JPH07248379A - Water stagnant place detecting method for synthetic resin conduit - Google Patents

Abstract

PURPOSE:To easily detect a water stagnant place in a synthetic resin conduit without requiring labor or cost. CONSTITUTION:From aboveground; an electromagnetic wave 5 is radiated to a synthetic resin conduit 2 buried in the soil 1. When stagnant water exists in the conduit 2, intensity of a reflected wave 6 of the radiated electromagnetic wave 5 is heightened, and an image displayed on a display means 12 becomes dark. On the other hand, when the stagnant water does not exists in the conduit 2, the intensity of the reflected wave 6 is reduced, and the display image becomes light. Thereby, when the intensity of the reflected wave 6 is not less than predetermined reference intensity, it is detected as a water stagnant place in the conduit 2.

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 pool location of a synthetic resin conduit that is buried in the ground and used as a gas pipe, etc. The present invention relates to a method for detecting a water pool location of a synthetic resin conduit using an exploration device.

[0002]

2. Description of the Related Art Pipes such as gas pipes, water pipes, sewer pipes, electric cables and telephone cables are buried in the ground. A polyethylene (PE) conduit is also used as the gas pipe. The polyethylene pipe has lower pressure resistance than the metal pipe, but has an advantage of being less likely to be corroded.

When water accumulates in the above-mentioned gas pipe, gas supply failure and pulsation occur in the gas flow. Therefore, when the above-mentioned problem occurs, the water pool location in the gas pipe is inspected. As a method of detecting a water pool, there is a method of inserting a small television camera into a live tube, that is, a conduit in which a gas is flowing, to display the inside of the gas pipe, and visually search for the water pool. There is also a method of inserting a sensor capable of detecting water.

[0004]

Although the above-mentioned method for detecting a water pool is to insert a small-sized television camera or a moisture detection sensor into a conduit, the camera extends to the back of a long conduit. It is difficult to insert a sensor or sensor. Further, since the conduit is not a straight pipe and is bent or branched, it is necessary to excavate the soil to expose the conduit in order to insert the detecting means. For this reason, it is very troublesome and the cost for excavation is required.
Further, since the gas pipes and the water pipes are laid along the road, there is an inconvenience that traffic such as vehicles running on the road must be cut off for excavation.

Further, in order to inspect the pool of water in the lead-in pipe to the customer, it is necessary to remove the gas meter for individually measuring the amount of gas used, which is troublesome.

[0006] An object of the present invention is to provide a method for detecting a water pool location of a synthetic resin conduit which can be easily detected without much labor and cost.

[0007]

According to the present invention, an electromagnetic wave is radiated from the ground into a synthetic resin conduit buried in the ground, and when the reflection strength of the electromagnetic wave is equal to or higher than a predetermined reference strength, it is detected as a water pool location. A method for detecting a pool of water in a synthetic resin conduit.

Further, the present invention is characterized in that the reflection intensity of the electromagnetic wave is displayed as an image and the water pool location is detected based on the density of the image.

[0009]

According to the present invention, the water pool portion in the synthetic resin conduit buried in the ground is detected by the reflection intensity when electromagnetic waves are radiated from the ground into the conduit, and the reflection intensity is a predetermined criterion. When the strength is higher than that, it is judged as a water pool. That is, when there is no water pool in the conduit, since the conduit is made of synthetic resin and has relatively low conductivity, the reflection intensity of electromagnetic waves emitted from the ground is low. On the other hand, when there is a pool of water in the conduit, the conductivity of the pooled water is higher than that of the synthetic resin, so that the reflection intensity of electromagnetic waves emitted from the ground is high. Therefore, it is possible to detect a pool of water when it is determined that it is a pool of water when a reflection intensity higher than a predetermined reference intensity is obtained.

According to the present invention, the reflection intensity of electromagnetic waves radiated from the ground is displayed as an image using a mobile measuring device called a radar locator, and the water pool is formed based on the contrast of the image according to the reflection intensity. The location can be detected.

