JPH10132540A - Method of determining reflected acoustic wave in acoustic pipeline length measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erroneous determination and perform a precise length measurement by using the reflected sound wave after the lapse of a prescribed timing as length measuring data. SOLUTION: After one (A) of end parts of a pipeline having a sound generating means 15 and a sound collecting means 16 arranged therein is matched with one of end parts of a pipeline on a pipe arrangement view, the acoustic length measurement for the actual pipeline is performed. There is a possibility that such as reflected sound wave obtained at a prescribed timing from the start of receipt is a reflected acoustic wave caused by a steady wave by the presence of a reflecting source such as joint in a position extremely close to the sound generating means 15, and the reflected acoustic wave not from an end part other than the one of the end parts in the actual pipeline of the received data of the reflected acoustic wave obtained as the result of acoustic length measurement can be prevented from being erroneously determined as the reflected acoustic wave from the end part other than the one end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining a reflected sound wave when measuring the distance of a pipeline using sound waves.

[0002]

2. Description of the Related Art Pipes such as gas pipes and water pipes buried underground may be deteriorated due to corrosion due to long-term installation, or may be damaged by external force. In such a case,
An in-pipe repair method of repairing the inside of the pipe by lining it with a liquid resin or the like is used.

[0003] In the above-mentioned construction method, when the amount of resin supplied into the repair pipeline is not appropriate, for example, when the amount is excessive, the resin is wasted, and when the amount is insufficient, the lining is not used. Will be insufficient. Therefore, since the inner diameter of the pipe is known, it is necessary to accurately measure the length of the buried pipe to be repaired.

As a means for measuring the length of a buried pipe, a sonic pipe length measuring system as shown in FIG. 4 has been conventionally developed. Fig. 4 shows the main pipe 1 buried under the road.
A case is shown in which the length of the service pipe 11 drawn from 0 to the demand destination is measured. In this case, the length of the service pipe 11 (hereinafter referred to as a length measuring pipe) extending to the ground is shown. Remove the gas meter 12 attached to the upper end and remove the length measuring pipe 1
The sound-generating / sound-collecting portion 14 of the sonic pipe length measuring device 13 is attached to the above-mentioned opening on the ground. The sonic wave length measuring device 13
Since it is the same as that used in the embodiment of the present invention, it will be described below with reference to FIG. In FIG.
Sound generation and sound collection part 14 attached to the sonic type pipe length measuring device 13
Is fixed by screwing a screw 14 a into a ground opening of the length measuring pipe 11, in which a sound generating means 15 for sending a pulsed sound wave into the length measuring pipe 11, 1
A sound collecting means 16 for collecting reflected sound waves from inside 1 is arranged. The sound collecting means 16 can collect reflected sound waves reflected from a joint located at the length measuring pipe 11, an open end or a branch, as a reflection source. The acoustic pipe length measuring device 13 includes a CPU 13a, a memory 13b, a display 13c, a D / A converter 13d, amplifiers 13e and 13f, and an A / D converter 13 which are main components of a control unit.
g. The sounding means 15 sends a pulsed sound wave into the length measuring pipe 11 by a pulse sound signal which is converted into an analog signal by the D / A converter 13d based on a command from the CPU 13a and amplified by the amplifier 13e. . On the other hand, the sound collecting means 16 collects the pulsed sound waves reflected at the connecting portion, the open portion, the branch portion, and the like of the length measuring pipe 11 and outputs the sound to the amplifier 13f. In the amplifier 13f, the received signal corresponding to the collected pulsed sound wave is amplified and output to the A / D converter 13g, and the received signal is converted into a digital signal,
Output to the PU 13a. The CPU 13a includes a timing circuit therein, measures the time from when the sound wave is transmitted to when the sound is collected, converts the time into a pipe length, and displays the result on the display 13c. The memory 13b stores sound velocity value data of a fluid (air, natural gas, or the like) in the length measuring pipe 11, and measures a temperature at the time of measurement with a temperature sensor (thermistor) as a temperature measuring means to be a reference. The switch S is switched depending on the temperature, the type of gas to be measured, the temperature, and the like. By switching the switch S, a reference sound speed value can be set in accordance with a change in sound speed due to the type of gas, temperature, and the like.

