JP3160733B2 - Water leak detection method for impermeable structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting leakage of water from a water-blocking structure having electrical insulation, such as a waste disposal tank or a water storage tank.

[0002]

2. Description of the Related Art As a water impermeable structure, a water storage tank and a final disposal site using a water impermeable sheet are known. The following method is known as a method for detecting water leakage in this type of impermeable structure.

<1> Electrodes are installed inside and outside the water-blocking structure, and the inner electrode and the current sensor are integrally movable so that the inner electrode is appropriately moved while applying a voltage between the two electrodes. A method of detecting the position of water leakage from the direction of the current flowing from the inner electrode.

<2> Electrodes are fixedly installed inside and outside the water-impermeable structure, and a plurality of current vector sensors are installed at predetermined positions inside the water-impermeable structure. A method of measuring the magnitude and direction of current at a sensor installation position and calculating a water leakage position.

[0005]

Problems to be Solved by the Invention The above-mentioned conventional water leak detection method has the following problems. <A> In the method of <1>, it is necessary to move the current sensor for measurement. In other words, it is necessary to perform operations such as mounting the current sensor in the waterborne moving object (ship) and moving the waterborne moving object, and the work process requires a great deal of time and labor. In addition, it cannot be applied to final disposal sites where fixed objects are landfilled.

<B> In the method of <2>, it is necessary to detect disturbance in the current direction due to the damaged hole with two or more sensors. That is, it is necessary to previously install a large number of sensors at appropriate intervals in the water-blocking structure, and the installation work is complicated.

[0007]

[Object of the present invention] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make measurement work easy by installing only one current direction sensor in a water-blocking structure. It is an object of the present invention to provide a method for detecting water leakage in a water-impervious structure that can be performed easily.

[0008]

Means for Solving the Problems That is, the present invention relates to a water-blocking structure having an electrically insulating property, in which a current direction sensor is installed in the water-blocking structure and switched to the inside of the water-blocking structure. After embedding a plurality of possible internal electrodes, embedding an external electrode outside the impermeable structure, applying a voltage between one internal electrode and the external electrode, measuring the current vector with a current direction sensor, and then A method for detecting a water leak in a water-blocking structure, comprising: measuring a change in a current vector indicated by a current direction sensor by switching to an internal electrode, and detecting the presence or absence of a leak based on whether or not the current vector has changed. .

[0009]

An embodiment of the present invention will be described below with reference to the drawings. <A> Water-impervious structure Fig. 1 shows the case where the water-impervious structure is a final disposal site. This water-impervious structure 60 has a water-impervious sheet 6 in a hole dug in the ground.
1 is laid. The water shielding sheet 61 is formed of a sheet having an electrically insulating property. Impermeable structure 60
Inside, a gas vent pipe 62 having a perforated structure for discharging gas generated from the waste 63 is installed in advance.

<B> Configuration of Water Leak Detection Device (FIG. 1) FIG. The water leak detection device 10
It comprises an internal electrode 20, an external electrode 30, a current direction sensor 40, and a control unit 50. Hereinafter, each part will be described in detail.

<C> Electrodes (FIG. 1) The internal electrodes 20a and 20b are embedded in the waste 63 to be deposited and connected to the control unit 50. External electrode 30
Is buried in the ground around the impermeable structure 60 and the control unit 5
0 is connected. Internal electrode 20a or internal electrode 20
The control unit 50 is configured to apply a constant voltage between “b” and the external electrode 30. In addition, the configuration is such that the current supply circuit between the external electrode 30 and the internal electrode 20a or the internal electrode 20b can be arbitrarily switched.

<D> Control Unit 50 (FIGS. 1 and 2) The control unit 50 includes a constant voltage power supply 51, an oscillation circuit 52, a vector measurement circuit 53, and a switch 54. The constant voltage power supply 51 supplies a bias voltage to each circuit, and also supplies a voltage to be applied between one of the internal electrodes 20a and 20b and the external electrode 30. Oscillation circuit 5
Reference numeral 2 denotes a circuit that supplies a timing signal to a vector measurement circuit 53 described later. The vector measurement circuit 53 is a circuit that analyzes a current signal of the sensor 40 described later in the X direction and the Y direction separately, and analyzes the current values in the X direction and the Y direction to determine the current direction at the sensor installation position. You can ask. The vector measurement circuit 53 is a signal processing circuit for a current signal, and is configured by sequentially connecting a current-voltage conversion circuit, a filter amplifier, a gate circuit, and a smoothing circuit. Is equipped.

