JPH11281518A - Device for inspecting sealing of pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the sealing capability of an overall packing material in a device for inspecting the sealing of a joint part joining one pipe to another pipe. SOLUTION: A device for inspecting the sealing of a joint part comprises a ring-shaped packing material 8 arranged from the inner surface of one pipe 1 to the inner surface of another pipe 3 and a ring-shaped presser plate 33 which is arranged radially more inside than the packing material 8 and circumferentially presses the packing material 8 against the inner surfaces of the pipes. When the outer peripheral part of the packing material 8 does not receive a pressing force by the presser plate 33, it has slopes 18 in a direction distancing from the inner surfaces of the pipes as approaches the tip parts of the packing material 8 along the axes of the pipes. The outer peripheral part of the presser plate 33 has reversed slopes 37 in a direction approaching the inner surfaces of the pipes as approaches the tip parts of the presser plate 33 along the axes of the pipes at locations corresponding to the outer peripheral parts of the packing material 8 with the slopes 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint sealing inspection apparatus.

[0002]

2. Description of the Related Art After a pipe joint formed of a cast iron pipe or the like is joined, a seal test called a test band is performed to check whether or not the joint is joined in a well-sealed state. The device is being used.

FIG. 3 conceptually shows a conventional sealing test apparatus of this kind. Here, reference numeral 1 denotes one of the cast iron pipes joined to each other, and a receiving port 2 is formed at the tip thereof. Reference numeral 3 denotes the other tube, and an insertion port 4 to be inserted into the receiving port 2 of the one tube 1 is formed at the tip of the other tube. 5
Is an annular rubber sealing material, and the inner peripheral surface of the receptacle 2 and the insertion port 4
Is arranged between the socket and the outer peripheral surface to seal the space between the sockets. When the sealing member 5 is pressed by the pressing mechanism 6, the inner peripheral surface of the receiving port 2 and the outer peripheral surface of the insertion port 4 are pressed against each other with a predetermined sealing surface pressure. This forms the joint of the pipe.

[0004] Reference numeral 7 denotes a conventional sealing test device, which is an annular rubber packing material 8 disposed from the inner surface of the receptacle 2 to the inner surface of the insertion opening 4, and which is disposed radially inward of the packing material 8. Further, there is provided an annular metal pressing plate 9 for pressing the packing material 8 against the inner surfaces of the receiving port 2 and the insertion port 4 in the circumferential direction.

According to such a configuration, an annular closed space 10 is formed between the receiving port 2 and the insertion port 4 on the outer peripheral side of the packing material 8, so that a pressurized state is formed in the space 10. A pressurized fluid such as water is injected, and the change in the pressure over time is inspected. If the pressure does not decrease over time,
It can be determined that the sealing state of the joint is good. When the pressure decreases with the passage of time, it is detected that leakage from the joint to the outside of the pipe has occurred, and therefore, it is possible to determine that the sealing state of the joint is poor.

[0006]

However, in such a conventional device, the packing material 8 is simply pressed uniformly by the pressing plate 9 along the pipe axis direction and tightened. In order to exert it, a considerably strong pressing force must be applied. Further, in some cases, there is a problem that it is necessary to retighten the packing material in order to exert a required sealing ability.

Accordingly, an object of the present invention is to solve such a problem and improve the sealing ability of the packing material.

[0008]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention provides an airtightness inspection apparatus for inspecting fluid leakage inside and outside of a pipe at a joint connecting one pipe and the other pipe. An annular packing material disposed from the inner surface of one tube to the inner surface of the other tube; and an annular presser disposed radially inward of the packing material and pressing the packing material against the inner surface of the tube in the circumferential direction. And the outer peripheral portion of the packing material has a gradient in a direction away from the inner surface of the pipe as approaching the tip of the packing material along the pipe axis direction when not being pressed by the pressing plate, The outer peripheral portion of the pressing plate has a gradient in a direction approaching the inner surface of the pipe as approaching the distal end portion of the pressing plate along the pipe axis direction at a position corresponding to the outer peripheral portion having the gradient in the packing material. It is obtained by the.

