JPH0638046B2 - How to measure the traveling distance of a pig for pipe inspection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a pipe body inspection pig used for inspecting a pipe body, for example, while traveling a long-distance buried pipeline while confirming the traveling distance. The present invention relates to a traveling distance measuring method for a tubular body inspection pig, in which a means for correcting a traveling distance of a pig is improved.

(Prior Art) Generally, when inspecting a long-distance buried pipeline, after inserting a pipe inspection pig equipped with a point-contact type tachometer and an inspection measuring instrument into the pipeline, the air pressure is changed. The pipe inspection pig is run by using it, and the pulse generated each time it travels a predetermined distance from the tachometer is counted by the counter and converted into the distance, and the leakage magnetic flux detection means or the ultrasonic probe is used. The type of defect and the amount of defect are measured using an inspection measuring instrument including a child, and the defect state at a certain position of the pipeline is grasped.

By the way, as described above, in the rotary distance meter, the rotary arm is obliquely projected from the body of the pig, and the rotary roller with the encoder is attached to the arm tip end, and the rotary arm is formed by a spring or a spring. By pulling, the rotating roller at the tip of the rotating arm is always in contact with the tube surface. Therefore, when the traveling distance is measured using such a tachometer, a measurement error of about 1% always occurs due to a change in the spring or the tension force of the spring. This measurement error becomes larger as the pipeline becomes longer. As a result, when a defective portion of the pipe is detected while measuring the traveling distance using the distance measuring means as described above, when excavating the soil when repairing the defect, a completely different position from the defective position is dug up. There was a problem that the repair work could not proceed smoothly. Here, a need arises to correct the rotational distance type measurement distance.

Therefore, conventionally, as a means for accurately measuring the traveling distance or traveling position of an inspection pig, a pulse train generator and a transducer are installed on the pipeline side, while a transducer is mounted on the inspection pig side and the Receiving the transmitted ultrasonic wave, it reflexively generates ultrasonic wave from the inspection pig side, receives this ultrasonic wave on the pipeline side and receives the generated ultrasonic wave again on the inspection pig side, and from this reception time interval There is a device which obtains the position information of the inspection pig (Japanese Patent Laid-Open No. 1222412/1983).

Therefore, if such position information is used for the measured distance obtained by the pipe inspection pig as described above, it is possible to correct the measured distance of the tachometer and obtain a highly accurate traveling distance.

(Problems to be Solved by the Invention) However, it is difficult to provide an ultrasonic transmitting / receiving device in a pipeline, or providing an exposed portion for installing an ultrasonic transmitting / receiving device in a pipeline under various conditions. Often do not like.

The present invention has been made in view of the above circumstances, it is possible to accurately grasp the position without providing a special transmitting and receiving device in the pipeline, it is possible to perform a distance correction from this position information to measure a highly accurate distance, Thus, it is an object of the present invention to provide a method for measuring the traveling distance of a pipe inspection pig, which can improve the reliability of inspection results and the efficiency of repair work.

(Means and Actions for Solving Problems) A method for measuring a traveling distance of a pig for pipe inspection according to the present invention is to mark a number, a symbol, etc. on an inner surface of the pipe when the pipe is buried, while Point inspection type rotary distance meters are provided at a plurality of locations on the outer peripheral surface of the body of the inspection pig, and
A TV camera is mounted on the rearmost side of the pipe inspection pig, and the inside of the pipe behind the pipe inspection pig is photographed with the TV camera while the pipe inspection pig is running inside the pipe, and the captured image data The distance data measured by one odometer is superposed and recorded, and the mileage is obtained by correcting the distance data measured by the rotometer from the distance data, number and symbol projected on this image data. In addition, the curved shape of the tubular body is calculated from the difference between the distance data measured by the rotary distance meters.

(Example) An example of a pipe inspection pig to which the method of the present invention is applied will be described below with reference to FIGS. 1 and 2. First
FIG. 1 is a configuration diagram showing a pipe body inspection pig running in the pipe body 10 with a part thereof cut away. The tubular body 10 has the tubular body 10
When burying, the serial number or pipe number or symbol etc. shall be attached to the pipe surface near the welded part in advance. Further, for the existing pipe, the pipe inspection pig itself is provided with a conventionally known welding portion detection means and marking means for attaching a number or a symbol in the pipe based on the welding position detected by this detection means, While marking the number in the pipe, check the number etc. while traveling.

