JPH0783646A - Position detection of gas cutoff part composed of service tee, socket and bend by use of sound waves - Google Patents

Abstract

PURPOSE:To simply and precisely detect the existence and the position of a joint or the like in a pipe line, especially the position of a gas cutoff part which is composed of a service tee, a socket, and a bend, by effectively making use of a sound-wave detection technique. CONSTITUTION:An acoustic unit 8 in which a transmission part 9 and a reception part 10 for sound waves as well as a temperature sensor 11 have been constituted is mounted on, and attached to, a proper part in a pipe line which is provided with a gas cutoff part 4 composed of a service tee 5, a socket 6, and a bend 7 and with other joints, reflected waves of pulse-shaped sound waves, at a single cycle, which are transmitted from the transmission part 9 are received by the reception part 10, the amplitude level of the reflected waves is measured with the passage of time, and their peak groups are detected. An amplitude level in a first peak is compared with an amplitude level in a fifth peak in the respective peak groups, the peak group in which the latter amplitude level is larger is judged as the corresponding part of the gas cutoff part 4, and a distance up to the gas cutoff part 4 is found on the basis of the speed of sound and of the elapsed time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of detecting the position of a gas shutoff portion consisting of a service tee, a socket and a bend by means of sound waves.

[0002] A gas shut-off section consisting of a service tee, a socket and a bend is installed in a city gas pipeline system between a land and a road occupied or owned by a customer, that is, between a supply pipe and an inner pipe. In an emergency, the gas supply can be cut off. Therefore, it is necessary that the position of the gas blocking portion can be accurately detected. Incidentally, such a gas cutoff portion may be commonly used as a Marusa.

FIG. 1 shows an example of a gas conduit system.
Reference numeral 1 is a main branch pipe, 2 is a supply pipe, 3 is an inner pipe, and 4 is a gas blocking portion which is a target of the present invention.
Is a configuration in which a service Q 5 capable of shutting off gas is connected to the supply pipe 2 via a socket 6 and to the inner pipe 3 via a bend 7. Hereinafter, the gas blocking unit 4 having such a configuration will be simply described as a gas blocking unit. The supply pipe 2 and the inner pipe 3 are connected to each other through joints such as bends, elbows, sockets, es cheeses, etc., as required for installation.

As one of the measuring methods for such a buried conduit, a method utilizing acoustic wave detection technology has been proposed. In this method, an acoustic unit consisting of a transmitting unit, a receiving unit and a temperature sensor is mounted at an appropriate place in the pipeline, and among the reflected waves of pulsed sound waves transmitted from the transmitting unit, only the peak with the maximum amplitude is received at the receiving unit. The length is measured by multiplying the time elapsed from the detection and emission of the pulsed sound wave to the return of the peak by the speed of sound.

[0005]

As described above, according to the conventional length measuring method using the acoustic wave detection technique, the pipe line portion where the peak of the maximum amplitude occurs, that is, the length to the open end or the closed end of the pipe line is measured. However, it is not used at all as a method for detecting the presence of joints such as bends, elbows, sockets, and es cheeses provided between them, and for measuring the distance to them. Therefore, according to the conventional sound wave detection technique, it is not possible to detect the position of the joints, but it is impossible to identify the position of the gas blocking unit having the above-described configuration from the other joints and detect the position. The present invention has been devised in view of the above point, and an object thereof is to effectively apply a sound wave detection technique to the detection of the position of the gas blocking unit.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a sound wave transmitting portion is provided at a proper position of a pipe having a gas shutoff portion including a service tee, a socket and a bend, and another joint. An acoustic unit consisting of a receiver and a temperature sensor is installed, and the reflected wave of a single-cycle pulsed sound wave transmitted from the transmitter is received at the receiver and the amplitude level of the reflected wave is measured over time, and its peak While detecting the groups, the amplitude level of the first peak and the amplitude level of the fifth peak in each peak group are compared, and the latter peak group having a large amplitude level is determined as the corresponding portion of the gas cutoff unit. We propose a method to detect the position of the gas cutoff part from the speed of sound and the elapsed time.

[0007]

When the pipes are provided with the above-mentioned bends, elbows, sockets, es cheeses, gas blocking parts, etc., the acoustic impedance becomes discontinuous at that part, and the sound will propagate through the straight pipe part. The single-cycle pulsed sound waves are partially reflected in response to changes in acoustic impedance.

On the other hand, at a connecting portion having a greatly different diameter, such as a connecting portion between the supply pipe and the main branch pipe, the pipe line is substantially open to the sound wave, and the acoustic impedance greatly changes. The pulsed sound waves that have propagated through the duct are mostly reflected and return to the transmission side.

Therefore, when the reflected waves are received with time, a portion consisting of a plurality of peaks, that is, a peak group, appears at a plurality of time points corresponding to the joints and the open end. Therefore, in order to detect the position of the gas blocking unit, first, the peak group by the gas blocking unit must be identified from among these peak groups.

First, the peak group due to the reflected wave from the open end is
Since the amplitude level as a whole is large as compared with the peak group from the fittings, the amplitude level can be discriminated from the amplitude level by comparison. In addition, even in the case of a joint, since the amplitude level of the reflected wave is small in the case of a socket, it is possible to make a discrimination by comparing the amplitude levels.