[0005]

However, in the case of using the above-mentioned sonic type pipe length measuring system, one of the ends intended for an actual pipe line (see FIG. An error occurs when estimating the distance from the other end (corresponding to the end of the service pipe 11 connected to the main pipe 10 in FIG. 4) from the other end (the end indicated by the symbol A). Cheap. The phenomenon described below corresponds to a case where the distance from one end to another end other than one end is measured when the pipeline constitutes an independent pipe. The first problem is that, when the length measuring pipe is long, the reflected sound wave is generated when the sound wave transmitted from one end of the pipe is reflected at the other end than the one end of the pipe. Becomes remarkable. As a second problem, if the cross-sectional area change at the other end than the one end of the conduit is small, the reflected sound wave at the other end than the one end becomes small. As a third problem, as shown in FIG. 5, one end (A) of the pipe P to be measured and one end other than one of the ends (FIG.
In FIG. 4, a reflection source whose reflected sound wave is relatively large during the period up to the end of the service pipe 11 connected to the main pipe 10 in FIG. As shown in FIG. 5, when the joints (C) and (D) are present, sound waves that pass through the joints and reach one end other than one end according to the number of these joints are present. Easy to be small. As a fourth problem, if a reflection source is located very close to the sound generator, a standing wave may be generated.

Conventionally, the maximum reflected sound wave among the received data relating to the reflected sound waves obtained by the sound wave length measuring system is regarded as a reflected sound wave from one end of the pipeline other than one of the ends thereof, and the reflected sound wave in the pipeline is considered. The distance from one of the ends to the other end was determined, and the amount of lining resin was determined according to that distance. The reflected sound wave may not be a reflected sound wave from an end other than one of the ends in the actual pipeline, and as a result, the distance determined using the reception timing of the maximum reflected sound wave may be different from that in the actual pipeline. The distance from one end to the other end may not be met.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems in the conventional sonic type pipe length measuring system. The length from one end to the other end in the actual pipeline by appropriately presenting data for estimating the length to It is an object of the present invention to provide a method for determining a reflected sound wave in a sound wave type pipe length measuring system.

In order to achieve this object, the invention according to claim 1 is a sound generating means for transmitting a pulsed sound wave from one of the ends of the pipe into the pipe, and one of the ends of the pipe. In the first method, the length of the pipeline is determined based on the time from when the pulsed acoustic wave is transmitted to when the pulsed acoustic wave is collected and the sound velocity value is used, using a sound collecting unit that collects the pulsed sound wave reflected in the pipeline. In a sonic pipe length measuring system for measuring the depth, a sound generating means and a sound collecting means are arranged at one end of the length measuring pipe, and the received data relating to the reflected sound wave is stored. It is characterized in that the reflected sound wave obtained after the elapse of the predetermined timing is used as the data for length measurement without treating the reflected sound wave from the predetermined timing to the data for the length measurement.

According to a second aspect of the present invention, in the method for determining a reflected sound wave in the sonic type pipe length measuring system according to the first aspect, among reflected sound waves obtained after the predetermined timing has elapsed, a plurality of reflected sound waves are arranged from the highest peak value. Is extracted as a determination target.

According to a third aspect of the present invention, there is provided a sound generating means for transmitting a pulsed sound wave from one end of a pipeline into the pipeline.
The time and sound speed from when the pulsed sound wave is transmitted to when the sound is collected by using sound collecting means for collecting the pulsed sound wave reflected in the pipe at one end of the pipe. In a sonic pipe length measuring system that measures the length of a pipe based on the value, a sound generating means and a sound collecting means are arranged at one of the ends of the length measuring pipe, and received data on reflected sound waves is stored. Among the obtained reflected sound waves, those having a plurality of ranks from the highest peak value are extracted as objects to be determined.

