JP2001349500A - Leakage detecting device for bellows type expansion pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leakage detecting device for a bellows type expansion pipe joint capable of visually confirming the presence or absence of the leakage at a glance. SOLUTION: This leakage detecting device for the bellows type expansion pipe joint A used as a pipe joint mounted on the way of a piping for gas or liquid, and having a bellows type expansion part 3 with a double pipe structure composed of an inner pipe 1 and an outer pipe 2, and a pressure detecting means 8 for detecting the pressure in a leakage detecting path 6, comprises a casing 10 communicated to the leakage detecting path 6, and the pressure detecting means 8 having a pressure sensitive operating means 11 accommodated in the casing 10 and operated in increasing the pressure in the leakage detecting path 6, and a detector 12 being projected from the casing at its tip by the operation of the pressure sensitive operating means 11, and the detector is projected from the casing when the inner pipe is damaged, and the pressure in the piping is introduced into the leakage detecting path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detecting device for a bellows-type telescopic joint having a double-tube type bellows-type telescopic part mainly used for connecting a fluid transport pipe.

[0002]

2. Description of the Related Art In piping for transporting liquids, gases, etc.,
Heat, vibration, and the like are generated by the transport of the fluid, and a bellows type expansion joint A as shown in, for example, FIG.

This type of bellows-type telescopic joint A has a bellows-type telescopic part 3 having a double pipe structure composed of an inner pipe 1 and an outer pipe 2. Has been absorbed. Therefore, the burden on the bellows-type telescopic joint A is large, and the bellows-type telescopic portion 3 needs to be regularly inspected and repaired, and if leakage is confirmed during the inspection, it must be promptly replaced. However, since the bellows type expansion / contraction part 3 has a double pipe structure, if the inner pipe 1 is damaged, it is obstructed by the outer pipe 2 and cannot be visually checked. there were. Therefore, a leak detection path 6 is provided which communicates with the gap 5 between the inner pipe 1 and the outer pipe 2 of the expansion and contraction section 3, and a pressure detecting means 8 such as a pressure gauge 7 is connected to the leak detection path 6. In order to prevent sudden accidents by detecting the leakage of fluid due to pressure changes due to breakage of pipes, the maintenance of pipelines is planned.

[0004]

However, in the prior art as described above, in order to check for the presence or absence of leakage, it is necessary to continuously take pressure data and read and confirm changes in the pressure data. The data is the same fluid, the volume of the void in the expansion and contraction area, ie, the size of the bellows type expansion joint, the temperature of the transport fluid,
The value differs depending on the temperature and the like, and there is a problem that the inspection takes time.

[0005] In view of the situation of the prior art, the present invention
An object of the present invention is to provide a leak detection device for a bellows-type expansion joint that can visually detect leakage of the bellows-type expansion joint.

[0006]

SUMMARY OF THE INVENTION The features of the present invention for solving the conventional problems as described above and achieving the intended purpose are as follows.
A pipe joint having a bellows-type expansion / contraction part of a double pipe structure provided in the middle of a pipe for gas or liquid and comprising an inner pipe and an outer pipe, wherein the joint between the inner pipe and the outer pipe of the expansion / contraction part A leak detecting device for a bellows-type telescopic joint having a leak detecting path communicating with an air gap, and pressure detecting means for detecting pressure in the leak detecting path, wherein a casing communicated with the leak detecting path; Pressure sensing means which is housed in the housing and operates by increasing the pressure in the leak detection path, and a sensing operator whose tip projects out of the casing by the operation of the pressure sensing means. With
The inner pipe is damaged, and the pressure in the pipe is introduced into the leak detection path so that the detection operator protrudes from the casing.

The pressure-sensitive operating means includes a bottomed cylindrical bellows having an open end fixed in the casing and having a leak detection path communicated with the opening, and a pressure-sensitive member between the movable end of the bellows and the casing. It is preferable that a detecting operation element is interlocked with the moving-side end of the bellows, and the spring is a coil spring, and the coil spring is connected to the inner surface of the casing top and the bellows. Between the outer surface of the movable side end of the bellows, one end of the rod-shaped detection operation element is fixed to the movement side end of the bellows, and the other end is passed through the inside of the coil spring to the detection operation element outlet of the casing. Preferably, it is inserted.

The pressure-sensitive operating means may be constituted by a piston housed in a casing, and a spring interposed between the upper surface of the piston and the casing, and the detecting operator may be linked to the piston. .

