Classifications

• • 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
  • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
  • G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
  • G01V3/104—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils
  • G01V3/105—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables

Definitions

• Device for detecting liquids or gases in solids including metallic particles, locating them and determining their size.
• the present invention relates to metal particle detectors included in bodies that are not very conductive of electricity, for example, metal inclusions that can be contained in wooden logs and the presence of which is very damaging to saws, or weapons hidden by people frequenting public places or luxury goods stores.
• this detection is carried out by measuring the variation in impedance of a flat cylindrical coil crossed in its middle by the object or the person to be checked, and excited by sinusoidal alternating current.
• the device according to the invention in addition to the detection of electrically conductive or magnetic objects, locates them and indicates their size. It is also not sensitive to radio interference.
• the device, object of the invention comprises two detection units each consisting of a flat quadrangular coil, radiating an electromagnetic field of well-defined frequency, and called later emitting rement, in the axis of which is placed a collector coil of the emitted magnetic field provided or not with a ferromagnetic focusing core and whose axis is simultaneously perpendicular to the emitting axis and parallel to the direction of movement of the object, and later called receiver.
• the receiver In the absence of any body conducting electricity or magnetic permeability different from that of vacuum, the receiver does not receive any magnetic flux, so there appears no voltage across its terminals.
• the device according to the invention has the advantage of providing a computable signal, the morphology of which depends on the distance separating the object from the plane of the transmitter and its electromagnetic mass.
• a digital computer of known technology therefore provides these two pieces of information, distance to the plane of the transmitter and size.
• a second identical unit using a different frequency to avoid the influence of mutual parasitic radiation, is arranged similarly on the path of the object, but angularly offset by 90o. It therefore provides the elements for determining the distance Z from the object to the transmitter and the electromagnetic size.
• the size of the object, its position in the plane XOZ, and in the direction of the displacement Y is known the size of the object, its position in the plane XOZ, and in the direction of the displacement Y.
• FIGS 1,2 and 3 attached illustrate by way of example an embodiment of the device according to the present invention.
• the device comprises two transmitters 1 and 2 and two receivers 3 and 4, joined by two frames 5 and 6.
• the two receivers have an electromagnetic shielding 7 and 8 open in order to overcome electrical radiation and well-known antenna effects.
• the signals are then filtered and amplified by the filter 9 and the amplifier 10.
• a zero compensation device (11) cancels the last parasitic voltages from the radiation of the fixed bodies located around the units and a synchronous demodulator 12 controlled by a synchronous sinusoidal voltage and followed by a DC amplifier 13 delivers the output signal.
• FIG. 4 shows the signals obtained by the device according to the invention for a determined and non-limiting geometrical configuration.
• the signal 14 comprises two bumps 15 and 16 whose temporal position relative to zero is characteristic of the distance separating the object from the plane of the transmitter. This position is independent of particle size. On the other hand, the amplitude 17 is characteristic of the object.
• the device according to the invention can be used in all cases where it is necessary OR useful to know the position of metallic objects or more generally electrically or magnetic conductors.
• the first is to detect metallic particles in wooden logs.
• the three-dimensional location thus allows the maximum valuation of the National Park; a not described marking device is associated with the computer.
• the second consists in detecting the weapons held by people frequenting public places: the knowledge of the position of the weapon on the individual allows the security agents to intervene discreetly and without risks.

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9230881

Family Applications (1)

Country Status (8)

Cited By (5)

Citations (3)

• 1979
  • 1979-10-22 FR FR7926116A patent/FR2468133A1/fr active Granted
• 1980
  • 1980-04-11 WO PCT/FR1980/000057 patent/WO1981001198A1/fr not_active Application Discontinuation
  • 1980-04-11 BR BR8008878A patent/BR8008878A/pt unknown
  • 1980-04-11 JP JP50076080A patent/JPS56501382A/ja active Pending
• 1981
  • 1981-05-04 EP EP80900665A patent/EP0038326A1/fr not_active Ceased
  • 1981-06-18 NO NO812076A patent/NO812076L/no unknown
  • 1981-06-22 DK DK275081A patent/DK275081A/da not_active Application Discontinuation
• 1982
  • 1982-03-13 ES ES510409A patent/ES510409A0/es active Granted

Patent Citations (3)

Also Published As

Similar Documents

Legal Events