Therefore, unlike the prior art, it is possible to detect a pool of water without inserting a detecting means such as a small TV camera or a moisture detecting sensor into the conduit, and to radiate electromagnetic waves from the ground, Since it is judged based on the reflection intensity, the labor and costly work of excavating the soil to expose the conduit are not required. Since excavation of soil is unnecessary, it is not necessary to block traffic such as vehicles running on roads. Further, it is not necessary to remove the gas meter for individually measuring the gas usage amount, and it is possible to detect the water pool location without trouble.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a detection means 1 used to detect a water pool location by a detection method according to an embodiment of the present invention.
7 is a block diagram showing an electrical configuration of FIG. Detection means 17
Is a mobile measuring device used for investigating the presence or absence or the position of a metal pipe buried in soil, which is a so-called radar locator. An example of the structure of the detecting means 17 described below is, for example, JP-A-61-651.
76, JP-A-63-222287. The detection means 17 includes antennas 3 and 7, a transmission circuit 4, a reception circuit 8, a processing circuit 9, a memory 11, a display means 12, and an input means 13.

A conduit 2 made of polyethylene for transporting gas is buried in the soil 1. In order to detect the water pool in the conduit 2, the detection means 17 arranged on the ground surface GL.
Of the transmitting circuit 4 of 100 MHz to 1000 MH
A pulse having a waveform of z shown in FIG. 2 (1) is generated, and the pulse is applied to the antenna 3. The electromagnetic wave 5 is radiated toward the soil 1 from the antenna 3 to which the pulse is applied. Electromagnetic waves 5 radiated from this antenna 3
Is reflected by the water 14 in the conduit 2 and its reflected wave 6
Is received by another antenna 7,
The signal having the waveform shown in (2) is given to the receiving circuit 8. From the antenna 3 to the electromagnetic wave 5 shown in FIG.
Is radiated and the time difference ΔT until the signal shown in FIG. 2B is received by the antenna 7 is determined by the distance between the ground surface GL and the surface of the water 14 in the conduit 2 and the ground surface GL and the conduit 2 Relative permittivity εr of soil 1 between the surface of water 14
It corresponds to. Transmitting antenna 3 and receiving antenna 7
Of the cross section of the soil 1 including the conduit 2 in the vertical plane, by fixing and integrally with each other and moving it across the conduit 2 buried in the ground as shown by the arrow 10 in FIG. The original image can be obtained.

The output of the receiving circuit 8 is given to a processing circuit 9 realized by a microcomputer or the like. A memory 11 is connected to the processing circuit 9. The original image and the like are stored in the memory 11. The obtained original image is visually displayed on the visual display means 12 realized by a cathode ray tube and liquid crystal. Input means 13 is connected to the processing circuit 9 to give an instruction to radiate the electromagnetic wave 5 or the like.

FIG. 2 received by the receiving antenna 7.
In the waveform shown in (2), the middle gradation is set to zero and the soil 1
2 represents the signal strength at the coordinate position, that is, the luminance which is the signal level, in a plurality of gradations. For example, as shown by reference numeral 15 in FIG. 2 (2), white is made positive, and as shown by reference numeral 16, Black is negative.

FIG. 3 shows the soil 1 using the detection means 17.
It is a figure which shows the method of detecting the water pool in the conduit 2 inside.
The detection means 17 is configured by housing the above-mentioned electrical components in the housing 20, and the wheels 18 are attached to the lower surface of the housing 20 to move the ground surface GL. Further, the operator 21 pushes the handle 19 provided on the housing 20 to walk to move the ground surface GL. As shown in FIG. 3 (1), the buried conduit 2
Electromagnetic waves 5 are radiated from the transmission circuit 4 of the detecting means 17 at the respective positions A to G on the ground surface GL immediately above. The electromagnetic waves 5 radiated at the respective positions A to G are reflected by the surface of the water 14 in the conduit 2, and are received by the receiving circuit 8 of the detecting means 17 as reflected waves 6. At each position A to G on the ground surface GL, based on the intensity of the reflected wave 6 and the time from the transmission of the electromagnetic wave 5 to the reception of the reflected wave 6, as shown in FIG. A crescent-shaped image 22 connecting A'to G'corresponding to ~ G is displayed on the display means 12.

