WO2012123993A1 - Transmitter for detecting in-pipe mobile body, in-pipe mobile body, and system for detecting in-pipe mobile body - Google Patents

Transmitter for detecting in-pipe mobile body, in-pipe mobile body, and system for detecting in-pipe mobile body Download PDF

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Publication number
WO2012123993A1
WO2012123993A1 PCT/JP2011/001586 JP2011001586W WO2012123993A1 WO 2012123993 A1 WO2012123993 A1 WO 2012123993A1 JP 2011001586 W JP2011001586 W JP 2011001586W WO 2012123993 A1 WO2012123993 A1 WO 2012123993A1
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WO
WIPO (PCT)
Prior art keywords
magnetic field
transmitter
permanent magnet
pipe
moving body
Prior art date
Application number
PCT/JP2011/001586
Other languages
French (fr)
Japanese (ja)
Inventor
茂治郎 清水
Original Assignee
Shimizu Shigejiro
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shimizu Shigejiro filed Critical Shimizu Shigejiro
Priority to PCT/JP2011/001586 priority Critical patent/WO2012123993A1/en
Priority to JP2011533900A priority patent/JP4902032B1/en
Publication of WO2012123993A1 publication Critical patent/WO2012123993A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/003—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring position, not involving coordinate determination
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/26—Pigs or moles, i.e. devices movable in a pipe or conduit with or without self-contained propulsion means
    • F16L55/48—Indicating the position of the pig or mole in the pipe or conduit
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/15—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for use during transport, e.g. by a person, vehicle or boat

Definitions

  • the present invention relates to a transmitter for detecting an in-pipe moving body mounted on the in-pipe moving body in order to detect the in-pipe moving body that moves inside the pipe and performs cleaning in the pipe from the outside of the pipe.
  • the present invention also relates to an in-pipe moving body on which the transmitter is mounted, and an in-pipe moving body detection system that accurately detects the position of the in-pipe moving body based on a rotating magnetic field generated from the transmitter.
  • an in-pipe moving body having an outer diameter approximately equal to the inner diameter of the pipe is used. After the in-pipe moving body is inserted into the pipe to be cleaned, a fluid is caused to flow through the pipe, and the in-pipe moving body is moved in the length direction of the pipe by the fluid pressure of the fluid. As a result, the residue in the pipe and the deposit attached to the inner peripheral wall of the pipe are discharged from the outlet of the pipe by the moving body in the pipe.
  • Such an in-pipe moving body is called a pig.
  • the transmitter in the pipe is equipped with a transmitter.
  • the signal from the transmitter is detected by the detector to identify the position of the in-pipe moving body.
  • a transmitter that generates a magnetic field for detection is known, and Patent Document 1 discloses an in-pipe moving body including this type of transmitter.
  • FIG. 5A and 5 (b) are explanatory views showing a moving body in a tube provided with a conventional transmitter that generates a magnetic field for detection.
  • the in-pipe moving body 100 has a bullet shape, and is inserted into the pipe 101 in a state where the tapered side is the front side in the moving direction M0.
  • the transmitter 102 includes an iron core 103 and an electromagnetic coil 105 including a coil 104 wound around the iron core 103, a pulse generation circuit 106 for applying a pulse current having a constant period to the electromagnetic coil 105, and a pulse generation circuit 106.
  • a battery 107 and a switch 108 for supplying electric power to the electromagnetic coil 105 via the switch are provided.
  • the transmitter 102 is mounted on the in-pipe moving body 100 with the center line L0 of the electromagnetic coil 105 along the moving direction M0 of the in-pipe moving body 100.
  • the in-pipe moving body 100 moves in the tube 101 while maintaining a posture in which the center line L0 of the electromagnetic coil 105 is parallel to the center axis 101A of the tube 101.
  • a magnetic sensor probe 110a is provided when detecting the moving body 100 in the pipe that is stopped in the pipe 101 horizontally buried in the ground several meters away from the ground 109.
  • the detected detector 110 is moved along the buried route on the ground.
  • the detector 110 detects a magnetic field vector of a magnetic field (two-dot chain line in the figure) periodically generated from the electromagnetic coil 105, and thereby identifies the position of the in-pipe moving body 100.
  • the transmitter 102 in the conventional in-pipe moving body is mounted on the in-pipe moving body 100 so that the magnetic pole surface 105a (the end surface of the iron core 103) of the electromagnetic coil 105 faces the moving direction M0 of the in-pipe moving body 100.
  • the detector 110 detects the maximum magnetic field from the transmitter 102, the direction of the magnetic field vector V0 coincides with the central axis 101A of the tube 101.
  • knowledge and skill regarding the magnetic field line route of the magnetic field generated by the transmitter 102 is required.
  • the transmitter 102 is mounted on the in-pipe moving body 100 so that the center line L0 of the electromagnetic coil 105 is along the vertical direction perpendicular to the moving direction M0 of the in-pipe moving body 100, and the magnetic pole surface 105a of the electromagnetic coil 105 is always on the ground side. It is conceivable to keep the state facing. In this way, the direction of the magnetic field from the transmitter 102 faces the radial direction of the tube 101. As a result, the detector 110 can detect a magnetic field vector from the magnetic pole surface 105a of the electromagnetic coil 105 toward the ground, so that the position of the in-pipe moving body 100 can be accurately identified from the outside of the tube 101 based on the direction of the magnetic field vector.
  • the magnetic pole surface 105a of the electromagnetic coil 105 mounted on the in-pipe moving body 100 cannot always be directed to the ground side. If the magnetic pole surface 105a of the electromagnetic coil 105 does not face the ground side, the position of the in-pipe moving body 100 cannot be specified accurately.
  • An object of the present invention is to propose a transmitter for detecting a moving body in a tube that generates a rotating magnetic field capable of accurately identifying the position of the moving body in the tube from the outside of the tube based on a magnetic field for position detection generated from the transmitter. It is in.
  • Another object of the present invention is to propose an in-pipe mobile body equipped with such a new transmitter and an in-pipe mobile body detection system for detecting the position of the in-pipe mobile body.
  • the present invention provides a transmission for detecting an in-pipe moving body mounted on the in-pipe moving body in order to detect the position of the in-pipe moving body from the outside of the pipe in which the in-pipe moving body moves.
  • a rotating magnetic field generating mechanism for generating the rotating magnetic field that rotates on an orthogonal plane orthogonal to the rotation center line around a rotation center line parallel to the center axis of the tube to which the moving body in the tube moves. It is characterized by having.
  • the rotating magnetic field generating mechanism generates a rotating magnetic field of 10 Hz or less. Since the transmission distance of the ultra-low frequency magnetic signal is long, the detection distance of the moving body in the tube can be increased by setting the frequency of the rotating magnetic field to 10 Hz or less. In addition, since the ultra-low frequency magnetic signal is transmitted in any environment such as vacuum, gas, water, underground, and metal, the position of the moving body in the pipe can be detected regardless of the laying environment of the pipe.
  • the rotating magnetic field generating mechanism includes a frequency control unit that switches a frequency of the rotating magnetic field. In this way, even when it is difficult to detect a rotating magnetic field having a specific frequency due to a disturbance magnetic field at the place where the pipe is laid, the position of the moving body in the pipe can be specified by detecting a rotating magnetic field having another frequency.
  • the rotating magnetic field generating mechanism includes a frequency control unit that continuously changes the frequency of the rotating magnetic field. In this way, even when it is difficult to detect a rotating magnetic field having a specific frequency due to a disturbance magnetic field at the place where the pipe is laid, the position of the moving body in the pipe can be specified by detecting a rotating magnetic field having another frequency.
  • the rotating magnetic field generating mechanism includes a permanent magnet and a rotation driving mechanism that rotates the permanent magnet so that the magnetic pole surface of the permanent magnet moves in the circumferential direction around the rotation center line. It is desirable. If it does in this way, the magnetic field from a transmitter can be made strong by using a permanent magnet with strong magnetic force. Compared with the case where a magnetic field is generated by exciting the coil, an increase in power consumption when the magnetic field from the transmitter is strong can be suppressed.
  • the rotation drive mechanism is provided with a motor, and the permanent magnet is attached to the rotation shaft of the motor.
  • the rotation drive mechanism includes a bearing mechanism for rotatably supporting the permanent magnet and a drive coil for rotating the permanent magnet by excitation. It is desirable.
  • the rotating magnetic field generating mechanism includes a second permanent magnet disposed on the outer peripheral side of the permanent magnet, and a second rotation center in which the magnetic pole surface of the second permanent magnet is parallel to the rotation center line. And a second permanent magnet bearing mechanism bearing mechanism that rotatably supports the second permanent magnet so as to move in the circumferential direction around the line. When the permanent magnet rotates, the second permanent magnet It is desirable for the magnet to rotate.
  • the rotating magnetic field generating mechanism in order to generate a rotating magnetic field without using a permanent magnet, includes a plurality of electromagnetic coils and an excitation control unit that excites the plurality of electromagnetic coils in a predetermined order,
  • the plurality of electromagnetic coils are arranged such that the axis of each electromagnetic coil extends in different directions perpendicular to the rotation center line.
  • the present invention is an in-pipe moving body on which a transmitter that generates a rotating magnetic field for position detection is mounted, and the transmitter is a transmitter having the above-described configuration.
  • the in-pipe moving body detection system of the present invention detects a rotating magnetic field generated from the transmitter mounted on the in-pipe moving body and the outside of the tube to which the in-pipe moving body moves, and moves in the pipe. And a detector for identifying the position of the body, wherein the transmitter is a transmitter having the above-described configuration.
  • the transmitter generates a rotating magnetic field that rotates about a rotation center line parallel to the central axis of the tube and on an orthogonal plane orthogonal to the rotation center line. Since this rotating magnetic field contains a magnetic field vector that goes to the outside of the tube on an orthogonal plane orthogonal to the central axis of the tube, if the magnetic field vector is detected by a detector, the outside of the tube is based on the direction of the magnetic field vector. Therefore, the position of the moving body in the pipe can be accurately identified. Since the rotating magnetic field generated by the transmitter is a magnetic signal including a frequency component, the magnetic field from the transmitter can be distinguished from a disturbance magnetic field such as geomagnetism using the frequency component. That is, since noise due to a disturbance magnetic field can be removed, the magnetic field from the transmitter can be detected with high sensitivity. Further, since noise due to a disturbance magnetic field can be removed, the detection distance of the moving body in the tube can be increased.
  • FIG. 1A is an explanatory diagram showing a pig detection system to which the present invention is applied
  • FIG. 1B is an explanatory diagram showing a transmitter of the pig detection system.
  • a pig (moving body in pipe) 2 for cleaning the inside of the pipe 1 laid on the site of a factory is made of foamed urethane or rubber, and has a bullet shape with a tapered tip.
  • a pig 2 having an outer diameter substantially equal to the inner diameter of the tube 1 is prepared, the pig 2 is inserted into the tube 1 from the distal end side, and a fluid flows through the tube 1.
  • the pig 2 is pushed by the fluid pressure F1 of the fluid and moves in the axial direction of the tube 1 along the inner peripheral surface of the tube 1. Residue 3 such as adhering matter adhering to the inner wall of the tube 1 is transferred while being scraped off by the pig 2, and is discharged to the outside together with the pig 2 from the outlet (not shown) of the tube 1.
  • the transmitter 2 that generates a rotating magnetic field for position detection for detecting the position of the pig 2 is mounted on the pig 2.
  • the rotating magnetic field generating mechanism 10 of the transmitter 4 generates a rotating magnetic field that rotates on an orthogonal plane A orthogonal to the central axis 1A of the tube 1.
  • the rotating magnetic field from the transmitter 4 is detected by the detector 5 arranged outside the pipe 1, and the position of the pig 2 in the pipe 1 is determined. Identify.
  • the transmitter 4 and the detector 5 constitute a pig detection system 6.
  • the transmitter 4 includes a sealed case 11 made of a nonmagnetic member and a rotating magnetic field generation mechanism 10 housed in the case 11.
  • the rotating magnetic field generating mechanism 10 includes a permanent magnet 12 and a rotation driving mechanism 13 that rotates the permanent magnet 12.
  • the rotation drive mechanism 13 includes a motor 131, a frequency control circuit (frequency control unit) 132 that controls the frequency of the rotating magnetic field by driving the motor 131, and a battery that supplies power to the motor 131 via the frequency control circuit 132.
  • 133 and a switch 134 are provided.
  • the permanent magnet 12 has a cylindrical shape and is magnetized in two poles so that both end faces thereof are the magnetic pole faces 12a.
  • the permanent magnet 12 is fixed to the tip of the rotating shaft 131a of the motor 131 at the center in the central axis direction. Further, the permanent magnet 12 is fixed to the rotating shaft 131a so that the central axis thereof is orthogonal to the rotational center line L1 of the rotating shaft 131a. When the motor 131 rotates, the permanent magnet 12 rotates with the magnetic pole surface 12a about the rotation center line L1.
  • the transmitter 4 is mounted on the pig 2 so that the rotation center line L1 of the rotating shaft 131a of the motor 131 faces the moving direction M1 of the pig 2.
  • the pig 2 moves in the tube 1 while maintaining a posture in which the rotation center line L1 is parallel to the center axis 1A of the tube 1. Therefore, when the motor 131 rotates, the transmitter 4 causes the rotation center line L1 parallel to the center axis 1A of the tube 1 to be centered on the orthogonal plane A perpendicular to the rotation center line L1 (center axis 1A of the tube 1).
  • a rotating magnetic field is generated that rotates.
  • the frequency control circuit 132 sets the frequency of the rotating magnetic field by controlling the rotation speed of the motor 131.
  • the frequency control circuit 132 drives and controls the motor 131 so that the permanent magnet 12 rotates at a rotation speed of 10 rotations / second, and a 10 Hz rotating magnetic field is generated from the transmitter 4.
  • the battery 133 is a lithium ion secondary battery, and can be charged from the outside in a contactless manner while the transmitter 4 is mounted on the pig 2.
  • the switch 134 can be remotely operated without contact from the outside while being mounted on the pig 2.
  • the detector 5 is based on a magnetic field sensor probe 22 having a coil 21 and an induced electromotive force generated in proportion to the strength of the magnetic field when the magnetic field is linked to the coil 21.
  • a magnetic field detection circuit 23 that detects the magnetic field, and a display unit 24 that displays the strength of the magnetic field based on the output from the magnetic field detection circuit 23.
