JPH09280992A - Detecting system for leakage occurrence position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting system for leakage occurrence position capable of accurately detecting leakage occurrence position in a short time in a management type wastewater treatment plant. SOLUTION: Sets of wire electrodes A1 to A5, B1 to B5 of upstream and downstream of a water shielding film 10 are sequentially selected, and the current flowing between the electrodes of each set is phase detected by the same phase as or 90-degree different phase from the two-phase AC power source 15 by first and second phase detectors 16, 17. A squaring circuit 18 receives the output of the detector 16, outputs the square value. A divider 19 divides the output from the circuit 18 as a numerator by the output from the detector 17 as a denominator. As a result, in the case of the combination of the electrode near the leakage occurrence position due to the damage of the film 10, the output of the divider 19 is raised from the value between the other electrodes, thereby detecting the leakage occurrence position.

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 a water leakage generation position in a managed final disposal site constructed by installing a water-blocking film such as synthetic resin or synthetic rubber sheet or asphalt.

[0002]

2. Description of the Related Art Conventionally, in an artificial management type final treatment plant using a water-blocking membrane, the water-blocking membrane may be damaged by cracks or the like and the contaminated liquid in the treatment plant may leak. When water leakage occurs, groundwater pollution and pollution problems will occur. Therefore, it is necessary to regularly inspect the water-blocking membrane and, if damage occurs to the water-blocking membrane, detect the leaked location and perform appropriate repairs.

The following method is known as a method of detecting the position of water leakage of such a water-blocking film. A fixed electrode is installed in the ground below the water blocking film, and an application electrode is arranged on the ground surface above the water blocking film, and a voltage is applied between the fixed electrode and the application electrode. Multipoint measurement is performed while moving the potential generated by the current flowing from the applying electrode toward the water-blocking film at predetermined intervals by using a measuring electrode connected by a floating cord or the like. Then, an equipotential curve is drawn from the potential at each measurement point, and when a part of this equipotential curve is disturbed, this disturbed portion is detected as a water leakage occurrence point.

[0004]

However, in the above-mentioned conventional leakage position detecting method, the coordinates of the measurement point must be accurately obtained and the measurement electrode must be finely moved before measurement.
A slight disturbance of the potential at the location of water leakage does not appear on the equipotential curve. For this reason, when the area of the management-type terminal treatment plant is large, the number of potential measurement points becomes enormous, and there is a drawback that the measurement takes a considerable period of time.

Further, in the conventional method, since the electric potential is measured on the ground surface, the electric current flowing on the ground surface decreases when the water-blocking sheet is deep, so that the electric potential generated on the ground surface becomes weak and the location of water leakage is detected. It had the drawback of becoming difficult.

An object of the present invention is to provide a new detection technique which does not have such drawbacks.

[0007]

According to the present invention, in a control type final disposal plant constructed by installing a water-blocking film, the water-blocking film is arranged parallel to the upper side of the water-blocking film at a predetermined interval. A plurality of wire-shaped electrodes, a plurality of wire-shaped electrodes arranged parallel to the lower side of the water-blocking film and at a predetermined interval so as to be orthogonal to the upper wire-shaped electrode, an AC power supply, and this AC power supply Selection switching means for sequentially applying the above voltage to each one arbitrary set of the upper and lower wire electrodes, and a current detection circuit for detecting a current flowing between the upper and lower wire electrodes. And a first phase detection circuit that receives the output of the current detection circuit and performs phase detection at the same phase as the applied voltage; and that receives the output of the current detection circuit and performs phase detection at a phase that is 90 degrees ahead of the applied voltage. A second phase detection circuit for performing the first phase detection circuit;
A square circuit for receiving the output of the phase detection circuit and outputting the squared value thereof, and the output of the square circuit as the numerator,
A division circuit that outputs the result of dividing the output of the squaring circuit by the output of the second phase detection circuit with the output of the phase detection circuit as the denominator, and includes a set of the upper and lower wire-shaped electrodes. The currents flowing between the electrodes of each set are sequentially selected and the phase detection is performed in two phases. When the combination of the electrodes is close to the position where water leakage occurs due to the breakage of the water shield film, the output of the division circuit is changed to another. A leakage water generation position detection method characterized in that the leakage water generation position is detected because it rises above the value between the electrodes is obtained.