The above-mentioned detecting means 17 has been used for investigating the presence or the position of a metal conduit tube conventionally buried in soil, and the radiated electromagnetic wave 5 is reflected by the buried metal conduit tube and reflected. The wave 6 is received by the detection means 17. In the present embodiment, such a detection means 17 is used to detect the water pool location in the conduit 2 made of synthetic resin made of polyethylene, for example.

FIG. 4 is a diagram showing the intensity of the reflected wave 6.
FIG. 4 (1) shows the case of a metal conduit, and FIG.
Shows the case of a polyethylene conduit. The radiated electromagnetic wave 5 is first reflected on the ground surface. The reflection intensity of the portion indicated by the symbol L1 is due to reflection on the ground surface. Then, the electromagnetic wave 5 that has entered the soil 1 reaches the conduit 2 and is reflected. The reflection intensity of the portion represented by the symbol L2 is
This is due to the reflection at the conduit 2. For metal conduits,
Since the conductivity is relatively large, the intensity of the reflected wave 6 is large. On the other hand, in the case of the polyethylene conduit, the conductivity of the polyethylene conduit is smaller than that of the metal tube, so that the intensity of the reflected wave 6 becomes small. For example, nominal diameter 50A at a depth of 1m from the ground surface
When a conduit (outer diameter 60.5 mm) is buried, the reflected wave 6
It was confirmed that the strength ratio of was about 3/1 for metal tube / polyethylene tube.

Further, when water is accumulated in the polyethylene conduit, the conductivity of water is higher than that of polyethylene, so that the reflection intensity is higher than the reflection intensity of the polyethylene conduit shown in FIG. 4 (2). It was confirmed that the intensity was obtained, for example, the intensity comparable to the reflection intensity of the metal conduit as shown in FIG. 4 (1) was obtained.

FIG. 5 shows an image 2 displayed on the display means 12.
It is a figure which shows 3,24. FIG. 5 (1) shows an image 23 when the metal conduit is searched, and FIG. 5 (2) shows an image 24 when the polyethylene conduit is searched. Further, as shown in FIG. 6, the images 23 and 24 show a case where the conduits 29a to 29e buried at the depth of 0.3 m to 1.5 m from the ground surface GL are searched. . Further, in the case of the polyethylene conduit, there is no water pool in the conduits 29a to 29d, and there is a water pool in the conduit 29e.

In the metal conduit, the reflected wave 6 is used as described above.
The image is displayed relatively dark because of the high intensity. On the other hand, in the case where water is not accumulated in the polyethylene conduit, the intensity of the reflected wave 6 is small, so that the image is displayed light. Further, when the water is accumulated, the intensity of the reflected wave 6 which is almost the same as that of the metal conduit is obtained, so that the image is displayed dark.

FIG. 7 is a diagram showing display images 25 to 28 corresponding to the amount of water accumulated in the polyethylene conduit. FIG. 7 (1) shows a case where water is not accumulated, FIG. 7 (2) shows a case where about 1/3 of water is accumulated, and FIG. 7 (3) shows 1
A case where water is accumulated in about 1/2 is shown, and FIG. 7 (4) shows a case where the inside of the conduit is filled with water. In the cross-sectional view showing the amount of water shown, the amount of water in the conduit is shown by hatching. These display images 25-28 are
A polyethylene conduit with a nominal diameter of 50A was buried at a depth of 1.5m from the ground surface GL. Under the surface layer made of asphalt AS (dense particles) with a thickness of 5cm,
A subgrade made of crushed stone with a grain size of 10 cm is provided. The soil is sand. Under conditions similar to those of a so-called general paved road, if a water pool of about 1/3 occurs in the conduit, the intensity of the reflected wave 6 is 2. as compared with the case where no water is pooled. It was confirmed to be 93 times. Further, the displayed image becomes darker as shown in the drawing, and the water pool can be visually recognized.