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention.
2 will be described. Note that the same parts as those in the above-described conventional example are denoted by the same reference numerals and described.

In the figure, A is a bellows-type telescopic joint for connecting a fluid transport pipe, 3 is a bellows-type telescopic part, 6 is a leak detecting path, and 8 is a pressure detecting means.

The bellows-type telescopic joint A has a bellows-type telescopic part 3 having a double pipe structure composed of an inner pipe 1 and an outer pipe 2 as in the above-mentioned conventional example. A leak detecting path 6 is formed by providing a detecting pipe 9 communicating with a gap 5 between the outer pipe 2 and the outer pipe 2 on the surface of the outer pipe 2, and a pressure detecting means 8 is connected to the leak detecting path 6.

As shown in FIG. 1, a bellows-type pressure detector B is used for the pressure detecting means 8, and the bellows-type pressure detector B has a tubular casing 1 connected to a leak detection path 6.
0, pressure-sensitive operating means 11 which is accommodated in casing 10 and operates by increasing the pressure in leak detection path 6
And a detection operator 12 whose tip projects from the inside of the casing 10 by the operation of the pressure-sensitive operation means 11.

The casing 10 comprises a cylindrical portion 13 formed in a cylindrical shape having a bottom with an open upper side, and a lid portion 14 for closing the upper opening of the cylindrical portion 13. A connecting portion 15 is provided for communicating the casing 10 with the leak detection path 6 through the communication port 9, and a detection operator outlet 14 a into which the detection operator 12 is inserted is formed at the center of the lid 14.

The pressure-sensitive operating means 11 comprises a bellows 16 connected to the leak detection path 6 and a spring 17 interposed between the bellows 16 and the lid 14 of the casing. The bellows 16 is formed in the shape of a bellows cylinder with one end opened and a detection tube 9 is connected to an opening end thereof, and a rod-shaped detection operator 1 is provided on one end side upper surface.
2 is fixed. The spring 17 uses a coil spring.
Detector outlet 14 of casing lid 14 through the inside
a.

With this configuration, the bellows-type pressure detector B is normally urged downward by the spring 17 with the bellows 16 contracted in a bellows state, and is fixed to the moving-side end of the bellows 16 during normal operation. The detection operation element 12 is also retracted into the casing 10. In this state, the pressure-sensitive operation means is balanced by the pushing force by the pressure of the gas in the bellows and the pushing force by the spring. However, when the inner pipe 1 of the bellows-type expansion and contraction section 3 is broken such as a crack, and a pressure higher than the pressure in the gap is introduced from the transport pipe 4 into the gap 5, the pressure also increases in the bellows 14, As shown in FIG. 2, the bellows of the bellows 14 are stretched against the spring 17 and the detection operating element 12 is pushed up, and the detection operating element 12 protrudes from the casing 10 and the inner tube 1 is closed. Signal damage.
At this time, the pressure at which the pressure-sensitive operating means 11 operates is determined by the spring constant of the spring.

As the pressure detecting means 8, the pressure sensitive operating means 11 may be changed to the above-mentioned bellows type, and a piston type pressure detector C using a piston type may be used as shown in FIG.

The piston type pressure detector C includes a piston 20
And a pressure-sensitive operating means 11 composed of a spring 15 interposed between the upper surface of the piston 20 and the casing. The tip of the piston upper surface projects from the inside of the casing 10 by the operation of the pressure-sensitive operating means 11. Detector 12
Are provided to protrude. As a result, when a pressure higher than the pressure in the gap is introduced into the gap 5 due to the breakage of the inner pipe 1, the spring 15 as shown in FIG.
The detection operator 12 projects from the casing in conjunction with the piston 20 to notify the damage of the inner pipe 1.

The above-described pressure detecting means 11
Then, even if a volume change occurs in the gap 5 and the detector malfunctions, the valve 21 is opened to release the pressure, and the detection operator 12 is pushed in so that the normal state can be quickly restored. Has become.

