JP2009236691A - System and method for searching buried pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for searching a buried pipe, suitable for searching a position of a pipe which is buried in the earth, a building frame or the like, such as a gas pipe or the like. <P>SOLUTION: A sonic wave transmitted from a sonic wave transmitter 2 continuously changes in a frequency band of 400-600 Hz and with a cycle of 0.5 seconds. The sonic signal synthesized in an acoustic synthesizing portion 2b is amplified in an amplifying portion 2c and then transmitted from a speaker 2a into a pipe. At a receiving apparatus 3 side, a pickup 3a is put on the ground surface of a place which is expected as a buried position beforehand and sonic vibration propagating from the inside of the pipe to the ground surface is probed. Concretely, the pickup 3a scans around an estimated buried position, and a position where a level display of a display portion 3e indicates the maximum value is specified as a buried position. The position is marked on a road and reflected on a map. Buried positions along the whole length of the pipe can be determined by sequentially carrying out the process at specified intervals on the road. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exploration technique for a buried pipe position, and more particularly to a buried pipe exploration apparatus and method suitable for exploring a position of a pipe buried in the ground, a building enclosure, etc., such as a gas pipe.

Conventionally, use of an electromagnetic locator has been common as a non-opening exploration method for gas piping and the like. However, in recent years, polyethylene pipes (PE pipes), which have been spreading widely, have often been located in locator wires for position exploration that break at the wiring connection due to electrolytic corrosion or the like, which has been an obstacle to exploration. Also, the steel pipe has a problem that the exploration accuracy is lowered when an insulating joint or valve insulation is interposed in the middle of the pipe. Furthermore, although it is relatively easy to search for a large-diameter pipe, there is a problem that the sensitivity is lowered in a small-diameter pipe such as a branch pipe (in-house pipe).
To deal with these problems, a sound source is attached to the open end of a branch pipe above the branch, and sound waves are transmitted from here to the inside of the pipe to detect acoustic vibrations propagating in the pipe at the estimated ground surface. An acoustic exploration technique for specifying a position has been proposed (for example, Patent Document 1).
Moreover, the technique which transmits simultaneously the sound wave of a several different frequency (for example, 150Hz-300Hz) about a transmitted sound wave is disclosed (patent document 2). Furthermore, a technique for intermittently transmitting a sound wave appropriately selected from a frequency of 300 Hz to 1100 Hz is disclosed (Patent Document 3).

JP-A-7-146218 JP 2005-308445 A JP-A-8-271370

In the acoustic exploration technique, the transmitted sound wave has a fixed frequency even if it is transmitted by a plurality of types of frequencies. However, the detection sensitivity on the ground surface varies greatly depending on the embedded environment such as the pipe type of the embedded pipe, the soil at the detection position, the pavement state, and the like, and there is a problem that it is difficult to appropriately cope with these in the conventional frequency fixing method. There is also a problem that it is difficult to distinguish background noise and detected vibration. For these reasons, the acoustic exploration method is not widely used.
The present invention solves such a problem, and provides a buried pipe exploration apparatus and method with high exploration accuracy, easy discrimination from background noise, and high practicality.

The gist of the present invention is as follows. That is, the fuel gas buried piping position locator according to the present invention is:
(1) A buried pipe exploration device for exploring a pipe burying position by transmitting a signal sound from a sound source installed in a pipe opening to the inside of the pipe and detecting propagation vibration using a detection means outside the buried layer. The signal sound is a sound wave that continuously changes in a predetermined frequency band with a predetermined period.
According to the present invention, since the frequency of the sound wave propagating from the sound source is continuously changed, it is characterized in that tracking is easy when scanning using the detection unit, and discrimination from background noise is easy.
Note that the continuous change in the frequency band is not limited to a smooth change, and may be a step change.
(2) The predetermined frequency band is 400 Hz to 600 Hz.
(3) The predetermined period is in a range of 0.25 seconds to 0.75 seconds.

