JPS6357992A - Expansion joint - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to piping of various high-temperature equipment (thermal power plants, chemical plants, etc.) and low-temperature equipment. Regarding fittings.

[Conventional technology]

In places where significant thermal expansion and contraction occurs due to temperature differences during operation, stoppage, or operation of equipment, such as piping of various high-temperature equipment (thermal power plants, chemical plants, etc.) and low-temperature equipment, Expansion joints are usually installed to prevent piping from deforming or breaking.

The above-mentioned expansion joints generally use bellows to absorb thermal expansion and contraction, but in the conventional joints, the bellows had a single-layer structure.

[Problem that the invention seeks to solve]

In the conventional type, the bellows had a single-layer structure, so if the internal fluid flowing through the expansion joint body is highly corrosive, the inner surface of the bellows, which is the stagnation part of the internal fluid, will corrode. There was a risk of damage and internal fluid leaking outside. In particular, if the internal fluid is flammable or toxic, the trouble caused when the bellows is damaged becomes serious.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an extremely safe expansion joint in which there is no risk of internal fluid leaking to the outside even if a portion of the bellows is damaged, thereby avoiding danger.

[Means for solving problems]

In order to solve the above-mentioned problems and achieve the object, the present invention takes the following measures. That is, the bellows attached to the expansion joint body are formed into a multilayer structure with a predetermined gap, and an inert gas having a pressure higher than the pressure of the internal fluid flowing through the expansion joint body is filled in the gap between the bellows. We decided to introduce . Note that it is desirable that the inert gas introduction means be equipped with pressure monitoring means.

[Effect]

By taking such measures, even if the inner bellows is damaged due to corrosion, the outer bellows will be directly exposed to the internal fluid due to the action of the high-pressure inert gas that exists between the outer bellows and the outer bellows. be prevented from being exposed. Therefore, there is no possibility that the internal fluid will leak to the outside.

If an inert gas monitoring means is provided, damage to the inner bellows can be detected by a drop in gas pressure, and the health of the outer bellows can be confirmed.

〔Example〕

FIG. 1 is a sectional view showing the structure of a first embodiment of the present invention. In FIG. 1, reference numerals 11.21 denote a pair of opposing flanges, and guide pipes 12.22 are provided at opposing ends of the pair of flanges 11.21, respectively. A collar 13.23 is attached to the outer periphery of the open end of each of these guide pipes 12.22. A bellows 30 is provided between these collars 13, 23. This bellows 30 has an inner bellows 31
and an outer bellows 32 are formed in a double structure with a predetermined gap. For example, He is present in the gap of the double-structured bellows 30, that is, between the inner bellows 31 and the outer bellows 32.

An inert gas such as Ar or even N2 is introduced into the gas introduction pipe 3.
It will be introduced through 3.

The pressure of this inert gas is set to be higher than the internal fluid flowing through the interior of the expansion joint body. Note that 40 is an inner cylinder, one end of which is joined to the inner circumferential surface of one of the guide pipes 12 via a weld bead 41.

In the expansion joint of this embodiment with the above configuration, the bellows 3
0 has a double structure consisting of an inner bellows 31 and an outer bellows 32, and high-pressure inert gas is introduced into the gap between them, so that the following effects are achieved. For example, even if the internal fluid is corrosive and damage occurs due to corrosion on the inner surface of the inner bellows 31 in the stagnation area between the inner bellows 31 and the inner bellows 31, the action of the high-pressure inert gas , the outer bellows 32 is not directly exposed to corrosive internal fluids. As a result, even if damage occurs to the inner bellows 31, trouble will not occur immediately, and it can be used safely for a considerable period of time.

FIG. 2 is a sectional view showing the configuration of a second embodiment of the present invention. The difference between this embodiment and the first embodiment is that after sealing an inert gas into the gap of the bellows 3o through a gas introduction pipe 33, a pressure gauge 34 is attached to the end of the gas introduction pipe 33.
The point is that the pressure drop of the enclosed inert gas is monitored.

According to this embodiment configured in this manner, not only the same operation and effect as in the first embodiment can be achieved, but also the pressure drop of the enclosed inert gas can be immediately recognized by the pressure gauge 34, so that damage to the inner bellows 31 can be prevented. can be detected accurately, and the degree of damage and the health of the outer bellows 32 can be confirmed based on the degree of pressure drop. Therefore, the preparation period for the replacement expansion joint can be appropriately secured.

Note that the present invention is not limited to the above embodiments. For example, in the above embodiment, the number of ridges of the bellows 30 is Mita, and the bellows 30 has a double structure of the inner bellows 31 and the outer bellows 32, but the number of ridges and the number of stacked bellows 30 are , of course, can be arbitrarily set depending on usage conditions and the like. Further, in the above embodiment, the present invention is applied to an expansion joint in which the bellows are installed at only one location, but it is also applicable to an expansion joint in which the bellows are installed at multiple locations. Furthermore, although the above embodiments have been described assuming that the internal fluid is gas, the present invention is not necessarily limited to gas, and the present invention is also applicable when the internal fluid is liquid. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, the bellows attached to the expansion joint main body is formed into a multilayer structure with a predetermined gap, and the pressure inside the gap of the bellows is higher than the pressure of the internal fluid flowing through the expansion joint main body. Inert gas is introduced, so even if the inner bellows is damaged due to corrosion, the high pressure inert gas that exists between the outer bellows and the outer bellows will prevent the inner fluid from flowing into the outer bellows. Direct exposure is prevented, and as a result, there is no risk of internal fluid leaking to the outside, making it possible to provide a highly safe expansion joint that can avoid danger.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of the first embodiment of the present invention, and FIG.
The figure is a sectional view showing a second embodiment of the present invention. 11.21...Flange, 12.22...Guide vibe, 13.23...Collar, 30...Bellows,
31...Inner bellows, 32...Outer bellows, 3
3... Gas introduction pipe, 34... Pressure gauge, 40... Inner cylinder, 41... Welding speed. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 2

Claims (2)

[Claims] (1) An expansion joint body, a bellows attached to the body and formed in a multilayer structure with a predetermined gap, and a pressure higher than the pressure of the internal fluid flowing through the expansion joint body in the gap between the bellows. An expansion joint characterized by comprising: an inert gas introducing means for introducing an inert gas having the following properties. (2) The expansion joint according to claim 1, wherein the inert gas introduction means includes pressure monitoring means.