  • the induced electromotive force generated in the coil 21 is generated when a magnetic field (magnetic flux) passes through the coil 21. Accordingly, the magnetic field sensor probe 22 has directivity, and the direction of the magnetic field sensor probe 22 at the time when the induced electromotive force is generated is configured to indicate the direction of the magnetic field vector of the detected magnetic field.
  • the magnetic field detection circuit 23 includes a high-order bandpass filter 231 and a signal amplification circuit 232. Therefore, the detector 5 can remove noise caused by a disturbance magnetic field such as geomagnetism that does not include a frequency component, and can detect a magnetic signal including a frequency component of 10 Hz from the transmitter 4 with high sensitivity.
  • a disturbance magnetic field such as geomagnetism that does not include a frequency component
  • the rotating magnetic field generated from the transmitter 4 is a rotating magnetic field that rotates on the orthogonal plane A perpendicular to the rotation center line L1 around the rotation center line L1 parallel to the center axis 1A of the tube 1.
  • the rotating magnetic field includes a magnetic field vector V ⁇ b> 1 that goes on the orthogonal plane A orthogonal to the central axis 1 ⁇ / b> A of the tube 1 toward the outside of the tube 1. Therefore, if the magnetic field sensor probe 22 is directed to the ground 1a and a magnetic field whose intensity changes at 10 Hz is detected by the detector 5, the magnetic field vector V1 heading from the magnetic pole surface 12a of the permanent magnet 12 of the transmitter 4 to the ground can be detected.
  • the position of the pig 2 can be accurately identified from the outside of the tube 1.
  • the direction in which the magnetic field sensor probe 22 faces coincides with the direction of the magnetic field vector V ⁇ b> 1 from the magnetic pole surface 12 a of the permanent magnet 12 toward the ground. Therefore, it can be seen that the pig 2 is located in the tube 1 on the extension line of the magnetic field sensor probe 22.
  • the rotating magnetic field generated by the transmitter 4 is an extremely low frequency magnetic signal of 10 Hz.
  • the detector 5 can detect the rotating magnetic field from the transmitter 4 with high sensitivity without being affected by noise such as a disturbance magnetic field by removing magnetic frequency components other than 10 Hz. Therefore, the position of the pig 2 can be specified with high accuracy, and the detection distance of the pig 2 becomes long.
  • the rotating magnetic field generated by the transmitter 4 is an extremely low frequency magnetic signal
  • the transmission distance is long. Therefore, the detection distance capable of detecting the pig 2 is long.
  • the ultra-low frequency magnetic signal is transmitted in any environment including vacuum, gas, water, underground, and metal, the position of the pig 2 can be detected regardless of the laying environment of the tube 1.
  • the magnetic field from the transmitter 4 can be strengthened by using the permanent magnet 12 having a strong magnetic force. Compared with the case where a magnetic field is generated by exciting a coil, an increase in power consumption required when the magnetic field from the transmitter 4 is strong can be suppressed. Further, when the magnetic field from the transmitter 4 is made strong, there is no need to increase the size of the permanent magnet 12, so that the transmitter 4 does not increase in size and become heavy.
  • the frequency control circuit 132 can switch the frequency of the rotating magnetic field from the transmitter 4.
  • the frequency control circuit 132 selectively switches the frequency of the rotating magnetic field from the transmitter 4 to either the first frequency or the second frequency lower than the first frequency by setting from the outside. Can do. More specifically, the frequency control circuit 132 rotates the motor by selectively switching the rotation speed between a first speed of 10 rotations / second and a second speed of 8 rotations / second slower than the first rotation speed. The frequency of the magnetic field is switched to 10 Hz (first frequency) or 8 Hz (second frequency). In this way, even if it is difficult to detect the magnetic signal of the first frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
  • the frequency control circuit 132 can switch the frequency of the rotating magnetic field from the transmitter 4 between the first frequency and the second frequency lower than the first frequency every time a predetermined time elapses. . Even in this case, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
  • the frequency control circuit 132 may continuously change the frequency of the rotating magnetic field from the transmitter 4 between the first frequency and the first frequency. In this way, since the magnetic signal from the transmitter 4 continuously changes, even when it is difficult to detect a magnetic signal of a specific frequency due to a disturbance magnetic field at the place where the tube 1 is laid, And the position of the pig 2 can be specified.
  • the frequency control circuit 132 may stop the rotation of the motor 131 every time a predetermined time elapses. In this way, since the consumption of the battery 133 can be suppressed, the time during which the transmitter can operate can be extended. As a result, the operating time for operating the pig 2 can be extended. Further, since the magnetic field is generated from the permanent magnet 12 even when the rotation of the motor 131 is stopped, the magnetic field from the permanent magnet 12 is detected by the detector 5 so that the pig 2 The position can be specified.
  • the rotating magnetic field generating mechanism includes the second permanent magnet supported on the outer peripheral side of the permanent magnet 12 so as to be rotatable around the second rotation center line parallel to the rotation center line L1.
  • the second permanent magnet may be rotated when the permanent magnet 12 rotates.
  • FIG. 2 is an explanatory diagram of a transmitter according to a modified example in which the rotating magnetic field generating mechanism includes the second permanent magnet, and the inside of the pig 2 is viewed from the direction of the rotation center line L1.
  • the rotating magnetic field generation mechanism 10A includes four permanent magnets 141 to 144 arranged at equal angular intervals around the rotation center line L1 as the second permanent magnet 14.
  • the permanent magnets 141 to 144 are two-pole magnetized so that both end surfaces thereof are the magnetic pole surfaces 141a to 144a, and are arranged at positions overlapping when viewed from a direction orthogonal to the rotation center line L1.
  • the permanent magnets 141 to 144 are rotated by the bearing mechanisms (second permanent magnet bearing mechanisms) 15 around the rotation center lines (second center axis) L141 to L144 parallel to the rotation center axis L1. Supported as possible.
  • the central permanent magnet 12 rotates around the rotation center axis L1 in the direction of the arrow, the permanent magnets 141 to 144 are arranged in the circumferential direction in which the magnetic pole surfaces 141a to 144a are indicated by arrows around the rotation center lines L141 to L144. Rotate to move to.
  • the rotating magnetic field around the rotation center line L1 by the permanent magnet 12 and the rotation center lines L141 to 144 by the permanent magnets 141 to 144 are provided on the orthogonal plane A orthogonal to the rotation center line L1, the rotating magnetic field around the rotation center line L1 by the permanent magnet 12 and the rotation center lines L141 to 144 by the permanent magnets 141 to 144 are provided.
  • a rotating magnetic field around L144 is generated.
  • the magnetic field from the transmitter 4A becomes strong, and a large magnetic field vector can be detected by the detector 5.
  • the permanent magnets 141 to 144 arranged on the outer peripheral side of the permanent magnet 12 are rotated along with the rotation of the permanent magnet 12, it is necessary to newly provide a rotation drive mechanism in order to rotate the permanent magnets 141 to 144. Absent. Therefore, an increase in power consumption when the magnetic field from the transmitter 4A is strong can be suppressed.
  • the number of the second permanent magnets 14 arranged on the outer periphery of the permanent magnet 12 may be one, or five or more.
  • FIG. 3A is a schematic block diagram of another example of the transmitter
  • FIG. 3B is a perspective view showing the permanent magnet, the bearing mechanism, and the drive coil of the transmitter of this example.
  • C is a time chart of the excitation current applied to the drive coil.
  • the transmitter 7 of this example can be used as an alternative to the transmitter 4 described above.
  • the transmitter 7 of this example includes a sealed nonmagnetic case 30 and a rotating magnetic field generation mechanism 31 housed in the case 30.
  • the rotating magnetic field generating mechanism 31 includes a permanent magnet 32 and a rotation driving mechanism 33 that rotates the permanent magnet 32.
  • the rotation drive mechanism 33 includes a bearing mechanism 34 (see FIG. 3B) for rotatably supporting the permanent magnet 32, first and second drive coils 35 and 36 that rotate the permanent magnet 32 by excitation, A frequency control circuit (frequency control unit) 37 that controls the frequency of the rotating magnetic field by controlling the excitation current to the first and second drive coils 35 and 36, and the first and second through the frequency control circuit 37.
  • a battery 38 for supplying an excitation current to the two drive coils 35 and 36 and a switch 39 are provided.
  • the battery 38 is a lithium ion secondary battery, and can be charged from the outside in a contactless manner while the transmitter 7 is mounted on the pig 2.
  • the switch 39 is also mounted on the pig 2 and can be operated from the outside without contact.
  • the permanent magnet 32 has a rectangular parallelepiped shape.
  • a pair of parallel shafts 341 projecting from the central portion are provided on a pair of parallel end faces facing the moving direction M1 of the pig 2.
  • the permanent magnet 32 is magnetized in two poles, and one of a pair of a pair of parallel end faces different from the pair of parallel end faces provided with the support shaft 341 in the permanent magnet 32.
  • the end face is a magnetic pole face 32a.
  • the shaft end portions of the pair of support shafts 341 are rotatably supported by bearings 342. That is, the permanent magnet 32 is supported by the bearing mechanism 34 including the support shaft 341 and the bearing 342 in a rotatable state with the center axis of the support shaft 341 as the rotation center line L2.
  • the shaft end of each support shaft 341 is a conical pivot
  • the bearing 342 is a pivot ball bearing provided with a bearing.
  • the transmitter 7 is mounted on the pig 2 such that the rotation center line L2 is along the moving direction M1 of the pig 2. Further, the pig 2 moves in the tube 1 while maintaining a posture in which the rotation center line L2 is parallel to the center axis 1A of the tube 1.
  • the first and second drive coils 35 and 36 are rectangular air-core coils, both of which are a pair of parallel first coil portions 351 and 361 extending in a direction perpendicular to the moving direction M1 of the pig 2, and the movement of the pig 2.
  • a pair of parallel second coil portions 352 and 362 extending along the direction M1 is provided.
  • the first and second drive coils 35 and 36 are disposed such that the first coil portions 351 and 361 are orthogonal to each other at the center, and the permanent magnet 32 is disposed inside the first and second drive coils 35 and 36.
  • the bearing mechanism 34 is arrange
  • the rotation center line L2 of the permanent magnet 32 extends in parallel with the pair of second coil portions 352 and 362 in the middle of the pair of second coil portions 352 and 362 of the drive coils 35 and 36, respectively.
  • the frequency control circuit 37 sets the excitation current generation circuit 371 for generating an excitation current for exciting the first and second drive coils 35 and 36 and the frequency of the rotating magnetic field generated by the transmitter 7 to 10 Hz or 8 Hz.
  • the setting for the frequency setting circuit 372 can be set in a non-contact state from the outside.
  • the frequency control circuit 37 performs so-called one-phase excitation.
  • the excitation current I1 in the positive direction to the first drive coil 35 and the second drive coil 36 are supplied.
  • the excitation current I2 in the forward direction, the excitation current I3 in the reverse direction to the first drive coil 35, and the excitation current I4 in the reverse direction to the second drive coil 36 are repeatedly applied in this order.
  • the permanent magnet 32 rotates so that the magnetic pole surface 32a moves in the circumferential direction around the rotation center line L2.
  • the transmitter 7 generates a rotating magnetic field that rotates on the orthogonal plane A perpendicular to the rotation center line L2 around the rotation center line L2 parallel to the center axis 1A of the tube 1.
  • the frequency control circuit 37 sets an exciting current for rotating the permanent magnet 32 at 10 rotations / second or 8 rotations / second by setting the frequency of the rotating magnetic field to the frequency setting circuit 372. Apply to the drive coil. Therefore, a rotating magnetic field of 10 Hz or 8 Hz is generated from the transmitter 7.
  • the transmitter 7 generates a rotating magnetic field that rotates on the orthogonal plane A perpendicular to the rotation center line L2 around the rotation center line L2 parallel to the center axis 1A of the tube 1.
  • the rotating magnetic field includes a magnetic field vector that goes to the outside of the tube 1 on the orthogonal plane A orthogonal to the central axis 1A of the tube 1.
  • the rotating magnetic field generated by the transmitter 7 is an extremely low frequency magnetic signal of 10 Hz or 8 Hz. Further, a rotating magnetic field is generated using the magnetic field of the permanent magnet 32. Therefore, even when the transmitter 7 of this example is used instead of the transmitter 4, the same operation and effect as the above embodiment can be obtained, and the position of the pig 2 from the outside of the tube 1 can be obtained. It can be accurately identified.
  • the frequency of the rotating magnetic field can be selectively switched to either 10 Hz or 8 Hz. Therefore, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
  • a magnetic sensor such as a Hall element is disposed on the outer peripheral side of the permanent magnet 32 to detect the angular position of the permanent magnet 32 around the rotation center line L2 of the N or S pole, and the frequency control circuit is based on this angular position.
  • 37 may be configured to control application of excitation current to the first drive coil 35 and the second drive coil 36. In this way, the rotation of the permanent magnet 32 can be stabilized from the beginning of excitation of the first drive coil 35 and the second drive coil 36.
  • so-called two-phase excitation may be performed by the frequency control circuit 37 in order to rotate the permanent magnet 32 stably.
  • the frequency setting circuit 372 may switch the frequency of the rotating magnetic field every time a predetermined time elapses between 10 Hz and 8 Hz. In this way, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
  • the frequency setting circuit 372 may continuously change the frequency of the rotating magnetic field between 10 Hz and 8 Hz. In this way, even when it is difficult to detect a magnetic signal of a specific frequency due to a disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting a magnetic signal of another frequency.
  • the frequency setting circuit 372 may stop the rotation of the permanent magnet 32 every time a predetermined time elapses. In this way, since the consumption of the battery 38 can be suppressed, the time during which the transmitter 7 can operate can be extended. As a result, the operating time for operating the pig 2 can be extended. Further, since the magnetic field is generated even when the rotation of the permanent magnet 32 is stopped, the position of the pig 2 is specified from the outside of the tube 1 by detecting the magnetic field from the permanent magnet 32 by the detector 5. Can do.
  • the rotating magnetic field generating mechanism is disposed on the outer peripheral side of the permanent magnet 32 and the drive coil 35, and the second permanent magnet.
  • a second permanent magnet bearing mechanism that rotatably supports the second permanent magnet so that the magnetic pole surface of the permanent magnet moves in the circumferential direction around a second rotation center line parallel to the rotation center line L2.
  • the second permanent magnet can be rotated when the permanent magnet 32 rotates.
  • one permanent magnet can also be provided as a 2nd permanent magnet, and a some permanent magnet can also be provided.
  • the detector 5 can detect a large magnetic field vector.