The pipe body inspection pig is provided with seal cups 12 and 13 which are in contact with the pipe surface and maintain a sealing property at the outer peripheral portion and the rear outer peripheral portion of the pig main body 11 having a predetermined length. Therefore, the pipe inspection pig is provided with the seal cups 12, 1
If a pressure difference is created in the pipe body 10 at the boundary of 3, the vehicle can travel using this pressure difference. Reference numeral 14 denotes an eddy current sensor, which is provided behind the seal cup 12 and at a peripheral portion of the pig body at a predetermined distance to detect a welded portion and a defective portion during traveling of the pig. Also,
A rolling contact type distance meter 15 is attached to the outside of the pig body 11 located between the eddy current sensor 14 and the seal cup 13. The rotary distance meter 15 includes an arm 15b which is always pulled by a spring or a spring 15a so as to be rotatable in the tube surface direction, a rotary roller 15c which is rotatably supported by a tip of the arm, and a rotary roller 15c. Rotating roller 15
Encoder 15d that generates a pulse every predetermined rotation of c
Etc.

On the other hand, inside the pig main body 11, a television camera 16 is installed at least at the rearmost side in the rear tube axis direction, and image data of the television camera 16 is recorded, though it depends on the inspection content of the tubular body 10. VTR 17, battery power supply 1
8 and a data processing system 19 are mounted. Other,
When measuring the profile of the tubular body 10, an inclinometer, an inner diameter measuring device, and the like are provided. In addition, in the case of a multi-connection pig, the television camera 16 shall be mounted in the last pig.

Next, FIG. 2 is an electrical system configuration diagram of the measuring device and the data processing system 19 mounted on the pipe inspection pig. In the figure, reference numeral 21 denotes a CPU that performs a predetermined process in accordance with program data, and a bus line 22 and a control line 23 for address / data etc. are derived from the CPU 21. ROM2 for storing program data and necessary fixed data in the bus line 12 and the like
4. A RAM 25 for storing various measurement data and an interface 26 for outputting the data stored in the RAM 25 to an external host computer 41 after collecting the pipe inspection pig are connected. 27 is an inclinometer, 28 is an A / D converter, 29 is an inner diameter measuring instrument, 30 is an existing pipe, and marking means for marking a number, a symbol, etc. on the inner surface of the pipe when the pipe surface is not numbered. is there.

Further, a preset counter 31 is connected to the output side of any one of the rotary distance meters 15A (15), and a reset signal is given every time the output pulse from the rotary distance system 15A reaches a preset value, that is, every reference distance. It has a function. This counter 32 is the other tachometer 15
It is connected to the output side of B (15) and is reset to zero every time a reset signal is received. Reference numeral 33 is a counter for counting the output pulse of the rotary distance meter 15B and converting the distance, 3
4 is a branch circuit, 35 is an I / O having a data latch function
Reference numeral 36 is a port, 36 is a superimpose for superimposing distance data on image data from the television camera 16, and 42 is a monitor device which is installed outside the pipe and monitors the image data of the VTR 17 after the pipe inspection pig is collected.

Therefore, according to the configuration of the above embodiment, when a differential pressure state is created inside the tubular body 10 with the seal cup 12 or 13 as a boundary, the tubular body inspection pig runs in the direction in which the differential pressure is small. In addition to the differential pressure traveling means, for example, a self-propelled means for traveling while rotating a rotating body that has a built-in drive source and is protruded from the body of the pig body 11 or is artificially or mechanically extended by attaching a rope. Alternatively, it may be pulled and run.

Then, when the pipe inspection pig travels inside the pipe, the odometers 15A and 15B rotate as the pig travels, and a pulse is output at each predetermined rotation speed (predetermined distance). The output pulses of these tachometers 15A and 15B are counted by the preset counter 31 and the counters 32 and 33, and the count value is sent to the I / O port 35 and latched. At this time, the preset counter 31
Sends a reset signal to the I / O port 35 and the counter 32 when the count value of the output pulse from the tachometer 15A reaches the preset value. This gives I
On the / O port side, the distance data of the other rotary distance meter 15B can be secured in synchronization with the reference distance data of one rotary distance meter 15A. Then, the CPU 21 reads the data stored in the I / O port 35 at a predetermined timing and stores it in the RAM 25, and the external host computer 41 collects the two distance data and calculates the curved shape of the tubular body 10. You can also

