JP2913604B2 - Object position detection device installed in a concealed place - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for exploring the position of an object provided in a concealed place such as an underground pipe from the ground or the like.

FIG. 3 is a simplified plan view for explaining a prior art. For example, a narrow alley of about 2.0m in the outdoor area 30
Underground buried pipes 31 indicated by broken lines are buried, and pipes 32, 3 for supplying city gas from the
3 is provided, and a gas meter is provided in the conduit 32 as indicated by reference numerals 34 and 35. Between the gas meters 34 and 35, for example, 2 kHz from an oscillator 38 via lead wires 36 and 37.
An AC signal of z is supplied, whereby a signal of 2 kHz is transmitted to the pipelines 31, 32, 33 to generate a magnetic field. As a result, a magnetic field generated from the conduits 31, 32, 33 buried underground is received by a receiver on the ground, and the buried position is searched.

Problems to be solved by the invention In this prior art, the same 2 kHz
A magnetic field of frequency z is generated. Therefore 2 kHz on the ground
When detecting the magnetic field of not only the magnetic field from the underground pipes 31, 32, and 33, but also the magnetic field from the lead wires 36 and 37 are detected at the same time, and therefore, from the underground pipes 31, 32, and 33, Only the magnetic field cannot be detected selectively. Therefore, it is impossible to accurately detect the position of the underground pipes 31, 32, 33 from the ground.

In order to solve this problem, it is necessary to arrange the lead wire fictitiously to prevent the adverse effect of the magnetic field generated from the lead wire. Providing such a lead wire deteriorates workability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus for searching for a position of an object provided in a concealed place so that the position of the object provided in the concealed place can be accurately searched.

Means for Solving the Problems The present invention is directed to an oscillator, which is disposed at two connection places spaced apart along an object provided in a concealed place, is connected to the object at the connection place, and outputs the output of the oscillator. A pair of frequency converters for dividing or multiplying and transmitting the divided or multiplied output signal between connection points of the object, and a receiver for selectively receiving a signal of the divided or multiplied frequency And a position locating device provided in a concealed place.

Further, the present invention provides a DC power supply, which is disposed at two connection places spaced apart along an object provided in a concealed place, is connected to the object at the connection place, and has the same power by the DC power supply. A pair of oscillators that oscillate and oscillate at a frequency to transmit an oscillation output between connection points of the object, and a receiver that receives the output of the oscillator; It is a position search device.

According to the present invention, the output from one oscillator common to an object provided in a concealed place, for example, two connection places provided at a distance between steel pipes buried in the ground, is divided or multiplied. Frequency converters that perform frequency conversion are arranged respectively, and the frequency converters are connected to respective connection locations, and the frequency of the output of the oscillator is divided or multiplied between the connection locations of the object, and the frequency is converted. Transmit the output signal. Outside, for example, on the ground, a signal of a divided or multiplied frequency, which is a magnetic field generated from an object by a receiver,
Receive selectively. Therefore, the receiver can accurately locate the object located in the concealed place without being adversely affected by a magnetic field generated from a lead wire or the like connected between the oscillator and the two frequency converters. Can be explored.

Further, according to the present invention, a pair of oscillators are respectively arranged at two connection places having an interval between objects provided in a concealed place, and the oscillators are powered by a DC power supply and synchronized at the same frequency. Oscillating, thereby causing the object to transmit an oscillating output between two connection locations. On the outside such as on the ground, a magnetic field generated from an object is received by a receiver, and the position of the object is searched. In this manner, the position of the object can be accurately searched without being adversely affected by a magnetic field generated from a lead wire connecting the DC power supply and each oscillator.

Embodiment FIG. 1 is a system diagram of an embodiment of the present invention. Ground 1
Is buried underground pipe 2 such as a steel pipe for transporting a fluid such as city gas. On the ground, an oscillator 3 that derives an oscillation output of, for example, 98 kHz is provided. The 98 kHz oscillation output signal from the output terminal 4 of the oscillator 3 is supplied to a frequency converter 6 via a lead 5 and to another frequency converter 8 via a lead 7. Each of the frequency converters 6 is provided with connection locations 9 and 10 such as two gas meters or the like spaced along the longitudinal direction of the underground pipe 2. The frequency converter 6 divides the 98 kHz signal from the lead wire 5 into 2 kHz and gives the signal from the lead wire 11 to the underground pipe 2 at the connection location 9. Another frequency converter 8 divides the 98 kHz signal from the line 7 into 2 kHz, and
And is applied from the lead wire 13 to the underground pipe 2 at the connection location 10. In this way, a 2 kHz signal is transmitted to the underground pipe 2 between the connection locations 9 and 10.