FIG. 8 is a plan view showing the buried conduit 2 for explaining a specific detecting method. The burial position of the conduit 2 is approximately clear by a design drawing at the time of piping and a locating wire, that is, a metal wire provided along the synthetic resin conduit 2. Based on this, first, a search is performed in a direction orthogonal to the direction considered to be the pipe axis direction of the conduit 2. At this time, the accurate position of the conduit 2 is confirmed, the depth is measured, and the marking M1 is attached to the ground surface corresponding to the substantially central point of the conduit 2. Then, the same search is repeated with a fixed interval of, for example, 5 m or 10 m, and markings M2 and M3 are attached.
Finally, search to connect the markings M1 to M3,
Where the reflection intensity is high, that is, the display means 12
The place where the image displayed in is dark is recognized as a water pool.

As described above, according to the present embodiment, it is possible to detect a water pool location without inserting a detecting means such as a small TV camera or a moisture detecting sensor into the conduit 2 as in the prior art. For this reason, it is not necessary to excavate the soil 1, and it is possible to easily detect the water pool location without labor and cost. Further, since it is not necessary to excavate the soil 1, it is not necessary to block vehicles running on the road. Further, even when detecting the water pool in the lead-in pipe, it is not necessary to remove the gas meter, so that the detection can be performed without trouble.

[0025]

As described above, according to the present invention, when the reflection intensity when the electromagnetic wave is radiated from the ground to the synthetic resin conduit buried in the ground is equal to or higher than the predetermined reference intensity, the inside of the conduit is Detect as a water pool. Further, the reflection intensity is displayed as an image, and the water pool location is detected based on the shade of the image according to the reflection intensity.

Therefore, it is not necessary to excavate the soil, and it is possible to easily detect the water pool location without labor and cost. Further, since it is not necessary to excavate the soil, it is not necessary to block traffic such as vehicles running on the road. Further, even in the detection of the inside of the lead-in pipe, it is not necessary to remove the gas meter, and it is possible to detect the water pool location without trouble.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a detection means 17 used to detect a water pool location by a detection method according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing the waveforms of an electromagnetic wave 5 radiated by the detection means 17 and a reflected wave 6 received.

FIG. 3 is a diagram showing a method of detecting a water pool in the conduit 2 in the soil 1 by using the detection means 17.

FIG. 4 is a diagram showing the intensity of a reflected wave 6.

5 is a diagram showing images 23 and 24 displayed on the display unit 12. FIG.

FIG. 6 is a diagram showing positions of buried conduits 29a to 29e.

FIG. 7 is a diagram showing display images 25 to 28 corresponding to the amount of water accumulated in the polyethylene conduit.

FIG. 8 is a plan view showing a buried conduit 2 for explaining a specific detection method.

[Explanation of symbols]

 1 Soil 2 Conduit 3,7 Antenna 4 Transmission Circuit 5 Electromagnetic Wave 6 Reflected Wave 8 Reception Circuit 12 Display Means 14 Water 17 Detection Means

Claims (2)

[Claims] 1. A synthetic resin characterized by radiating electromagnetic waves from the ground into a synthetic resin conduit buried in the ground and detecting the electromagnetic waves as a water pool when the reflection intensity of the electromagnetic waves exceeds a predetermined reference intensity. A method for detecting water pools in a manufactured pipe. 2. The method for detecting a pool of water in a synthetic resin conduit according to claim 1, wherein the reflection intensity of electromagnetic waves is displayed as an image and the pool of water is detected based on the density of the image.