(4) The detection means further includes means for enabling visual confirmation of a level change of the detected propagation vibration accompanying a minute change in the detection position.
(5) The detection means further includes means for enabling an auditory confirmation of a level change in detected propagation vibration accompanying a minute change in the detection position.
By enabling visual confirmation, it is possible to identify even minute changes that cannot be captured by digital display or analog display.
(6) The listening means further includes means for enabling auditory confirmation by a plurality of persons.
By enabling visual confirmation by a plurality of people, there is a feature that a more objective determination is possible.
(7) The buried pipe exploration device, wherein the detection means further comprises means for appropriately changing the predetermined frequency band and / or the predetermined period to the sound source. .
According to the present invention, it is possible to select an optimal frequency band and cycle according to the pipe embedment environment such as the pipe type, the soil at the detection position, and the pavement state, and it is possible to always ensure high detection performance.

In addition, the fuel gas buried piping position exploration device according to the present invention,
(8) A buried pipe exploration method for exploring a pipe buried position by propagating a signal sound from a pipe opening into the pipe and detecting the signal sound at a position outside the buried layer, wherein the signal sound is It is a sound wave that changes in a frequency band of 400 Hz to 600 Hz and a cycle of 0.25 seconds to 0.75 seconds.
(9) In the above (8), the frequency band and / or period of the signal sound is appropriately changed in response to a change in the level of detected propagation vibration accompanying a minute change in the detection position.

  According to the present invention, it is possible to ensure detection sensitivity regardless of the buried environment such as the type of buried piping, the soil at the detection position, and the pavement state.

Hereinafter, embodiments of the present invention will be described in more detail with reference to FIGS. The scope of the present invention is described in the scope of claims, and is not limited to the following embodiments.
<First embodiment>
FIG. 1 is a diagram showing an overall configuration of an embedded piping exploration device 1 according to the present embodiment. The buried pipe exploration device 1 includes a sound wave transmission device 2 provided in a stand pipe portion 6 (position A) of a branch pipe 5 in a gas conduit 4 route buried in soil, and a pipe burying estimated position separated from the position A. The receiving apparatus 3 arranged on the ground surface at (position B) is provided as a main configuration.
The sound wave transmitting device 2 includes a signal oscillating unit 2 b that oscillates a predetermined signal, a power amplifying unit 2 c, an output adjusting unit 2 d, and a speaker 2 a attached to the opening of the standing tube unit 6. As a result, the sound wave transmitting device 2 oscillates a signal wave that continuously changes with a desired frequency band and period in the signal oscillation unit 2b, amplifies the signal wave in the power amplification unit 2c, and generates a sound wave from the speaker 2a. It is comprised so that it may transmit in a pipe. Further, the output of the sound wave transmitted from the speaker 2a into the tube is adjusted by the output adjusting unit 2d so as to be at an optimum level for exploration.
The receiving device 3 includes a pickup 3a, and a receiving device main body 3b including a voltage amplifying unit 3c, a filter unit 3d, a sensitivity adjusting unit 3g, a power amplifying unit 3h, and a display unit 3e as main components. Thereby, the receiving device 3 is transmitted as a sound wave from the sound wave transmitting device 2, propagates through the buried gas conduit 1, and further detects a vibration wave reaching the ground surface position B by the pickup 3a and outputs it as an electric signal. . Furthermore, the main body 3b is configured to display the level on the display unit by performing voltage amplification and filtering. Further, the receiving device 3 is configured to be able to output the received vibration wave to the external headphones 3f after being amplified by the power amplifier 3h. Further, the sensitivity of the receiving device 3 is adjusted to a sensitivity suitable for exploration by the sensitivity adjustment unit 3g.