[0019]

As described above, in the leak detecting apparatus for a bellows-type expansion joint according to the present invention, the casing communicated with the leak detecting path, and the pressure in the leak detecting path accommodated in the casing. Pressure sensing means having pressure sensing means which operates when the pressure rises, and a sensing action element whose tip projects from the inside of the casing by the operation of the pressure sensing action means. By introducing the pressure in the pipe into the passage, the detection operator is made to protrude from the inside of the casing. Unlike the case of using a pressure gauge, there is no need to continuously collect data, and it is possible to check the presence or absence of leakage at a glance, shorten inspection time, and use a bellows type telescopic pipe joint as shown in the data. It can be detected and small, in various cases without being affected by the temperature of the transport fluid.

The pressure-sensitive operating means includes a bottomed cylindrical bellows having an open end fixed in the casing and having a leak detection passage communicating with the opening, and a pressure-sensitive operating means disposed between the movable end of the bellows and the casing. The bellows is configured such that a detection operator is interlocked with the moving-side end of the bellows, the spring is a coil spring, and the coil spring is formed on the inner surface of the casing top and the outer surface of the moving-side end of the bellows. And one end of the rod-shaped detection operator is fixed to the moving-side end of the bellows, and the other end is inserted into the detection operator outlet of the casing through the inside of the coil spring. It reacts only when the pressure in the air gap changes greatly due to breakage of the inner tube, etc.
Further, the detection pressure is set according to the spring coefficient of the spring, and the set detection pressure can be easily changed by changing the spring to one having a different strength.

Further, by using a piston type pressure-sensitive operating means, the volume between the piston and the bottom of the casing is changed, the pressure after the operation is reduced, and the pressure-sensitive operating means is less likely to be burdened.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a pressure detecting means of a leak detecting device for a bellows type expansion joint according to the present invention.

FIG. 2 is a longitudinal sectional view showing an operation state (at the time of abnormality) of the pressure detecting means.

FIG. 3 is a longitudinal sectional view showing another embodiment of the pressure detecting means of the leak detecting device for a bellows type expansion joint according to the present invention.

FIG. 4 is a vertical cross-sectional view showing an operation state (at an abnormal time) of the pressure detecting means according to the first embodiment.

FIG. 5 is a longitudinal sectional view showing a conventional example of a leak detecting device for a bellows type expansion joint according to the present invention.

[Explanation of symbols]

 Reference Signs List A bellows-type telescopic joint B bellows-type pressure detector C piston-type pressure detector 1 inner pipe 2 outer pipe 3 bellows-type telescopic part 4 transport pipe 5 air gap 6 leak detection path 8 pressure detection means 9 detection pipe 10 casing 11 Pressure-sensitive operating means 12 Detecting operator 13 Cylindrical part 14 Lid 14a Detecting operator outlet 15 Connection 16 Bellows 17 Spring 20 Piston 21 Valve

Claims (4)

[Claims] 1. A pipe joint having a bellows-type expansion and contraction portion provided in the middle of a gas or liquid pipe and having a double pipe structure composed of an inner pipe and an outer pipe, wherein the inner pipe and the outer pipe of the expansion and contraction section are provided. A leak detecting device for a bellows-type telescopic joint, comprising: a leak detecting path communicating with a gap between the pipe and a pressure detecting means for detecting a pressure in the leak detecting path; A casing, a pressure-sensitive operation means housed in the casing and operated by increasing the pressure in the leak detection path, and a detection operator whose tip projects out of the casing by the operation of the pressure-sensitive operation means. A bellows-type, wherein the inner pipe is damaged and pressure in the pipe is introduced into the leak detection path so that the detection operator projects from the casing. Telescopic fittings Leak detection device. 2. A pressure-sensitive operating means, comprising: a bottomed cylindrical bellows having an open end fixed in a casing and having a leak detection path communicating with the opening; and a pressure-sensitive operating means disposed between the movable end of the bellows and the casing. The leak detecting device for a bellows-type telescopic joint according to claim 1, wherein the bellows-type telescopic joint is constituted by a spring interposed between the bellows and a detecting operator in conjunction with a moving-side end of the bellows. 3. A coil spring, wherein the coil spring is interposed between the inner surface of the top of the casing and the outer surface of the moving end of the bellows, and one end of a rod-shaped sensing element is moved to the moving end of the bellows. 3. The leak detecting device for a bellows-type telescopic joint according to claim 2, wherein the other end side is inserted into the detection operator outlet of the casing through the coil spring. 4. The pressure-sensitive operation means comprises a piston housed in a casing and a spring interposed between the upper surface of the piston and the casing, and a detection operator is linked to the piston. The leak detecting device for a bellows type expansion joint according to claim 1.