JP2002070062A - Detecting method for underground buried piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting method for underground buried piping, allowing the arrangement, depth and/or pipe type of the buried piping to be known without excavating the ground, having the excellent accuracy of the detection of a buried position, and saving labor for installation construction. SOLUTION: A piping detector arranged on the ground is provided with a primary magnetic- field transmitting part composed of a spectral spreading signal generating part 1, a transmitting part 2 and an antenna part 3, a secondary magnetic-field receiving part composed of the primary magnetic-field transmitting part, the common antenna part 3 and a receiving part 4, a computing part composed of a frequency conversion part 5 and a spectral inverse spreading signal processing part 6, and a display part 7. The underground buried piping is installed by means of a joint or a synthetic resin pipe undergoing the burial or outer fixation of a magnetic-field resonator generating a secondary magnetic field by primary magnetic-field energy transferred from the primary magnetic-field transmitting part. The primary magnetic field is transmitted from the primary magnetic-field transmitting part of the piping detector to the underground buried piping, and the secondary magnetic-field receiving part receives secondary magnetic-field energy generated from the magnetic-field resonator by the above primary magnetic field. Only a target signal is detected from the signals of the received secondary magnetic field, the position and type of the joint or the pipe are decided in the computing part according to the strength and wavelength of the target signal, and the decided position and type are displayed on the display part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a buried position, a depth and / or a buried state of a synthetic resin buried underground pipe such as an electric conduit, a water and sewage pipe, a gas pipe, etc. The present invention relates to a method for detecting a pipe type from the ground without excavating the ground.

[0002]

2. Description of the Related Art In recent years, there has been an increase in the number of pipes using synthetic resin pipe material as underground pipes, and various pipe types are buried in the ground. For this reason, when laying a new buried pipe, repairing the existing pipe, paving the ground, and excavating the ground due to plumbing work such as
It is necessary to know in advance the condition and type of buried pipe before the pipe is exposed during excavation.

[0003] For this purpose, at the time of construction of these buried pipes, a buried position detecting conductor (so-called locator cable) so that the buried pipe position, pipe depth and / or buried pipe type can be identified from the ground. When locating the pipes, the locator cable is energized and the generated magnetic field is detected from the ground surface, or a marker strip for marking is placed between the pipe and the ground surface. There is a method of burying along a pipe so that when the ground is dug back, if a band is dug, the pipe is buried underneath.

However, in the method of installing the locator cable, the work involved in installing the conductor at the construction site requires a lot of time and labor to attach and fix the conductor to the pipe. Since it is a copper wire covered with vinyl resin, polyethylene, rubber, or the like, there has been a problem that the wire may be broken due to an unexpected situation after the construction and detection may not be possible.

[0005] In the method of burying the band for sign,
Since the strip is placed and buried between the pipe and the ground surface, there is a problem that the positioning accuracy is low as in the case where the marker is buried.In addition, excavation must be performed at least until the marker strip appears. There was a problem that it was necessary to know the piping position before excavation.

[0006] Furthermore, a marker (a marker (trade name, Fujitecom Co., Ltd.) or the like) that receives the primary magnetic field and generates a secondary magnetic field is buried in the vicinity of the piping position, and these buried objects are detected from the ground by a dedicated detector. There is a method to detect by.

In this method, since the marker is placed between the pipe and the ground surface and buried, the marker is erroneously excavated and lost or moved during other works, and the marker itself is buried during the burial work. In addition, there is a problem that the embedded position is easily displaced and therefore the positional accuracy is easily deviated.In addition, since the detection method is a so-called magnetic field coupling method and is easily affected by external noise, the laying distance between the markers is set to a predetermined distance. There was a problem that it took a lot of time and labor for construction, for example, it was necessary to open it and the sign strip had to be buried vertically.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the location, depth and / or type of a buried pipe can be known without excavating the ground, and the detection accuracy of the buried position is good, and the installation work is difficult. The purpose of the present invention is to provide a method for detecting underground buried pipes with a small amount of water.

