JPH073864A - Leak detection method for vacuum line - Google Patents

Abstract

(57) [Summary] [Purpose] To identify the leak point P of the vacuum pipeline 1 and facilitate excavation work for repairing the leak point P. [Structure] Section valves V1 to V5 are provided at appropriate intervals in the vacuum pipeline 1.
Check line 6 is installed near each downstream side of each section valve.
And the pressure extraction line 4 near the upstream side.
A branch pipe, insert a plug 9 into the vacuum line 1 from the inspection line 6 of the upstream section valve V3 at the leak point P, and connect a vacuum system 12 to the pressure extraction line 4 of the downstream section valve V2 at the leak point P. Start, and intermittently advance the plug 9 toward the downstream side,
Air is supplied to the plug 9 to bring the stop position in close contact with the inner surface of the vacuum pipeline 1 stepwise closer to the downstream section valve V2, and the degree of vacuum between the plug 9 stop position and the downstream section valve V2 with the passage of time The leakage point P is specified by measuring the decrease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detecting method for a vacuum pipeline for detecting a leak location of a vacuum pipeline buried in the ground such as a vacuum sewer pipe.

[0002]

2. Description of the Related Art In a vacuum pipeline 1 such as an underground buried type vacuum sewer pipe shown in FIG. 7, for example, a plurality of section valves V1, V2, V3, V are provided at appropriate intervals from the downstream side of the vacuum pipeline 1.
4, V5 are interposed, and the section valve V is connected from the section valve V5 on the upstream side to the section valve V1 on the downstream side in the operating state of the vacuum pump 2.
Leakage point detection, which is performed by confirming that there is a leak point at a position upstream of the closed section valve by measuring a decrease in the degree of vacuum in the vacuum pipeline 1 while sequentially closing 4, V3 and V2. The method is known. According to this type of conventional leak point detection method, if there is a leak point P between the section valves V2 and V3, V5, V4, V
When the section valve is closed in the order of 3, V2, the section valve V5,
Even if V4 and V3 are closed, the degree of vacuum continues to drop, and the section valve V2
The vacuum level stops decreasing by closing the
The vacuum line 1 on the downstream side of 2 can be maintained at a predetermined vacuum degree. Therefore, it can be confirmed that the leakage point P exists in the vacuum pipeline 1 between the section valves V2 and V3. However, the leakage point P cannot be specified between the section valves V2 and V3. Therefore, there is a drawback that the excavation work for repairing the leakage point P is difficult.

[0003]

The problem to be solved is that it is difficult to identify the leaked portion, and it is difficult to perform excavation work for repairing the leaked portion.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a plurality of section valves are provided in a vacuum line at appropriate intervals, and a pressure extraction line is provided with a stop valve near the upstream side of each section valve. However, an inspection pipeline that is normally closed by a closing member is branched near the downstream side of each section valve, and a pair of section valves adjacent to each other at the upstream position and the downstream position are closed. A plug that opens an inspection pipe line in the vicinity and expands from here to an outer diameter that is in close contact with the inner surface of the vacuum pipe when fluid is supplied, and that elastically contracts to an outer diameter that allows forward and backward movement in the vacuum pipe when fluid is not supplied Is supplied to the vacuum pipe line in a fluid non-supply state, and a vacuum system is connected to the pressure take-out pipe line in the vicinity of the downstream side section valve upstream side of the pair of section valves to start the fluid supply operation to the plug. Fluid non-supply by repeating fluid non-supply operation During operation, the plug is moved forward intermittently, and while gradually approaching the plug stop position during fluid supply operation to the downstream section valve, the degree of vacuum between the plug stop position and the downstream section valve is measured and the distance between the pair of section valves is increased. The feature was to identify the leaked part of the vacuum pipe line of, and to achieve the purpose of facilitating the excavation work to repair the leaked part.

[0005]

According to the present invention, the plug is intermittently advanced from the upstream side of the pair of section valves toward the downstream section valve, and the plug stop position at the time of fluid supply operation is gradually approached to the downstream section valve. On the other hand, by measuring the decrease in the degree of vacuum with the passage of time between the plug stop position and the downstream section valve, and confirming the position where the decrease in the degree of vacuum has stopped, the stop position where the decrease in the degree of vacuum stopped and the It is possible to specify that there is a leakage point between the stop positions in front of the steps.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a piping system diagram showing an embodiment of the present invention. It should be noted that the same or corresponding portions as those in the conventional example will be described by attaching the same reference numerals. In FIG. 1, a plurality of section valves V1, V2, V3 are provided at appropriate intervals from the downstream side of the vacuum pipeline 1.
V4, V5 are installed, and each section valve V1, V2, V3, V
4, the pressure extraction pipe line 4 provided with a shutoff valve 3 near the upstream side of each of V4 and V5 is branched, and each section valve V1, V2, V3.
An inspection pipeline 6 that is normally closed by the closing member 5 is branched near the downstream side of each of V4 and V5. The inner diameter of the inspection pipeline 6 is set to a value equal to the inner diameter of the vacuum pipeline 1.

On the other hand, as shown in FIG.
When air is supplied by the manual pump 8 via the inside of the vacuum pipeline 1 as shown in FIG. 3, it expands to an outer diameter that closely adheres to the inner surface of the vacuum pipeline 1 and removes air. A plug 9 that is elastically contracted to an outer diameter that can be moved back and forth is provided, and the tip of a wire 11 that is fed or wound from a winch 10 is connected to this plug 9.