On the other hand, as described above, the shape of the peak group corresponding to the gas blocking portion formed of the unique combination of the service charge, the socket and the bend is different from the shape of the peak group corresponding to other joints. The morphology is shown. That is, in the peak group corresponding to the gas cutoff section, clear peaks having a predetermined amplitude level or more occur five times on the positive and negative sides, and the fifth peak has a larger amplitude level than the first peak.

Further, depending on the adjustment of the threshold of the amplitude level for judging as a peak, the number of peaks is 5 even in other joints such as a combination of bend, elbow and straight pipe.
Or more, but as mentioned above, 1
When the amplitude levels of the second and fifth peaks are compared, the amplitude level of the first peak is always higher.

Therefore, for the peak groups having the first to at least the fifth peaks, the amplitude levels of the first and fifth peaks are compared, and the amplitude level of the fifth peak is the amplitude level of the first peak. Larger peaks can be identified as corresponding to the gas block.

After the peak group corresponding to the gas cutoff portion is specified as described above, the elapsed time until the peak having the largest amplitude level in the peak group reaches,
The distance from the acoustic unit to the gas cutoff portion can be obtained from the speed of sound derived from the gas temperature in the pipeline detected by the temperature sensor, and the position of the gas cutoff portion can be detected from this distance.

[0015]

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows an example of a gas conduit system as described above, that is, an example of a pipeline to which the present invention is applied, and FIG.
It is explanatory drawing which shows notionally the apparatus which applies the method of this invention.

In FIG. 2, reference numeral 8 is an acoustic unit, and a speaker 9 that constitutes a sound wave transmitting portion, a microphone 10 that constitutes a receiving portion, and a temperature sensor 11 are installed in the acoustic unit 8, and these are respectively wired. It is connected to the measuring device 12 via. The measuring device 12 generates a single-cycle sine wave based on the signal from the signal processing means 13, amplifies it, and supplies it to the speaker 9.
4, pre-processing means 15 for pre-processing the signal from the microphone 10 and outputting it to the signal processing means 13, and pre-processing for pre-processing the signal from the temperature sensor 11 and outputting it to the signal processing means 13. It is composed of means 16 and output means 17 for outputting the signal processing result of the signal processing means 13.
For example, the signal processing means 13 is composed of a CPU of a microcomputer device, and the signal processing means 13 outputs a digital signal sequence corresponding to a sine wave of a single cycle to the pulse generating means 14 and the preprocessing means 15, 16
The digital signal from is processed and the processed result is output to the output means 17 such as a display device.

Therefore, the pulse generating means 14 converts the digital signal train from the signal processing means 13 into an analog signal,
It is composed of a D / A converter that generates a single-cycle sine wave, an amplifier, and the like. The pre-processing means 15 is composed of an amplifier that amplifies the analog signal from the microphone 10 to a predetermined level, an A / D converter that converts the amplified signal into a digital signal, and the like. The front-end processing means 16 is composed of an A / D converter or the like that converts the analog signal from the temperature sensor 11 into a digital signal. In the above description, other components necessary for operation, such as an I / O device, RAM, ROM, etc., are omitted from illustration and illustration.

In the above construction, when detecting the position of the gas cutoff portion 4, the connection between the straight pipe portion of the inner pipe 3 and the meter cock 18 is disconnected in the pipe line shown in FIG. The acoustic unit 8 is attached to the upper end, and in this state, a single-cycle sine wave is emitted from the speaker 9, the reflected wave is received by the microphone 10, and the temperature of the gas in the pipe is measured by the temperature sensor 11. The signal processing means 13 performs processing. In the above measurement, the pulse generation means 14 transmits the pulsed sound wave in a single cycle and receives the reflected wave a number of times at predetermined time intervals, and increases the S / N ratio by averaging these data. be able to.

3 to 7 show a test pipeline in which various joints are combined in the middle of the pipeline with both ends open, and the acoustic unit 8 is attached to one end of the pipeline, and a sine of a single cycle is formed. It shows the result of emitting a sound wave of a wave and measuring the received amplitude level of the reflected wave over time.

In this case, the common test conditions are as follows. Pipe length: 8m Pipe diameter: 25mm Sound wave: 300Hz

The joints of FIGS. 3 to 7 are as follows. Fig. 3: Gas shutoff part (service che + socket + bend) Fig. 4: Bend + elbow Fig. 5: Bend + straight pipe 50cm + elbow Fig. 6: Bend + nipple + bend + socket Fig. 7: Socket

As can be seen from the above measurement results, both the transmitted sound wave A and the reflected wave B from the open end of the pipe have high amplitude levels, and between these A and B, corresponding to joints. Since the reflected wave C having a low amplitude level appears, it is understood that the reflected wave from the open end and the reflected wave from the joint can be easily identified by comparing the amplitude levels.

On the other hand, even in the case of the same joints, in the case of the socket, the amplitude level of the reflected wave is smaller than that of the other as shown in FIG. You know you will get.