On the ground, the operator carries the receiver 14. This receiver
Reference numeral 14 denotes an antenna 15 for detecting a magnetic field generated from the underground pipe 2, and a filter 16 for wave-passing only a 2 kHz component of the signal detected by the antenna 15 to pass therethrough.
And 2k corresponding to the level of the 2kHz signal from the filter 16.
And a display means 17 for displaying an electric field strength of Hz. Receiver 14
By moving the receiver 14 along a place where the received electric field strength displayed by the display means 17 is large, the buried position of the underground pipe 2 can be searched and found on the ground. .

In this way, the receiver 14 accurately detects the magnetic field due to the 2 kHz signal from the underground pipe 2 without being adversely affected by the magnetic field generated by the 98 kHz signal transmitted to the lead wires 5 and 7. Therefore, the position of the underground pipe 2 can be accurately searched.

According to the experiment of the present inventor, when the output of the frequency converters 6 and 8 is 1.0 W directly above the underground pipe 2 between the connection locations 9 and 10 and the underground pipe 2 is 1.5 m underground, Receiver 14
The received electric field strength of 2 kHz detected by the above method is 6 mV / m, whereas the display means 17 of the 98 kHz magnetic field from the lead wires 5 and 7 laid near the underground pipe 2. Thus, the received electric field strength detected was 0.2 mV / m. As a result, it was confirmed that the position of the underground pipe 2 can be accurately detected.

As another embodiment of the present invention, instead of dividing the frequency, the frequency converters 9 and 8 multiply the frequency signal from the oscillator 3 to a higher frequency and transmit the frequency signal to the underground pipe 2 at the connection locations 9 and 10, and In 14,
The magnetic field from the underground pipe 2 based on the multiplied signal may be selectively received.

FIG. 2 is a system diagram of another embodiment of the present invention. The electric power from the DC power supply 20 is supplied to the underground pipe 2 buried in the ground 1.
A pair of oscillators 21 and 22 disposed at connection locations 9 and 10 are provided via lines 23 and 24, whereby the oscillators 21 and 22 oscillate with power from the DC power supply 20. Oscillator 2
The oscillation frequencies of 1,22 are the same value, for example, 2 kHz. Oscillation output signals of the oscillators 21 and 22 are supplied to the underground pipe 2 at connection points 9 and 10 via lines 25 and 26. As a result, the oscillation output is transmitted to the underground pipe 2 between the connection locations 9 and 10. On the ground, the receiver 14 selectively detects a 2 kHz magnetic field generated by the underground pipe 2. The receiver 14 detects the magnetic field from the underground pipe 2 without being adversely affected by the magnetic field generated from the lines 23 and 24, and thereby accurately locates the underground pipe 2 from the ground. Can be explored.

Advantageous Effects of the Invention As described above, according to the present invention, a pair of frequency converters are respectively arranged at two connection places having an interval between objects provided in a concealed place, and an output from one oscillator is provided to the object. Since the divided or multiplied output signal is transmitted and the magnetic field generated from the object is received outside the ground or the like, it is generated from the lead wire connecting the oscillator and the frequency converter. The position of the object can be probed without being adversely affected by the magnetic field.

Further, according to the present invention, a pair of oscillators are provided at two connection locations having an interval between objects provided in a concealed location, and the oscillators are powered by a common DC power supply and are synchronized at the same frequency. Oscillates and transmits an oscillating output between connection points of an object to generate a magnetic field. On the outside such as on the ground, a receiver receives a magnetic field generated from an object and searches for the position of the object. In this way, the position of the object can be accurately searched without being adversely affected by the magnetic field generated by the lead wire between the DC power supply and the oscillator.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of one embodiment of the present invention, FIG. 2 is an overall system diagram of another embodiment of the present invention, and FIG. 3 is a simplified plan view of the prior art. 1 ... ground, 2 ... underground pipe, 3 ... oscillator, 5,7 ...
… Lead wire, 6,8… frequency converter, 9,10 …… connection place, 14… receiver, 15 …… antenna, 16 …… filter,
17 …… Electric field strength display

Continuation of the front page (56) References JP-A-63-300900 (JP, A) JP-A-54-60958 (JP, A) JP-A-3-1626693 (JP, A) JP-A 1-227088 (JP) , A) JP-A-62-79347 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01V 3/12

Claims (2)

(57) [Claims] An oscillator is disposed at two connection places spaced apart along an object provided at a concealment place and connected to the object at the connection place, and the output of the oscillator is divided or multiplied. A pair of frequency converters for transmitting a divided or multiplied output signal between connection points of the object, and a receiver for selectively receiving a signal of a divided or multiplied frequency. A position detection device provided in a concealed place. 2. A DC power supply, wherein the DC power supply is disposed at two connection places spaced apart along an object provided in a concealed place, connected to the object at the connection place, and is connected to the same object by the power of the DC power supply. A pair of oscillators that oscillate and oscillate at a frequency to transmit an oscillation output between connection points of the object, and a receiver that receives the output of the oscillator; Positioning device.