Abstract: Radio-frequency transmission device comprising a transmission antenna (2) and a receiving antenna (4), characterized by comprising one or more passive resonant circuits (5) positioned between the transmission and receiving antennas (2, 4).

Abstract: Radio-frequency transmission device comprising a transmission antenna (2) and a receiving antenna (4), characterised by comprising one or more passive resonant circuits (5) positioned between the transmission and receiving antennas (2, 4).

Abstract: Radio-frequency transmission device comprising a transmission antenna (2) and a receiving antenna (4), characterised by comprising one or more passive resonant circuits (5) positioned between the transmission and receiving antennas (2, 4).

Abstract: Device for transmission of electromagnetic radiation through a wall. In order to couple transmission-reception means (2, 4) located on each side of the wall (6), this device comprises two antennas (12, 14) placed on each side of this wall and connected to each other through this wall. Electromagnetic protection means (20) are arranged on all or some of the surfaces of the wall facing the antennas and are made of an electrically conducting material. This device is particularly applicable to a transmitter-receiver system for which one of the components is in a slightly conducting container.

Abstract: This invention relates to a measurement device comprising at least one sensor (20) designed to be installed on a mobile element (8) free to move with respect to a base (14), the mobile element being capable of moving into several positions with respect to the base (14) including a so-called proximity position in which it is close to the base (14). The sensor (20) cooperates with a power supply device comprising a rechargeable energy source (22) equipped with at least one first charging antenna (23-1) located on the mobile element (8) and at least one second charging antenna (23-2) located on the base (14), to be coupled to the first charging antenna (23-1) to recharge the energy source (22). Coupling between the two charging antennas (23-1, 23-2) is only made when the mobile element (8) is in the proximity position.

Abstract: Radio-frequency transmission device comprising a transmission antenna (2) and a receiving antenna (4), characterised by comprising one or more passive resonant circuits (5) positioned between the transmission and receiving antennae (2, 4).

Abstract: This invention relates to a measurement device comprising at least one sensor (20) designed to be installed on a mobile element (8) free to move with respect to a base (14), the mobile element being capable of moving into several positions with respect to the base (14) including a so-called proximity position in which it is close to the base (14). The sensor (20) cooperates with a power supply device comprising a rechargeable energy source (22) equipped with at least one first charging antenna (23-1) located on the mobile element (8) and at least one second charging antenna (23-2) located on the base (14), to be coupled to the first charging antenna (23-1) to recharge the energy source (22). Coupling between the two charging antennas (23-1, 23-2) is only made when the mobile element (8) is in the proximity position.

Abstract: A device for evaluating the density of protons present in a given body with the possibility of identifying the material forming part of the constitution of the body and to which the protons belong. The device includes a permanent magnet having north and south poles, the magnet presenting a longitudinal axis of symmetry and a plane of symmetry perpendicular to the axis; two coils disposed at opposite ends of the magnet, centered on the axis, and symmetrical about the plane; a radio frequency electricity generator connected to the two coils in such a manner that the radio frequency electric current feeds the two cols so that the faces of the two coils respectively facing the two poles of the permanent magnet are of the same magnetic kind; and a receiver connected to the two cols to analyze the electrical signals delivered at the output of the two coils when the generator is disconnected from the two coils.

Abstract: A tyre (6) pressure sensor comprises a pressure-sensitive part (8), in particular with a deformable membrane (10), mounted in the centre of the hub (7) of wheel (2), and a transducer part (12) housed in the axle (1) of wheel (2). This arrangement in which the sensor is separated into two mutually rotating parts is nonetheless more practical and simpler than devices in which electric connection is required between a wheel carrying the sensor assembly and the read device.

Abstract: The invention relates to an NMR device for detection of resonant protons contained in an object. The device comprises permanent magnets for producing a static and uniform magnetic field in a region located outside the device with respect to which the object will be positioned, these permanent magnets being laid out around an axis on which the said region is located, such that their magnetization direction is directed towards the said region and such that the magnetization values of the permanent magnets combine their effects to produce the static and uniform magnetic field in the said region. The device also comprises means for emission of an electromagnetic signal to the said region and reception of an electromagnetic signal returned from the said region in response to the emitted signal, these means being located inside the space delimited by the said permanent magnets.