Next, the buried pipe exploration method in this embodiment will be described. The sound wave transmitted from the sound wave transmitting device 2 is a wave that continuously changes with a frequency band of 400 to 600 Hz and a period of 0.5 seconds as shown in FIG. The sound wave synthesized in the signal oscillating unit 2b is amplified in the amplifying unit 2c and is transmitted into the tube by the speaker 2a.
On the receiving device 3 side, a pickup 3a is placed in advance on the ground surface at the expected position of pipe burying, and the sound wave vibration transmitted from the inside of the pipe to the ground surface is searched. Specifically, the area around the estimated embedded position is scanned with the pickup 3a, the level display movement of the display unit 3e of the receiving device 3 is tracked, and the position indicating the highest level is specified as the embedded position. Mark the location on the road and drop it on the map. By sequentially performing this process at predetermined intervals on the road, it is possible to grasp the buried position over the entire length of the road.
In the present embodiment, an example in which the level display of the display unit 3e is determined by visual tracking is shown, but auditory determination using the headphones 3f may be used. Furthermore, it can also be set as the form determined by multiple persons by connecting with a speaker.

<Second Embodiment>
Next, another embodiment of the present invention will be described. The configuration of the buried piping exploration device according to the present embodiment is the same as that of the above-described embodiment, and thus the description thereof is omitted. The difference from the above-described embodiment is that the frequency band and period of the sound wave to be transmitted are changed corresponding to the detection state on the receiving device side.
FIG. 3 is a diagram illustrating an example of frequency band change. In the first step, sound waves that continuously change at the maximum frequency f1, the minimum frequency f1 ′, and the period t1 are transmitted from the transmitting device side. Here, f1 ≦ 600 Hz, f1 ′ ≧ 400 Hz, and 0.25 sec <t1 <0.5 sec are adjusted. With this setting, the receiving device scans the pickup, tracks the display level, and searches the buried position. If determination by this setting is difficult, the next step is to change to a frequency band sound wave that continuously changes at the maximum frequency f2, the minimum frequency f2 ′, and the period t2 from the transmitting device side, and perform the same search. . The frequency band and period of the sound wave in the second step are different from those in the first step, but are the same in that f2 ≦ 600 Hz, f2 ′ ≧ 400 Hz, and 0.25 sec <t2 <0.5 sec. is there.
The frequency band and the period are changed until the position can be specified in this way. When the position can be specified, the process is repeated by moving to another point.
This enables exploration using a frequency band and period suitable for the buried environment, such as soil quality.

<Third embodiment>
Furthermore, another embodiment of the present invention will be described. FIG. 4 is a diagram illustrating an overall configuration of the buried pipe exploration device 20 according to the present embodiment. The buried pipe exploration device 20 is different from the above-described buried pipe exploration device 1 in that a frequency band instruction unit 22a for instructing the receiver 22 to change the frequency band and a transmission unit 22b for wirelessly transmitting the selected frequency band are attached. In addition, the transmitter 21 is provided with a receiver 21a that receives a selected frequency band transmitted from the receiver. Since other configurations are the same as those of the buried pipe exploration device 1, description thereof is omitted.
With such a configuration, in the second embodiment described above, it is necessary for the measurer to contact the transmitter at every step when changing the frequency band, whereas in this embodiment, the frequency band desired by the measurer is required. Is wirelessly commanded from the receiving device side, and the sound wave in the frequency band selected from the transmitting device side is immediately transmitted. This further promotes exploration efficiency.

Hereinafter, the content of the test conducted in order to confirm the effect of this invention is demonstrated.
(Test method)
A 50φ PE pipe having a total length of 44 m was embedded in soil having a depth of 60 cm, and a sound source was attached to the vertical pipe opening on one end side. Place the receiving device at the position of every 2.5m, P1 to P17 like 2.5m, 5.0m, 7.5m, ... in order from the sound source, and transmit sound waves in the frequency range of 100-1000Hz from the sound source. Then, the vibration sound propagating to the ground surface was measured. 5A and 5B are plots of frequency-sound pressure level (dB) characteristics at P1 to P9 and P10 to P17, respectively.
From these figures, the sound pressure level is relatively high in the range of 400 to 600 Hz, and the attenuation of the sound pressure level is small regardless of the distance from the sound source, so that measurement variations can be eliminated and detection accuracy is high. I understand.