The invention described in claim 4 is the invention according to claim 2 or 3.
In the reflected sound wave discrimination method in the sonic pipe length measuring system described above, the extracted reflected sound wave has a new peak value at a timing excluding a predetermined range around the timing at which the peak value is selected. It is characterized by being sequentially extracted.

The invention according to claim 5 is the invention according to claim 2 or 3.
In the above described reflected sound wave discrimination method in the sound wave type pipe length measuring system, a deviation of a peak height based on a highest peak value is determined for the extracted reflected sound wave.

[0013]

According to the first aspect of the present invention, the reflected sound wave between the start of reception and the predetermined timing is not treated as length measurement data on the reception data, and the reflected sound wave after the lapse of the predetermined timing is regarded as the length measurement data. By doing so, even if there is a reflection source near the sounding means, it is possible to prevent erroneous determination that the reflected sound wave from the reflection source is from one end other than one end of the conduit.

According to the second and third aspects of the present invention, by extracting a plurality of peak values in the descending order, one of the ends of the pipe line to be obtained on the piping diagram from the extracted peak values. By selecting the peak value most suitable for the length from the end to the other end, errors relating to the actual length of the pipeline can be reduced.

According to the fourth aspect of the present invention, a signal having a new peak value is sequentially extracted at a timing excluding a predetermined range around the timing at which the peak value is selected, so that the same reflected sound wave is extracted from the same reflected sound wave. It is possible to prevent the peak value from being selected again.

According to the present invention, the height of the peak value of the extracted reflected sound wave is presented as a deviation,
When estimating the length from one end of the conduit to the other end, it can be determined from the deviation that the sound wave is a reflected sound wave from the other end than the one end. .

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below. As the sonic pipe length measuring apparatus used in the reflected acoustic wave discriminating method according to the present invention, an apparatus having the same configuration as that described above with reference to FIG. 1 is used. FIG. 2 is a timing chart for explaining the principle of the reflected signal discrimination method according to the present invention. This timing chart shows received data relating to the reflected signal when a sound wave is transmitted from the sound generator 21. In FIG. 2, a received signal related to the reflected sound wave having the highest peak value is obtained at the earliest time from the reception start time, and after the received signal is received, the reflected sound waves related to the reflected sound waves having various peak values are obtained. A received signal has been obtained.

In the present invention, on the reception timing of the obtained reflected sound wave, a predetermined timing (T1) from the start of reception.
Do not handle the reflected sound wave received inside as data for length measurement. This is to prevent erroneous determination of the received signal due to the standing wave, and tentatively, as shown in FIG. 4, one of the ends of the pipeline where the sound generation / sound collection portion 14 is located (see FIG. 4). 4 out of
In the case where a joint T serving as a reflection source is attached at a position very close to the end indicated by the symbol A), a standing wave is generated due to the presence of the joint T, and this standing wave is transmitted to the end of the pipeline. This is to prevent the sound wave from being regarded as a reflected sound wave from an end other than one of the above.

Among the reception timings of the reflected sound wave excluding the reflected sound wave obtained during the predetermined timing from the start of reception, as shown by reference numerals (1), (2) and (3) in FIG. A reflected sound wave of a plurality of ranks is extracted from the highest peak value. A method of sequentially extracting a plurality of reflected sound waves having the highest peak value in the following manner is as follows. In FIG. 2, a predetermined range of timing (T0) around the reception timing at which the peak value is selected (the timing indicated by reference numeral T3 in FIG. 2).
The reflected sound waves having new peak values are sequentially extracted at the timing excluding (in the order of the reception timings indicated by reference numerals T4 and T2 in FIG. 2). This prevents duplicated extraction of the same reflected sound wave when the next highest peak value is present in the received signal of the same reflected sound wave even if the peak value once extracted is excluded. can do. The extracted reflected sound waves are received at their reception timings (T2, T2).
The distance is calculated from 3, T4).

