JPH07146374A - Device and method for locating buried pipeline - Google Patents

Abstract

PURPOSE:To accurately locate a buried pipeline from the ground surface without digging the ground by utilizing a magnetic field. CONSTITUTION:A transmission coil TC generates a magnetic field against a buried supply pipe 21 and a reception coil RC1 detects the magnetic field and outputs received signals. The received signals are amplified to a prescribed level and an amplitude signal output module RB1 rectifies the signals and outputs amplitude signals. A phase difference signal output module RQ1 compares the received signals with a reference signal outputted from a transmitter TRA and outputs the compared results as phase difference signals. When the amplitude signals and phase difference signals are used jointly, the underground supply pipe 21 can be located without digging the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buried pipe position specifying device and a specifying method thereof, and more particularly to a buried pipe position specifying device for specifying branch positions of buried gas pipes, chemical plant pipes and the like buried underground. Regarding the position specifying method.

[0002]

2. Description of the Related Art In order to supply city gas to homes and the like, a supply pipe having a diameter smaller than that of the branch pipe is branched from a branch pipe buried underground and supplied to each home and the like. is doing. Such a supply pipe needs to be removed from a safety point of view, for example, when the supply of city gas to the user is stopped.

Conventionally, the work for removing the supply pipe has been performed with reference to FIGS.
As shown in FIG. 3, an embedded pipe position specifying device 30 including a transmitter 31 that generates a magnetic field by passing a current through an object and a receiver 32 that detects the magnetic field generated in the object by a magnetic sensor is used. It was The buried pipe position identifying device 30 is directly connected to the buried branch pipe via the supply pipe by several 1
A high frequency power of 0 KHz is supplied to generate a magnetic field, and the leaking magnetic field is detected by the receiver 32 arranged on the ground surface. In the detection by the receiver 32, as shown in FIG. 4, after the buried position of the branch pipe 33 is specified by the strength of the signal received by the receiver 32, the branch position is estimated from the piping drawing at the time of the buried condition.

However, in the buried pipe position specifying method using the buried pipe position specifying device 30 described above, although the position of the straight pipe can be estimated, the leakage magnetic field is disturbed near the branch position, so that the branch position is estimated. May cause an error. If there is a pipe buried adjacent to the pipe whose position is to be evaluated, an error may occur due to the influence of the adjacent pipe. Therefore, when the position is evaluated by the buried pipe position identifying device 30, it is necessary to excavate a relatively wide range in consideration of the error.

Due to recent traffic conditions, it has become difficult to easily excavate roads and the like, and it is necessary to more accurately specify the branching position from the economical point of view.

[0006]

[Purpose] The present invention has been made to solve such a conventional problem, and it is possible to accurately specify the position of a buried pipe on the ground without excavating the buried pipe by utilizing a magnetic field. It is an object of the present invention to provide a buried pipe position specifying device and a position specifying method therefor.

[0007]

The buried pipe position specifying device of the present invention which achieves the above object has a reference signal generating means for generating a reference signal, and an amplifier for amplifying the reference signal to a predetermined electric power and in-phase with the reference signal. A transmitter comprising a transmission signal amplifying means for outputting a transmission signal of, and a transmission coil inserted into the buried pipe, for generating a magnetic field in the buried pipe based on the transmission signal output from the transmission signal amplifying means of the transmitter, A reception coil that receives the magnetic field generated by the transmission coil on the ground and outputs a reception signal, and an amplitude signal output means that amplifies and rectifies the reception signal output from the reception coil to a predetermined level and outputs an amplitude signal, a reference And a receiver equipped with a phase difference signal output means for comparing the phases of a signal and a received signal and outputting a phase difference signal, and a plurality of receiving coils and receivers may be provided. .

The buried pipe position specifying method by the above-mentioned buried pipe position specifying device generates a magnetic field outside the buried pipe, receives the magnetic field on the ground and converts it into an amplitude signal and a phase difference signal, and the amplitude signal and the phase difference signal. The location of the buried pipe is specified based on

[0009]

When the transmission signal sent from the transmission signal amplifying means of the transmitter is applied to the transmission coil inserted in the buried pipe, a magnetic field is generated in the buried pipe, and this magnetic field causes eddy currents inside and outside the buried pipe. Occurs. When a leak magnetic field formed by an eddy current on the outer wall of the buried pipe is detected by the receiving coil, a receiving signal is generated in the receiving coil. The reception signal output from the reception coil is amplified to a predetermined level, rectified by the amplitude signal output means, and then the amplitude signal is output from the amplitude signal output means. Further, the amplified reception signal and the reference signal output from the transmitter are compared by the phase difference signal output means, and the comparison result is output as a phase difference signal. By using such an amplitude signal and a phase difference signal together, the position of the transmission coil can be accurately specified. This makes it possible to identify the position of the buried pipe without excavating the pipe in the soil. Further, by arranging a plurality of receiving coils connected to a plurality of receivers at regular intervals, it is possible to measure the distribution of the magnetic field leaking without moving the receiving coils and identify the position of the buried pipe. It will be possible.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the buried pipe position specifying device of the present invention is a reference signal generator 2 which is a reference signal generating means.
And a transmitter TRA provided with a transmission signal output amplifier 3 which is a transmission signal output amplifying means, a transmission coil TC driven based on a transmission signal from the transmitter TRA, and a transmission coil TC.
By a receiving coil RCn (n is 1 to 6 for the sake of description), amplitude signal output modules RB _{1 to} RB ₆ that are amplitude signal output means, and phase difference signals that are phase difference signal output means. A receiver RECn (where n is 1 to 6 for the sake of description) having output modules RQ _{1 to} RQ ₆ .