同表より、４５０−５５０Ｈｚにおいて、識別性能が良好であることが証明された。 Using the test apparatus of Example 1, an auditory sensory test was further performed. Sound waves of 250 to 350 Hz, 450 to 550 Hz, and 650 to 750 Hz are continuously transmitted from the sound source at a period of 0.5 seconds, and three test subjects listen on the receiving device side using headphones, and transfer characteristics (from the sound source) Change in detection level depending on the distance) and ease of listening. Table 1 shows the results.

From the table, it was proved that the discrimination performance was good at 450-550 Hz.

  INDUSTRIAL APPLICABILITY The present invention can be widely used not only for gas piping but also for position exploration of piping in which an opening can be provided on the ground.

It is a figure which shows the structure of the buried piping search apparatus 1 which concerns on 1st embodiment. It is a figure which shows the frequency band of the sound wave transmitted from the sound wave transmitter 2, and a periodic characteristic. It is a figure which shows the frequency band and periodic characteristic of the sound wave transmitted in 2nd embodiment. It is a figure which shows the structure of the buried piping search apparatus 20 which concerns on 3rd embodiment. In Example 1, the frequency-sound pressure level (dB) characteristic in the positions P1-P9 is plotted. In Example 1, the frequency-sound pressure level (dB) characteristics at the positions P10 to P17 are plotted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20 ...... Embedded piping exploration device 2, 21 ... Sound wave transmission device 2a Speaker 2b ... Signal oscillation unit 2c ... Power amplification unit 2d ... Output adjustment unit 3, 22 ································································· Pickup 3c ··· Voltage amplifier 3d ··· Filter portion 3e ··· Display portion 3f · Headphone 3g · Sensitivity adjuster 3h · · 4 ... Gas conduit 5 ... Branch pipe 6 ... Stand pipe

Claims (9)

A buried pipe exploration device for exploring a pipe burying position by propagating signal sound from a sound source installed in a pipe opening to the inside of the pipe and detecting propagation vibration using a detection means outside the buried layer,
The buried pipe exploration device, wherein the signal sound is a sound wave that continuously changes within a predetermined frequency band with a predetermined period. The buried piping exploration device according to claim 1, wherein the predetermined frequency band is 400 Hz to 600 Hz. The buried pipe exploration device according to claim 1 or 2, wherein the predetermined period is in a range of 0.25 seconds to 0.75 seconds. The buried pipe exploration device according to claim 1, wherein the detection means further comprises display means for enabling visual confirmation of a level change of detected propagation vibration accompanying a minute change in the detection position. The buried pipe exploration device according to any one of claims 1 to 4, wherein the detection means further comprises listening means for enabling auditory confirmation of a level change of detected propagation vibration accompanying a minute change in a detection position. The buried pipe exploration device according to claim 5, wherein the listening means further includes means for enabling auditory confirmation by a plurality of persons. The said detection means is further equipped with the means which can change suitably the said predetermined frequency band and / or the said predetermined period with respect to the said sound source, The 1st thru | or 6 characterized by the above-mentioned. Underground piping exploration equipment. A buried pipe exploration method for exploring a pipe buried position by propagating a signal sound from the pipe opening to the inside of the pipe and detecting the signal sound at a position outside the buried layer,
The buried pipe exploration method, wherein the signal sound is a sound wave that changes in a frequency band of 400 Hz to 600 Hz and a period of 0.25 seconds to 0.75 seconds. 9. The buried pipe exploration method according to claim 8, further comprising changing the frequency band and / or cycle of the signal sound as appropriate in response to a level change of detected propagation vibration accompanying a minute change in the detection position.

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