JP2608618B2 - Metal long object buried position measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a long metal object buried in the ground, such as an electric cable, a metal pipe, a gas pipe, a water pipe, or the like that houses them, from the ground. The present invention relates to an apparatus for measuring a buried position and a depth by using a guidance system.

[Prior Art] Long metal objects buried underground, such as electric cables,
As a conventional method of exploring a metal pipe, a gas pipe, a water pipe, and the like containing them from the ground, an induction current is generated in a long metal object by a transmission coil, and the reception coil is moved horizontally to generate the induction current. The position at which the output voltage obtained by the magnetic field caused by the magnetic field shows the maximum value is determined, it is detected that a long metal object is buried immediately below the position, and the height of the receiving coil is changed at that position to receive the signal. Depth was measured by calculating the output voltage of two places above and below the coil.

That is, as shown in FIGS. 6 (a) and (b),
On the ground that the long metal product 1 is believed will have been embedded, when a pulse current or alternating current of a certain frequency from the oscillator 62 to the transmitter coil 61, the magnetic field H _61, produced by One by it, metal The induced current I flows through the long object 1. When a receiving coil 63 is placed in a cylindrical magnetic field H ₆₃ generated by the induced current I, a current flows through the coil 63, and a voltage between both ends of the coil 63 is measured by a voltmeter 64.

At this time, the receiver coil 63 is horizontally moved on the ground with the coil axis being horizontal, and at the same time, its direction is also changed.
If the position and orientation at which the output voltage is maximized are found, it means that the long object 1 is buried immediately below that position, and that the long object 1 runs in a direction perpendicular to the coil axis. Become. That is, as shown in FIG. 6 (b), the receive coil 63 at a location L _1, redirected at the coil axis horizontal, the orientation with the maximum value of the output voltage that appears in a voltmeter 64 Ask. This direction is a direction orthogonal to the long metal object 1. The strength of the magnetic field at that position is H,
The horizontal component is Hx, the length of a straight line connecting the long metal object 1 and the receiving coil 63 is R, the vertical component is D, the horizontal component is L, the horizontal component of the magnetic field is Hx, Assuming that the angle between the above and the linear direction of the length R is θ, the strength of the magnetic field of the horizontal component is Hx = Hsinθ, H = K / R, D / R =
Since sin θ, Hx = KD / (L ² + D ² ) where K is a constant determined in proportion to the magnitude of the induced current, and the horizontal component distance L = 0 maximizes the magnetic field strength Hx. a position that, the it can be seen that the long metal product 1 immediately below the position L ₀ of the output voltage is maximized by moving the connexion receiving coil 63 horizontally exists.

[Problems to be Solved by the Invention] As described above, in the conventional measuring method, the receiving coil 63 is moved horizontally, and the position where the current induced there is maximum is obtained.
L ₀ , that is, a position at which the output voltage of the voltmeter 64 becomes maximum is obtained.In order to move the receiving device having the receiving coil 63 in the hand and move it horizontally, the receiving coil 63 Due to small differences such as height of the coil axis, horizontality of the coil axis, direction of a right angle to a long object, etc., it is easy for individual differences to occur in the measured value of the output voltage, and the position showing the maximum value of the output voltage is
It is difficult to determine the exact burying position and depth because the range that is difficult to identify with the eyes of the measurer is wide.

[Means for Solving the Problems] A buried position measuring apparatus of the present invention reduces the individual difference of the measured values by the above-mentioned measurer, and can accurately determine the buried position and depth. And two transmission coils provided with a coil axis in the same plane and orthogonal to the rotation axis, for each of the two drive rotation axes parallel to each other at regular intervals in the horizontal plane. A transmitter that is connected to the coil via a changeover switch, selectively generates a magnetic field with the transmission coils, and causes the magnetic field to generate an induced current without being connected to the buried metal long object; A rotation angle detector of the rotation shaft driven through a switch, the rotation angle, an induced current generated in the embedded metal long object by the transmission coil, and the like, and the position of the long object is input. A transmitting device comprising an arithmetic processor and a receiver, a receiving coil for detecting the induced current, and a receiving device comprising a transmitter for transmitting the induced current to a receiver of the transmitting device. The arithmetic processing unit is configured to determine a rotation angle from a horizontal position of a coil axis of the transmission coil when it is measured that an induction current of the buried metal long object caused by a coil current of one transmission coil is zero. A rotation angle from the horizontal position of the coil axis of the transmission coil when the induction current of the buried metal long object caused by the coil current of the other transmission coil is measured to be zero, and a predetermined rotation angle. The embedding position of a long object is determined from the distance between the measurement positions of these two transmission coils.