The reference signal generator 2 is installed in the transmission signal transmission circuit 1 in the transmitter TRA, and the transmission signal transmission circuit 1 is further provided with a transmission signal output amplifier 3 and a reference signal generation circuit 4. One output side of the reference signal generator 2 is connected to the input side of the transmission signal output amplifier 3, and the output side of this transmission signal output amplifier 3 is connected to the transmission terminal T ₀ . Also,
The transmission terminal T ₀ is connected to the transmission coil TC by the pair core wire P ₀ of the cable CBL ₀ . The other output side of the standard signal generator 2 is connected to the input side of the reference signal generation circuit 4, and the six output sides of this reference signal generation circuit 4 are the reference signal terminals T ₁
~ T ₆ is connected. The reference signal terminal T ₁ through T ₆ each reference terminal R of the phase difference signal output module RQ ₁ to Rq ₆ installed in the receiver REC ₁ ~REC ₆ to be described later
Connected with T ₄ .

The transmission signal f ₀ is transmitted to the pair core wire P ₀ connecting the transmission terminal T ₀ of the transmission signal transmission circuit 1 and the transmission coil TC. The transmission signal f ₀ uses a relatively low frequency band of several Hz to several tens of Hz because it is necessary to pass through the supply pipe 21 made of metal. By transmitting this transmission signal f ₀ to the transmission coil TC, the transmission coil TC
Is applied to generate a magnetic field, and the magnetic field causes the supply tube 2
Eddy currents are generated inside and outside 1. The leakage magnetic field formed by the eddy current on the outer wall of the supply pipe 21
Detected by the C ₁ ~RC _6.

The receiving coils RC _{1 to} RC ₆ are connected to the cable CB.
Receive signal circuits RCC _{1 to} RCC with paired cores P _{1 to} P ₆ of L _1.
Six receiving terminals RT ₁ and RT ₂ are connected. This pair core P ₁ to P ₆ the received signal f ₁ ~f ₆ is received. The received signals f _{1 to} f ₆ are received signal amplification module R
It is sent to A _{1 to} RA ₆ . Received signal amplification module RA
_{1 to} RA ₆ are respectively connected by a differential amplifier 5, a low pass filter 6, a receiving amplifier 7, and a band pass filter 8,
One and the other input sides of the differential amplifier 5 are receiving terminals RT
₁ , connected with RT ₂ . Further, the output side of the differential amplifier 5 passes through the low pass filter 6, the receiving amplifier 7, and the band pass filter 8 and the input side of the amplitude signal output modules RB _{1 to} RB ₆ and the phase difference signal output modules RQ _{1 to} RQ ₆ . Each is connected to the input side.

[0014] After the amplitude signal output module RB ₁ ~RB ₆ is a received signal f ₁ ~f ₆ amplified by the received signal amplifier module RA ₁ to RA ₆ rectifies the AC full-wave rectifier 9 and DC conversion, amplitude Amplitude output terminal RT as signal data
Output from ₅ . Phase difference signal output module RQ _{1 to} R
Q ₆ is composed of a phase comparator 10 and a waveform shaping circuit 11, respectively. One input side of the phase comparator 10 is connected to the reception signal amplification modules RA _{1 to} RA _6, and the phase comparator 10 is connected.
The other input side of is connected to the reference terminal RT ₄ . As a result, the phase comparator 10 compares the reference signal from the transmission signal transmission circuit 1 with the reception signals from the reception signal amplification modules RA _{1 to} RA ₆ . The comparison result is converted into direct current by the waveform shaping circuit 11, and is output from the phase difference output terminal RT ₆ as phase difference signal data.

In such a buried pipe position specifying device, as shown in FIG. 2, a transmitting coil TC and a receiving coil RC are provided.
When and are arranged so that their central axes are orthogonal to each other, the output intensity of the amplitude signal becomes substantially zero when the central axes of the receiving coils RC are aligned directly above the transmitting coil TC. Further, since the phase difference signal is inverted when the receiver coil RC is moved to the left or right around the transmitter coil TC, the fact that the center axis of the receiver coil RC is directly above the transmitter coil TC indicates the center of the phase difference signal inversion. You can ask the department. Therefore, by superimposing the position at which the output intensity of the amplitude signal becomes substantially zero and the position at the center of the inversion of the phase difference signal, the position of the transmission coil TC can be accurately specified.

