JPH0636395Y2 - Expansion joint device for piping - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an expansion joint device for piping, and more particularly to an expansion joint device for piping having a double bellows structure used for a fluid having strong reactivity or a fluid mixed with slurry.

Technical background of the invention and its problems The expansion joint device for piping installed in the piping line absorbs the expansion and contraction of the pipe in the axial direction or the displacement in the direction perpendicular to the axis to protect the pipe and the joint flange attached to the pipe. ing. A bellows is used in this expansion joint device for piping to absorb expansion and contraction and displacement of the piping. The bellows include a metal welded bellows made by alternately welding the inner diameter and the outer diameter of a washer-like metal plate obtained by press-molding a thin metal plate, and a so-called formed bellows formed by hydraulically or rolling a thin metal pipe.

However, the welded bellows has an advantage that it is superior in pressure resistance to the molded bellows, and structurally, the stress generated in the bellows can be reduced, and thus the durability is also excellent.

However, when a fluid containing slurry or a fluid with high viscosity flows, foreign matter enters the expansion and contraction recesses of the welded bellows, and the expansion and contraction that is the role of the bellows cannot be performed. Abnormal bending stress may act and the bellows may eventually break.

Therefore, conventionally, as shown in Japanese Utility Model Publication No. 49-9776,
A pipe expansion joint device having a structure in which a cylindrical cloth having flare portions at both ends is fitted and inserted inside a welded bellows, and the flare portions are sandwiched and fixed by a pipe joint flange is preferably used. By thus inserting the cylindrical cloth into the inside of the welded bellows, it is possible to prevent the entry of impurities such as slurry and to follow the expansion and contraction and displacement of the bellows. Since it is made of woven fabric, especially when a dangerous fluid with strong reactivity flows through the equipment, if the welding bellows is damaged due to fatigue in the event that the fluid penetrates through the woven fabric, it may cause serious damage. May cause problems.

Further, in particular, when using such a pipe expansion joint device in the food and bio fields and cleaning the inside of the pipe, if there is a cylindrical cloth made of woven cloth, the cleaning effect remains poor. .

The purpose of the present invention is to solve the above disadvantages of the prior art, and it is possible to secure the safety even for a highly reactive dangerous fluid, and to flow a fluid containing a slurry. Even in such a case, it is an object of the present invention to provide an expansion joint device for a pipe, in which expansion and contraction of the bellows can be expanded and contracted favorably without being clogged with foreign matter, and sterilization and cleaning of the inside of the pipe can be easily performed.

SUMMARY OF THE INVENTION In order to achieve such an object, the present invention provides a pair of pipes connected to other pipes or equipment with an inner bellows which is a stretchable molded bellows and constitutes a part of a flow path. , A metal thin plate is punched into a hollow disk shape, and comprises an expandable metal welded bellows in which the inner peripheral edge and the outer peripheral edge are alternately welded in the axial direction, and an outer bellows surrounding the inner bellows. It is characterized in that it is doubly connected and a sealed space is formed between the inner bellows and the outer bellows.

According to the expansion joint device for piping according to the present invention,
Since the inner bellows, which is in contact with the fluid flowing inside the device, is formed by the molded bellows, even if the fluid contains impurities such as slurry, the impurities are not caught in the expansion / contraction recesses. It is possible to effectively prevent breakage of the bellows. Further, since the portion in contact with the fluid is the molded bellows, foreign matter is unlikely to adhere to this bellows, and even if it adheres, foreign matter can be easily washed.

Moreover, in the expansion joint for piping according to the present invention, the metal welded bellows excellent in pressure resistance and repeated life are arranged on the outside of the molded bellows, and the sealed space is formed between these bellows. Even if the molded bellows breaks and the internal fluid leaks, the metal welded bellows can prevent the fluid from flowing out. If the sealed space is filled with an inert gas such as N ₂ or Ar, it can be used, for example, as an expansion joint device for pipes in which a special fluid that explodes when it reacts with air flows. If the leak detecting means is installed at the tip of the through hole communicating with the space, it is possible to easily detect the abnormality of the bellows.

Detailed Description of the Invention Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a sectional view of an essential part of an expansion joint device for piping according to an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part of an expansion joint device for piping according to another embodiment of the present invention.

In the expansion joint device 2 for piping shown in FIG. 1, a pair of short pipes 4,
4 are connected via an inner bellows 6 and an outer bellows 8 mounted on the outer circumference thereof. In the figure,
Although these bellows 6 and 8 are partially omitted, they are actually continuous in the axial direction. At one end of each short pipe 4,4 is a flange for connecting to other pipes or equipment.
10 and 10 are joined or formed. In addition, each short pipe 4,4
Both ends of the inner bellows 6 are joined to the other end of the inner bellows 6.

Further, disc-shaped outer bellows receivers 12 and 12 are attached to the outer circumferences of the short pipes 4 and 4, and disc-shaped support holders 14 and 14 are joined so as to closely contact the outer sides of the disc-shaped bellows. Has been done. Both support holders 14 and 14 have an outer diameter larger than that of the outer bellows receivers 12 and 12, and are erected by connecting rods 16 arranged at a plurality of positions in the circumferential direction. This connecting rod 16
The threaded portions 16a, 16a formed on both ends of the support holder 14 are loosely inserted into the through holes 18, 18 formed on the outer periphery of the support holder 14, and the double nuts 20 are screwed so that they are located on both sides of each support holder 14. It is supposed to meet. Such a connecting rod 16 is for adjusting the expansion / contraction allowance of the bellows 6, 8 by adjusting the screwing position of the double nut screwed to the threaded portion.