With such a configuration, the outer peripheral portion of the holding plate has a gradient in a direction opposite to that of the outer peripheral portion of the packing material. This packing material is pressed so as to eliminate the problem, and therefore, an even compressive force acts on the outer periphery of the packing material along the pipe axis direction, thereby increasing the overall sealing ability of the packing material. become. Moreover, the outer periphery of the packing material
As the packing material has a gradient in the direction away from the inner surface of the pipe as it approaches the tip end of the packing material along the pipe axis direction, the packing is based on the fact that the outer periphery of the holding plate has a gradient in the opposite direction to the outer circumference of the packing material. The more pressure is applied to the closed space formed by the material, the more strongly the tip side of the packing material is pressed against the inner surface of the pipe, and the greater the sealing effect of the packing material. In addition, since the outer peripheral portion of the packing material has a gradient, it is possible to cope with a case where the joint portion of the pipe is bent.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 and 2 by attaching the same reference numerals to the same members as those shown in FIG. . Here, the packing material 8 is formed by integrally forming a receiving side press contact portion 12, an insertion side press contact portion 13, and a tube axial connecting portion 14 connecting these press contact portions 12, 13 to each other. .
Three seal projections 15, 16, 17 are integrally formed on the outer periphery of the press contact portions 12, 13, respectively. These seal projections 15, 16 and 17 are each formed so that the cross section becomes triangular, and the outer diameter gradually decreases as approaching the tip of the packing material 8 along the pipe axis direction. That is, the projections 15, 16, 17 are formed so that their outer diameters become smaller in the order of the projections 15, 16, and 17 and are separated from the inner surfaces of the tubes 1, 3. As a result, the packing material 8 has a gradient 18 at a predetermined angle θ in a direction away from the inner surfaces of the pipes 1 and 3 as approaching the tip portion along the pipe axis direction at the outer peripheral portion. As shown in FIG. 1, when the packing material 8 is not compressed, the inner peripheral surfaces 36 of the press contact portions 12, 13 and the connecting portion 14 are formed by the same cylindrical surface parallel to the pipe axis. ing.

Reference numeral 30 denotes a pressing device, which has a support ring 31 having an annular frame structure. A cylinder device 32 is attached to the support ring 31 at a plurality of positions in the circumferential direction, and an annular holding plate 33 is attached to an extendable end of the cylinder device 32. The pressing plate 33 is divided into a plurality in the circumferential direction corresponding to the cylinder device 32. In the holding plate 33, a packing receiving portion 34 having a U-shaped cross section and a reinforcing rib 35 provided on the back side of the packing receiving portion 34, that is, on a radially inner side, are integrally formed by an aluminum casting or the like. It has a lightweight configuration. The above-described support ring 31 can also be formed of an aluminum casting or the like, so that the entire pressing device 30 can be made lightweight.

A packing receiving portion 34 for holding the packing material 8 in the pressing plate 33 of the pressing device 30 includes:
A gradient 37 is formed on the outer periphery of the packing material 8 at a position corresponding to the gradient 18, at an angle θ in a direction approaching the inner surfaces of the pipes 1 and 3 as approaching the tip of the holding plate 33 along the pipe axis direction. That is, the gradient 37 of the holding plate 33 is
It is formed in a direction opposite to the gradient 18 of the packing material 8. When the packing material 8 is not compressed, a gap 27 is formed between the end surface 25 of the packing material 8 and the end 26 of the packing receiving portion 34 along the tube axis direction.

In such a configuration, when inspecting the tightness of the pipe joint, the packing material 8 and the pressing device 30 are set at predetermined positions as shown in FIG. Then, as described above, the inner peripheral surface 36 of the packing material 8 is formed in a direction parallel to the pipe axis, and the packing receiving portion 34 of the holding plate 33 is formed with a gradient 37. As shown, the packing receiving portion 34 and the packing material 8 are in contact only at the corners at both ends of the packing material 8, and gaps 27 and 38 are formed between the packing receiving portion 34 and the packing material 8 in other portions. become.