8 to 11 are enlarged views of the portion of the reflected wave from the joints in the data of FIGS. 3 to 6. In these figures, the peak of the reflected wave is detected as a threshold value which is equal to or higher than the range described in each figure, that is, the amplitude level of the boundary value of this range.

First, in the case of the gas cutoff section, the peak is detected five times from a1 to a5 as shown in FIG.
The amplitude level of a5 becomes larger than the amplitude level of a1.

Next, in the case of bend + elbow and bend + straight tube + elbow, their peaks are detected four times from b1 to b4 and from c1 to c4, as shown in FIGS. 9 and 10, respectively. Since the peak-shaped portions next to b4 and c4 respectively do not reach the threshold, they are not detected as peaks. Therefore, in this case, by comparing the numbers of peaks, it is possible to identify the reflected wave of the gas blocking portion.

In the case of the next bend + nipple + bend + socket, the peak is d, as shown in FIG.
It was detected 5 times from 1 to d5, and the number of detected peaks is the same as that of the gas cutoff section. Also in the former two cases, if the threshold values to be detected as peaks are smaller than the amplitude levels of the next peak-shaped portions of b4 and c4, respectively, those peak-shaped portions are also detected as peaks, and therefore, those peak-shaped portions are detected. The number of peaks is 5 or more. Therefore, in these cases, it is not possible to distinguish from the reflected wave of the gas cutoff portion by comparing the number of peaks.

Then, comparing the reflected wave of the gas cutoff portion with the reflected waves of the other joints, the amplitude level of the fifth peak a5 is larger than that of the first peak a1 in the former reflected wave as described above. On the other hand, in the reflected waves of other joints, the fifth peak a5 has a smaller amplitude level than the first peak a1. Therefore, by determining such a difference, the reflected wave of the gas blocking portion and the reflected wave of other joints can be distinguished.

The difference is determined by detecting the peak of the amplitude level larger than the predetermined threshold value and then detecting the fifth peak a.
In addition to the procedure of comparing the amplitude level of 5 with the amplitude level of the first peak a1, after detecting the first peak with an amplitude level larger than a predetermined threshold value, the amplitude level of this first peak is set to the threshold value. As a result, it is possible to detect an odd-numbered peak and determine whether the peak group is due to a reflected wave from the gas cutoff portion or other joints by detecting whether or not the fifth peak is detected. it can.

After the peak group corresponding to the gas cutoff portion is specified as described above, the elapsed time until the peak having the largest amplitude level in the peak group, that is, the peak a3 in FIG. The acoustic unit 8 is detected by the sound velocity derived from the gas temperature in the pipeline detected by the temperature sensor 11.
To the gas cutoff portion, and the position of the gas cutoff portion can be detected from this distance.

[0031]

Since the present invention is as described above, it is possible to effectively utilize the sound wave detection technology to detect the existence and position of the joints in the pipeline, and to use the service team among the joints. There is an effect that the position of the gas blocking portion including the socket and the bend can be easily and accurately detected by distinguishing it from other positions.

[Brief description of drawings]

FIG. 1 is an explanatory view conceptually showing an apparatus to which a position detecting method for a gas blocking unit according to the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of a conduit for detecting the position of a gas blocking unit by applying the method of the present invention.

FIG. 3 shows an example of a measurement result to which the present invention is applied.

FIG. 4 shows another example of the measurement result to which the present invention is applied.

FIG. 5 shows still another example of the measurement result to which the present invention is applied.

FIG. 6 shows still another example of the measurement result to which the present invention is applied.

FIG. 7 shows still another example of the measurement result to which the present invention is applied.

FIG. 8 is an explanatory diagram showing an enlarged part of a reflected wave in FIG.

9 is an explanatory diagram showing an enlarged part of a reflected wave in FIG.

10 is an explanatory diagram showing an enlarged part of a reflected wave in FIG.

11 is an explanatory diagram showing an enlarged part of a reflected wave in FIG.

[Explanation of symbols]

1 main pipe 2 supply pipe 3 inner pipe 4 gas shutoff part (service che + socket + bend) 5 service che 6 socket 7 bend 8 acoustic unit 9 speaker 10 microphone 11 temperature sensor 12 measuring device 13 signal processing means 14 pulse generating means 15 Pretreatment means 16 Pretreatment means 17 Output means 18 Meter cock

Claims (1)

[Claims] 1. An acoustic unit comprising a sound wave transmitting portion, a receiving portion and a temperature sensor is mounted at an appropriate position of a pipeline having a gas shutoff portion including a service tee, a socket and a bend, and other joints, and from the transmitting portion. The reflected wave of the single-cycle pulsed sound wave transmitted is received by the receiving unit, the amplitude level of the reflected wave is measured over time, and the peak group is detected, and the amplitude level of the first peak in each peak group is detected. And the amplitude level of the fifth peak are compared with each other, the latter peak group having a large amplitude level is determined as the corresponding portion of the gas cutoff portion, and the distance to the gas cutoff portion is derived from the sound velocity and the elapsed time. A method for detecting the position of a gas shutoff portion including a service tee, a socket, and a bend by sound waves, characterized by