A method of identifying the buried pipe position by the thus-constructed buried pipe position identifying device will be described below. The transmission signal T ₀ is transmitted from the transmission signal transmission circuit 1 and is inserted into the supply pipe 21 which is supplied to each home or the like.
When C is applied, a magnetic field is generated, and this magnetic field generates an eddy current inside and outside the supply pipe 21. The receiving coil R is applied to the leakage magnetic field formed by the eddy current on the outer wall of the supply pipe 21.
When C ₁ is moved closer, a reception signal f ₁ is generated in the reception coil RC _{1 according} to the approach position. The reception signal f ₁ is subjected to common-mode noise removal by the differential amplifier 5 of the reception signal amplification module RA ₁ and high-frequency components removed by the low-pass filter 6, and the full-wave signal of the amplitude signal output module RB ₁ via the reception amplifier 7 and the band-pass filter 8. The signal is output to the input side of the rectifier 9 and one input side of the phase comparator 10 of the phase difference signal output module RQ ₁ .

The full-wave rectifier 9 of the amplitude signal output module RB ₁ rectifies the received signal amplified by the received signal amplifying module RA _{1 and} converts it to DC, and then outputs it as amplitude data from the amplitude output terminal RT ₅ . Using this amplitude data, the receiving coil RC ₁ is moved to a position where the output intensity of the amplitude data becomes substantially zero. The phase comparator 10 of the phase difference signal output module RQ ₁ outputs the comparison result obtained by comparing the reference signal from the transmission signal sending circuit 1 and the reception signal amplified by the reception signal amplification module RA ₁ as phase difference signal data. Output from terminal RT ₆ . The receiving coil RC ₁ is moved until the center of inversion of the phase difference data can be obtained by using this phase difference signal data.

By using the amplitude data and the phase difference data together to specify the position of the transmission coil TC, the buried position of the supply pipe 21 can be specified accurately. In addition,
If a plurality of receiving coils and receivers are provided, the distribution of the leaking magnetic field can be measured without moving the receiving coils.

[0019]

As is apparent from the above embodiments, the piping position specifying device of the present invention is a reference signal generating means for generating a reference signal, and amplifies the reference signal to a predetermined power to transmit the signal in phase with the reference signal. A transmitter comprising a transmission signal amplifying means for outputting a signal, a transmission coil inserted into the buried pipe and generating a magnetic field in the buried pipe based on a transmission signal output from the transmission signal amplifying means of the transmitter, and a transmission coil The receiving coil that receives the magnetic field generated by the above on the ground and outputs the receiving signal, and the amplitude signal output means that amplifies and rectifies the receiving signal output from the receiving coil to a predetermined level, and outputs the amplitude signal, the reference signal and The position of the transmission coil is determined based on the amplitude signal and the phase difference signal by including a receiver having a phase difference signal output means for comparing the phases of the reception signals and outputting the phase difference signal. Since it is possible to specify the probability,
It is possible to identify the position of the buried pipe without excavating. Further, by providing a plurality of receiving coils and receivers, it is possible to measure the distribution of the leaking magnetic field without moving the receiving coils and specify the buried pipe position.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a buried pipe position identifying device according to the present invention.

FIG. 2 is a diagram showing changes in an amplitude output signal and a phase difference output signal depending on relative positions of a transmission coil and a reception coil.

FIG. 3 is a diagram showing an embodiment of a conventional buried pipe position identifying device.

FIG. 4 is a diagram showing a position specifying method by a conventional buried pipe position specifying device.

[Explanation of symbols]

2 ... reference signal generator (reference signal generating means) 3 ... transmission signal power amplifier (transmission signal output amplifying means) TRA ... transmitter TC ... transmitter coil RC ... receiving coil RB ₁ ~RB ₆ ... amplitude signal output module (amplitude signal Output means) RQ _{1 to} RQ ₆ ... Phase difference signal output module (phase difference signal output means) REC _{1 to} REC ₆ ... Receiver

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshihide Kawabe 2-12-12 Nishichuo, Kure City, Hiroshima Prefecture

Claims (3)

[Claims] 1. A buried pipe position specifying device for specifying the position of a buried pipe, wherein a reference signal generating means for generating a reference signal, the reference signal is amplified to a predetermined power, and a transmission signal in phase with the reference signal is output. A transmitter composed of the transmission signal amplifying means, and a transmission coil that is inserted into the buried pipe and generates a magnetic field in the buried pipe based on the transmission signal output from the transmission signal amplifying means of the transmitter;
A reception coil that receives the magnetic field generated by the transmission coil on the ground and outputs a reception signal, and an amplitude signal that amplifies and rectifies the reception signal output from the reception coil to a predetermined level and outputs an amplitude signal. An embedded pipe position specifying device comprising: an output means; and a receiver including a phase difference signal output means for comparing the phases of the reference signal and the received signal and outputting a phase difference signal. 2. The buried pipe position specifying device according to claim 1, wherein a plurality of the receiving coils and the receiver are provided. 3. A magnetic field is generated outside the buried pipe, the magnetic field is received on the ground and converted into an amplitude signal and a phase difference signal, and the position of the buried pipe is specified based on the amplitude signal and the phase difference signal. A method for identifying the position of a buried pipe, which is characterized in that