[0008]

In the above method, wire-shaped electrodes are arranged on the upper side and the lower side of the water-blocking film at a predetermined interval, and the upper and lower electrodes are respectively set to 1
By sequentially selecting each one, the currents flowing between the upper and lower electrodes are subjected to phase detection at phases different from each other by 90 degrees, and the squared output of the first phase detection circuit is divided by the output of the second phase detection circuit. Therefore, by correcting the non-uniformity of electric conductivity inside the disposal site, it becomes possible to accurately detect the damaged position of the impermeable film in the ground over a wide range.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, preferred embodiments of a water leakage generation position detecting method according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a water leakage occurrence position detection method according to the present invention. Incidentally, the water leak occurrence position detection is to detect the water leak in the flat portion of the bottom of the water shield film, and is not applied to the surrounding vertical portion. Refers to the flat part.

In this example, a plurality of wire electrodes A1 to A5 (here, five for convenience) are arranged in parallel to each other on the upper side of the water-blocking film 10 and on the lower side thereof. Wire electrode B so as to cross with
1 to B5 are arranged in parallel with each other over the entire length of the water shield film 10. The output of the two-phase AC power supply 11 is power-amplified by the power amplifier circuit 12, passes through the current detection circuit 13, and selects one of the plurality of wire-shaped electrodes A1 to A5.
It is applied to a selected one of the wire-shaped electrodes A1 to A5 on the upper side of the water shield film 10 via the (switch) selector 14. It is also applied from the current detection circuit 13 to the selected one of the lower wire-shaped electrodes B1 to B5 via the second SW selector 15. That is, the first and second S
The W selectors 14 and 15 respectively select a combination of one of the wire-shaped electrodes A1 to A5 and one of the wire-shaped electrodes B1 to B5 at regular intervals and repeat the operation of switching in sequence. The switching is performed at time intervals of, for example, several seconds to ten seconds.

As a result, the wire-shaped electrodes A1 to A5
The current flowing between them can be detected at all the intersections (here, 25) formed between and the wire-shaped electrodes B1 to B5.

If the water-blocking film 10 is not damaged, the water-blocking film 10
The current flowing between the upper and lower wire-shaped electrodes becomes the current flowing through the capacitive component of the water-blocking film 10. Therefore, the output of the first phase detection circuit 16 that performs detection in a phase synchronized with the applied voltage has a smaller value than the output of the second phase detection circuit 17 that performs detection in a phase that is 90 degrees different from the applied voltage. Become.

On the other hand, when the water shield film 10 is damaged, an electric current easily flows through the damaged portion, and therefore the water shield film 10
If the intersection of the upper and lower wire-shaped electrode combinations is close to the damaged part, the output of the first phase detection circuit 16 will output a relatively larger value than the intersection of the other combinations.
The output of the second phase detection circuit 17 outputs a relatively small value.

However, these situations can be said when the electric conductivity inside the disposal site is evenly distributed, and the ground water distribution condition becomes non-uniform, resulting in non-uniform electric conductivity. In some cases, a correction calculation is required to remove this effect.

FIG. 2 is an equivalent circuit of the disposal site and the ground by the lumped constant display which is the basis of the correction calculation according to the present invention.
In this equivalent circuit, C is the capacitance component of the water-blocking film 10 and R is
1 is the resistance of the damaged portion of the water-blocking film 10, and R2 is the sum of the contact resistance of the electrodes and the ground resistance. When a voltage is applied from the AC power supply to the equivalent circuit, the voltage corresponding to the output current obtained from the phase detection circuit is V0 for the applied voltage, Is the output for which phase detection is performed in the same phase as the applied voltage, and phase detection for the 90-degree advanced phase. When the output is Ic and the angular frequency of the applied voltage is ω, Is and Ic are represented by the following formulas (1) and (2).

[0016]

[Equation 1]

[Equation 2] When the ground resistance increases, the current flowing through the damaged portion of the water shield film 10 decreases. Therefore, the correction coefficient is most preferably a coefficient proportional to the increase amount of the resistance R2. Although it is not possible to separate only the resistor R2 from the equations (1) and (2),
Focusing on the tan ⁻¹ term, when the correction coefficient K is obtained by dividing the expression (1) by the expression (2), the correction coefficient K is expressed by the following expression (3).

[0017]

(Equation 3) In the equation (3), the numerator includes the term of the resistance R2 and the denominator does not include the term of the resistance R2. Therefore, the correction constant K is the phase detection output with the same phase as the applied voltage, that is, the first By multiplying by the output Is of the phase detection circuit 16 (K · Is = Is ² / Ic), it becomes possible to correct the influence depending on the resistor R2. Such correction calculation is performed by a squaring circuit 18 that receives the output of the first phase detection circuit 16 and outputs the squared value thereof, and the squaring circuit 18
Is used as the numerator, and the output Ic of the second phase detection circuit 17
Is used as a denominator, and the output of the squaring circuit 18 is divided by the output of the second phase detection circuit 17 to output the result.