[0009]

According to a first aspect of the present invention, there is provided a method of detecting a buried underground pipe according to the present invention, comprising the steps of: generating a spread spectrum signal; a transmitting section; and an antenna section. A primary magnetic field transmitting unit, a secondary magnetic field receiving unit including a primary magnetic field transmitting unit and a common antenna unit and a receiving unit, an arithmetic unit including a frequency conversion unit and a spectrum despread signal processing unit, and a display unit. A magnetic field resonator that generates a secondary magnetic field by the primary magnetic field energy transmitted from the primary magnetic field transmitting unit from the primary magnetic field transmitting unit of the pipe detector arranged on the ground provided is made of a synthetic resin path embedded or circumscribed and fixed. A primary magnetic field is transmitted toward an underground pipe laid by a pipe or a joint, and a secondary magnetic field energy generated by the magnetic field resonator is received by the primary magnetic field transmitted from the primary magnetic field transmission unit. Receiving only the target signal from the received secondary magnetic field signal, determining the position and type of the pipe or joint from the intensity and wavelength in the calculation unit, and displaying the result on the display unit. This is a method for detecting underground buried piping.

According to a second aspect of the present invention, there is provided a method of detecting a buried underground pipe (invention 2), wherein the magnetic field resonator comprises a resonance circuit comprising a capacitor, a resistor, and an electric wire buried and wound in a pipe or joint. Invention 1 is a method for detecting a buried underground pipe according to Invention 1, wherein the resonance circuit is buried in a pipe or a joint.

According to a third aspect of the present invention, there is provided a method of detecting a buried underground pipe (invention 3), wherein a magnetic field resonator is buried in a pipe or a joint and is projected from an outer surface of a pipe or a joint to which a wound electric wire is connected. Invention 1 is a method of detecting a buried underground pipe, comprising a resonance circuit in which a capacitor and a resistor are connected to terminals.

According to a fourth aspect of the present invention, there is provided a method of detecting an underground pipe, wherein the magnetic field resonator comprises a resonance circuit comprising a capacitor, a resistor and a coil wound with an electric wire, and the resonance circuit comprises a synthetic resin. A method for detecting an underground pipe according to Invention 1, wherein the pipe is stored in a container made of plastic, and the container made of synthetic resin is embedded in a pipe or a joint.

According to a fifth aspect of the present invention, there is provided a method of detecting an underground pipe, wherein the magnetic field resonator comprises a resonance circuit comprising a capacitor, a resistor and a coil wound with an electric wire, and the resonance circuit is formed of a synthetic resin. A method for detecting a buried underground pipe according to the first aspect of the present invention, wherein the pipe is stored in a container made of plastic, and the container made of synthetic resin is circumscribed and fixed to a pipe or a joint.

According to a sixth aspect of the present invention, there is provided a method of detecting underground pipes, wherein the number of turns of the coil and / or the capacity of the condenser are different for each type of pipe. A method for detecting underground pipes according to inventions 1 to 5, which is a feature of the invention.

The underground pipe applied to the present invention is not particularly limited as long as it is a pipe composed of a synthetic resin pipe and a synthetic resin joint. For example, there is a buried polyethylene pipe made of polyethylene or the like. .

According to the underground pipe detection method of the present invention, a magnetic field resonator buried underground is generated by receiving a primary magnetic field energy transmitted from a pipe detector disposed on the ground by a magnetic field coupling communication method. The secondary magnetic field, so-called echo, is detected by a secondary magnetic field detector provided in the pipe detector, and the embedded position of the magnetic field resonator is known. The method of the present invention is a spread spectrum communication method. This is different from the conventional magnetic field coupling communication method.

Spread spectrum communication is a method in which a target signal is spread on a frequency axis, and when a large noise enters, the signal is demodulated by performing despreading to demodulate only the signal, thereby canceling the noise and extracting an echo. It is. Therefore, the position of the buried pipe can be easily detected particularly in the case of performing pipe detection in a poor noise environment such as a road where automobiles travel heavily, because it is hardly affected by external noise. In the present invention, for example, detection is possible even in a region where the S / N ratio is 0 dB, and since electromagnetic waves in the long-wave band are used, detection can be performed with little influence from soil, voids, and moisture.

The pipe detector placed on the ground is movable, and converts a spread spectrum signal into a long wave band (LF band: 243k).
Hz), a primary magnetic field transmitting unit including a transmitting unit for transmitting magnetic field energy to an antenna and an antenna unit for transmitting a magnetic field underground, and an antenna unit and an echo common to the primary magnetic field transmitting unit. A secondary magnetic field receiving section comprising an echo receiving section; a computing section comprising a frequency converting section for converting a received echo into a frequency suitable for signal processing; and a signal processing section for performing spectrum despreading, and a display for displaying the computation result. Section.