<E> Sensor (FIG. 2) As the sensor 40, for example, a known sensor capable of measuring current values in the X and Y directions orthogonal to each other as shown in FIG. 2 can be employed. The sensor 40 is inserted into an existing gas vent tube 62.

[0014]

Next, a method for detecting water leakage will be described. <A> Installation of water leakage detection device The internal electrode 20a and the internal electrode 20b
Buried inside. It is preferable that the burying position is buried at a symmetric position with respect to the gas vent pipe 62. Next, the external electrode 3
0 is buried in the ground outside the impermeable structure 60. Then, the sensor 40 is inserted into the existing vent pipe 62. Since the lower end of the gas vent pipe 62 reaches near the bottom surface of the water shielding structure 60, the sensor 40 can be installed near the water shielding sheet 61 via the gas vent pipe 62.

<B> Measurement of Current Direction The internal electrode 20a and the external electrode 3
A voltage is applied between zero. At this time, the current value in the X direction and the Y direction is detected by the sensor 40, and the current vector in the X direction and the Y direction of the current value is measured via the current-voltage conversion circuit, the filter amplifier, the gate circuit, and the smoothing circuit. If the current vectors in the X and Y directions are obtained, the current directions can be obtained by simple drawing or calculation.

<C> The internal electrode pressurizing switch 54 is operated to set the internal electrodes for pressurizing the voltage to two.
Switch from 0a to 20b. Then, the current direction is measured in the same manner as in <b>.

<D> No Water Leakage (FIG. 3) When there is no breakage opening 70 in the impermeable sheet 61 and no waste 63 leaks from the impermeable structure 60, as shown in FIG.
The current flows from the internal electrode 20a or the internal electrode 20b in a direction such that the current spreads over the entire impermeable structure 60, and the state of this flow is uniquely determined by the positions of the internal electrodes 20a and 20b and the shape of the impermeable structure 60. .

<E> At the time of water leakage If there is a breakage hole 70 in the water-blocking sheet 61 and the waste 63 leaks from the water-blocking structure 60, the electric current passes through the inside of the breakage hole 70 to the internal electrode 20 a or 20 b. It flows between the external electrodes 30. Therefore, the direction of the current detected by the sensor 40 is the same as the direction of the electric lines of force formed between the internal electrode 20a or 20b and the breakage opening 70. Therefore,
Since the current direction is different from that at the time of non-water leakage, it can be confirmed that the water shielding sheet 61 is leaking. The position of the damage port 70 can be confirmed from the current direction indicated by the sensor 40.

[0019]

As described above, the present invention has the following effects. <B> A sensor can be provided in a gas vent pipe already provided in the water-blocking structure. For this reason, since it is not necessary to separately provide a sensor arrangement hole, the measurement operation in the current direction can be easily performed.

<B> Unlike the conventional case, the sensor does not need to be moved, and the presence or absence and the position of the damaged opening can be measured with one sensor, so that the measurement work does not require time and labor.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a water leakage detection device.

FIG. 2 is an explanatory diagram of a sensor and a vector measurement circuit.

FIG. 3 is an explanatory diagram of current direction measurement.

FIG. 4 is an explanatory diagram of current direction measurement.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-134237 (JP, A) JP-A-3-29830 (JP, A) JP-A-1-17843 (JP, A) JP-A-5-208 18849 (JP, A) The 81st Annual Meeting of the Japan Society of Geospatial Exploration, January 11, 2001 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 3/16

Claims (1)

(57) [Claims] 1. A water-impervious structure showing electrical insulation, wherein a current direction sensor is installed in the water-impervious structure, and a plurality of switchable internal electrodes are embedded inside the water-impervious structure. An external electrode is buried outside the impermeable structure, a voltage is applied between one internal electrode and the external electrode, and the current vector is measured by the current direction sensor. A method for detecting water leakage in a water-impervious structure, comprising: measuring a change in a current vector indicated by (a), and detecting the presence or absence of water leakage based on whether or not the current vector has changed.