[Operation] According to the metal long object burying position measuring apparatus of the present invention, an induced current is generated in the long object by the magnetic field generated by the coil current of the transmission coil crossing the long metal object.
The direction of the coil axis of either the transmitting coil or the receiving coil of the receiving device is rotated so that the current is measured to be zero, and the rotation angle from the horizontal position is obtained at two different positions. Therefore, as will be described later, since the range of the rotation angle at which the induced current is measured to be zero is very narrow, the burying position of the long metal object can be obtained very accurately.

In addition, two transmitting coils are provided orthogonal to the rotation axis by defining an interval between two points where the rotation angle is to be measured, and the two coils described above when the induced current of the long metal object becomes zero due to their rotation.
By inputting the rotation angle of the location to the arithmetic processing unit and also inputting and setting the above-mentioned two predetermined intervals to the arithmetic processing unit, the position of the buried depth as well as the position on the ground surface is displayed on the display. Can be displayed.

[Embodiment] With reference to Fig. 1, an embodiment of an apparatus for measuring a buried position of a long metal object according to the present invention will be described first.

11 transmitting apparatus 12 shall apply in the receiving apparatus constituting it and set the two transmission coils 13 _A, 13 _B is provided in the transmitting apparatus 11, parallel it is spaced filed in a horizontal plane mounted orthogonally on the same plane to the rotation axis 14 _a, 14 _B provided, is by connexion rotate each motor 15 _a, 15 _B. 16 _A, 16 _B is the rotary shaft 14 _A, 14 in the rotation angle detector respectively provided _B, that this shall the transmission coil 13 _A, 1
3 rotation angles from each of the horizontal position of the coil axis of _B is detected. 17 is a transmitter, is switched connected to one of the transmission coil 13 _A or 13 _B by switching switch SW1. The numeral 18 denotes a power source connected through a switching switch SW2 to the motor 15 _A, 15 _B, switching switch S
W1 and interlocked with SW2, when the transmitter 17 is connected to the transmitter coil 13 _A side, the power supply 18 are to be connected to the motor 15 _A side by switching switch SW2. Reference numeral 19 denotes a radio receiver which receives a signal regarding the magnitude of the induced current value of the buried metal long object 1 from the radio transmitter of the receiver 12, and 20 denotes information regarding the induced current value received by the receiver 19 and the rotation. arithmetic processor from the information about the respective rotation angles of the angular detectors 16 _a, 16 _B and the arithmetic processing for calculating the embedded position and depth of the long metal product, 21 results and induced current of the processing It is a display that displays a value, two rotation angles, and the like.

The receiving device 12 includes a receiving coil 22 and a detection amplifier.
23 and a wireless transmitter 24, which wirelessly transmits a pulse signal relating to an induced current value of the buried metal long object 1, and
The radio receiver 19 receives the data.

 Next, the measurement operation will be described with reference to FIG.

First, the location where the long metal product 1 is that it would have been buried, bring the transmitting unit 11 and receiving unit 12, passing a pulse current to the transmitter coil 13 _A through switch SW1 from the transmitter 17 An induced current I is generated in the long metal object 1 buried in the ground by a magnetic field created by the magnetic field.
This induced current I is crossed by a receiving coil 22 of the receiving device 12 with a cylindrical magnetic field generated by the same, whereby a pulse current is induced therein and amplified by a detection amplifier 23.
The radio receiver 19 of the transmitter 11 uses the pulse wave from the radio transmitter 24.
Is received. Then, the pulse current at that time, the output voltage of the receiving coil 22, or the induced current is displayed on the display 21 through the arithmetic processor 20.

In the above description, when the transmitting device 11 is horizontally moved and its direction is changed, as the transmitting coil 13 _A approaches directly above the long metal object 1, the coil axis becomes in the direction orthogonal to the long object 1. As approaching, the induced current I increases,
Similarly, it is easy to increase the measured value of the induced current I as the receiving device 12 approaches directly above and as the direction of the receiving coil 22 approaches the direction orthogonal to the long object 1. Will be appreciated.

Then, the transmission coil 13 _A, the motor 15 _A is rotated through the power supply 18 SW2, the coil axis of the transmission coil 13 _A is directed to a long metal product 1, the induction current I is zero that occurs therein ( 0). Therefore, when the induced current I becomes zero (0), the metal elongated object 1 is moved in the direction of the coil axis.
It will be seen that will exist.

Similarly, the transmission coil 13 _B the switch SW1 of the transmitter 17
Switch to side, SW2 of the power supply 18 by so doing switches on the motor 15 _B-side, rotating the transmission coil 13 _B, the long metal in the direction of the coil axis when the induced current I is shown as zero (0) It is known that object 1 will be present.