In the case where a plurality of reflected sound waves having the highest peak value described in FIG. 2 are extracted in order, as described above, the reflected sound waves after a predetermined timing has elapsed from the start of reception are targeted. It is also possible to make it not limited to. In this case, the reflected sound wave before the lapse of a predetermined timing after the start of reception is also an object, but from the plurality of obtained reflected sound waves, one of the ends of the pipe line is taken into consideration by referring to a piping diagram. By selecting a reasonable length to the other end, the distance from one of the ends in the pipeline to the other end can be determined.

On the other hand, a plurality of reflected sound waves extracted in order from the highest peak value have a deviation with respect to the peak height determined based on the highest peak value.
As shown in FIG. FIG.
Indicates a display state on the display unit 24. With reference to the reflected sound wave having the highest peak value (the received signal indicated by the symbol (1) in FIG. 2), the peak value of the subsequent height is determined. The deviation with respect to the height of the peak of the reflected sound waves (reception signals indicated by reference numerals (2) and (3) in FIG. 2) is displayed.

In the present invention, based on the principle described above, one of the ends of the pipe line to be obtained on the pipe diagram is selected from the received data of the reflected sound waves obtained as the result of the sound wave length measurement. The distance to the other end can be estimated by the following procedure. First, the sound generator 21 and the sound collector 2
2 (see FIGS. 1 and 4).
The middle part (end indicated by reference symbol A) is aligned with one of the ends of the pipeline in the piping diagram, and then the acoustic wave length measurement is performed on the actual pipeline. According to the present invention, such a reflected sound wave obtained at a predetermined timing from the start of reception may be a reflected sound wave caused by a standing wave due to the presence of a reflection source such as a joint at a position very close to the sound generating means. In the received data of the reflected sound wave obtained as a result of the sound wave length measurement, the reflected sound wave which is not from one end of the actual pipe line other than the one end Erroneous determination as reflected sound waves from

On the other hand, a plurality of reflected sound waves are extracted in order from the reflected sound wave having the highest peak value in the received data relating to the reflected sound waves obtained as a result of the sound wave length measurement, and the distance obtained from the reception timing and the reflections thereof are obtained. The deviation regarding the peak height of the sound wave is displayed by the display 24. The display of the distance means that the data for selecting the distance from one end of the pipeline to the other end on the piping diagram is displayed. The distance closest to the distance from one end of the pipeline to the other end is easily determined as the distance from one end of the pipeline to the other end. Can be inferred. In addition, when the distance is selected, it can be confirmed whether or not the reflected sound wave is a reflected sound wave from an end other than one of the ends of the actual pipeline by a deviation relating to the height of the peak.

[0024]

As described above, according to the first to fifth aspects of the present invention, even if one of the above-mentioned phenomena is affected, one end of the conduit to one end other than the other end is affected. The data for estimating the length of the pipe can be presented from the sound wave length measurement results so that the distance from one end of the pipeline to the other end can be properly determined. it can. In particular, according to the first aspect of the present invention, the reflected sound wave from the start of reception on the reception data during a predetermined timing is not treated as data for length measurement, and the reflected sound wave after the lapse of the predetermined timing is converted into data for length measurement. By doing so, even if there is a reflection source near the sound generating means, it is possible to prevent erroneous determination that the reflected sound wave from the reflection source is from one end other than one end of the pipeline. In addition, it is possible to prevent a length measurement error of a pipeline from increasing when a standing wave is generated.

According to the second and third aspects of the present invention, by extracting a plurality of peak values in descending order, the end of the pipe line to be determined on the piping diagram from the extracted peak values. By choosing the peak value that best fits the length from one of the sections to the other end, errors in the actual length of the pipeline can be reduced,
Even if the reflected sound wave is attenuated, the reflected sound wave becomes smaller, or the reflected sound wave is obtained from a reflection source other than one end of the pipeline, the end of the pipeline on the piping diagram It is possible to appropriately select the reflected sound waves from the end other than one of the above.

