instead of the butting portions 57 and 67, the resin coating layers 52 and 62 may be provided in a cylindrical portion where they are fitted to each other, and packing may be attached to the fitting portion. An annular groove 63 and a conduit pipe connection port 64 are provided on the inner surface of the end of the resin coating layer 62, and the outer resin coating layer 4 of the metal bellows tube 4 to be connected is provided in the annular groove 63.
A seal packing 65 that abuts on and seals with No. 1 is mounted.

The conduit pipe connection port 64 has an inner peripheral surface for housing the conduit pipe 7 made of a vinyl chloride accordion tube,
Two notch windows 66 are provided at symmetrical positions in the circumferential direction at the ends, and the bellows tube 7 fitted with a watertight packing 71 fitted into the outer peripheral concave groove 72 of the end portion of the resin bellows tube 7 is inserted and cut. A U-shaped stopper 73 that fits into the concave groove 72 of the bellows tube 7 is attached to the cutout window 66, and the resin bellows tube 7 is hermetically sealed and connected to the conduit tube connection port 64. . As shown in FIG. 4, the terminal portion of the conduit pipe 7 is located at the above-ground piping position and the outer resin coating layer 41 of the conduit pipe 7 and the bellows pipe 4 made of metal.
A soft resin cap 74 is attached so as to prevent rainwater or the like from entering the conduit tube 7.

Next, an embodiment of a pipe joint structure for connecting the metal bellows tube 4 will be described. In FIG. 2, the upper half sectional view shows a state before connection, and the lower half sectional view shows a state after connection.
Numeral 1 denotes a joint body, in which an airtight surface 14 facing a nut side is provided in a through hole 11, a heat-resistant gasket 12 is mounted thereon, a fireproof expansion packing 13 is mounted, and a diameter of the joint is reduced toward the airtight surface. The tapered inner surface 15 is then replaced with an annular groove 16,
A female screw 17 is provided. On the outer surface on the opposite side, an annular protrusion 55 for strengthening the adhesion to the resin coating layer 52 and a rubber packing 54 for maintaining the sealing property are attached, and the resin coating layer 52 is formed by injection molding. The nut 3 is a metal bellows tube 4
A male screw 31 having an opening hole diameter through which the male screw 31 is inserted and screwed to the joint body 1 is provided, and an annular projection 32 is formed on the inner end of the male screw on the radially inner side. Here, the sleeve 2 for holding the corrugation at the distal end of the bellows tube 4 is locked.

As shown in FIG. 3, the sleeve 2 has an integral ring 21 at the rear and a segment 22 at the front which can be enlarged and contracted by a slit. At the front end, there is a projection 23 directed inward in the radial direction. The inner end circle formed by this projection 23 is formed smaller than the outer diameter of the bellows tube 4 to be inserted and slightly larger than the diameter of the valley. Sleeve 2 is brass plate 26
And the resin layer 27, and receives a pressing force from the nut 3 on the outer peripheral end surface 24. A claw 25 is provided on the outer peripheral surface of the rear end. The claw 25 is rotatably locked in the annular projection 32 of the nut 3 so as to be rotatable in the axial direction.

The connection with the metal bellows tube 4 is made by first setting the joint body 1 and the nut 3 with the spacer 5 sandwiched therebetween in a state where the joint body 1 and the nut 3 are screwed in a predetermined length in advance as shown in the upper half sectional view of FIG. The bellows tube 4 removes the outer resin coating layer 41 at the connection end by 4 to 5 ridges from the end, and inserts the nut 3 from the rear end into the joint. Since the peak 42 at the tip of the bellows tube 4 pushes the protrusion 23 of the sleeve, the sleeve 2 advances to the position where the sleeve 23 is engaged with the nut. In the state where the bellows tube 4 enters the first valley 43, the tip of the bellows tube 4 hits the packing 13 on the airtight surface, and the operation of inserting the tube is completed. Even if the tube is pulled out in this state, the protrusion 23 of the sleeve 2 is locked to the crest 42 at the tip of the tube and moved toward the nut, and the outer peripheral surface of the protrusion 23 of the sleeve is separated from the annular groove 16 of the joint body. As a result, the tube 23 moves to the small diameter portion of the inner diameter of the main body, and the projection 23 does not expand and the tube 4 is prevented from coming off. Therefore, by inserting the tube 4 and pulling the tube 4 in the withdrawing direction, it can be easily confirmed whether or not the tube 4 has been correctly inserted into the joint.