  • the second permanent magnet arranged around the permanent magnet 32 rotates with the rotation of the permanent magnet 32, it is not necessary to provide a new rotation drive mechanism for rotating the second permanent magnet. Therefore, an increase in power consumption when the magnetic field from the transmitter is strong can be suppressed.
  • FIG. 4A is a schematic block diagram of another example of the transmitter
  • FIG. 4B is a perspective view showing the electromagnetic coil of this example
  • FIG. 4C is an application to the electromagnetic coil. It is a time chart of the exciting current to be performed.
  • the transmitter 8 of this example can be used as an alternative to the transmitters 4 and 7 described above.
  • the transmitter 8 of this example includes a sealed nonmagnetic case 40 and a rotating magnetic field generating mechanism 41 mounted inside the case 40.
  • the rotating magnetic field generating mechanism 41 is a frequency control circuit that controls the frequency of the rotating magnetic field by controlling the first and second electromagnetic coils 42 and 43 and the exciting current to the first and second electromagnetic coils 42 and 43.
  • (Excitation control unit, frequency control unit) 44, a battery 45 for supplying excitation current to the first and second electromagnetic coils 42 and 43 via the frequency control circuit 44, and a switch 46 are provided.
  • the battery 45 is a lithium ion secondary battery, and can be charged in a non-contact manner from the outside while the transmitter 8 is mounted on the pig 2. Further, the switch 46 is also mounted on the pig 2 and can be operated from the outside without contact.
  • the first and second electromagnetic coils 42 and 43 are configured by winding a first coil 421 and a second coil 431 around a cross-shaped iron core 400.
  • the iron core 400 includes four arm portions 400a to 400d having the same shape extending radially at an angular interval of 90 °.
  • the first coil 421 is wound around one pair of arm portions 400a and 400c that extend coaxially with an angular interval of 180 ° among the four arm portions 400a to 400d.
  • a first electromagnetic coil 42 is configured.
  • the second coil 431 is wound around the other pair of arms 400b and 400d extending coaxially with an angular interval of 180 ° out of the four arms 400a to 400d.
  • the second electromagnetic coil 43 is configured.
  • the rotation center line L3 extending in the direction perpendicular to the four arm portions 400a to 400d extends from the center of the four radial arm portions 400a to 400d. It is mounted on the pig 2 along M1. The pig 2 moves in the tube 1 while maintaining a posture in which the rotation center line L3 is parallel to the center axis 1A of the tube 1.
  • the frequency control circuit 44 sets the excitation current generation circuit 441 that generates an excitation current for exciting the first and second electromagnetic coils 42 and 43 and the frequency of the rotating magnetic field generated by the transmitter 7 to 10 Hz or 8 Hz.
  • the setting for the frequency setting circuit 442 can be set in a non-contact state from the outside.
  • the frequency control circuit 44 has a positive exciting current I1 to the first electromagnetic coil 42, a positive exciting current I2 to the second electromagnetic coil 43, and the first electromagnetic coil.
  • the exciting current I3 in the reverse direction to the coil 42 and the exciting current I4 in the reverse direction to the second electromagnetic coil 43 are repeatedly applied in this order.
  • the magnetic pole surfaces 42a and 43a (N pole and S pole) of the first and second electromagnetic coils 42 and 43 generated by the excitation move in the circumferential direction around the rotation center line L3.
  • a rotating magnetic field is generated from the transmitter 8 around the rotation center line L3 parallel to the central axis 1A of the tube 1 and rotating on the orthogonal plane A orthogonal to the rotation center line L3.
  • the frequency control circuit 44 sets the excitation current that moves the magnetic pole faces 42a and 43a around the rotation center line at 10 rotations / second or 8 rotations / second. Applied to the first electromagnetic coil 42 and the second electromagnetic coil 43. Therefore, a rotating magnetic field of 10 Hz or 8 Hz is generated from the transmitter 8.
  • the transmitter 8 generates a rotating magnetic field that rotates about the rotation center line L3 parallel to the center axis 1A of the tube 1 and on the orthogonal plane A orthogonal to the rotation center line L3.
  • the rotating magnetic field includes a magnetic field vector that goes to the outside of the tube 1 on the orthogonal plane A orthogonal to the central axis 1A of the tube 1.
  • the rotating magnetic field generated by the transmitter 8 is an extremely low frequency magnetic signal of 10 Hz or 8 Hz. Therefore, even when the transmitter 8 of this example is used in place of the transmitters 4 and 7, the same operation and effect as in the above embodiment can be obtained, and the pig 2 The position can be accurately identified.
  • the frequency of the rotating magnetic field can be selectively switched to either 10 Hz or 8 Hz. Therefore, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
  • the transmitter 8 of this example since the transmitter 8 of this example generates a rotating magnetic field by electrical control, the frequency of the rotating magnetic field generated by the transmitter 8 can be accurately controlled.
  • the frequency setting circuit 442 may switch the frequency of the rotating magnetic field every time a predetermined time elapses between 10 Hz and 8 Hz. In this way, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
  • the frequency setting circuit 442 may continuously change the frequency of the rotating magnetic field between 10 Hz and 8 Hz. In this way, even when it is difficult to detect a magnetic signal of a specific frequency due to a disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting a magnetic signal of another frequency.
  • the rotating magnetic field is generated by the two electromagnetic coils 42 and 43, but the rotating magnetic field may be generated by using three or more electromagnetic coils.
  • the iron core 400 may be omitted, and a rotating magnetic field may be generated by exciting the first coil 421 and the second coil 431.
  • the position of the pig 2 is specified using one detector 5, but the position of the pig 2 may be specified using a plurality of detectors. In this way, for example, even if the buried path of the tube 1 is unknown, the position of the pig 2 is accurately determined based on the magnetic field vector of the magnetic field from the transmitters 4, 7, 8 detected by each detector 5. Can be specified.
  • the magnetic field vector of the rotating magnetic field generated by the transmitters 4, 7, and 8 is detected by the detector 5.
  • the detection is performed only for the strength of the rotating magnetic field generated by the transmitter 4.
  • the position of the pig 2 may be specified using a container.

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Abstract

The transmitter (4) of a pig detection system (6) is provided with a permanent magnet (12) and a motor (131) which rotates the permanent magnet (12) in such a manner that the magnetic pole surface (12a) of the permanent magnet (12) moves in the circumferential direction about a rotation axis (L1) which is parallel to the axis (1A) of a pipe (1). When the motor (131) rotates, a rotating magnetic field which rotates in a perpendicular plane (A) perpendicular to the rotation axis (L1) and which is centered on the rotation axis (L1) is generated by the transmitter (4). The rotating magnetic field includes a magnetic field vector (V1) which is directed outward of the pipe (1) and which is present in the perpendicular plane (A) perpendicular to the axis (1A) of the pipe (1). The position of a pig (2) can be accurately specified from the outside of the pipe (1) on the basis of the magnetic field vector (V1). Because the rotating magnetic field includes a frequency component, the rotating magnetic field generated by the transmitter (4) and a disturbance magnetic field, such as earth's magnetism, can be discriminated from each other utilizing the frequency component.

Description

管内移動体探知用の発信器、管内移動体および管内移動体探知システムTransmitter for detecting moving object in tube, moving object in tube, and moving object detecting system in tube
　本発明は管の内部を移動して管内洗浄などを行う管内移動体を管の外側から探知するために当該管内移動体に搭載される管内移動体探知用の発信器に関する。また、本発明は、当該発信器が搭載されている管内移動体、および、当該発信器から発生する回転磁界に基づき管内移動体の位置を正確に探知する管内移動体探知システムに関する。 The present invention relates to a transmitter for detecting an in-pipe moving body mounted on the in-pipe moving body in order to detect the in-pipe moving body that moves inside the pipe and performs cleaning in the pipe from the outside of the pipe. The present invention also relates to an in-pipe moving body on which the transmitter is mounted, and an in-pipe moving body detection system that accurately detects the position of the in-pipe moving body based on a rotating magnetic field generated from the transmitter.
　工場の敷地内に埋設された管の内部洗浄を行うために、管の内径にほぼ等しい外径寸法の管内移動体が使用されている。管内移動体を洗浄対象の管に挿入した後、管に流体を流し、流体の流体圧によって管内移動体を管の長さ方向に移動させる。これにより管内の残留物や管の内周壁に付着していた付着物が、管内移動体によって管の出口から排出される。このような管内移動体はピグと呼ばれている。 In order to perform internal cleaning of the pipes embedded in the factory premises, an in-pipe moving body having an outer diameter approximately equal to the inner diameter of the pipe is used. After the in-pipe moving body is inserted into the pipe to be cleaned, a fluid is caused to flow through the pipe, and the in-pipe moving body is moved in the length direction of the pipe by the fluid pressure of the fluid. As a result, the residue in the pipe and the deposit attached to the inner peripheral wall of the pipe are discharged from the outlet of the pipe by the moving body in the pipe. Such an in-pipe moving body is called a pig.
　管内移動体には発信器が搭載されている。管内移動体が管内の途中位置で停止してしまった場合などにおいて、発信器からの信号を探知器によって検出して、管内移動体の位置を特定している。発信器としては検出用の磁界を発生するものが知られており、特許文献１には、この形式の発信器を備えた管内移動体が開示されている。 The transmitter in the pipe is equipped with a transmitter. When the in-pipe moving body stops at an intermediate position in the pipe, the signal from the transmitter is detected by the detector to identify the position of the in-pipe moving body. A transmitter that generates a magnetic field for detection is known, and Patent Document 1 discloses an in-pipe moving body including this type of transmitter.
　図５（ａ）、（ｂ）は、従来における検出用の磁界を発生する発信器を備えた管内移動体を示す説明図である。図５（ａ）に示すように、管内移動体１００は弾丸形状をしており、先細りとなっている側が移動方向Ｍ０の前側となる状態で管１０１に挿入される。発信器１０２は、鉄芯１０３および鉄芯１０３に巻き回したコイル１０４を備えた電磁コイル１０５と、電磁コイル１０５に一定周期のパルス電流を印加するためのパルス発生回路１０６と、パルス発生回路１０６を介して電磁コイル１０５に電力を供給する電池１０７およびスイッチ１０８とを備えている。発信器１０２は電磁コイル１０５の中心線Ｌ０が管内移動体１００の移動方向Ｍ０に沿う状態で管内移動体１００に搭載されている。管内移動体１００は、電磁コイル１０５の中心線Ｌ０が管１０１の中心軸線１０１Ａと平行となる姿勢を維持したまま、管１０１内を移動する。 5 (a) and 5 (b) are explanatory views showing a moving body in a tube provided with a conventional transmitter that generates a magnetic field for detection. As shown in FIG. 5A, the in-pipe moving body 100 has a bullet shape, and is inserted into the pipe 101 in a state where the tapered side is the front side in the moving direction M0. The transmitter 102 includes an iron core 103 and an electromagnetic coil 105 including a coil 104 wound around the iron core 103, a pulse generation circuit 106 for applying a pulse current having a constant period to the electromagnetic coil 105, and a pulse generation circuit 106. A battery 107 and a switch 108 for supplying electric power to the electromagnetic coil 105 via the switch are provided. The transmitter 102 is mounted on the in-pipe moving body 100 with the center line L0 of the electromagnetic coil 105 along the moving direction M0 of the in-pipe moving body 100. The in-pipe moving body 100 moves in the tube 101 while maintaining a posture in which the center line L0 of the electromagnetic coil 105 is parallel to the center axis 101A of the tube 101.
　図５（ｂ）に示すように、地面１０９から数メートル離れた地中に水平に埋設された管１０１内で停止している管内移動体１００を探知する際には、磁気センサプローブ１１０ａを備えた探知器１１０を地上で埋設経路に沿って移動させる。探知器１１０は、電磁コイル１０５から周期的に発生している磁界（図中の二点鎖線）の磁界ベクトルを検出し、これにより、管内移動体１００の位置を特定する。 As shown in FIG. 5B, a magnetic sensor probe 110a is provided when detecting the moving body 100 in the pipe that is stopped in the pipe 101 horizontally buried in the ground several meters away from the ground 109. The detected detector 110 is moved along the buried route on the ground. The detector 110 detects a magnetic field vector of a magnetic field (two-dot chain line in the figure) periodically generated from the electromagnetic coil 105, and thereby identifies the position of the in-pipe moving body 100.
特開２００１－２３５０８９号公報JP 2001-235089 A
　従来の管内移動体における発信器１０２は、電磁コイル１０５の磁極面１０５ａ（鉄芯１０３の端面）が管内移動体１００の移動方向Ｍ０を向くように、管内移動体１００に搭載されている。探知器１１０が発信器１０２からの最大磁界を検出したときに磁界ベクトルＶ０の方向は管１０１の中心軸線１０１Ａに一致する。磁界ベクトルＶ０の方向から管内における管内移動体１００の位置を検出するためには、発信器１０２が発生する磁界の磁力線ルートに関する知識や熟練が必要である。 The transmitter 102 in the conventional in-pipe moving body is mounted on the in-pipe moving body 100 so that the magnetic pole surface 105a (the end surface of the iron core 103) of the electromagnetic coil 105 faces the moving direction M0 of the in-pipe moving body 100. When the detector 110 detects the maximum magnetic field from the transmitter 102, the direction of the magnetic field vector V0 coincides with the central axis 101A of the tube 101. In order to detect the position of the moving body 100 in the tube from the direction of the magnetic field vector V0, knowledge and skill regarding the magnetic field line route of the magnetic field generated by the transmitter 102 is required.
　そこで、電磁コイル１０５の中心線Ｌ０を管内移動体１００の移動方向Ｍ０と直交する上下方向に沿うように発信器１０２を管内移動体１００に搭載し、電磁コイル１０５の磁極面１０５ａが常に地上側を向く状態としておくことが考えられる。このようにすれば、発信器１０２からの磁界の方向が管１０１の半径方向を向く。この結果、探知器１１０によって、電磁コイル１０５の磁極面１０５ａから地上に向かう磁界ベクトルを検出できるので、磁界ベクトルの方向に基づいて管内移動体１００の位置を管１０１の外側から精度よく特定できる。 Therefore, the transmitter 102 is mounted on the in-pipe moving body 100 so that the center line L0 of the electromagnetic coil 105 is along the vertical direction perpendicular to the moving direction M0 of the in-pipe moving body 100, and the magnetic pole surface 105a of the electromagnetic coil 105 is always on the ground side. It is conceivable to keep the state facing. In this way, the direction of the magnetic field from the transmitter 102 faces the radial direction of the tube 101. As a result, the detector 110 can detect a magnetic field vector from the magnetic pole surface 105a of the electromagnetic coil 105 toward the ground, so that the position of the in-pipe moving body 100 can be accurately identified from the outside of the tube 101 based on the direction of the magnetic field vector.
