JPH074941A - In-pipe inspection device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an in-pipe inspection device capable of accurately and easily detecting the position of an obstacle inside a buried pipe or the like. [Structure] The inspection device 10 includes a transceiver 15 having an antenna 13, a processing device 16 and the like. The transceiver 15 comprises a transmitter 12 and a receiver 14. The transmitter 12 transmits a frequency determined by the inner diameter of the pipe, the receiver 14 receives the reflected wave, and the processor 16 measures the time between them. . The distance from this time to the obstacle is calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-pipe inspection device for inspecting the position of an obstacle such as a clog that occurs inside a pipe such as a gas pipe.

[0002]

2. Description of the Related Art Conventionally, as a method for inspecting whether foreign matter such as earth and sand has entered a pipe such as a gas pipe buried in the ground, a camera for inspection is inserted into the pipe to inspect the inside of the pipe. The condition of the image is taken, and the screen taken is observed to determine if there is any abnormality, or a self-propelled robot is introduced into the pipe,
The condition inside the pipe was inspected (Japanese Patent Laid-Open No. 59-147).
260 publication). Also, a method of inserting a pig having an outer diameter substantially equal to the inner diameter of the tube, or a method of sending out a sound wave to the inside of the tube and receiving the reflected wave to check the internal state of the tube (Japanese Patent Publication No. 51- No. 18836) was known.

[0003]

However, in the case of a camera or a robot, it is impossible to enter a complicatedly bent pipe, and there is a straight pipe without bending, or even if there are few bent portions, the number is small. Only applicable. Further, there is a problem that an insertion port for inserting the camera or the like into the pipe is required, and excavation work or the like is required to use the existing pipe, which takes time and labor. Furthermore, the distance that can be inspected in one inspection is limited by the length of the electric wire connected to the robot and the like, so the number of inspections increases when the inspection distance is long, and it costs a lot of money. Was there. Also, when sending a sound wave into the pipe and inspecting the internal state from the reflected wave, the change is sufficient unless the pipe is completely blocked or completely open to the atmosphere. However, there is a problem that it cannot detect small changes and cannot detect minute changes.

[0004]

In order to solve the above problems and to easily and reliably inspect a long-distance pipe, the present invention has an inspection apparatus configured as follows. That is, a transmitter / receiver that transmits a radio wave of a predetermined frequency inside the pipe and receives the reflection of the transmitted radio wave, and the time interval between the transmission of the radio wave from this transceiver and the reception of the reflected wave is measured. The in-pipe inspection device is composed of the measuring device that operates and the detecting unit that converts this time interval into a distance.

[0005]

When a radio wave having a predetermined frequency determined from the inner diameter of the pipe is transmitted into the pipe, the attenuation inside is small and the electric wave can reach far away without decreasing its strength. Also, if there is a foreign substance inside the tube, the electromagnetic wave is reflected by this foreign substance.
Therefore, when a radio wave of a predetermined frequency is first transmitted from the transmitter / receiver, the radio wave propagates in the pipe to a distant place, and if there is an obstacle in the middle, it is reflected by it. When reflected, the radio waves return inside the pipe and are received by the receiver of the transceiver, so the distance from the transceiver to the obstacle can be detected by measuring the time interval from transmission to reception and converting it to the distance. it can.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the in-pipe inspection device of the present invention will be described below by taking a household gas pipe buried under a road as an example.

A gas pipe for domestic use under such a road is shown in FIG.
As shown in FIG. 5, the main branch pipe 2 buried under the road and the inner pipe 4 branching from the main branch pipe 2 are combined, and a meter 6 is attached to the end of the inner pipe 4, and from there, Guided to the home.

The inspection is for inspecting the internal state of the main branch pipe 2, and the inspection device is shown in FIG. The inspection device 10 includes a transceiver 15 in which a wireless transmitter 12 and receiver 14 are integrated,
And a processing device 16, a display device 18, and the like. The transmitter 12 of the transmitter / receiver 15 is capable of transmitting a radio wave having a frequency of GHz unit, and an antenna 13 for transmission / reception is attached to the tip of the connected conductive wire 21. The antenna 13 is also connected to the receiving unit 14, and receives the radio wave emitted from the transmitting unit 12 and reflected.
Then, the signal is amplified and sent to the processing device 16.

The processing device 16 compares the radio wave transmitted by the transmitter 12 with the radio wave received by the receiver 14 and measures the time interval between them. Then, this time interval is halved and multiplied by the speed of light to calculate the distance to the obstacle. The determined distance is sent to the display device 18, and the display device 1
8 displays the value.