For this reason, as shown in FIG. 2, when the cylinder device 32 is extended and the pressing plate 33 is moved radially outward, the rubber packing material 8 fills the gaps 27 and 38 to fill the inner peripheral surface. 36 is elastically deformed so as to contact the packing receiving portion 34 on the entire surface. As a result, the outer peripheral portion of the packing material 8 is deformed so that the gradient 18 is eliminated, so that an equal compressive force acts on all the seal protrusions 15, 16, and 17.

As a result, the overall sealing ability of the packing material 8 can be increased. The packing material 8
Since the outer peripheral portion has a slope 18, it is possible to cope with a case where the joint portion between the pipes 1 and 3 is bent. Further, in the compressed state of the packing material 8 shown in FIG. 2, when a fluid pressure is applied to the sealed space 39 on the outer peripheral side of the packing material 8 in order to inspect the sealing property of the joint portion, the packing material 8 is thereby moved to the pipe shaft. In the direction of elastic deformation, the force of which
Acts on 7. Then, due to the reaction from the gradient 37 at that time, the press-contact portions 12 and 13 of the packing material 8 become
3 is strongly pressed against the inner surface of the
The sealing ability of is improved.

That is, in this case, when a fluid pressure is applied to the closed space 39, the packing material 8 tries to expand outward along the pipe axis direction. 15, 16, and 17 are sequentially pressed against the inner surfaces of the pipes 1 and 3, thereby increasing the sealing effect of the receiving-side pressing portion 12 and the insertion-side pressing portion 13. Therefore, when a fluid pressure is applied to the closed space 39, the cylinder device 32
The required sealing performance can be exerted without retightening the packing material 8 by the above method.

[0017]

As described above, according to the present invention, when the outer peripheral portion of the packing material is not pressed by the pressing plate, the outer periphery of the packing material moves away from the inner surface of the pipe as it approaches the tip of the packing material along the pipe axis direction. Direction, and the outer peripheral portion of the presser plate approaches the inner surface of the pipe as it approaches the distal end portion of the presser plate along the pipe axis direction at a position corresponding to the outer peripheral portion of the packing material having the gradient. Since the outer peripheral portion of the holding plate has a gradient in the opposite direction to the outer peripheral portion of the packing material, the packing material is pressed against the inner surface of the pipe by the pressing plate. This packing material is pressed so as to eliminate the gradient, so that a uniform compressive force can be applied to the outer peripheral portion of the packing material along the pipe axis direction,
Thereby, the overall sealing ability of the packing material can be increased.

[Brief description of the drawings]

FIG. 1 is a detailed view of a main part of a pipe joint sealing inspection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an operation state of the airtightness inspection device.

FIG. 3 is a view conceptually showing a conventional pipe joint sealing inspection apparatus.

[Explanation of symbols]

 Reference Signs List 1 cast iron tube 3 cast iron tube 8 packing material 18 gradient 33 holding plate 37 gradient

Continued on the front page (72) Inventor Masayoshi Ozawa 2-16-1, Sakaemachi, Funabashi City, Chiba Prefecture Inside the Kubota Funabashi Plant (72) Inventor Tsune Suzuki 2-16-1, Sakaemachi, Funabashi City, Chiba Prefecture Stock Company Kubota Funabashi Factory

Claims (1)

[Claims] An airtightness inspection device for inspecting fluid leakage inside and outside of a pipe at a joint portion joining one pipe and the other pipe, wherein an inner surface of one pipe and an inner surface of another pipe are provided. And an annular pressing plate disposed radially inward of the packing material and pressing the packing material against the inner surface of the pipe in the circumferential direction, and an outer peripheral portion of the packing material. Has a gradient in a direction away from the inner surface of the pipe as it approaches the tip of the packing material along the pipe axis direction when not being pressed by the holding plate, and the outer peripheral portion of the holding plate is the packing material in the packing material. A pipe joint sealability inspection device, characterized in that at a position corresponding to an outer peripheral portion having a gradient, a gradient in a direction of approaching a pipe inner surface as approaching a tip end portion of a holding plate along a pipe axis direction is provided.