　しかしながら、管内を移動する管内移動体１００はその周方向の向きが不定であるので、管内移動体１００に搭載した電磁コイル１０５の磁極面１０５ａを常に地上側を向く状態としておくことができない。電磁コイル１０５の磁極面１０５ａが地上側を向いていなければ、管内移動体１００の位置を正確に特定することができない。 However, since the in-pipe moving body 100 moving in the pipe has an indefinite direction in the circumferential direction, the magnetic pole surface 105a of the electromagnetic coil 105 mounted on the in-pipe moving body 100 cannot always be directed to the ground side. If the magnetic pole surface 105a of the electromagnetic coil 105 does not face the ground side, the position of the in-pipe moving body 100 cannot be specified accurately.
　本発明の課題は、発信器から発生する位置検出用の磁界に基づき管内移動体の位置を管の外側から正確に特定可能な回転磁界を発生する管内移動体探知用の発信器を提案することにある。 An object of the present invention is to propose a transmitter for detecting a moving body in a tube that generates a rotating magnetic field capable of accurately identifying the position of the moving body in the tube from the outside of the tube based on a magnetic field for position detection generated from the transmitter. It is in.
　また、本発明の課題は、かかる新たな発信器が搭載された管内移動体、および当該管内移動体の位置を探知するための管内移動体探知システムを提案することにある。 Another object of the present invention is to propose an in-pipe mobile body equipped with such a new transmitter and an in-pipe mobile body detection system for detecting the position of the in-pipe mobile body.
　上記の課題を解決するために、本発明は、管内移動体が移動する管の外側から当該管内移動体の位置を検出するために、当該管内移動体に搭載される管内移動体探知用の発信器であって、前記管内移動体が移動する管の中心軸線に平行な回転中心線を中心として、当該回転中心線に直交する直交面上を回転する前記回転磁界を発生させる回転磁界発生機構を備えていることを特徴としている。 In order to solve the above-described problems, the present invention provides a transmission for detecting an in-pipe moving body mounted on the in-pipe moving body in order to detect the position of the in-pipe moving body from the outside of the pipe in which the in-pipe moving body moves. A rotating magnetic field generating mechanism for generating the rotating magnetic field that rotates on an orthogonal plane orthogonal to the rotation center line around a rotation center line parallel to the center axis of the tube to which the moving body in the tube moves. It is characterized by having.
　本発明において、前記回転磁界発生機構は１０Ｈｚ以下の回転磁界を発生させることが望ましい。超低周波の磁気信号の伝達距離は長いので、回転磁界の周波数を１０Ｈｚ以下としておけば、管内移動体の検出距離を長くすることができる。また、超低周波の磁気信号は、真空中、気体中、水中、地中、金属中のいずれの環境下でも伝達されるので、管の敷設環境に拘わらず管内移動体の位置を検出できる。 In the present invention, it is desirable that the rotating magnetic field generating mechanism generates a rotating magnetic field of 10 Hz or less. Since the transmission distance of the ultra-low frequency magnetic signal is long, the detection distance of the moving body in the tube can be increased by setting the frequency of the rotating magnetic field to 10 Hz or less. In addition, since the ultra-low frequency magnetic signal is transmitted in any environment such as vacuum, gas, water, underground, and metal, the position of the moving body in the pipe can be detected regardless of the laying environment of the pipe.
　本発明において、前記回転磁界発生機構は、前記回転磁界の周波数を切り替える周波数制御部を備えていることが望ましい。このようにすれば、管の敷設場所における外乱磁界によって特定の周波数の回転磁界の検出が困難な場合でも、他の周波数の回転磁界を検出して、管内移動体の位置を特定できる。 In the present invention, it is desirable that the rotating magnetic field generating mechanism includes a frequency control unit that switches a frequency of the rotating magnetic field. In this way, even when it is difficult to detect a rotating magnetic field having a specific frequency due to a disturbance magnetic field at the place where the pipe is laid, the position of the moving body in the pipe can be specified by detecting a rotating magnetic field having another frequency.
　本発明において、前記回転磁界発生機構は、前記回転磁界の周波数を連続的に変化させる周波数制御部を備えていることが望ましい。このようにすれば、管の敷設場所における外乱磁界によって特定の周波数の回転磁界の検出が困難な場合でも、他の周波数の回転磁界を検出して、管内移動体の位置を特定できる。 In the present invention, it is desirable that the rotating magnetic field generating mechanism includes a frequency control unit that continuously changes the frequency of the rotating magnetic field. In this way, even when it is difficult to detect a rotating magnetic field having a specific frequency due to a disturbance magnetic field at the place where the pipe is laid, the position of the moving body in the pipe can be specified by detecting a rotating magnetic field having another frequency.
　本発明において、前記回転磁界発生機構は、永久磁石と、この永久磁石の磁極面が前記回転中心線の回りを周方向に移動するように当該永久磁石を回転させる回転駆動機構とを備えていることが望ましい。このようにすれば、磁力の強い永久磁石を用いることによって発信器からの磁界を強力なものとすることができる。コイルを励磁することによって磁界を発生させる場合と比較して、発信器からの磁界を強力なものとする場合の消費電力の増加を抑制できる。 In the present invention, the rotating magnetic field generating mechanism includes a permanent magnet and a rotation driving mechanism that rotates the permanent magnet so that the magnetic pole surface of the permanent magnet moves in the circumferential direction around the rotation center line. It is desirable. If it does in this way, the magnetic field from a transmitter can be made strong by using a permanent magnet with strong magnetic force. Compared with the case where a magnetic field is generated by exciting the coil, an increase in power consumption when the magnetic field from the transmitter is strong can be suppressed.
　この場合において、発信器を簡単な構成にするために、前記回転駆動機構は、モータを備えており、前記永久磁石は前記モータの回転軸に取り付けられていることが望ましい。また、発信器をより簡単な構成にするために、前記回転駆動機構は、前記永久磁石を回転可能に支持するための軸受機構と、励磁により前記永久磁石を回転させる駆動コイルとを備えていることが望ましい。 In this case, in order to make the transmitter simple, it is desirable that the rotation drive mechanism is provided with a motor, and the permanent magnet is attached to the rotation shaft of the motor. In order to make the transmitter simpler, the rotation drive mechanism includes a bearing mechanism for rotatably supporting the permanent magnet and a drive coil for rotating the permanent magnet by excitation. It is desirable.
　本発明において、前記回転磁界発生機構は、前記永久磁石の外周側に配置された第２の永久磁石と、この第２の永久磁石の磁極面が前記回転中心線と平行な第２の回転中心線回りを周方向に移動するように当該第２の永久磁石を回転可能に支持する第２の永久磁石用軸受機構軸受機構とを備えており、前記永久磁石が回転すると、前記第２の永久磁石が連れ回りすることが望ましい。 In the present invention, the rotating magnetic field generating mechanism includes a second permanent magnet disposed on the outer peripheral side of the permanent magnet, and a second rotation center in which the magnetic pole surface of the second permanent magnet is parallel to the rotation center line. And a second permanent magnet bearing mechanism bearing mechanism that rotatably supports the second permanent magnet so as to move in the circumferential direction around the line. When the permanent magnet rotates, the second permanent magnet It is desirable for the magnet to rotate.
このようにすれば、回転中心線に直交する直交面上に、回転中心線回りの回転磁界に加えて、第２の永久磁石による第２の回転中心線回りの回転磁界を発生させることができるので、発信器からの磁界を強力なものとすることができる。また、第２の永久磁石は永久磁石の回転に連れ回りするので、第２の永久磁石を回転させるために新たに回転駆動機構を設ける必要がない。よって、発信器からの磁界を強力なものとする場合の消費電力の増加を抑制できる。 In this way, on the orthogonal plane orthogonal to the rotation center line, in addition to the rotation magnetic field around the rotation center line, a rotation magnetic field around the second rotation center line by the second permanent magnet can be generated. Therefore, the magnetic field from the transmitter can be made strong. Further, since the second permanent magnet is rotated along with the rotation of the permanent magnet, it is not necessary to newly provide a rotation drive mechanism for rotating the second permanent magnet. Therefore, an increase in power consumption when the magnetic field from the transmitter is strong can be suppressed.
　本発明において、永久磁石を用いないで回転磁界を発生させるために、前記回転磁界発生機構は、複数の電磁コイルと、前記複数の電磁コイルを所定の順番で励磁する励磁制御部とを備え、前記複数の電磁コイルは、各電磁コイルの軸線が前記回転中心線と直交して互いに異なる方向に延びるように配置されている。 In the present invention, in order to generate a rotating magnetic field without using a permanent magnet, the rotating magnetic field generating mechanism includes a plurality of electromagnetic coils and an excitation control unit that excites the plurality of electromagnetic coils in a predetermined order, The plurality of electromagnetic coils are arranged such that the axis of each electromagnetic coil extends in different directions perpendicular to the rotation center line.
　次に、本発明は、位置検出用の回転磁界を発生する発信器が搭載されている管内移動体であって、前記発信器は上記構成の発信器であることを特徴としている。 Next, the present invention is an in-pipe moving body on which a transmitter that generates a rotating magnetic field for position detection is mounted, and the transmitter is a transmitter having the above-described configuration.
　また、本発明の管内移動体探知システムは、管内移動体に搭載されている発信器と、前記管内移動体が移動する管の外側から前記発信器が発生する回転磁界を検出して当該管内移動体の位置を特定する探知器とを有し、前記発信器は上記構成の発信器であることを特徴としている。 Further, the in-pipe moving body detection system of the present invention detects a rotating magnetic field generated from the transmitter mounted on the in-pipe moving body and the outside of the tube to which the in-pipe moving body moves, and moves in the pipe. And a detector for identifying the position of the body, wherein the transmitter is a transmitter having the above-described configuration.
　本発明によれば、発信器からは、管の中心軸線と平行な回転中心線を中心として、この回転中心線に直交する直交面上を回転する回転磁界が発生する。この回転磁界には管の中心軸線と直交する直交面上を管の外側に向かう磁界ベクトルが含まれているので、磁界ベクトルを探知器によって検出すれば、磁界ベクトルの方向に基づいて管の外側から管内移動体の位置を正確に特定できる。また、発信器が発生させる回転磁界は周波数成分を含んだ磁気信号なので、周波数成分を利用して発信器からの磁界と地磁気などの外乱磁界とを区別できる。すなわち、外乱磁界によるノイズを除去することが可能となるので、発信器からの磁界を感度良く検出できる。また、外乱磁界によるノイズを除去することが可能となるので、管内移動体の検出距離を長くすることができる。 According to the present invention, the transmitter generates a rotating magnetic field that rotates about a rotation center line parallel to the central axis of the tube and on an orthogonal plane orthogonal to the rotation center line. Since this rotating magnetic field contains a magnetic field vector that goes to the outside of the tube on an orthogonal plane orthogonal to the central axis of the tube, if the magnetic field vector is detected by a detector, the outside of the tube is based on the direction of the magnetic field vector. Therefore, the position of the moving body in the pipe can be accurately identified. Since the rotating magnetic field generated by the transmitter is a magnetic signal including a frequency component, the magnetic field from the transmitter can be distinguished from a disturbance magnetic field such as geomagnetism using the frequency component. That is, since noise due to a disturbance magnetic field can be removed, the magnetic field from the transmitter can be detected with high sensitivity. Further, since noise due to a disturbance magnetic field can be removed, the detection distance of the moving body in the tube can be increased.
本発明を適用した管内移動体探知システムおよび発信器を示す説明図である。It is explanatory drawing which shows the in-pipe mobile body detection system and transmitter to which this invention is applied. 図１の発信器の変形例を示す説明図である。It is explanatory drawing which shows the modification of the transmitter of FIG. 管内移動体探知システムの発信器の別の例を示す説明図である。It is explanatory drawing which shows another example of the transmitter of the in-pipe mobile body detection system. 管内移動体探知システムの発信器の更に別の例を示す説明図である。It is explanatory drawing which shows another example of the transmitter of the in-pipe mobile body detection system. 従来例の管内移動体探知システムおよび発信器を示す説明図である。It is explanatory drawing which shows the in-pipe mobile body detection system and transmitter of a prior art example.
　以下に図面を参照して、本発明の実施の形態に係るピグ探知システム（管内移動体探知システム）を説明する。 Hereinafter, a pig detection system (in-pipe moving body detection system) according to an embodiment of the present invention will be described with reference to the drawings.
（全体構成）
　図１（ａ）は本発明を適用したピグ探知システムを示す説明図であり、図１（ｂ）はピグ探知システムの発信器を示す説明図である。工場の敷地内等に敷設された管１の内部を洗浄するためのピグ（管内移動体）２は発泡ウレタンやゴムなどからなり、先端が先細りの弾丸形状をしている。管１の内部を洗浄する際には、管１の内径にほぼ等しい外径のピグ２を用意し、当該ピグ２をその先端側から管１に挿入し、管１に流体を流す。ピグ２は、流体の流体圧Ｆ１によって押されて、管１の内周面に沿って当該管１の軸線方向に移動する。管１の内壁に付着していた付着物などの残留物３は、ピグ２によって掻き取られながら移送され、ピグ２と共に管１の出口(不図示）から外部に排出される。 (overall structure)
FIG. 1A is an explanatory diagram showing a pig detection system to which the present invention is applied, and FIG. 1B is an explanatory diagram showing a transmitter of the pig detection system. A pig (moving body in pipe) 2 for cleaning the inside of the pipe 1 laid on the site of a factory is made of foamed urethane or rubber, and has a bullet shape with a tapered tip. When cleaning the inside of the tube 1, a pig 2 having an outer diameter substantially equal to the inner diameter of the tube 1 is prepared, the pig 2 is inserted into the tube 1 from the distal end side, and a fluid flows through the tube 1. The pig 2 is pushed by the fluid pressure F1 of the fluid and moves in the axial direction of the tube 1 along the inner peripheral surface of the tube 1. Residue 3 such as adhering matter adhering to the inner wall of the tube 1 is transferred while being scraped off by the pig 2, and is discharged to the outside together with the pig 2 from the outlet (not shown) of the tube 1.