Thus, a demand length and the corners of both ends between transmission coil 13 _A, 13 _B, since the second corner of one side and both ends of the triangle is determined, obtaining the embedded position and depth of the long metal product 1 be able to.

In order to facilitate understanding of the above measuring method, its basic principle will be described with reference to FIGS.

First, in FIG. 2, 1 is a long metal object buried underground, 2 is the ground surface, 17 is a transmitter, 13 is a transmission coil,
The coil axis is located in a plane orthogonal to the long metal object 1, R is the length of a straight line connecting the transmission coil 13 and the long metal object 1, and D is the length of its vertical component. Let L be the length of the horizontal component, and θ be the angle between the straight line of length R and the straight line of length L.

Assuming now that the coil axis of the transmission coil 13 is placed horizontally, the current I induced in the long metal object 1 at that time is I = Ksinθ / RK, where K is a constant R = L ² + D ² , sinθ = D Since / R, the induced current I = 0 when D = 0, and the maximum induced current I when L = 0.

Next, as shown in FIG. 3A with the same configuration as FIG. 2, the direction of the coil axis of the transmitting coil 13 is set in a plane orthogonal to the long metal object 1 in which the transmitting coil 13 is included, that is, on the ground surface 2. As for the case where orthogonal to a plane rotated from the horizontal position by an angle _{θ 1, I = Ksin (θ} -θ 1) / R der connexion, induction current I is a function of theta _1, the theta _{1 =} theta At this time, the induced current I becomes zero (0).

This is shown in FIG. In FIG. 3, the vertical axis represents the induced current I, and the horizontal axis represents the rotation angle of the coil axis rotated from the horizontal position. As can be seen from the figure, a very steep change occurs near the induced current I of zero (0), so that the direction of the transmitting coil 13 where θ ₁ = θ can accurately determine the position of the buried metal elongated body 1. It can be seen that the induced current I flows even when θ ₁ is slightly away from θ, and that the current greatly changes. On the other hand, when θ ₁ = 90 ° + θ, the induced current I has the maximum value. However, the change in the value is small even in the vicinity thereof, so that the position where the maximum value is present tends to cause a considerable error.

Next, as shown in FIG.
13 is set so that the induced current I becomes zero (0) at two different positions L ₁ and L ₂ at the same height on the ground surface in a plane orthogonal to the long metal object 1 including the same. Rotate to.
The rotation angle theta _A from the horizontal position in the position L ₁ of the coil axis of this _time, the rotation angle from the horizontal position in the position L ₂ theta
FIG. 4 (b) and (c) show changes in the induced current I flowing through the long metal object 1 with respect to those changes when _B is set. In the figure, the vertical axis induced current I, the horizontal axis represents the rotational angle theta _A and theta _B.

Now, assuming that the distance between the positions L ₁ and L ₂ is L _AB , the distance of the horizontal component from those positions to the long metal object 1 is L _A and L _B , and the distance of the vertical component is D, _{L AB = L a + L B} = L D = L a tanθ a = L B tanθ B on two formulas from _{D = Ltanθ a tanθ B / (} tanθ a + tanθ B) L a = Ltanθ B / (tanθ a + tanθ B) Alternatively, the position and the depth of the buried metal long object can be obtained as L _B = Ltan θ _A / (tan θ _A + tan θ _B ).

In the above description, the coil axis of the transmission coil 13 is
At two places, place on the same plane and
The case where the direction of the coil axis is rotated in a plane perpendicular to the plane is described. However, as shown in FIGS. Even if the direction of the axis of the coil of the transmitting coil 13 is rotated at two positions in a plane that is not orthogonal to the long metal object 1 but in a plane that is perpendicular to the metal long object 1, the buried position and the depth are exactly the same. You can ask. In this case, if the angle between the plane including the coil axes at the two locations and the long metal object 1 is smaller than the right angle, the induced current I only decreases accordingly. As long as it does not become small, that is, as long as the induced current I does not become so small, the buried position can be accurately obtained.

According to a further basic principle of this measuring method, the height of the two positions by the transmitting coil may be different from the ground surface,
It will also be readily apparent, though less practical, that the plane containing the coil axis at two locations and on which it rotates may be inclined with respect to the ground surface.

In the above embodiments, transmission coil 13 _A, 13 _B
Although the case where the direction of the coil axis is rotated to change the current induced in the long metal object has been described, as another embodiment, the induced current is generated in the long metal object by one transmission coil. On the receiving device side, by rotating the coil axes of the two receiving coils at different positions, the induced current is actually flowing, but from the horizontal position where the measured value becomes zero (0). It will be easily understood that the rotation angles can be determined, and the embedment position of the long metal object on the receiver side can be determined from the rotation angles and the distance between the two receiving coils.