In this way, when the output of the division circuit 19 for the upper and lower wire-shaped electrode intersections of the water-impervious film 10 is displayed, the division is performed when the wire-shaped electrode combination intersections near the damaged portion of the water-impervious film 10 are displayed. The output of the circuit 19 shows a large value, and the output of the division circuit 19 tends to decrease as the combination intersection of the wire-shaped electrodes moves away from the damaged portion of the water-blocking film 10, and the position where the water leakage occurs is known. It becomes possible.

FIG. 3 is a three-dimensional display of measurement data obtained by taking the output of the division circuit 19 into the computer 21 via the A / D converter 20 and processing it with the spline function. Intersection (here 1
It can be seen that there are peaks other than 2 × 13 (156 points). Therefore, the measurement resolution is improved more than the wire-shaped electrode installation interval above and below the water-blocking film 10, and the wire-shaped electrode installation interval can be installed at an interval of several times the measurement resolution required for repair. .

[0020]

As is apparent from the above description, in the present invention, a plurality of wire electrodes are installed so as to be perpendicular to the upper and lower sides of the water-blocking film of the control type terminal treatment plant, and the upper and lower wire electrodes are arranged. A combination of electrodes is selected one after another for energization, and the energizing current is synchronized with the outputs of the two-phase AC power supply that are 90 degrees out of phase with each other, and the phase detection is performed by the two phase detection circuits and the two phases are detected. The output of the detection circuit is processed by a squaring circuit and a division circuit, and the output value of the division circuit for the combination between each wire-shaped electrode is displayed, so that the location of damage to the water-blocking film can be known in a short time. be able to.

Further, according to the present invention, it is possible to correct the influence of the change of the wire electrode installation condition and the change factor of the water content of the ground on which the wire electrode is installed.
This makes it easy to identify the location of damage to the water-blocking film.

Further, according to the present invention, since the wire-shaped electrode is arranged right above the water-blocking film, the difference in the electrical characteristics depending on the kind of waste treated in the treatment plant and the depth of the buried waste can be detected. It also has the effect of not affecting accuracy.

Therefore, not only is the effect obtained economically, but the position where the water leakage is generated can be detected early and the environmental damage can be minimized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of a disposal site, ground, etc. for explaining a correction calculation according to the present invention.

FIG. 3 is a three-dimensional display of the measurement result of the present invention.

[Explanation of symbols]

 A1 to A5, B1 to B5 Wire-shaped electrodes 10 Water-blocking film 11 Two-phase AC power supply 12 Power amplification circuit 13 Current detection circuit 14, 15 SW selector 16 First phase detection circuit 17 Second phase detection circuit 18 Square circuit 19 Division circuit 20 A / D converter 21 Computer

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ken Arai 2-3-5 No. 507, Shiki-shi, Saitama 507

Claims (1)

[Claims] 1. A management-type terminal treatment plant constructed with a water-impervious film, wherein a plurality of wire-shaped electrodes are arranged parallel to the upper side of the water-impervious film at predetermined intervals, and the water-impermeable member. A plurality of wire electrodes arranged at a predetermined interval so as to be parallel to the lower side of the membrane and orthogonal to the upper wire electrodes; an AC power supply; and a voltage of this AC power supply for the upper wire and the lower wire. Selection switching means for sequentially applying to each arbitrary set of strip electrodes, a current detection circuit for detecting a current flowing between the upper and lower wire electrodes, and an output of the current detection circuit. A first phase detection circuit that performs phase detection at the same phase as the applied voltage; and a second phase detection circuit that receives the output of the current detection circuit and performs phase detection at a phase that is 90 degrees ahead of the applied voltage, The output of the first phase detection circuit is received and the squared value is A square circuit for applying a force to the output, and the output of the square circuit is used as the numerator, and the output of the second phase detection circuit is used as a denominator, and the output of the square circuit is divided by the output of the second phase detection circuit. A pair of upper and lower wire-shaped electrodes are sequentially selected, and the current flowing between the electrodes of each pair is phase-detected in two phases. A water leakage generation position detection method, wherein the water leakage generation position is detected because the output of the division circuit rises above the value between other electrodes when a combination of close electrodes is obtained.