Next, an example of the inspection procedure will be described. As shown in FIG. 2, first, the meter 6 close to the portion to be inspected is selected, and the service pipe 4 is removed from this meter 6. The antenna 13 of the transmitter / receiver 15 is inserted from the opening end of the removed inner pipe 4 and fed into the main branch pipe 2 until the antenna 13 arrives. At that time, the gas supply to the main branch pipe 2 may be stopped or may be performed without stopping the supply. When the supply is not stopped, the open end of the service pipe 4 is sealed so that the gas does not leak outside.

In this way, if the antenna 13 of the transmitter / receiver 15 is arranged in the vicinity of the inspected portion of the main branch pipe 2,
From the transmitter 12, a radio wave having a frequency equal to or higher than the value obtained by the following formula: frequency = light speed / {1.706 × inner diameter of tube} is transmitted.
For example, if the main branch pipe 2 is a 100 A pipe having an inner diameter of about 105 mm, it is a radio wave having a frequency of 1.67 GHz or higher. Thus, a radio wave having a frequency equal to or higher than the frequency calculated from the above equation has a property of propagating inside the pipe with little attenuation if the pipe has the inner diameter substituted into the calculation formula.

As soon as the radio wave of a predetermined frequency is transmitted from the transmission section 12, the reception section 14 is set to be receivable so that the reflected wave can be received. The receiving unit 14 may be in the receiving state at all times. Then, the electric wave reflected by the obstacle 20 returns inside the pipe and is received by the receiving unit 14 via the antenna 13. The received radio waves are amplified, and then the processing device 16
And the signal is binarized so that a signal above a certain level is set to 1 and a signal below that level is set to 0,
The radio wave transmitted from the transmission unit 12 is compared, and the elapsed time from the transmission to the return is detected. Then, the distance to the obstacle 20 is calculated from this elapsed time and displayed on the display device 18.

When the reflected wave is not observed, it is determined that the obstacle 20 is not within the range where the radio wave can reach, reflect and return. Further, when the antenna 13 is located in the middle of the pipe and the radio waves spread in both directions inside the pipe, it cannot be determined in which direction the obstacle 20 exists even if the obstacle 20 is sensed. In that case, The inspection is performed again with a slight distance, and it is determined that the obstacle 20 is on the moving side when the distance is short and on the opposite side when the distance is far.

As described above, according to the present embodiment, the antenna 13 of the transceiver 15 is inserted from the mounting portion of the household meter 6 and fed into the main branch pipe 2 to be inspected, and then the transmitting portion 12 is used. By measuring the reflection time until the transmitted electric wave returns, the antenna 13 is blocked by the obstacle 20.
The distance to can be accurately inspected. Moreover, since radio waves are used, the inspection distance can be set as long as 50 m or more, and the main branch pipe 2 can be inspected over a long distance with a small number of inspections. Further, even if the main branch pipe 2 is complicatedly bent, the amount of attenuation is small and an accurate inspection can be easily performed.

Although the gas pipe is inspected in the above embodiment, the inspection apparatus of the present invention is not limited to the inspection of the gas pipe.

Further, although the antenna 13 and the like are inserted through the connection port of the meter 6 in the above embodiment, the insertion of the antenna 13 and the like is not limited to this, and the antenna can be appropriately selected and inserted from there. It may be from another place.

[0017]

According to the in-pipe inspection device of the present invention, a transmitter / receiver for transmitting an electric wave into the pipe and receiving a reflection of the emitted electric wave, and a time interval from the transmission to the reception of the received wave are measured. Since it is composed of a processing device for calculating the distance from the reflector to the reflector, it is possible to accurately inspect the position of a clog or the like occurring in the pipe. Moreover, since radio waves are used, it is possible to easily inspect even when the pipe is complicatedly bent, and it is possible to set a long inspection distance.
It is possible to inspect a pipe over a long distance with a small number of inspections.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an inspection apparatus of the present invention.

FIG. 2 is a diagram showing an example of use of the inspection apparatus of the present invention.

[Explanation of symbols]

 Two branch pipes 4 Service pipe 6 Meter 10 Inspection device 12 Transmitter 13 Antenna 14 Receiver 15 Transceiver 16 Processor 18 Display 20 Obstacle

Claims (1)

[Claims] 1. A transmitter / receiver for transmitting a radio wave of a predetermined frequency into a pipe and receiving the radio wave reflected by an obstacle in the pipe, and a period from the transmitter / receiver transmitting the radio wave to receiving the radio wave. And a measuring device for measuring a time interval between the two.