[Effects of the Invention] According to the metal long object embedding position measuring device of the present invention, the coil axis of the transmission or reception coil when the measured value of the induced current generated in the long metal object becomes zero (0). Since the rotation angle of the direction is measured, the change of the induced current at that time changes greatly with a slight change of the rotation angle, and the rotation angle can be obtained very accurately. Even if the plane including the rotation plane of the coil axis is not exactly perpendicular to the long metal object at the two positions measured in
The rotation angle of the coil axis at which the measured value of the induced current becomes zero (0) can be read very accurately, and therefore, the embedded position and depth of the long metal object can be determined very accurately.

Also, two transmission coils are provided at regular intervals, and each is rotated in a plane orthogonal to the ground surface,
Since the rotation angles are input to the arithmetic processing unit at the set value of the fixed interval, the measurement can be easily and accurately performed by bringing the device to the measurement site and performing the measurement operation.

In addition, the rotation angle at which the measured value of the induced current is zero (0) is determined by one of the transmission coils, and the rotation angle at which the measured value of the induced current is zero (0) is determined by the other transmission coil, and these are processed. By inputting these signals into the vessel, the position of the buried metal long object can be detected from these rotation angles and the predetermined distance between the measurement positions of the two transmission coils, so that the two transmission coils are rotated. With such a simple operation, the position can be detected. In addition, since a magnetic field is generated in the transmitting coil by the transmitter and the magnetic field generates an induced current without connection to the long buried metal object, the measurement can be very easily performed from this point as well.

[Brief description of the drawings]

FIG. 1 is a perspective view including a block diagram showing the structure of a metal long object buried position measuring apparatus of the present invention, and FIGS. 2 to 5 are metal lengths for explaining the basic principle of the measuring method of the present invention. FIG. 2 shows a state in which a transmission coil is operated on a measuring object, FIG. 2 is a front view thereof, FIG. 3 (a) is a front view thereof, and FIG. 2 (b) is an induced current and a rotation angle of the transmission coil. Fig. 4 (a) is a front view, and Fig. 4 (b)
And (c) are curve diagrams showing the relationship between the induced current and the rotation angle of the transmission coil, and FIGS. 5 (a) and (b) are front and plan views showing another operation state and FIG. FIG. 2 is a simplified perspective view of a measuring device for explaining the measuring method of FIG. 1; metal long object, 2; ground surface, 11; transmitting device, 12; receiving device,
13, 13 _A , 13 _B ; transmit coil, 14 _A , 14 _B ; rotary axis, 15 _A , 1
5 _B; motor, 16 _A, 16 _B; rotation angle detector, 17; oscillator, 18; power, 19; wireless receiver, 20; arithmetic processor, 21; indicator, 22; receiving coil, 23; detection Amplifier, 24; wireless transmitter.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Michio Kawashima, 1-3-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Tokyo Electric Power Company (72) Hideo Kancho 1-3-1, 1-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Tokyo Electric Power Company (72) Inventor Kiyoshi Takatsuka 1-5-1 Kiba, Koto-ku, Tokyo Inside Fujikura Electric Wire Co., Ltd. (72) Inventor Yoshimasa Inoue 1-15-1 Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Yasuo Yamamura 10-1 Koto, Higashi-cho, Iwakura-shi, Aichi Prefecture Takachiho Sangyo Co., Ltd. Iwakura Plant (56) References JP-A-57-200802 (JP, A) JP-A-55-27989 (JP, A )

Claims (1)

(57) [Claims] 1. Two transmission coils, each of which has a coil axis in the same plane and is orthogonal to the rotation axis, for each of two drive rotation axes parallel to each other at a fixed interval in a horizontal plane. A transmitter that is connected to the transmission coil via a changeover switch, selectively generates a magnetic field with the transmission coil, and generates an induced current without connection to the long buried metal object by the magnetic field; A rotation angle detector for the rotating shaft driven via a changeover switch, an arithmetic process for calculating the position of the long object by inputting the rotation angle, an induced current generated in the long buried metal object by the transmission coil, and the like. A transmitting device comprising: a receiver; and a receiving device comprising: a receiving coil configured to detect the induced current; and a transmitting device configured to transmit the induced current to a receiver of the transmitting device. And the arithmetic processing unit, from the horizontal position of the coil axis of the transmission coil when it is measured that the induction current of the buried metal long object caused by the coil current of one transmission coil is zero And the rotation angle of
A rotation angle from the horizontal position of the coil axis of the transmission coil when the induction current of the buried metal long object caused by the coil current of the other transmission coil is measured to be zero,
A burying position measuring device for a long metal object, wherein a burying position of a long object is obtained from a predetermined distance between the measurement positions of the two transmission coils.