The primary magnetic field transmitting section provided in the pipe detector is not particularly limited as long as it has a function of generating the above-mentioned spread spectrum signal, is easily mounted on the pipe detector, and is small. For example, as the antenna, a magnetic field generator using a normal loop antenna is most suitably applicable because of its wide detection range, ease of maintenance, and ease of mounting on a detector.

The secondary magnetic field receiving unit is not particularly limited as long as it can receive a weak secondary magnetic field generated by the resonator. For example, the secondary magnetic field receiving unit uses a common loop type antenna with the primary magnetic field transmitting unit. , And the signal received from the antenna is despread by frequency conversion and signal processing to extract only the target signal, which is most suitably applied.

The magnetic field resonator is composed of a resonance circuit composed of a coiled electric wire (hereinafter referred to as a coil), a capacitor and, if necessary, a resistor. When a primary magnetic field is received, a voltage is induced in the coil. When energy is stored in the capacitor and the primary magnetic field is stopped, the stored energy flows through the coil to generate a secondary magnetic field (hereinafter referred to as an echo).

The magnetic field resonator generates an echo having a frequency uniquely determined by the frequency of the primary magnetic field, depending on the number of turns of the coil used in the resonance circuit and / or the capacity of the capacitor. Therefore, in the present invention, by defining the number of coil turns of the resonator and / or the capacity of the capacitor as different numbers of turns and / or capacities for each pipe type,
By transmitting a primary magnetic field having a frequency corresponding to this and changing the secondary magnetic field frequency generated by the resonance circuit according to the pipe type, it is possible to detect only the target pipe type. Also, the amount of energy received by the receiver differs depending on the depth of the buried echo. Therefore, the amount of this energy is detected and the buried pipe is calculated from the difference from the primary magnetic field transmission energy and the loss specific to the resonance circuit. You can know the depth of burial.

The magnetic field resonator does not require a power supply because it utilizes magnetic field resonance, and is buried or externally fixed to a pipe or joint.

In the case where the synthetic resin is a pipe or joint made of polyethylene, a pipe formed by an electric fusion method is often used as the pipe method. In the electric fusion method, usually, an electric fusion joint or the like is provided in which a wire which generates heat by energization is wound and buried in a circumferential direction in a joint wall, and terminals to which both ends thereof are connected protrude outward from the joint. Is used.

In this case, an electric wire wound and buried in an electric fusion joint or the like is used as a coil, and a capacitor and a resistor, if necessary, are connected to both terminals to form a resonance circuit, which functions as a magnetic field resonator. You may make it do. The capacitor and the resistor may be formed by being buried in a joint or the like in advance, or may be externally connected to both terminals.

The magnetic field resonator may be one in which a resonance circuit comprising a coil, a capacitor and, if necessary, a resistor is hermetically stored in a container made of synthetic resin. In this case, the synthetic resin container may be embedded in a pipe member in advance, or may be fixed to a necessary portion of the pipe with a synthetic resin adhesive tape such as an insulating tape or an adhesive. In this case, it is better not to fix the magnetic field resonator so that it is wound around a pipe or a joint with a metal wire.
The reason is that the metal wire wound and used functions as a coil and may hinder detection.

Whichever of the above methods is adopted,
Since the magnetic field resonator is fixed to the pipe, the magnetic field resonator does not deviate from the pipe position after the pipe is buried or move erroneously in other works.

(Operation) In the present invention, since the number of turns of the coil used in the magnetic field resonator and / or the capacity of the capacitor are determined for each pipe type, the primary magnetic field having a frequency corresponding to the determined number is transmitted. Since a specific echo is generated and only that echo is detected, it is hard to be affected by other pipes buried in the vicinity at the same time, and it is possible to detect only a specific pipe type. Also, since it is a spread spectrum communication method using a spread spectrum signal in a long wave band, it is possible to detect piping even under inferior noise,
Hardly affected by moisture. Further, since the magnetic field resonator is fixed to the pipe or the joint, construction work other than the pipe laying is not required, and at the same time, the pipe or the joint itself can be detected.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the underground pipe of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a block diagram illustrating the function of a pipe detector according to the present invention.

The signal having a frequency determined for each pipe type created by the spread spectrum signal creating section 1 is spread along the frequency axis, and is excited by the transmitting section 2 to generate a primary magnetic field from the loop antenna section 3. Sent intermittently into the ground.