According to the fourth aspect of the present invention, one having a new peak value is sequentially extracted at a timing excluding a predetermined range from the timing at which the peak value is selected, so that the same reflection value is obtained. Since it is possible to prevent the peak value from being selected again from the sound wave,
Errors in extracting reflected sound waves when affected by the above-described phenomenon are reduced.

According to the fifth aspect of the present invention,
The height of the peak value of the extracted reflected sound wave is presented as a deviation, so that when estimating the length from one end of the actual pipeline to the other end, the end of the Since it can be determined from the deviation that the sound wave is a reflected sound wave from an end other than one end, it is possible to improve the accuracy of extracting the reflected sound wave in an actual pipeline.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining an apparatus used in a sonic pipe length measuring method according to the present invention.

FIG. 2 is a reception timing chart of reflected sound waves for describing a reflected signal determination method according to the present invention.

FIG. 3 is a schematic diagram showing an example of display contents of a display used in the sonic pipe length measuring device shown in FIG.

FIG. 4 is a schematic diagram of a pipe for explaining an acoustic pipe length measuring system.

5A and 5B are a schematic diagram of a pipeline and a reception timing chart of a reflected acoustic wave for explaining a problem in the sonic pipeline length measurement system.

[Explanation of symbols]

 Reference Signs List 20 sound wave type pipeline survey device 21 sound generation means 22 sound collection means 20, 21 pipeline 22, 23 branch pipe A one end of pipeline B other end of pipeline end

Claims (5)

[Claims] 1. A sound generating means for transmitting a pulsed sound wave from one end of a pipe into the pipe, and a pulsed sound wave reflected in the pipe at one end of the pipe. In a sound wave type pipe length measuring system that measures the length of a pipe based on the time and sound velocity value from the time when the pulsed sound wave is transmitted to the time when the sound is collected using sound collecting means for collecting sound, A sound generating means and a sound collecting means are arranged at one of the ends of the length measuring pipe, and receive data relating to the reflected sound waves are stored. A reflected sound wave determination method in a sound wave type pipe length measuring system, wherein a reflected sound wave obtained after a predetermined timing elapses without being treated as data is used as length measurement data. 2. The reflected sound wave discrimination method in the sonic pipe length measuring system according to claim 1, wherein, among reflected sound waves obtained after the lapse of the predetermined timing, a plurality of reflected sound waves having a plurality of ranks from a highest peak value are determined. A reflected sound wave discriminating method in a sound wave type pipe length measuring system, which is extracted. 3. A sound generating means for transmitting a pulsed sound wave from one end of the pipe into the pipe, and a pulsed sound wave reflected in the pipe at one end of the pipe. In a sound wave type pipe length measuring system that measures the length of a pipe based on the time and sound velocity value from the time when the pulsed sound wave is transmitted to the time when the sound is collected using sound collecting means for collecting sound, A sound generating means and a sound collecting means are arranged at one of the ends of the length measuring pipe, receiving data regarding reflected sound waves are stored, and among the obtained reflected sound waves, those having a plurality of ranks are determined from the highest peak value. A reflected sound wave discriminating method in a sound wave type pipe length measuring system, which is extracted as an object. 4. A reflected sound wave discrimination method in a sound wave type pipe length measuring system according to claim 2 or 3, wherein the extracted reflected sound wave is excluded from a predetermined range around a timing at which a peak value is selected. A reflected sound wave discriminating method in a sound wave type pipe length measuring system, wherein a signal having a new peak value is sequentially extracted at a timing. 5. The reflected sound wave discrimination method in the sound wave type pipe length measuring system according to claim 2 or 3, wherein a deviation of a peak height of the extracted reflected sound wave with respect to a highest peak value is determined. A method for determining a reflected sound wave in a sound wave type pipe length measuring system.