　ピグ２には、当該ピグ２の位置を検出するための位置検出用の回転磁界を発生する発信器４が搭載されている。発信器４の回転磁界発生機構１０は、管１の中心軸線１Ａと直交する直交面Ａ上を回転する回転磁界を発生する。ピグ２が管１内で停止してしまった場合などには、管１の外に配置されている探知器５によって発信器４からの回転磁界を検出し、管１内におけるピグ２の位置を特定する。これら発信器４および探知器５によってピグ探知システム６が構成される。 The transmitter 2 that generates a rotating magnetic field for position detection for detecting the position of the pig 2 is mounted on the pig 2. The rotating magnetic field generating mechanism 10 of the transmitter 4 generates a rotating magnetic field that rotates on an orthogonal plane A orthogonal to the central axis 1A of the tube 1. When the pig 2 stops in the pipe 1, the rotating magnetic field from the transmitter 4 is detected by the detector 5 arranged outside the pipe 1, and the position of the pig 2 in the pipe 1 is determined. Identify. The transmitter 4 and the detector 5 constitute a pig detection system 6.
（発信器）
　発信器４は、図１（ｂ）に示すように、非磁性部材からなる密閉されたケース１１と、ケース１１に収納されている回転磁界発生機構１０を備えている。回転磁界発生機構１０は永久磁石１２と、永久磁石１２を回転させる回転駆動機構１３を備えている。回転駆動機構１３はモータ１３１と、モータ１３１を駆動制御することによって回転磁界の周波数を制御する周波数制御回路（周波数制御部）１３２と、周波数制御回路１３２を介してモータ１３１に電力を供給する電池１３３と、スイッチ１３４を備えている。 (Transmitter)
As shown in FIG. 1B, the transmitter 4 includes a sealed case 11 made of a nonmagnetic member and a rotating magnetic field generation mechanism 10 housed in the case 11. The rotating magnetic field generating mechanism 10 includes a permanent magnet 12 and a rotation driving mechanism 13 that rotates the permanent magnet 12. The rotation drive mechanism 13 includes a motor 131, a frequency control circuit (frequency control unit) 132 that controls the frequency of the rotating magnetic field by driving the motor 131, and a battery that supplies power to the motor 131 via the frequency control circuit 132. 133 and a switch 134 are provided.
　永久磁石１２は円柱形状をしており、その両端面が磁極面１２ａとなるように２極着磁されている。永久磁石１２は、その中心軸線方向の中央部において、モータ１３１の回転軸１３１ａの先端に固定されている。また、永久磁石１２は、その中心軸線が回転軸１３１ａの回転中心線Ｌ１に直交する姿勢で回転軸１３１ａに固定されている。モータ１３１が回転すると、永久磁石１２は磁極面１２ａが回転中心線Ｌ１を中心として回転する。 The permanent magnet 12 has a cylindrical shape and is magnetized in two poles so that both end faces thereof are the magnetic pole faces 12a. The permanent magnet 12 is fixed to the tip of the rotating shaft 131a of the motor 131 at the center in the central axis direction. Further, the permanent magnet 12 is fixed to the rotating shaft 131a so that the central axis thereof is orthogonal to the rotational center line L1 of the rotating shaft 131a. When the motor 131 rotates, the permanent magnet 12 rotates with the magnetic pole surface 12a about the rotation center line L1.
　発信器４は、モータ１３１の回転軸１３１ａの回転中心線Ｌ１がピグ２の移動方向Ｍ１を向くように、ピグ２に搭載されている。ピグ２は、その回転中心線Ｌ１が管１の中心軸線１Ａと平行となる姿勢を維持したまま管１内を移動する。従って、モータ１３１が回転すると、発信器４からは、管１の中心軸線１Ａに平行な回転中心線Ｌ１を中心として、回転中心線Ｌ１（管１の中心軸線１Ａ）に直交する直交面Ａ上を回転する回転磁界が発生する。 The transmitter 4 is mounted on the pig 2 so that the rotation center line L1 of the rotating shaft 131a of the motor 131 faces the moving direction M1 of the pig 2. The pig 2 moves in the tube 1 while maintaining a posture in which the rotation center line L1 is parallel to the center axis 1A of the tube 1. Therefore, when the motor 131 rotates, the transmitter 4 causes the rotation center line L1 parallel to the center axis 1A of the tube 1 to be centered on the orthogonal plane A perpendicular to the rotation center line L1 (center axis 1A of the tube 1). A rotating magnetic field is generated that rotates.
　周波数制御回路１３２は、モータ１３１の回転速度を制御することにより、回転磁界の周波数を設定する。周波数制御回路１３２は、永久磁石１２が１０回転／秒の回転速度で回転するようにモータ１３１を駆動制御しており、発信器４からは１０Ｈｚの回転磁界が発生する。電池１３３はリチウムイオン２次電池であり、発信器４がピグ２に搭載された状態のままで、外部から非接触で充電可能である。また、スイッチ１３４もピグ２に搭載された状態のままで、外部から非接触で遠隔操作できる。 The frequency control circuit 132 sets the frequency of the rotating magnetic field by controlling the rotation speed of the motor 131. The frequency control circuit 132 drives and controls the motor 131 so that the permanent magnet 12 rotates at a rotation speed of 10 rotations / second, and a 10 Hz rotating magnetic field is generated from the transmitter 4. The battery 133 is a lithium ion secondary battery, and can be charged from the outside in a contactless manner while the transmitter 4 is mounted on the pig 2. In addition, the switch 134 can be remotely operated without contact from the outside while being mounted on the pig 2.
（探知器）
　探知器５は、図１（ａ）に示すように、コイル２１を備えた磁界センサプローブ２２と、コイル２１に磁界が鎖交したときに磁界の強度に比例して発生する誘導起電力に基づいて磁界を検出する磁界検出回路２３と、磁界検出回路２３からの出力に基づいて磁界の強さを表示する表示部２４を備えている。 (Detector)
As shown in FIG. 1A, the detector 5 is based on a magnetic field sensor probe 22 having a coil 21 and an induced electromotive force generated in proportion to the strength of the magnetic field when the magnetic field is linked to the coil 21. A magnetic field detection circuit 23 that detects the magnetic field, and a display unit 24 that displays the strength of the magnetic field based on the output from the magnetic field detection circuit 23.
　コイル２１に発生する誘導起電力は、磁界(磁束）がコイル２１内を通過することにより発生するものである。従って、磁界センサプローブ２２は指向性を備えており、誘導起電力が発生した時点における磁界センサプローブ２２の方向が、検出した磁界の磁界ベクトルの方向を示すように構成されている。 The induced electromotive force generated in the coil 21 is generated when a magnetic field (magnetic flux) passes through the coil 21. Accordingly, the magnetic field sensor probe 22 has directivity, and the direction of the magnetic field sensor probe 22 at the time when the induced electromotive force is generated is configured to indicate the direction of the magnetic field vector of the detected magnetic field.
　磁界検出回路２３は、高次のバンドパスフィルタ２３１と信号増幅回路２３２を備えている。従って、探知器５は、周波数成分を含まない地磁気などの外乱磁界によるノイズを除去して、発信器４からの１０Ｈｚの周波数成分を含む磁気信号を感度良く検出できる。 The magnetic field detection circuit 23 includes a high-order bandpass filter 231 and a signal amplification circuit 232. Therefore, the detector 5 can remove noise caused by a disturbance magnetic field such as geomagnetism that does not include a frequency component, and can detect a magnetic signal including a frequency component of 10 Hz from the transmitter 4 with high sensitivity.
（ピグ探知方法）
　地面１ａから数メートル離れた地中に水平に埋設された管１内で停止したピグ２を探知する場合には、図１（ａ）に示すように、磁界センサプローブ２２を地面１ａに向ける。この状態で探知器５を地上で管１の埋設経路に沿って移動させ、発信器４からの回転磁界を検出してピグ２の位置を特定する。 (Pig detection method)
When detecting the pig 2 stopped in the pipe 1 embedded horizontally in the ground several meters away from the ground 1a, the magnetic field sensor probe 22 is directed toward the ground 1a as shown in FIG. In this state, the detector 5 is moved along the buried path of the pipe 1 on the ground, the rotating magnetic field from the transmitter 4 is detected, and the position of the pig 2 is specified.
　発信器４から発生している回転磁界は、管１の中心軸線１Ａと平行な回転中心線Ｌ１を中心として、この回転中心線Ｌ１に直交する直交面Ａ上を回転する回転磁界である。回転磁界には、管１の中心軸線１Ａと直交する直交面Ａ上を管１の外側に向かう磁界ベクトルＶ１が含まれている。従って、磁界センサプローブ２２を地面１ａに向け、探知器５によって１０Ｈｚで強度が変化する磁界を検出すれば、発信器４の永久磁石１２の磁極面１２ａから地上に向かう磁界ベクトルＶ１を検出できる。この磁界ベクトルＶ１に基づいて管１の外側からピグ２の位置を精度よく特定できる。すなわち、探知器５によって最大強度の磁界が周期的に検出される時点では、磁界センサプローブ２２の向いている方向が永久磁石１２の磁極面１２ａから地上に向かう磁界ベクトルＶ１の方向に一致する。したがって、磁界センサプローブ２２の延長線上の管１内にピグ２が位置していることが分かる。 The rotating magnetic field generated from the transmitter 4 is a rotating magnetic field that rotates on the orthogonal plane A perpendicular to the rotation center line L1 around the rotation center line L1 parallel to the center axis 1A of the tube 1. The rotating magnetic field includes a magnetic field vector V <b> 1 that goes on the orthogonal plane A orthogonal to the central axis 1 </ b> A of the tube 1 toward the outside of the tube 1. Therefore, if the magnetic field sensor probe 22 is directed to the ground 1a and a magnetic field whose intensity changes at 10 Hz is detected by the detector 5, the magnetic field vector V1 heading from the magnetic pole surface 12a of the permanent magnet 12 of the transmitter 4 to the ground can be detected. Based on this magnetic field vector V1, the position of the pig 2 can be accurately identified from the outside of the tube 1. In other words, when the magnetic field with the maximum intensity is periodically detected by the detector 5, the direction in which the magnetic field sensor probe 22 faces coincides with the direction of the magnetic field vector V <b> 1 from the magnetic pole surface 12 a of the permanent magnet 12 toward the ground. Therefore, it can be seen that the pig 2 is located in the tube 1 on the extension line of the magnetic field sensor probe 22.
　発信器４が発生する回転磁界は１０Ｈｚの超低周波の磁気信号である。探知器５は、１０Ｈｚ以外の磁気周波数成分を除去することにより、外乱磁界などのノイズに影響されずに、発信器４からの回転磁界を感度良く検出できる。よって、ピグ２の位置を精度よく特定でき、ピグ２の検出距離も長くなる。 The rotating magnetic field generated by the transmitter 4 is an extremely low frequency magnetic signal of 10 Hz. The detector 5 can detect the rotating magnetic field from the transmitter 4 with high sensitivity without being affected by noise such as a disturbance magnetic field by removing magnetic frequency components other than 10 Hz. Therefore, the position of the pig 2 can be specified with high accuracy, and the detection distance of the pig 2 becomes long.
　さらに、発信器４が発生する回転磁界は超低周波の磁気信号であるので伝達距離が長い。従って、ピグ２を検出可能な検出距離が長い。また、超低周波の磁気信号は、真空中、気体中、水中、地中、金属中のいずれの環境下でも伝達するので、管１の敷設環境に拘わらず、ピグ２の位置を検出できる。 Furthermore, since the rotating magnetic field generated by the transmitter 4 is an extremely low frequency magnetic signal, the transmission distance is long. Therefore, the detection distance capable of detecting the pig 2 is long. In addition, since the ultra-low frequency magnetic signal is transmitted in any environment including vacuum, gas, water, underground, and metal, the position of the pig 2 can be detected regardless of the laying environment of the tube 1.
　また、磁力の強い永久磁石１２を用いることによって発信器４からの磁界を強くすることができる。コイルを励磁することによって磁界を発生する場合と比較して、発信器４からの磁界を強力なものとする場合に必要な消費電力の増加を抑制できる。また、発信器４からの磁界を強力なものとする場合に、永久磁石１２を大型化する必要がないので、発信器４が大型化して重くなることもない。 Moreover, the magnetic field from the transmitter 4 can be strengthened by using the permanent magnet 12 having a strong magnetic force. Compared with the case where a magnetic field is generated by exciting a coil, an increase in power consumption required when the magnetic field from the transmitter 4 is strong can be suppressed. Further, when the magnetic field from the transmitter 4 is made strong, there is no need to increase the size of the permanent magnet 12, so that the transmitter 4 does not increase in size and become heavy.
（発信器の変形例）
　上記の実施の形態において、周波数制御回路１３２は、発信器４からの回転磁界の周波数を切り替えるものとすることができる。 (Modified example of transmitter)
In the above embodiment, the frequency control circuit 132 can switch the frequency of the rotating magnetic field from the transmitter 4.
　例えば、外部からの設定により、周波数制御回路１３２が、発信器４からの回転磁界の周波数を第１周波数および第１周波数よりも低い第２周波数のいずれか一方に選択的に切り替えるものとすることができる。より具体的には、周波数制御回路１３２が、モータの回転速度を１０回転／秒の第１速度と、これよりも遅い８回転／秒の第２速度の間で選択的に切り替えることにより、回転磁界の周波数を１０Ｈｚ（第１周波数）または８Ｈｚ（第２周波数）に切り替える。このようにすれば、管１の敷設場所における外乱磁界によって第１の周波数の磁気信号の検出が困難な場合でも、他方の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 For example, it is assumed that the frequency control circuit 132 selectively switches the frequency of the rotating magnetic field from the transmitter 4 to either the first frequency or the second frequency lower than the first frequency by setting from the outside. Can do. More specifically, the frequency control circuit 132 rotates the motor by selectively switching the rotation speed between a first speed of 10 rotations / second and a second speed of 8 rotations / second slower than the first rotation speed. The frequency of the magnetic field is switched to 10 Hz (first frequency) or 8 Hz (second frequency). In this way, even if it is difficult to detect the magnetic signal of the first frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
　また、周波数制御回路１３２が、発信器４からの回転磁界の周波数を、第１周波数と第１周波数よりも低い第２周波数との間で所定時間が経過する毎に切り替えるようにすることができる。このようにしても、管１の敷設場所における外乱磁界によって一方の周波数の磁気信号の検出が困難な場合でも、他方の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Further, the frequency control circuit 132 can switch the frequency of the rotating magnetic field from the transmitter 4 between the first frequency and the second frequency lower than the first frequency every time a predetermined time elapses. . Even in this case, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
　或いは、周波数制御回路１３２が、発信器４からの回転磁界の周波数を、第１周波数と第１周波数との間で連続的に変化させてもよい。このようにすれば、発信器４からの磁気信号が連続的に変化するので、管１の敷設場所における外乱磁界によって特定の周波数の磁気信号の検出が困難な場合でも、他の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Alternatively, the frequency control circuit 132 may continuously change the frequency of the rotating magnetic field from the transmitter 4 between the first frequency and the first frequency. In this way, since the magnetic signal from the transmitter 4 continuously changes, even when it is difficult to detect a magnetic signal of a specific frequency due to a disturbance magnetic field at the place where the tube 1 is laid, And the position of the pig 2 can be specified.