If a magnetic field pendulum corresponding to the frequency of the primary magnetic field exists in the ground, a voltage is induced in a coil (wound wire) of a vibration circuit incorporated therein, and energy is accumulated in the capacitor. When the transmission of the primary magnetic field is stopped,
The energy stored in the capacitor is emitted from the coil as a secondary magnetic field (echo) having a constant frequency.
Since the primary magnetic field is transmitted intermittently, an echo is generated each time.

The echo is received by the antenna unit 3 and amplified by the receiving unit 4. The amplified echo signal is converted to a frequency suitable for signal processing by the frequency conversion unit 5 and transmitted to the spectrum despread signal processing unit 6 where the spectrum is despread, and only the target signal is extracted and The strength is calculated and the burial depth of the field oscillator is determined. The display unit 7 displays the pipe type for each type of the magnetic field transducer determined from the determined depth and the frequency of the echo.

FIG. 2 is an explanatory diagram of a resonance circuit of the magnetic field oscillator. In FIG. 2A, a coil 8 wound with a predetermined number of turns is used.
Although a parallel resonance circuit in which the capacitor 9, the capacitor 9 and the resistor 10 are connected in parallel is used, these may be a series resonance circuit connected in series as shown in FIG. The operation of these resonance circuits is as described above, and will not be described again.

FIG. 3 shows an example of the magnetic field oscillator. In this example, a polyethylene electrofusion joint 11 in which a resonance circuit is embedded is used.
(Hereinafter referred to as an EF joint).

The heat-generating electric wire 12 of the EF joint 11 is embedded in the vicinity of the inner surface of the joint 11 by being wound in the circumferential direction. A capacitor 9 and a resistor 1 are connected to one end of the wound wire 12.
0 is connected, buried in the joint 11, and the wound electric wire 12 functions as the coil 8, and the EF joint 11 as a whole constitutes a resonance circuit. The number of turns varies depending on the size of the joint 11, and in this case, the capacity of the condenser 9 is changed to control the frequency of the echo.

In the case of using the joint 11 in which the resonance circuit is buried, the installation of the magnetic field oscillator ends at the same time when the piping is completed. In addition, the magnetic vibrator embedded joint is manufactured by simultaneously arranging the heating wires 12 when winding them, and then laminating a polyethylene resin thereon.

FIG. 4 shows an EF joint 1 having a magnetic field oscillator in which a capacitor 9 and a resistor 10 are circumscribed in a resonance circuit.
FIG. A capacitor 9 and a resistor 1 are connected to the external terminal 13 of the heating wire projecting from the outer surface of the EF joint 11.
0 is connected. Also in this case, the EF joint 1 of FIG.
The heating wire 12 wound in the same manner as
And the frequency of the echo is also
The circuit is configured by changing the capacitance of the circuit.

When the capacitor 9 and the resistor 10 are circumscribed, there is an advantage that the conventional EF joint 11 can be used as it is.

FIG. 5 is an explanatory diagram of the usage of a magnetic field oscillator in which a resonance circuit including a coil 8, a capacitor 9, and a resistor 10 is stored in a synthetic resin container 14. In this case, the magnetic vibrator of the present invention can be used for all the synthetic resin tubes, but the number of windings of the coil 8 and the condenser 9 are set so as to transmit an echo frequency determined for each tube type.
Is determined and used as a magnetic field resonator dedicated to the tube type. In addition, the material of the synthetic resin container 14 for storing the magnetic field resonator is not particularly limited as long as it has a magnetic field permeability and does not cause a magnetic field change, and at the same time has strength and corrosion resistance enough to withstand burying underground. And thermoplastic synthetic resins such as polyethylene and vinyl chloride resins; fiber-reinforced thermosetting synthetic resins such as polyester resins and epoxy resins combined with glass fibers;

The magnetic field vibrator stored in the synthetic resin container 14 may be used by embedding the container in a pipe or a joint, or may be used by circumscribing a pipe. When buried, the EF joint 11 may be buried while avoiding the heat-generating electric wire 12, and may be buried, for example, as shown in FIG. In this case, if the coil 8 is formed into a loop shape wound in a spider web shape, the thickness of the entire magnetic field vibrator can be reduced, so that the magnetic field vibrator is easily embedded and is convenient.

Further, as shown in FIG. 5B, the magnetic field resonator stored in the synthetic resin container 14 may be fixed around the upper or side of the pipe by winding with an insulating tape (not shown) or the like.
In this case, it is desirable to keep the magnetic field resonator from falling down as much as possible, and it is desirable not to use a metal wire as a fixing method.