Abstract: Device for transmission of electromagnetic radiation through a wall.

Abstract: The present invention relates to a device for evaluating the density of protons present in a given body 100 with the possibility of identifying the material forming part of the constitution of the body and to which the protons belong.

Abstract: The invention involves the characterization of a permeable porous object. It involves the following steps: placing the object in an air-tight container, creating a partial vacuum in the container containing the aforesaid object, measuring the residual pressure in the container in which the partial vacuum is formed, introducing a quantity of polarized gas into the container in partial vacuum, measuring the residual pressure in the container after introduction of the aforesaid quantity of polarized gas, determination of the density of the polarized gas introduced into the container from the aforesaid pressure measurements, NMR measurement of the mass quantity of polarized gas contained in a known volume of the object placed in the air-tight container, determination of the porosity of the object by calculation of the ratio of the mass quantity of polarized gas to the density of the polarized gas introduced into the container.

Abstract: A well logging system using an induction measurement. The system includes an emitting coil and a plurality of receiving coils. The emitting coil induces eddy currents in the medium surrounding the coils. The receiving coils then measure magnetic fields produced by the eddy currents. Two of the receiving coils are selected at a time and used as a receiving coil and a counter-receiving coil. The signal generated in the two coils are used to determine a weighted difference to better define the vertical resolution of the device. Compensation coils may be added to remove fields which are induced in the receiving coils directly from the transmitting coil.

Abstract: The porosity and permeability of a geological formation (2) are determined on the basis of an electrofiltering phenomenon by exploiting the existence of non-linear electrofiltering phenomena. One or two pressure generators (11 ) are used to propagate a pressure wave in the formation. Electrodes (14, 15) applied against the wall of the formation pick up the electric response of the formation. The detection of a resonance frequency or a phase shift corresponding to an extremum of the electric response of the formation makes it possible to calculate the porosity or permeability of the formation or find their values from charts.

Abstract: A device for the measurement by induction of a medium through a metal wall using a transmission portion permitting the induction of a signal in the medium beyond the metal wall and a receiver for receiving a signal transmitted by the medium in response to the induced signal. The transmission portion includes at least one current generator directly connected to the metal wall in such a way that the current passing into the wall induces a signal beyond the wall.

Abstract: A device for induction measurement of a medium adjacent a cylindrical, metallic, magnetic walled well of a well casing includes at least two magnetic circuits for magnetically saturating the metallic wall. Each of the magnetic circuits has a plate-like central portion, situated between two lateral portions, each of which lateral portions has a lateral end which comes into contact with the wall, along a zone parallel to the cylindrical axis of the wall. After magnetic saturation of the metallic wall, an induction signal is induced into the medium beyond the metallic wall and retransmitted by the medium in response to the induction signal.

Abstract: The disclosure relates to an open magnetic structure for producing an intense, stable magnetic field, which is amplitude and direction-controlled in a region adjacent to said structure, having at least one magnetic source (4) for producing said magnetic field, characterized in that it also comprises at least one pole piece (5, 6) associated with the magnetic source and having a shape designed so as to control the magnetic field produced.Application to petroleum or oil research in drilled wells and to surface magnetic imaging.

Abstract: A microdevice is provided for measuring the electromagnetic characteristics of a medium in a borehole. The microdevice includes at least one emitting or transmitting coil (31), and at least one receiving coil (41,51). The microdevice generates an A.C. voltage at the terminals of the transmitting coil and measures a signal at the terminals of the receiving coil. The microdevice also includes an E-shaped electrically insulating, soft magnetic material circuit serving as a support for each of the coils and which is positioned adjacent to the medium in the borehole.

Abstract: Line for transferring a liquefied gas between a storage vessel and a use vessel. It comprises a transfer tube (10), an outer tube (12) surrounding the transfer tube (10) and a shield (14) formed by an element located between the transfer tube (10) and the outer tube (12). Bypasses (16,18,20,22) having one end connected to the transfer tube (10) in thermal contact with the shield (14) for establishing a heat exchange relationship between said shield and the liquefied gas vapors and another end connected to a liquefied gas vapor recovery line.