After the bellows tube 4 is inserted into the sleeve 2 from the nut side, the spacer 5 is removed and the nut 3 is tightened by rotation. As a result, the pressing surface 34 of the nut is brought into contact with the contact surface 24 of the sleeve 2 via the sliding ring 6. The sleeve 2 compresses the tip peak 42 of the bellows tube to the airtight surface 14 while the protrusion 23 is narrowed by the tapered inner surface 15 of the main body, and the tip peak 42
Is compressed by the gasket 12 to obtain perfect airtightness. In the pipe joint of this embodiment, it is only necessary to tighten the nut after inserting the pipe, and the connection operation is easy. The above-mentioned pipe joint structure is not limited to this, and another pipe joint structure may be used as long as the metal bellows pipe is connected by screwing the joint body and the nut.

[0014]

As described above, the transition joint of the present invention has no corrosion problem even when used in the same buried pipe portion as the resin pipe, and can be easily piped according to the situation at the site. For this reason, it is suitable as, for example, a resin pipe and a pipe joint for connecting a metal bellows pipe connected to a gas meter on the ground by setting up a pipe from an underground buried portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a transition joint according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a connection portion of the transition joint 10 of the present embodiment with a bellows tube, wherein an upper half shows a state before connection and a lower half shows a state after connection.

FIG. 3 is a perspective view showing a sleeve 2 of FIG. 2;

FIG. 4 is a diagram illustrating a state in which a metal bellows pipe is connected to a resin pipe of an underground pipe and the pipe is connected to a gas meter on the ground, showing a use state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Joint main body 2 Sleeve 3 Nut 4 Metal bellows tube 5 Spacer 6 Slip ring 11 Through hole 12 Gasket 13 Fireproof expansion packing 14 Airtight surface 15 Tapered inner surface 16 Annular concave groove 17 Female thread 21 Ring 23 Projection 24 Outer peripheral end surface 25 Claw 26 Brass plate 27 Resin layer 32 Annular protrusion 34 Nut pressing surface 41 Outer resin coating layer 42 Tip on top 52 Outer resin coating layer 53 Cylindrical body 54 Rubber ring 55 Projection 56 Polygonal part 61 Rib 62 Outer resin coating layer 63 Concave groove 64 Conduit pipe connection port 65 Packing 66 Window 72 Conduit pipe concave groove 73 Stopper 74 Cap

Claims (3)

[Claims] 1. A joint body having a joint body and a nut screwed to the joint body, and a resin coating layer provided on outer surfaces of the joint body and the nut of a pipe joint for connecting a bellows pipe made of metal. The members are hermetically contacted via a packing, and a tubular body connected to a resin pipe is provided at an end of the joint body-side resin coating layer so as to protrude therefrom. A conduit pipe socket is provided at an end of the nut-side resin coating layer. A transition joint, wherein a conduit pipe inserted into an outer surface of the metal bellows pipe connected to the socket is hermetically connected via a packing. 2. The pipe joint has a joint body and a nut screwed to the joint body, a sleeve is engaged with the nut, and an end crest of a metal bellows tube is formed at an end of the sleeve. 2. The transition joint according to claim 1, wherein the transition joint is connected by crimping. 3. The transition joint according to claim 1, wherein the conduit pipe is formed of a bellows pipe made of resin.