Further, the pipe inspection pig sequentially photographs the pipe surface behind the pig by using the television camera 16 at the tail end of the pig while illuminating the inside of the pipe with an illumination device (not shown) during traveling. The image data captured by the television camera 16 including the numbers or symbols attached to the tube is sent to the superimposing device 36, where the distance data converted by the counter 33 is superimposed on the image data. V
Recorded in TR17. When the pipe is an existing pipe and the pipe is not numbered, the CPU 21 takes in an output signal from the inner diameter measuring device 29 including the eddy current sensor 14 at a predetermined timing and determines that the welding portion is a marking portion. Three
0 is operated to sequentially add numbers and the like in the tube, and the numbers are taken by the television camera 16. As a result, VTR17
The image data including the number and the distance data is recorded on the VTR1 after the pig is collected.
By displaying or printing out the image data of No. 6, it is possible to know how much the distance data measured by the rotary distance meter 15B deviates, and to easily correct the measured distance. Also, the data of each required measuring instrument is RAM2.
Since the data is stored in No. 5, the host computer 41 can read out those data after the pig is collected, and the required inspection or profile of the tubular body 10 can be obtained.

Although the preset counter 31 is connected to the output side of the rotary distance meter 15A in the above embodiment, a normal counter may be used. In this case, the counter 33 is omitted and the rotation distance system 1
The output of either counter on the output side of 5A or 15B may be connected to the branch circuit 34. In addition, the present invention can be modified in various ways without departing from the scope of the invention.

(Effects of the Invention) As described in detail above, according to the present invention, a number assigned in advance in a pipe by using a television camera installed at the end of a pig,
Since the images of the symbols and so on were recorded and the distance data measured by the rangefinder was superimposed on this image data and recorded, accurate position information can be detected without installing a special transmission / reception device in the pipeline. It is possible to provide a method for measuring the traveling distance of a pig for pipe inspection, which can correct the measurement distance with high accuracy, can improve the reliability of the inspection result, and greatly contribute to the improvement of the efficiency of the repair work. Further, in the present invention, the rotary distance meters are provided at a plurality of positions on the outer peripheral surface of the body portion of the tubular body inspection pig. Then, the curved shape of the tubular body is calculated from the difference between the respective distance data measured by the respective tachometers.

In this way, the bending state of the buried pipe can also be detected.
That is, there are many cases where pipes buried in the ground are forcibly bent vertically due to subsidence or artificial underground construction. Since it does not appear as an abnormal defect on the inner peripheral surface, it cannot be detected only by the above-mentioned ordinary defect detection method or the video data of the television camera. However, it can be surely detected by detecting the difference between the respective distance data.

In addition, by averaging the distance data from each tachometer arranged at multiple positions on the outer peripheral surface of the body of the tubular body inspection pig, the traveling distance of the tubular body inspection pig due to bending of the tubular body The error of can be made smaller.

[Brief description of drawings]

FIG. 1 and FIG. 2 are shown for explaining a method for measuring a traveling distance of a pig for pipe inspection according to the present invention.
FIG. 1 is an internal configuration diagram of a tubular body inspection pig to which the method of the present invention is applied, and FIG. 2 is an electrical system configuration diagram equipped with a tubular body inspection pig. 10 ... Tube, 11 ... Pig main body, 12, 13 ... Seal cup, 14 ... Eddy current sensor, 15 (15A, 15
B) …… Turometer, 16 …… TV camera, 17 ……
VTR, 19 ... Data processing system, 21 ... CPU, 31
…… Preset counter, 32,33 …… Counter, 3
4 ... Branch circuit, 36 ... Superimpose, 30 ...
... marking means, 41 ... host computer, 42
...... Monitor device.

Claims (1)

[Claims] 1. A travel distance measuring method for a pipe inspection pig in the case where a pipe inspection pig is run inside a buried pipe to perform a predetermined inspection at each position of the pipe, A number, a symbol, etc. are marked on the inner surface of the pipe body when the pipe body is buried, while point-contact type rotary distance meters are provided at a plurality of locations on the outer peripheral surface of the body portion of the pipe body inspection pig, and A television camera is mounted on the rearmost side of the tubular body inspection pig, and the inside of the tubular body behind the tubular body inspection pig is photographed by the television camera while the tubular body inspection pig is running inside the pipe, and is photographed. The distance data measured by one rotary rangefinder is superimposed on the recorded image data and recorded, and the distance data measured by the rotary rangefinder is corrected from the distance data, the number and the symbol projected on this image data. To obtain the mileage, and A method for measuring a travel distance of a pig for pipe inspection, wherein a curved shape of the pipe is calculated from a difference between respective distance data measured by the tachometers.