　また、周波数制御回路１３２は、所定時間が経過する毎にモータ１３１の回転を停止させてもよい。このようにすれば、電池１３３の消耗を抑制できるので、発信器が動作可能な時間を延ばすことができる。この結果、ピグ２を稼動させる稼働時間を延ばすことができる。また、モータ１３１の回転が停止している状態でも永久磁石１２からは磁界が発生しているので、探知器５によって永久磁石１２からの磁界を検出することにより、管１の外側からピグ２の位置を特定することができる。 Further, the frequency control circuit 132 may stop the rotation of the motor 131 every time a predetermined time elapses. In this way, since the consumption of the battery 133 can be suppressed, the time during which the transmitter can operate can be extended. As a result, the operating time for operating the pig 2 can be extended. Further, since the magnetic field is generated from the permanent magnet 12 even when the rotation of the motor 131 is stopped, the magnetic field from the permanent magnet 12 is detected by the detector 5 so that the pig 2 The position can be specified.
　さらに、上記の実施の形態において、回転磁界発生機構が、永久磁石１２の外周側に回転中心線Ｌ１と平行な第２の回転中心線回りに回転可能に支持されている第２の永久磁石を備え、永久磁石１２が回転すると、第２の永久磁石が連れ回りするように構成してもよい。 Further, in the above-described embodiment, the rotating magnetic field generating mechanism includes the second permanent magnet supported on the outer peripheral side of the permanent magnet 12 so as to be rotatable around the second rotation center line parallel to the rotation center line L1. The second permanent magnet may be rotated when the permanent magnet 12 rotates.
　図２は回転磁界発生機構に第２の永久磁石を備える変形例の発信器の説明図であり、ピグ２の内部を回転中心線Ｌ１の方向から見たものである。なお、変形例の発信器４Ａは上記の発信器４と同一の構成を備えているので、対応する構成には同一の符号を付して、その説明を省略する。変形例の発信器４Ａは、回転磁界発生機構１０Ａが、第２の永久磁石１４として、回転中心線Ｌ１回りに等角度間隔で配置された４つの永久磁石１４１～１４４を備えている。各永久磁石１４１～１４４は、その両端面が磁極面１４１ａ～１４４ａとなるように２極着磁されており、回転中心線Ｌ１と直交する方向から見たときに重なる位置に配置されている。また、各永久磁石１４１～１４４は、各軸受機構（第２の永久磁石用軸受機構）１５によって回転中心軸Ｌ１と平行な各回転中心線（第２の中心軸線）Ｌ１４１～Ｌ１４４の回りを回転可能に支持されている。中心の永久磁石１２が回転中心軸Ｌ１を中心に矢印の方向に回転すると、各永久磁石１４１～１４４は、各磁極面１４１ａ～１４４ａが各回転中心線Ｌ１４１～Ｌ１４４の回りを矢印で示す周方向に移動するように連れ回りする。 FIG. 2 is an explanatory diagram of a transmitter according to a modified example in which the rotating magnetic field generating mechanism includes the second permanent magnet, and the inside of the pig 2 is viewed from the direction of the rotation center line L1. In addition, since the transmitter 4A of the modified example has the same configuration as the transmitter 4 described above, the corresponding components are denoted by the same reference numerals and description thereof is omitted. In the transmitter 4A of the modified example, the rotating magnetic field generation mechanism 10A includes four permanent magnets 141 to 144 arranged at equal angular intervals around the rotation center line L1 as the second permanent magnet 14. The permanent magnets 141 to 144 are two-pole magnetized so that both end surfaces thereof are the magnetic pole surfaces 141a to 144a, and are arranged at positions overlapping when viewed from a direction orthogonal to the rotation center line L1. The permanent magnets 141 to 144 are rotated by the bearing mechanisms (second permanent magnet bearing mechanisms) 15 around the rotation center lines (second center axis) L141 to L144 parallel to the rotation center axis L1. Supported as possible. When the central permanent magnet 12 rotates around the rotation center axis L1 in the direction of the arrow, the permanent magnets 141 to 144 are arranged in the circumferential direction in which the magnetic pole surfaces 141a to 144a are indicated by arrows around the rotation center lines L141 to L144. Rotate to move to.
　変形例の発信器４Ａによれば、回転中心線Ｌ１に直交する直交面Ａ上に、永久磁石１２による回転中心線Ｌ１回りの回転磁界と、各永久磁石１４１～１４４による各回転中心線Ｌ１４１～Ｌ１４４回りの回転磁界が発生する。この結果、発信器４Ａからの磁界が強力なものとなり、探知器５によって大きな磁界ベクトルを検出することが可能となる。また、永久磁石１２の外周側に配置された各永久磁石１４１～１４４は永久磁石１２が回転すると連れ回りするので、各永久磁石１４１～１４４を回転させるために新たに回転駆動機構を設ける必要がない。よって、発信器４Ａからの磁界を強力なものとする場合の消費電力の増加を抑制できる。 According to the transmitter 4A of the modification, on the orthogonal plane A orthogonal to the rotation center line L1, the rotating magnetic field around the rotation center line L1 by the permanent magnet 12 and the rotation center lines L141 to 144 by the permanent magnets 141 to 144 are provided. A rotating magnetic field around L144 is generated. As a result, the magnetic field from the transmitter 4A becomes strong, and a large magnetic field vector can be detected by the detector 5. Further, since the permanent magnets 141 to 144 arranged on the outer peripheral side of the permanent magnet 12 are rotated along with the rotation of the permanent magnet 12, it is necessary to newly provide a rotation drive mechanism in order to rotate the permanent magnets 141 to 144. Absent. Therefore, an increase in power consumption when the magnetic field from the transmitter 4A is strong can be suppressed.
　なお、永久磁石１２の外周に配置する第２の永久磁石１４の数は１つでもよく、５つ以上でもよい。 Note that the number of the second permanent magnets 14 arranged on the outer periphery of the permanent magnet 12 may be one, or five or more.
（発信器の別の例）
　図３（ａ）は別の例の発信器の概略ブロック図であり、図３（ｂ）は本例の発信器の永久磁石、軸受機構および駆動コイルを取り出して示す斜視図であり、図３（ｃ）は駆動コイルへ印加する励磁電流のタイムチャートである。 (Another example of transmitter)
3A is a schematic block diagram of another example of the transmitter, and FIG. 3B is a perspective view showing the permanent magnet, the bearing mechanism, and the drive coil of the transmitter of this example. (C) is a time chart of the excitation current applied to the drive coil.
　本例の発信器７は上記の発信器４の代替として用いることが可能なものである。図３（ａ）に示すように、本例の発信器７は密閉された非磁性のケース３０と、ケース３０に収納された回転磁界発生機構３１を備えている。回転磁界発生機構３１は、永久磁石３２と、永久磁石３２を回転させる回転駆動機構３３を備えている。回転駆動機構３３は、永久磁石３２を回転可能に支持するための軸受機構３４（図３（ｂ）参照）と、励磁によって永久磁石３２を回転させる第１、第２駆動コイル３５、３６と、第１、第２駆動コイル３５、３６への励磁電流を制御することにより、回転磁界の周波数を制御する周波数制御回路（周波数制御部）３７と、この周波数制御回路３７を介して第１、第２駆動コイル３５、３６へ励磁電流を供給する電池３８と、スイッチ３９を備えている。電池３８はリチウムイオン２次電池であり、発信器７がピグ２に搭載された状態のままで、外部から非接触で充電可能となっている。また、スイッチ３９もピグ２に搭載された状態のままで、非接触で外部から操作可能となっている。 The transmitter 7 of this example can be used as an alternative to the transmitter 4 described above. As shown in FIG. 3A, the transmitter 7 of this example includes a sealed nonmagnetic case 30 and a rotating magnetic field generation mechanism 31 housed in the case 30. The rotating magnetic field generating mechanism 31 includes a permanent magnet 32 and a rotation driving mechanism 33 that rotates the permanent magnet 32. The rotation drive mechanism 33 includes a bearing mechanism 34 (see FIG. 3B) for rotatably supporting the permanent magnet 32, first and second drive coils 35 and 36 that rotate the permanent magnet 32 by excitation, A frequency control circuit (frequency control unit) 37 that controls the frequency of the rotating magnetic field by controlling the excitation current to the first and second drive coils 35 and 36, and the first and second through the frequency control circuit 37. A battery 38 for supplying an excitation current to the two drive coils 35 and 36 and a switch 39 are provided. The battery 38 is a lithium ion secondary battery, and can be charged from the outside in a contactless manner while the transmitter 7 is mounted on the pig 2. Further, the switch 39 is also mounted on the pig 2 and can be operated from the outside without contact.
　図３（ｂ）に示すように、永久磁石３２は直方体形状をしている。永久磁石３２において、ピグ２の移動方向Ｍ１に向いている一対の平行な端面には、それぞれ中央部分から突出する一対の支軸３４１が設けられている。また、永久磁石３２は２極着磁されており、永久磁石３２において支軸３４１が設けられた一対の平行な端面とは異なる２組の一対の平行な端面のうち、一方の組の一対の端面は磁極面３２ａとなっている。 As shown in FIG. 3B, the permanent magnet 32 has a rectangular parallelepiped shape. In the permanent magnet 32, a pair of parallel shafts 341 projecting from the central portion are provided on a pair of parallel end faces facing the moving direction M1 of the pig 2. Further, the permanent magnet 32 is magnetized in two poles, and one of a pair of a pair of parallel end faces different from the pair of parallel end faces provided with the support shaft 341 in the permanent magnet 32. The end face is a magnetic pole face 32a.
　一対の支軸３４１の軸端部は軸受３４２によって回転可能に支持されている。すなわち、永久磁石３２は、支軸３４１および軸受３４２から構成される軸受機構３４によって、支軸３４１の中心軸線を回転中心線Ｌ２として回転可能な状態で支持されている。本例では、各支軸３４１の軸端部が円錐形状のピボットとなっており、軸受３４２はベアリングを備えたピボット玉軸受となっている。ここで、発信器７は回転中心線Ｌ２がピグ２の移動方向Ｍ１に沿うようにしてピグ２に搭載されている。また、ピグ２は回転中心線Ｌ２が管１の中心軸線１Ａと平行となる姿勢を維持したまま管１内を移動する。 The shaft end portions of the pair of support shafts 341 are rotatably supported by bearings 342. That is, the permanent magnet 32 is supported by the bearing mechanism 34 including the support shaft 341 and the bearing 342 in a rotatable state with the center axis of the support shaft 341 as the rotation center line L2. In this example, the shaft end of each support shaft 341 is a conical pivot, and the bearing 342 is a pivot ball bearing provided with a bearing. Here, the transmitter 7 is mounted on the pig 2 such that the rotation center line L2 is along the moving direction M1 of the pig 2. Further, the pig 2 moves in the tube 1 while maintaining a posture in which the rotation center line L2 is parallel to the center axis 1A of the tube 1.
　第１、第２駆動コイル３５、３６は矩形の空芯コイルであり、いずれもピグ２の移動方向Ｍ１と直交する方向に延びる平行な一対の第１コイル部分３５１、３６１と、ピグ２の移動方向Ｍ１に沿って延びる平行な一対の第２コイル部分３５２、３６２を備えている。第１、第２駆動コイル３５、３６は、それぞれの第１コイル部分３５１、３６１が中央で直交するように配置されており、第１、第２駆動コイル３５、３６の内側には永久磁石３２および軸受機構３４が配置されている。永久磁石３２の回転中心線Ｌ２は、各駆動コイル３５、３６の一対の第２コイル部分３５２、３６２の中間において、これら一対の第２コイル部分３５２、３６２と平行に延びている。 The first and second drive coils 35 and 36 are rectangular air-core coils, both of which are a pair of parallel first coil portions 351 and 361 extending in a direction perpendicular to the moving direction M1 of the pig 2, and the movement of the pig 2. A pair of parallel second coil portions 352 and 362 extending along the direction M1 is provided. The first and second drive coils 35 and 36 are disposed such that the first coil portions 351 and 361 are orthogonal to each other at the center, and the permanent magnet 32 is disposed inside the first and second drive coils 35 and 36. And the bearing mechanism 34 is arrange | positioned. The rotation center line L2 of the permanent magnet 32 extends in parallel with the pair of second coil portions 352 and 362 in the middle of the pair of second coil portions 352 and 362 of the drive coils 35 and 36, respectively.
　周波数制御回路３７は、第１、第２駆動コイル３５、３６を励磁するための励磁電流を発生させる励磁電流発生回路３７１と、発信器７が発生させる回転磁界の周波数を１０Ｈｚまたは８Ｈｚに設定する周波数設定回路３７２と、励磁電流発生回路３７１が発生させた励磁電流を所定のタイミングで第１駆動コイル３５に印加するための第１ドライブ回路３７３と、励磁電流発生回路３７１が発生させた励磁電流を第１ドライブ回路３７３とは異なる所定のタイミングで第２駆動コイル３６に印加するための第２ドライブ回路３７４を備えている。周波数設定回路３７２に対する設定は外部から非接触の状態で設定可能となっている。 The frequency control circuit 37 sets the excitation current generation circuit 371 for generating an excitation current for exciting the first and second drive coils 35 and 36 and the frequency of the rotating magnetic field generated by the transmitter 7 to 10 Hz or 8 Hz. The frequency setting circuit 372, the first drive circuit 373 for applying the excitation current generated by the excitation current generation circuit 371 to the first drive coil 35 at a predetermined timing, and the excitation current generated by the excitation current generation circuit 371 Is applied to the second drive coil 36 at a predetermined timing different from that of the first drive circuit 373. The setting for the frequency setting circuit 372 can be set in a non-contact state from the outside.