In such a structure, it is assumed that the section valve V
If there is a leakage point P between 2 and V3, V
When closing the interval valve in the order of 5, V4, V3, V2,
Even if the section valves V5, V4, and V3 are closed, the degree of vacuum continues to decrease, and by closing the section valve V2, the degree of vacuum is stopped, and the vacuum pipe line 1 downstream of the section valve V2 can be maintained at a predetermined degree of vacuum. . Therefore, the leakage point P is the section valve V2.
It can be confirmed that it exists in the vacuum line 1 between V3 and V3.

If it is confirmed that the leakage point P exists in the vacuum line 1 between the section valves V2 and V3, with the section valves V2 and V3 closed, the vicinity of the section valve V2 upstream side as shown in FIG. The vacuum pump 12A and the intake pipe 12 are connected to the pressure extraction line 4 of
B, a vacuum system 12 equipped with a vacuum valve 12CT joint 12D, a vacuum gauge 12E, etc. is connected, the vacuum pump 12A is operated, and the inspection pipeline 6 near the downstream side of the section valve V3 is opened. That is, the closing member 5 is removed. Then, as shown in FIG. 5, the plug 9 elastically reduced in diameter while feeding the wire 11 from the winch 10 is pulled from the inspection pipe line 6 to the vacuum pipe line 1.
Insert inside.

The elastically reduced diameter plug 9 inserted into the vacuum conduit 1 keeps feeding the wire 11.
Due to the pressure difference between the upstream side and the downstream side in the vacuum conduit 1 caused by the operation of the vacuum pump 12A, the vacuum pump 1 advances toward the downstream side. When the plug 9 has advanced to an appropriate position, the feeding of the wire 11 by the winch 10 is stopped, and the air is supplied to the plug 9 through the pressurizing hose 7 by the manual operation of the manual pump 8. As a result, the plug 9 expands and comes into close contact with the inner surface of the vacuum conduit 1 as shown in FIG.
Then, the operation of the vacuum pump 12A is stopped. Assuming that FIG.
If there is a leaking point at point P in the vacuum pipe line 1 between the plug 9 and the section valve V2 shown in (4), the degree of vacuum decreases with time and can be read by the scale of the vacuum gauge 12E.

When such a phenomenon occurs, the leakage point P is located closer to the section valve V2 than the close contact position of the plug 9. Therefore, a valve (not shown) provided on the connection side of the manual pump 8 in the pressurizing hose 7 is omitted.
Open, the plug 9 is once elastically reduced in diameter as shown in FIG. 3, and the operation of the vacuum pump 12A is restarted.
Is advanced to an appropriate position, and the plug 9 is expanded here to be brought into close contact with the inner surface of the vacuum line 1 and then the vacuum pump 1
By repeating the above-described work of stopping the operation of 2A, the plug 9 is intermittently advanced and stopped to the virtual line a position, the virtual line b position, the virtual line c position, and the virtual line d position in FIG. . As a result, even if the plug 9 is brought into close contact with the inner surface of the vacuum pipeline 1 by expanding it at the position of the imaginary line d passing through the leakage point P, and then the operation of the vacuum pump 12A is stopped, the degree of vacuum does not decrease with time. . That is, the leakage point P in the vacuum line 1 between the section valves V2 and V3
Is present between the virtual line c position and the virtual line d position. Therefore, excavation work for repairing the leakage point P becomes easy.

After the leakage point P is specified, the plug 9 is elastically reduced in diameter by the same operation as described above, and the wire 11 is wound by the winch 10 to remove the plug 9 from the vacuum pipeline 1 and the inspection pipeline 6. The inspection line 6 may be closed by the closing member 5.

[0013]

As described above, the present invention has the advantage of facilitating excavation work for repairing a leak location because the leak location can be specified even if a leak occurs in the vacuum pipeline. Have.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a state in which the plug expands and is in close contact with the inner surface of the vacuum conduit.

FIG. 3 is an enlarged cross-sectional view of a plug elastically reduced in diameter so that it can be moved back and forth in a vacuum conduit.

FIG. 4 is an enlarged cross-sectional view showing a connected state of a vacuum system.

FIG. 5 is an enlarged cross-sectional view showing a state in which the plug is inserted into the vacuum pipeline from the inspection pipeline.

FIG. 6 is an operation explanatory diagram for identifying a leaked portion.

FIG. 7 is a piping system diagram of a conventional example.

[Explanation of symbols]

 1 Vacuum pipeline 3 Closing valve 4 Pressure extraction pipeline 5 Closing member 6 Inspection pipeline 9 Plug 12 Vacuum system P Leakage point V1-V5 Section valve

Claims (1)

[Claims] 1. A pressure extraction pipeline having a plurality of section valves interposed at appropriate intervals in a vacuum pipeline, and a stop valve provided near the upstream side of each section valve, and branched piping, and downstream of each section valve. The inspection pipeline that is normally closed by the closing member is branched near the side, and the inspection pipeline near the upstream side section valve downstream side is opened with a pair of section valves adjacent at the upstream position and the downstream position closed, From here, the plug that expands to an outer diameter that closely adheres to the inner surface of the vacuum pipeline when supplying fluid and elastically contracts to an outer diameter that allows forward and backward movement in the vacuum pipeline when not supplying the fluid is used in the vacuum tube in the non-fluid state A vacuum system is connected to the pressure extraction pipe line near the upstream side of the downstream side section valve in the pair of section valves and is activated by repeating the fluid supply operation and the fluid non-supply operation to the plug. Intermittently advance plug during non-supply operation While gradually advancing the plug stop position during fluid supply operation toward the downstream section valve, measure the degree of vacuum between the plug stop position and the downstream section valve to identify the leak point in the vacuum line between the pair of section valves. A method for detecting leaks in a vacuum line characterized by specifying.