JPS6114780Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pipe joint that is applied to a pipe-in-pipe construction method in which a new pipe is inserted into an existing pipe.

In the pipe-in-pipe construction method, it is preferable to use a new pipe with the largest possible diameter that can be inserted into the existing pipe in order to prevent the capacity of the pipe from decreasing as much as possible. To achieve this, the outer diameter of the socket that provides the maximum outer diameter should be made as small as possible compared to the bore diameter, but since the outer diameter of the socket is determined by the size of the sealing material that corresponds to the bore diameter, conventional It was not possible to reduce the outer diameter of the socket below a predetermined limit.

In order to reduce the outer diameter of the socket, it is possible to reduce the size of the sealing material accordingly, but if the sealing material is made smaller, the tightness of the joint and the integrity of the socket and insertion port will deteriorate. A problem arises. In addition, when the outer diameter of the socket is reduced, if a so-called detachment prevention function is to be provided to prevent the socket from being pulled out from the socket, a special detachment prevention structure will be required. .

Therefore, the present invention aims to provide a pipe joint for pipe-in-pipe construction that can obtain a predetermined seal surface pressure while using a small sealing material, has a detachment prevention structure, and can reduce the outer diameter of the socket. This is the purpose.

For this reason, the present invention provides a first annular groove formed near the opening end of the socket on the inner surface of the pipe socket, and a space between the first annular groove and the step surface at the rear end of the socket. At a position separated by a predetermined distance from the back end step surface, there is provided a receiving step surface in the pipe radial direction on the socket opening end side, a circumferential bottom surface in the tube axis direction, and a pressing step surface facing the receiving step surface. a lock ring is provided in the first annular groove, and a lock ring is provided in the first annular groove;
A headless bolt is provided which is screwed from the outside into a screw hole penetrating the socket wall from the annular groove of the socket, and engages the locking ring with the annular recess on the outer periphery of the socket in a state of being sunk in the wall. A sealing material for sealing the outer periphery of the mouth and an inner periphery of the socket and a pressing device for this sealing material are brought into contact with the receiving step surface of the sealing material, and the pressing device is brought into contact with the pressing step surface to form the second annular groove. It is set up inside.

Therefore, since the sealing material is pressed and compressed by the pressing device toward the receiving step surface of the second annular groove, a predetermined surface pressure can be obtained even though the sealing material can be made smaller. It is possible to ensure the tightness of the joint and the integrity of the socket and insertion port, and since the pressing device only presses the sealing material, it is possible to apply a more reliable pressing force to the sealing material. It is. In addition, a locking ring that engages with the annular recess on the outer periphery of the socket is provided in the first annular groove of the socket, so when pushing a new pipe into an existing pipe in the pipe-in-pipe construction method, it is difficult to push from the socket side. Force can be reliably transmitted to the socket via the annular recess, the lock ring and the first annular groove. In addition, since the detachment prevention structure can be housed inside the thin wall of the socket, the outer diameter of the socket can be reduced, and the diameter of the new pipe inserted in the pipe-in-pipe construction method can be increased. can. Further, since the second annular groove is provided at a position a predetermined distance away from the stepped surface at the rear end of the socket, the elasticity of the joint can be improved by that amount.

Hereinafter, one embodiment of the present invention will be described based on the drawings. In the drawing, 1 is the socket of the tube body 2, 3
is the insertion port of the tube body 4. Cement linings 5, 6 are provided on the inner surfaces of both tube bodies 2, 4.

An annular groove 7 is formed on the inner surface near the open end of the socket 1, and a lock ring 8 that is split into one piece in the circumferential direction and has a diameter reducing force is fitted into this annular groove 7. Further, this lock ring 8 is located within a wide annular recess 9 provided on the outer surface of the socket 3. 10 is a screw hole formed from inside the annular groove 7 through the wall of the socket 1. 11 is screwed into this screw hole 10 from the outside, holds the lock ring 8 in a reduced diameter state while recessed in the wall, and is capable of engaging with stepped portions 9a and 9b formed on both side walls of the annular recess 9. It is a headless bolt.

A socket 1 at a position between the annular groove 7 and the back end step surface 12 and a predetermined distance away from the back end step surface 12.
The inner surface includes a receiving step surface 13 on the open end side of the socket 1;
An annular groove 16 is formed surrounded by a circumferential bottom surface 14 and a pressing step surface 15 facing the receiving step surface 13 in the tube axis direction. Inside the annular groove 16, there is a relatively small sealing material 17 that seals the outer periphery of the socket 3 and the circumferential bottom surface 14 of the socket 1, and a pressing device 18 for this sealing material 17 pushes the sealing material 17 into the socket 1. The seal member 17 is disposed on the open end side, that is, in a state in which the sealing material 17 is in contact with the receiving step surface 13 . 19 is the peripheral bottom surface 14
It is an annular protrusion protruding from the receiving step surface 13 at an appropriate distance, and is configured to fit into an annular recess 20 formed on the outer periphery of the sealing material 17 . The pressing device 18 consists of a pressing ring 21 divided into circumferential parts, and pressing screws 22 screwed into the pressing ring 21 at appropriate intervals in the circumferential direction in the tube axis direction.
The head of the set screw 22 is in contact with the pressing step surface 15. Therefore, by turning the push screw 22, the sealing material 17 can be pressed.