　ここで、周波数制御回路３７は、所謂、１相励磁を行うものであり、図３（ｃ）に示すように、第１駆動コイル３５への正方向の励磁電流Ｉ１、第２駆動コイル３６への正方向の励磁電流Ｉ２、第１駆動コイル３５への逆方向への励磁電流Ｉ３、第２駆動コイル３６への逆方向への励磁電流Ｉ４を、この順番で繰り返し印加する。この結果、永久磁石３２は、その磁極面３２ａが回転中心線Ｌ２の回りに周方向に移動するように、回転する。従って、発信器７からは、管１の中心軸線１Ａと平行な回転中心線Ｌ２を中心として、この回転中心線Ｌ２に直交する直交面Ａ上を回転する回転磁界が発生する。また、本例では、周波数設定回路３７２に対する回転磁界の周波数の設定により、周波数制御回路３７は永久磁石３２を１０回転／秒または８回転／秒で回転させる励磁電流を第１駆動コイルおよび第２駆動コイルに印加する。従って、発信器７からは、１０Ｈｚまたは８Ｈｚの回転磁界が発生する。 Here, the frequency control circuit 37 performs so-called one-phase excitation. As shown in FIG. 3C, the excitation current I1 in the positive direction to the first drive coil 35 and the second drive coil 36 are supplied. The excitation current I2 in the forward direction, the excitation current I3 in the reverse direction to the first drive coil 35, and the excitation current I4 in the reverse direction to the second drive coil 36 are repeatedly applied in this order. As a result, the permanent magnet 32 rotates so that the magnetic pole surface 32a moves in the circumferential direction around the rotation center line L2. Accordingly, the transmitter 7 generates a rotating magnetic field that rotates on the orthogonal plane A perpendicular to the rotation center line L2 around the rotation center line L2 parallel to the center axis 1A of the tube 1. Further, in this example, the frequency control circuit 37 sets an exciting current for rotating the permanent magnet 32 at 10 rotations / second or 8 rotations / second by setting the frequency of the rotating magnetic field to the frequency setting circuit 372. Apply to the drive coil. Therefore, a rotating magnetic field of 10 Hz or 8 Hz is generated from the transmitter 7.
　本例においても、発信器７からは、管１の中心軸線１Ａと平行な回転中心線Ｌ２を中心として、この回転中心線Ｌ２に直交する直交面Ａ上を回転する回転磁界が発生しており、この回転磁界には管１の中心軸線１Ａと直交する直交面Ａ上を管１の外側に向かう磁界ベクトルが含まれている。また、発信器７が発生させる回転磁界は１０Ｈｚ或いは８Ｈｚの超低周波の磁気信号となっている。さらに、永久磁石３２の磁界を利用して回転磁界を発生させている。従って、上記の発信器４に替えて本例の発信器７を用いた場合においても、上記の実施の形態と同様の作用、効果を得ることができ、管１の外側からピグ２の位置を正確に特定できる。 Also in this example, the transmitter 7 generates a rotating magnetic field that rotates on the orthogonal plane A perpendicular to the rotation center line L2 around the rotation center line L2 parallel to the center axis 1A of the tube 1. The rotating magnetic field includes a magnetic field vector that goes to the outside of the tube 1 on the orthogonal plane A orthogonal to the central axis 1A of the tube 1. The rotating magnetic field generated by the transmitter 7 is an extremely low frequency magnetic signal of 10 Hz or 8 Hz. Further, a rotating magnetic field is generated using the magnetic field of the permanent magnet 32. Therefore, even when the transmitter 7 of this example is used instead of the transmitter 4, the same operation and effect as the above embodiment can be obtained, and the position of the pig 2 from the outside of the tube 1 can be obtained. It can be accurately identified.
　また、本例の発信器７では、回転磁界の周波数を１０Ｈｚおよび８Ｈｚのいずれか一方に選択的に切り替え可能となっている。従って、管１の敷設場所における外乱磁界によって一方の周波数の磁気信号の検出が困難な場合でも、他方の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Further, in the transmitter 7 of this example, the frequency of the rotating magnetic field can be selectively switched to either 10 Hz or 8 Hz. Therefore, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
　なお、永久磁石３２の外周側にホール素子などの磁気センサを配置して永久磁石３２のＮ極またはＳ極の回転中心線Ｌ２回りの角度位置を検出し、この角度位置に基づいて周波数制御回路３７が第１駆動コイル３５および第２駆動コイル３６への励磁電流の印加を制御するように構成してもよい。このようにすれば、第１駆動コイル３５および第２駆動コイル３６の励磁開始当初から永久磁石３２の回転を安定させることができる。 A magnetic sensor such as a Hall element is disposed on the outer peripheral side of the permanent magnet 32 to detect the angular position of the permanent magnet 32 around the rotation center line L2 of the N or S pole, and the frequency control circuit is based on this angular position. 37 may be configured to control application of excitation current to the first drive coil 35 and the second drive coil 36. In this way, the rotation of the permanent magnet 32 can be stabilized from the beginning of excitation of the first drive coil 35 and the second drive coil 36.
　また、永久磁石３２を安定的に回転させるために、周波数制御回路３７によって、所謂、２相励磁を行ってもよい。ただし、消費電力を少なくする観点からは、上記の発信器７のとおり１相励磁を行うことが好ましい。 Further, so-called two-phase excitation may be performed by the frequency control circuit 37 in order to rotate the permanent magnet 32 stably. However, from the viewpoint of reducing power consumption, it is preferable to perform one-phase excitation as in the transmitter 7 described above.
　さらに、周波数設定回路３７２は、回転磁界の周波数を１０Ｈｚと８Ｈｚとの間で予め定めた所定時間が経過する毎に切り替えるものとしてもよい。このようにすれば、管１の敷設場所における外乱磁界によって一方の周波数の磁気信号の検出が困難な場合でも、他方の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Furthermore, the frequency setting circuit 372 may switch the frequency of the rotating magnetic field every time a predetermined time elapses between 10 Hz and 8 Hz. In this way, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
　或いは、周波数設定回路３７２は、回転磁界の周波数を１０Ｈｚと８Ｈｚとの間で連続的に変化させるものとしてもよい。このようにすれば、管１の敷設場所における外乱磁界によって特定の周波数の磁気信号の検出が困難な場合でも、他の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Alternatively, the frequency setting circuit 372 may continuously change the frequency of the rotating magnetic field between 10 Hz and 8 Hz. In this way, even when it is difficult to detect a magnetic signal of a specific frequency due to a disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting a magnetic signal of another frequency.
　また、周波数設定回路３７２は、所定時間が経過する毎に永久磁石３２の回転を停止させてもよい。このようにすれば、電池３８の消耗を抑制できるので、発信器７が動作可能な時間を延ばすことができる。この結果、ピグ２を稼動させる稼働時間を延ばすことができる。また、永久磁石３２の回転が停止している状態でも磁界は発生しているので、探知器５によって永久磁石３２からの磁界を検出することによって管１の外側からピグ２の位置を特定することができる。 Further, the frequency setting circuit 372 may stop the rotation of the permanent magnet 32 every time a predetermined time elapses. In this way, since the consumption of the battery 38 can be suppressed, the time during which the transmitter 7 can operate can be extended. As a result, the operating time for operating the pig 2 can be extended. Further, since the magnetic field is generated even when the rotation of the permanent magnet 32 is stopped, the position of the pig 2 is specified from the outside of the tube 1 by detecting the magnetic field from the permanent magnet 32 by the detector 5. Can do.
　さらに、本例の発信器７においても、発信器４の変形例と同様に、回転磁界発生機構が永久磁石３２および駆動コイル３５の外周側に配置された第２の永久磁石と、この第２の永久磁石の磁極面が回転中心線Ｌ２と平行な第２の回転中心線回りを周方向に移動するように第２の永久磁石を回転可能に支持する第２の永久磁石用軸受機構とを備えており、永久磁石３２が回転すると、第２の永久磁石が連れ回りするように構成することができる。また、当該構成において、第２の永久磁石として１個の永久磁石を備えることもでき、複数の永久磁石を備えることもできる。このように構成すれば、回転中心線Ｌ２に直交する直交面Ａ上に、回転中心線回りの回転磁界と第２の回転中心線回りの回転磁界が発生するので、発信器からの磁界が強力になり、探知器５によって大きな磁界ベクトルを検出することができる。また、永久磁石３２の周りに配置された第２の永久磁石は永久磁石３２が回転すると連れ回りするので、第２の永久磁石を回転させるために新たに回転駆動機構を設ける必要がない。よって、発信器からの磁界を強力なものとする場合の消費電力の増加を抑制できる。 Further, in the transmitter 7 of the present example, as in the modification of the transmitter 4, the rotating magnetic field generating mechanism is disposed on the outer peripheral side of the permanent magnet 32 and the drive coil 35, and the second permanent magnet. A second permanent magnet bearing mechanism that rotatably supports the second permanent magnet so that the magnetic pole surface of the permanent magnet moves in the circumferential direction around a second rotation center line parallel to the rotation center line L2. The second permanent magnet can be rotated when the permanent magnet 32 rotates. Moreover, in the said structure, one permanent magnet can also be provided as a 2nd permanent magnet, and a some permanent magnet can also be provided. With this configuration, a rotating magnetic field around the rotation center line and a rotating magnetic field around the second rotation center line are generated on the orthogonal plane A orthogonal to the rotation center line L2, so that the magnetic field from the transmitter is strong. Thus, the detector 5 can detect a large magnetic field vector. In addition, since the second permanent magnet arranged around the permanent magnet 32 rotates with the rotation of the permanent magnet 32, it is not necessary to provide a new rotation drive mechanism for rotating the second permanent magnet. Therefore, an increase in power consumption when the magnetic field from the transmitter is strong can be suppressed.
（発信器の更に別の例）
　図４（ａ）は更に別の例の発信器の概略ブロック図であり、図４（ｂ）は本例の電磁コイルを取り出して示す斜視図であり、図４（ｃ）は電磁コイルへ印加する励磁電流のタイムチャートである。 (Another example of transmitter)
4A is a schematic block diagram of another example of the transmitter, FIG. 4B is a perspective view showing the electromagnetic coil of this example, and FIG. 4C is an application to the electromagnetic coil. It is a time chart of the exciting current to be performed.
　本例の発信器８は上記の発信器４、７の代替として用いることが可能なものである。図４（ａ）に示すように、本例の発信器８は密閉された非磁性のケース４０と、このケース４０の内部に搭載された回転磁界発生機構４１を備えている。回転磁界発生機構４１は、第１、第２電磁コイル４２、４３と、これら第１、第２電磁コイル４２、４３への励磁電流を制御することにより、回転磁界の周波数を制御する周波数制御回路（励磁制御部、周波数制御部）４４と、この周波数制御回路４４を介して第１、第２電磁コイル４２、４３へ励磁電流を供給する電池４５と、スイッチ４６を備えている。電池４５はリチウムイオン２次電池であり、発信器８がピグ２に搭載された状態のままで、外部から非接触で充電可能となっている。また、スイッチ４６もピグ２に搭載された状態のままで、非接触で外部から操作可能となっている。 The transmitter 8 of this example can be used as an alternative to the transmitters 4 and 7 described above. As shown in FIG. 4A, the transmitter 8 of this example includes a sealed nonmagnetic case 40 and a rotating magnetic field generating mechanism 41 mounted inside the case 40. The rotating magnetic field generating mechanism 41 is a frequency control circuit that controls the frequency of the rotating magnetic field by controlling the first and second electromagnetic coils 42 and 43 and the exciting current to the first and second electromagnetic coils 42 and 43. (Excitation control unit, frequency control unit) 44, a battery 45 for supplying excitation current to the first and second electromagnetic coils 42 and 43 via the frequency control circuit 44, and a switch 46 are provided. The battery 45 is a lithium ion secondary battery, and can be charged in a non-contact manner from the outside while the transmitter 8 is mounted on the pig 2. Further, the switch 46 is also mounted on the pig 2 and can be operated from the outside without contact.
　図４（ｂ）に示すように、第１、第２電磁コイル４２、４３は、十字形状の鉄芯４００に第１コイル４２１と第２コイル４３１が巻き回されることにより構成されている。より詳細には、鉄芯４００は９０°の角度間隔で放射状に延びる同一形状の４本の腕部４００ａ～４００ｄを備えている。第１コイル４２１は、４本の腕部４００ａ～４００ｄのうち１８０°の角度間隔を開けて同軸状に延びている一方の１対の腕部４００ａ、４００ｃに巻き回されており、これにより、第１電磁コイル４２が構成されている。また、第２コイル４３１は、４本の腕部４００ａ～４００ｄのうち１８０°の角度間隔を開けて同軸状に延びている他方の１対の腕部４００ｂ、４００ｄに巻き回されており、これにより、第２電磁コイル４３が構成されている。 As shown in FIG. 4B, the first and second electromagnetic coils 42 and 43 are configured by winding a first coil 421 and a second coil 431 around a cross-shaped iron core 400. More specifically, the iron core 400 includes four arm portions 400a to 400d having the same shape extending radially at an angular interval of 90 °. The first coil 421 is wound around one pair of arm portions 400a and 400c that extend coaxially with an angular interval of 180 ° among the four arm portions 400a to 400d. A first electromagnetic coil 42 is configured. The second coil 431 is wound around the other pair of arms 400b and 400d extending coaxially with an angular interval of 180 ° out of the four arms 400a to 400d. Thus, the second electromagnetic coil 43 is configured.
　第１、第２電磁コイル４２、４３は、放射状の４本の腕部４００ａ～４００ｄの中心を４本の腕部４００ａ～４００ｄと直交する方向に延びる回転中心線Ｌ３が、ピグ２の移動方向Ｍ１に沿うようにしてピグ２に搭載されている。ピグ２は、回転中心線Ｌ３が管１の中心軸線１Ａと平行となる姿勢を維持したまま管１内を移動する。 In the first and second electromagnetic coils 42 and 43, the rotation center line L3 extending in the direction perpendicular to the four arm portions 400a to 400d extends from the center of the four radial arm portions 400a to 400d. It is mounted on the pig 2 along M1. The pig 2 moves in the tube 1 while maintaining a posture in which the rotation center line L3 is parallel to the center axis 1A of the tube 1.
　周波数制御回路４４は、第１、第２電磁コイル４２、４３を励磁するための励磁電流を発生させる励磁電流発生回路４４１と、発信器７が発生させる回転磁界の周波数を１０Ｈｚまたは８Ｈｚに設定する周波数設定回路４４２と、励磁電流発生回路４４１が発生させた励磁電流を所定のタイミングで第１電磁コイル４２に印加するための第１ドライブ回路４４３と、励磁電流発生回路４４１が発生させた励磁電流を第１ドライブ回路４４３とは異なる所定のタイミングで第２電磁コイル４３に印加するための第２ドライブ回路４４４を備えている。周波数設定回路４４２に対する設定は外部から非接触の状態で設定可能となっている。 The frequency control circuit 44 sets the excitation current generation circuit 441 that generates an excitation current for exciting the first and second electromagnetic coils 42 and 43 and the frequency of the rotating magnetic field generated by the transmitter 7 to 10 Hz or 8 Hz. The frequency setting circuit 442, the first drive circuit 443 for applying the excitation current generated by the excitation current generation circuit 441 to the first electromagnetic coil 42 at a predetermined timing, and the excitation current generated by the excitation current generation circuit 441 Is provided to the second electromagnetic coil 43 at a predetermined timing different from that of the first drive circuit 443. The setting for the frequency setting circuit 442 can be set in a non-contact state from the outside.