When the magnetic field vibrator of the second aspect is embedded in the EF joint or circumscribed in the third aspect and the container-type magnetic field vibrator of the fourth aspect is used together, It is desirable that the direction of the winding center axis of the coil 8 used for the vibrator is perpendicular to the direction of the winding center axis of the heating wire 12 of the joint. That is, since the heating wire 12 wound around the EF joint 11 has the same function as the coil 8 of the resonance circuit, it causes the noise of the echo transmitted from the resonance circuit, and the pipe detection is not performed. This is because it may be certain.

As a matter common to all of the above, it is desirable that the winding center axis of the coil is perpendicular to the ground surface. That is, the coil performs transmission and reception of the magnetic field, but it is more efficient if the axis of the antenna is oriented forward in the traveling direction of the magnetic field. Therefore, it is desirable that the magnetic field resonator be marked so that the direction of its coil can be seen from the outside.

[0044]

As described above, the method for detecting underground buried pipes of the present invention can determine the arrangement, depth and / or pipe type of buried pipes without excavating the ground, and This is a method of detecting underground pipes that has good position detection accuracy and requires less installation work.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating functions of a pipe detector according to the present invention.

FIG. 2A is an explanatory diagram of a parallel resonance circuit. (B) It is explanatory drawing of a series resonance circuit.

FIG. 3 is an explanatory diagram of an EF joint in which a resonance circuit is embedded.

FIG. 4 is an explanatory diagram of an EF joint in which a capacitor and a resistor are circumscribed in the resonance circuit.

FIG. 5 (a) is a diagram illustrating the use of a joint in which a synthetic resin container containing a resonance circuit is embedded. (B) It is an explanatory view of use in which a synthetic resin container containing a resonance circuit is circumscribed and used for piping.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spread spectrum signal preparation part 2 Transmission part 3 Antenna part 4 Receiving part 5 Frequency conversion part 6 Spectrum despread signal processing part 7 Display part 8 Coil 9 Capacitor 10 Resistance 11 Electric fusion joint 12 Heating wire 13 External terminal 14 Synthetic resin Container

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01V 3/11 F16L 1/02 Z V

Claims (6)

[Claims] 1. A primary magnetic field transmission unit including a spread spectrum signal generation unit, a transmission unit, and an antenna unit, a secondary magnetic field reception unit including an antenna unit and a reception unit common to the primary magnetic field transmission unit, and a frequency conversion unit And a calculation unit comprising a spectrum despreading signal processing unit, and a display unit, from a primary magnetic field transmitting unit of a pipe detector arranged on the ground, and a secondary magnetic field transmitted from the primary magnetic field transmitting unit. A primary magnetic field is transmitted toward the underground pipe laid by a synthetic resin path pipe or a joint in which a magnetic field resonator that generates a magnetic field is embedded or circumscribed and fixed by the primary magnetic field transmitted from the primary magnetic field transmission unit. The secondary magnetic field energy generated by the magnetic field resonator is received by the secondary magnetic field receiving unit, and only the target signal is detected from the received signal of the secondary magnetic field, and the intensity and the wavelength are used to detect the above-mentioned pipe or joint. A method for detecting underground buried pipes, wherein a position and a type are determined by an arithmetic unit, and the result is displayed on a display unit. 2. The magnetic field resonator according to claim 1, wherein the magnetic field resonator includes a resonance circuit including a capacitor, a resistor, and an electric wire wound around the tube or the joint, and the resonance circuit is embedded in the tube or the joint. The method for detecting underground buried piping according to claim 1. 3. A magnetic field resonator, wherein a capacitor and a resistor are connected to a tube or a connection to which an electric wire wound and buried in a connection is connected to a tube or a resonance circuit connected to a terminal protruding on an outer surface of the connection. The underground pipe detection method according to claim 1, wherein: 4. A magnetic field resonator comprises a resonance circuit comprising a capacitor, a resistor and a coil around which an electric wire is wound. The resonance circuit is housed in a synthetic resin container, and the synthetic resin container is connected to a pipe or a joint. The underground pipe detection method according to claim 1, wherein the pipe is buried. 5. The magnetic field resonator comprises a resonance circuit comprising a capacitor, a resistor and a coil around which an electric wire is wound, and the resonance circuit is housed in a synthetic resin container, and the synthetic resin container is connected to a pipe or a joint. The method for detecting underground pipes according to claim 1, wherein the pipes are circumscribed and fixed. 6. The underground pipe detection according to claim 1, wherein the number of turns of the coil and / or the capacity of the condenser are different for each pipe type. Method.