The inner periphery of the socket 1 between the annular groove 16 and the step surface 12 at the back end has an inner diameter that fits loosely around the outer periphery of the socket 3 with a slight gap, and a groove facing toward the back side of the socket 1. A tapered surface 23 whose inner diameter gradually increases is formed. 24 is an insertion tapered surface formed on the outer periphery of the tip of the insertion port 3.

In the above configuration, when joining the tube bodies 2 and 4, first place the sealing material 17 and the pressing device 18 in the annular groove 16, positioning the sealing material 17 on the open end side of the socket 1, and positioning the sealing material 17 in the annular recess. The annular protrusion 19 is fitted into the annular groove 20 and the lock ring 8 is deposited into the annular groove 7.

Next, a lubricant such as thick soapy water is applied to the outer periphery of the socket 3, and the insertion tapered surface 24 compresses the sealing material 17 until it passes through the inner periphery of the sealing material 17 as shown by the imaginary line. Insert within 1. With the sealing material 17 secured to fit around the outer periphery of the socket 1 in this way, the set screw 22 of the pressing device 18 is turned to screw it out from the pressing ring 21, thereby compressing the sealing material 17 to a predetermined level. Generates seal surface pressure. In this way, although the small sealing material 17 is used, the same sealing surface pressure and the same integrity between the socket 1 and the socket 3 as when using a large sealing material corresponding to the diameter are ensured.

Thereafter, the socket 3 is inserted to the illustrated position, and the headless bolt 11 is screwed into the screw hole 10 to hold the lock ring 8 in a reduced diameter state in which it can engage with the stepped portions 9a and 9b.

As described above, according to the present invention, the sealing material is pressed and compressed by the pressing device toward the receiving step surface of the second annular groove, so even though the sealing material can be made smaller, the predetermined surface pressure cannot be maintained. This ensures the tightness of the joint, the integrity of the socket and the insertion port, etc. Moreover, since the pressing device presses only the sealing material, a more reliable pressing force can be applied to the seal. It is possible to give it to wood. Also,
A locking ring that engages with the annular recess on the outer periphery of the socket is provided in the first annular groove of the socket, so when pushing a new pipe into an existing pipe in the pipe-in-pipe construction method, the pushing force from the socket side is reduced. , the annular recess, the locking ring, and the first annular groove. In addition, since the detachment prevention structure can be housed inside the thin wall of the socket, the outside diameter of the socket can be reduced, and the diameter of the new pipe in the pipe-in-pipe construction method can be increased, reducing the efficiency of the pipeline. It can be prevented. In addition, since the annular groove of the seal part is formed at a predetermined distance from the back end step surface, the extension of the joint part can be set arbitrarily without being affected by the seal material and pressing device. Therefore, by increasing the width of the annular recess on the outer periphery of the socket, the amount of expansion and contraction can be increased and sufficient vibration resistance can be obtained. For example, if the inner periphery of the socket between the annular groove of the seal part and the back end section is formed into a tapered surface whose inner diameter gradually increases toward the back of the socket as in the above embodiment, the joint part can be Since it has flexibility, it can sufficiently follow the bending of the existing pipe, allowing smooth insertion of a new pipe, and improving the workability of the pipe-in-pipe construction method.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view showing an embodiment of the present invention. 1...Socket, 3...Socket, 7...Annular groove, 8...
... Lock ring, 9 ... Annular recess, 10 ... Screw hole, 11 ... Headless bolt, 12 ... Rear end stepped surface,
16... Annular groove, 17... Seal material, 18... Pressing device.

Claims (1)

[Scope of utility model registration request] A first annular groove formed near the opening end of the socket is provided on the inner surface of the pipe socket, and a groove is formed between the first annular groove and the stepped surface at the far end of the socket and at a predetermined distance from the stepped surface at the far end. A second annular groove having a receiving step surface in the pipe radial direction on the socket opening end side, a circumferential bottom surface in the tube axis direction, and a pressing step surface facing the receiving step surface is provided at a position separated by a distance. , a lock ring is provided in the first annular groove, and the lock ring is inserted from the outside into a screw hole penetrating the socket wall from the first annular groove, and is recessed in the wall. A headless bolt is provided to engage with an annular recess on the outer periphery, and a sealing material for sealing the outer periphery of the socket and the inner periphery of the socket, and a pressing device for this sealing material are brought into contact with the receiving step surface, and A pipe joint for pipe-in-pipe construction, characterized in that a pressing device is provided in the second annular groove in contact with the pressing step surface.