　ここで、周波数制御回路４４は、図４（ｃ）に示すように、第１電磁コイル４２への正方向の励磁電流Ｉ１、第２電磁コイル４３への正方向の励磁電流Ｉ２、第１電磁コイル４２への逆方向への励磁電流Ｉ３、第２電磁コイル４３への逆方向への励磁電流Ｉ４を、この順番で繰り返し印加する。このような励磁によれば、励磁により発生する第１、第２電磁コイル４２、４３の磁極面４２ａ、４３ａ（Ｎ極およびＳ極）が、回転中心線Ｌ３の回りを周方向に移動する。この結果、発信器８からは、管１の中心軸線１Ａと平行な回転中心線Ｌ３を中心として、この回転中心線Ｌ３に直交する直交面Ａ上を回転する回転磁界が発生する。 Here, as shown in FIG. 4 (c), the frequency control circuit 44 has a positive exciting current I1 to the first electromagnetic coil 42, a positive exciting current I2 to the second electromagnetic coil 43, and the first electromagnetic coil. The exciting current I3 in the reverse direction to the coil 42 and the exciting current I4 in the reverse direction to the second electromagnetic coil 43 are repeatedly applied in this order. According to such excitation, the magnetic pole surfaces 42a and 43a (N pole and S pole) of the first and second electromagnetic coils 42 and 43 generated by the excitation move in the circumferential direction around the rotation center line L3. As a result, a rotating magnetic field is generated from the transmitter 8 around the rotation center line L3 parallel to the central axis 1A of the tube 1 and rotating on the orthogonal plane A orthogonal to the rotation center line L3.
　本例では、周波数設定回路４４２に対する回転磁界の周波数の設定により、周波数制御回路４４は、磁極面４２ａ、４３ａを回転中心線回りに１０回転／秒または８回転／秒で移動させる励磁電流を第１電磁コイル４２および第２電磁コイル４３に印加する。従って、発信器８からは、１０Ｈｚまたは８Ｈｚの回転磁界が発生する。 In this example, by setting the frequency of the rotating magnetic field with respect to the frequency setting circuit 442, the frequency control circuit 44 sets the excitation current that moves the magnetic pole faces 42a and 43a around the rotation center line at 10 rotations / second or 8 rotations / second. Applied to the first electromagnetic coil 42 and the second electromagnetic coil 43. Therefore, a rotating magnetic field of 10 Hz or 8 Hz is generated from the transmitter 8.
　本例においても、発信器８からは、管１の中心軸線１Ａと平行な回転中心線Ｌ３を中心として、この回転中心線Ｌ３に直交する直交面Ａ上を回転する回転磁界が発生しており、この回転磁界には管１の中心軸線１Ａと直交する直交面Ａ上を管１の外側に向かう磁界ベクトルが含まれている。また、発信器８が発生させる回転磁界は１０Ｈｚ或いは８Ｈｚの超低周波の磁気信号となっている。従って、上記の発信器４、７に替えて本例の発信器８を用いた場合においても、上記の実施の形態と同様の作用、効果を得ることができ、管１の外側からピグ２の位置を正確に特定できる。 Also in this example, the transmitter 8 generates a rotating magnetic field that rotates about the rotation center line L3 parallel to the center axis 1A of the tube 1 and on the orthogonal plane A orthogonal to the rotation center line L3. The rotating magnetic field includes a magnetic field vector that goes to the outside of the tube 1 on the orthogonal plane A orthogonal to the central axis 1A of the tube 1. The rotating magnetic field generated by the transmitter 8 is an extremely low frequency magnetic signal of 10 Hz or 8 Hz. Therefore, even when the transmitter 8 of this example is used in place of the transmitters 4 and 7, the same operation and effect as in the above embodiment can be obtained, and the pig 2 The position can be accurately identified.
　また、本例の発信器８では、回転磁界の周波数を１０Ｈｚおよび８Ｈｚのいずれか一方に選択的に切り替え可能となっている。従って、管１の敷設場所における外乱磁界によって一方の周波数の磁気信号の検出が困難な場合でも、他方の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Further, in the transmitter 8 of this example, the frequency of the rotating magnetic field can be selectively switched to either 10 Hz or 8 Hz. Therefore, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
　さらに、本例の発信器８は、電気的な制御によって回転磁界を発生させているので、発信器８が発生させる回転磁界の周波数を正確に制御することができる。 Furthermore, since the transmitter 8 of this example generates a rotating magnetic field by electrical control, the frequency of the rotating magnetic field generated by the transmitter 8 can be accurately controlled.
　なお、周波数設定回路４４２は、回転磁界の周波数を１０Ｈｚと８Ｈｚとの間で予め定めた所定時間が経過する毎に切り替えるものとしてもよい。このようにすれば、管１の敷設場所における外乱磁界によって一方の周波数の磁気信号の検出が困難な場合でも、他方の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Note that the frequency setting circuit 442 may switch the frequency of the rotating magnetic field every time a predetermined time elapses between 10 Hz and 8 Hz. In this way, even when it is difficult to detect the magnetic signal of one frequency due to the disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting the magnetic signal of the other frequency.
　また、周波数設定回路４４２は、回転磁界の周波数を１０Ｈｚと８Ｈｚとの間で連続的に変化させるものとしてもよい。このようにすれば、管１の敷設場所における外乱磁界によって特定の周波数の磁気信号の検出が困難な場合でも、他の周波数の磁気信号を検出して、ピグ２の位置を特定できる。 Further, the frequency setting circuit 442 may continuously change the frequency of the rotating magnetic field between 10 Hz and 8 Hz. In this way, even when it is difficult to detect a magnetic signal of a specific frequency due to a disturbance magnetic field at the place where the tube 1 is laid, the position of the pig 2 can be specified by detecting a magnetic signal of another frequency.
　なお、本例の発信器８では２本の電磁コイル４２、４３により回転磁界を発生させているが、３本以上の電磁コイルを用いて回転磁界を発生させてもよい。 In the transmitter 8 of this example, the rotating magnetic field is generated by the two electromagnetic coils 42 and 43, but the rotating magnetic field may be generated by using three or more electromagnetic coils.
　また、鉄芯４００を省略し、第１コイル４２１および第２コイル４３１を励磁することによって回転磁界を発生させるように構成してもよい。 Further, the iron core 400 may be omitted, and a rotating magnetic field may be generated by exciting the first coil 421 and the second coil 431.
（その他の実施の形態）
　上記のピグ探知システム６では１台の探知器５を用いてピグ２の位置を特定しているが、複数台の探知器を用いてピグ２の位置を特定してもよい。このようにすれば、例えば、管１の埋設経路が不明であっても、各探知器５が検出した発信器４、７、８からの磁界の磁界ベクトルに基づいて、ピグ２の位置を正確に特定することができる。 (Other embodiments)
In the above-described pig detection system 6, the position of the pig 2 is specified using one detector 5, but the position of the pig 2 may be specified using a plurality of detectors. In this way, for example, even if the buried path of the tube 1 is unknown, the position of the pig 2 is accurately determined based on the magnetic field vector of the magnetic field from the transmitters 4, 7, 8 detected by each detector 5. Can be specified.
　また、上記のピグ探知システム６では探知器５によって発信器４、７、８が発生させる回転磁界の磁界ベクトルを検出しているが、発信器４が発生させる回転磁界の強度のみを検出する探知器を用いてピグ２の位置を特定してもよい。 In the above-described pig detection system 6, the magnetic field vector of the rotating magnetic field generated by the transmitters 4, 7, and 8 is detected by the detector 5. However, the detection is performed only for the strength of the rotating magnetic field generated by the transmitter 4. The position of the pig 2 may be specified using a container.

Claims (11)

  1. 　管内移動体が移動する管の外側から当該管内移動体の位置を検出するために、当該管内移動体に搭載される管内移動体探知用の発信器であって、
    　前記管内移動体が移動する管の中心軸線に平行な回転中心線を中心として、当該回転中心線に直交する直交面上を回転する前記回転磁界を発生させる回転磁界発生機構を備えていることを特徴とする管内移動体探知用の発信器。     In order to detect the position of the in-pipe moving body from the outside of the tube to which the in-pipe moving body moves, a transmitter for detecting the in-pipe moving body mounted on the in-pipe moving body,
    A rotating magnetic field generating mechanism that generates the rotating magnetic field that rotates on an orthogonal plane orthogonal to the rotation center line around a rotation center line parallel to the center axis of the tube in which the moving body in the tube moves; A transmitter for detecting moving bodies in the pipe.
  2. 　請求項１において、
    　前記回転磁界発生機構は１０Ｈｚ以下の回転磁界を発生させることを特徴とする管内移動体探知用の発信器。     In claim 1,
    The transmitter for detecting a moving body in a pipe, wherein the rotating magnetic field generating mechanism generates a rotating magnetic field of 10 Hz or less.
  3. 　請求項２において、
    　前記回転磁界発生機構は前記回転磁界の周波数を切り替える周波数制御部を備えていることを特徴とする管内移動体探知用の発信器。     In claim 2,
    The transmitter for detecting a moving body in a tube, wherein the rotating magnetic field generating mechanism includes a frequency control unit that switches a frequency of the rotating magnetic field.
  4. 　請求項２において、
    　前記回転磁界発生機構は前記回転磁界の周波数を連続的に変化させる周波数制御部を備えていることを特徴とする管内移動体探知用の発信器。     In claim 2,
    The transmitter for detecting a moving body in a tube, wherein the rotating magnetic field generating mechanism includes a frequency control unit that continuously changes the frequency of the rotating magnetic field.
  5. 　請求項１において、
    　前記回転磁界発生機構は、永久磁石と、この永久磁石の磁極面が前記回転中心線の回りを周方向に移動するように当該永久磁石を回転させる回転駆動機構とを備えていることを特徴とする管内移動体探知用の発信器。     In claim 1,
    The rotating magnetic field generating mechanism includes a permanent magnet and a rotation driving mechanism that rotates the permanent magnet so that the magnetic pole surface of the permanent magnet moves in the circumferential direction around the rotation center line. Transmitter for detecting moving objects in pipes.
  6. 　請求項５において、
    　前記回転駆動機構は、モータを備えており、
    　前記永久磁石は、前記モータの回転軸に取り付けられていることを特徴とする管内移動体探知用の発信器。     In claim 5,
    The rotational drive mechanism includes a motor,
    The transmitter for detecting a moving body in a pipe, wherein the permanent magnet is attached to a rotating shaft of the motor.
  7. 　請求項５において、
    　前記回転駆動機構は、前記永久磁石を回転可能に支持するための軸受機構と、励磁により前記永久磁石を回転させる駆動コイルとを備えていることを特徴とする管内移動体探知用の発信器。     In claim 5,
    The rotary drive mechanism includes a bearing mechanism for rotatably supporting the permanent magnet, and a drive coil for rotating the permanent magnet by excitation.
  8. 　請求項５において、
    　前記回転磁界発生機構は、前記永久磁石の外周側に配置された第２の永久磁石と、この第２の永久磁石の磁極面が前記回転中心線と平行な第２の回転中心線回りを周方向に移動するように当該第２の永久磁石を回転可能に支持する第２の永久磁石用軸受機構とを備えており、
    　前記永久磁石が回転すると、前記第２の永久磁石が連れ回りすることを特徴とする管内移動体探知用の発信器。     In claim 5,
    The rotating magnetic field generating mechanism includes a second permanent magnet disposed on the outer peripheral side of the permanent magnet, and a magnetic pole surface of the second permanent magnet that circulates around a second rotating center line parallel to the rotating center line. A second permanent magnet bearing mechanism that rotatably supports the second permanent magnet so as to move in a direction,
    A transmitter for detecting an in-pipe moving body, wherein the second permanent magnet rotates with the rotation of the permanent magnet.
  9. 　請求項１において、
    　前記回転磁界発生機構は、複数の電磁コイルと、前記複数の電磁コイルを所定の順番で励磁する励磁制御部とを備えており、
    　前記複数の電磁コイルは、各電磁コイルの軸線が前記回転中心線と直交して互いに異なる方向に延びるように配置されていることを特徴とする管内移動体探知用の発信器。     In claim 1,
    The rotating magnetic field generation mechanism includes a plurality of electromagnetic coils and an excitation control unit that excites the plurality of electromagnetic coils in a predetermined order.
    The transmitter for detecting a moving body in a pipe, wherein the plurality of electromagnetic coils are arranged such that axes of the electromagnetic coils extend in different directions perpendicular to the rotation center line.
  10. 　位置検出用の回転磁界を発生する発信器が搭載されている管内移動体であって、
    　前記発信器は請求項１ないし９のうちのいずれかの項に記載の前記発信器であることを特徴とする管内移動体。     An in-pipe moving body equipped with a transmitter that generates a rotating magnetic field for position detection,
    The in-pipe moving body, wherein the transmitter is the transmitter according to any one of claims 1 to 9.
  11. 　管内移動体に搭載されている発信器と、
    　前記管内移動体が移動する管の外側から前記発信器が発生する回転磁界を検出して当該管内移動体の位置を特定する探知器とを有し、
    　前記発信器は、請求項１ないし９のうちのいずかの項に記載の前記発信器であることを特徴とする管内移動体探知システム。     A transmitter mounted on a moving body in a pipe;
    A detector that detects a rotating magnetic field generated by the transmitter from the outside of the tube to which the moving body in the tube moves and identifies the position of the moving body in the tube;
    10. The in-pipe mobile object detection system according to claim 1, wherein the transmitter is the transmitter according to any one of claims 1 to 9.
PCT/JP2011/001586 2011-03-17 2011-03-17 Transmitter for detecting in-pipe mobile body, in-pipe mobile body, and system for detecting in-pipe mobile body WO2012123993A1 (en)

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JP2011533900A JP4902032B1 (en) 2011-03-17 2011-03-17 Transmitter for detecting moving object in tube, moving object in tube, and moving object detecting system in tube

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