Both ends of the outer bellows 8 are joined to the outer periphery of the outer bellows receiver 12, and a sealed space 22 is formed between the outer bellows 8 and the inner bellows 6.

In the present invention, the inner bellows 6 comprises a molded bellows. The molded bellows is formed by integrally molding a cylindrical body made of metal or synthetic resin into a bellows shape by means of blow molding, rolling molding, cutting, hydraulic molding or the like.

Further, in the present invention, the outer bellows 8 is made of a metal welded bellows. The metal welded bellows is obtained by punching a thin metal plate into a predetermined disc shape and subjecting it to concavo-convex processing, and alternately welding the inner edge and the outer edge thereof in the axial direction. In addition, the reason why the metal thin plate is subjected to the uneven processing is to increase the elasticity of the metal welded bellows.

In the present invention, the sealed space 22 is formed between the outer bellows 8 and the inner bellows 6 as described above.
The gas can also be filled with an inert gas such as N ₂ gas or Ar gas. Further, preferably, one of the bellows receivers 12 is formed with a through hole 24, and a leak detecting pipe 26 as a leak detecting means is communicated with the through hole 24.
The pressure in the sealed space 22 may be detected through 26. In this case, if the molded bellows 6 breaks and the internal fluid flows into the sealed space 22, this leak can be detected. In this case, since the outer bellows 8 is mounted on the outer peripheral side, the internal fluid does not leak outside the device.

According to the expansion joint device 2 for a pipe according to the present embodiment as described above, since the inner bellows 6 in contact with the fluid flowing inside the device 2 is formed by the molded bellows, the fluid contains impurities such as slurry. Even if it does, the foreign matter will not be caught in the expansion / contraction recess 6a, and therefore the breakage of the bellows can be effectively prevented. Further, since the portion in contact with the fluid is the molded bellows, foreign matter is unlikely to adhere to this bellows, and even if it adheres, foreign matter can be easily washed.

Moreover, in such an expansion joint 2 for piping, an outer bellows 8 made of a welded bellows excellent in pressure resistance and repeated life is arranged outside the inner bellows 6 made of a molded bellows. Sealed space between 22
Since the inner bellows 6 is formed, even if the inner bellows 6 is damaged and the internal fluid leaks, the outer bellows 8 made of the welded bellows can prevent the fluid from flowing out. Then, if the sealed space 22 is filled with an inert gas such as N ₂ or Ar, for example, it can be used as an expansion joint device for a pipe in which a special fluid that explodes when it reacts with air flows. If a leak detecting pipe 26 as a leak detecting means is connected to the tip of the through hole 24 communicating with the sealed space 22, the abnormality of the bellows can be easily detected.

It should be noted that the present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the present invention.

For example, as shown in FIG. 2, when the expansion joint 2a for piping according to the present invention has a long axial length, two or more inner bellows 6, 6 arranged in series in the axial direction are used. The inner short pipe 30 is joined between the two, and the outer short pipe 32 is joined via the flange portion 34 between the two or more outer bellows 8, 8 arranged in series on the outer side thereof in the axial direction. May be. Such a piping expansion joint 2a is also within the scope of the present invention.

Further, according to the present invention, the flange 10 formed or joined to one end of the short pipes 4, 4 provided at both ends of the device 2, 2a.
Is not necessarily essential, and may be another joint member.

Effect of the Invention As described above, according to the pipe expansion joint of the present invention, since the inner bellows in contact with the fluid flowing inside the device is formed by the molded bellows, the fluid contains impurities such as slurry. Even if it is included, this foreign substance is not caught in the expansion and contraction concave portion, and therefore the breakage of the bellows can be effectively prevented. Further, since the portion in contact with the fluid is the molded bellows, foreign matter is unlikely to adhere to this bellows, and even if it adheres, foreign matter can be easily washed.

Moreover, in the expansion joint for piping according to the present invention, the metal welded bellows excellent in pressure resistance and repeated life are arranged on the outside of the molded bellows, and the sealed space is formed between these bellows. Even if the molded bellows breaks and the internal fluid leaks, the metal welded bellows can prevent the fluid from flowing out. If the sealed space is filled with an inert gas such as N ₂ or Ar, it can be used, for example, as an expansion joint device for piping in which a special fluid that explodes when it reacts with air flows. If the leak detecting means is installed at the tip of the through hole communicating with the space, it is possible to easily detect the abnormality of the bellows.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an expansion joint device for piping according to an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part of an expansion joint device for piping according to another embodiment of the present invention. 2,2a …… Expansion joint for piping 4 …… Short pipe 6 …… Inner bellows, 8 …… Outer bellows

Claims (1)

[Scope of utility model registration request] 1. A pair of pipes connected to other pipes or devices, an inner bellows formed of a stretchable molded bellows and forming a part of a flow path, and a metal thin plate punched into a hollow disc shape. Along with
It consists of a stretchable metal welded bellows whose inner peripheral edge and outer peripheral edge are alternately welded in the axial direction, and is doubly connected with an outer bellows surrounding the inner bellows, and between the inner bellows and the outer bellows. An expansion joint device for piping, characterized in that a sealed space is formed in the interior.