Abstract: A logging probe supporting device includes a connector that can be plugged in at the bottom of the well with a logging cable contained in the inner space of rods to which the supporting device is fastened and fluid communicating openings provided between the inner space of the rods and the outside of the supporting device, the openings being arranged between the probe and connector. The device includes, between the openings and the connector, a shutoff such as check valves allowing fluid circulation from the inside towards the outside and preventing circulation from the outside towards the inside of the supporting device.

Abstract: The invention relates to a logging probe (2) supporting device (3) comprising connecting means (4) that can be plugged in at the bottom of the well with a logging cable contained in the inner space of rods (7) to which the supporting device is fastened, fluid communication means between the inner space of the rods and the outside of the supporting device, the communication means being arranged between the probe and the connecting means. The device comprises, between the communication means and the connecting means, shutoff means such as check valves allowing fluid circulation from the inside towards the outside and preventing circulation from the outside towards the inside of the supporting device.

Abstract: A non-efflorescing cementitious body is formed from sources of calcium aluminate, calcium silicate, calcium sulphate and reactive silica, these ingredients being present in such relative proportions that, upon hydration, both monosulphate (C3A.C?.12H) and hydrated alumina (AH3) are formed. Also disclosed is a hydraulic binder and a paste from which such bodies can be formed and a method for forming such bodies. In addition to exhibiting low efflorescence, these bodies retain satisfactory physical properties, especially good durability to natural weathering conditions.

Abstract: A hydrophone which is automatically inhibited when the immersion depth exceeds a predetermined threshold by action, on the push element (7) of a switch (6), of a flexible wall that bends under the action of the outside pressure. The hydrophone comprises a tubular body (1) with two chambers (1a, 1b) separated by a partition (2). One of the chambers is closed by a flexible diaphragm (4). Switch (6) is fixed at the center of one of the chambers. Diaphragm (4) can push down on and actuate push element (7) by bending. The body can advantageously consist of two parts that can be screwed onto one another, which allows easier adjustment of the inhibition pressure. A pressure-sensitive reception unit (S) is arranged in the other chamber.

Abstract: A non-efflorescing cementitious body is formed from sources of calcium aluminate, calcium silicate, calcium sulphate and reactive silica, these ingredients being present in such relative proportions that, upon hydration, both monosulphate (C3A.Cŝ.12H) and hydrated alumina (AH3) are formed. Also disclosed is a hydraulic binder and a paste from which such bodies can be formed and a method for forming such bodies. In addition to exhibiting low efflorescence, these bodies retain satisfactory physical properties, especially good durability to natural weathering conditions.

Abstract: Hydrophone which is automatically inhibited when the immersion depth exceeds a predetermined threshold by action, on the push element (7) of a switch (6), of a flexible wall that bends under the action of the outside pressure.

Abstract: Very low distortion hydrophone comprising at least one pair of sensitive elements (6 and 8) of piezoelectric type (for example and not limitatively), associated with at least one of the opposite flexible faces of a housing (1) formed by assembling cups (2 and 3) with rigid edges. The opposite faces of one of the discs, (6), are provided with electrodes over the total surface thereof. On the other hand, at least one of electrodes (9a and 9b) associated with the opposite faces of second disc (8) only covers one or more portions (an annular strip for example) of each of these faces in an external zone of each cup (2, 3) more subjected to nonlinear stresses. Electrodes (7 and 9) of the two sensitive discs (6 and 8) are interconnected so as to make the difference between the electric signals generated by the two discs in response to the pressures applied, with the effect, experimentally verified, that the distortion resulting from this layout, notably due to a second harmonic (2), is practically suppressed.

Abstract: Hydrophone with two unsymmetrically connected sensitive elements. The hydrophone comprises a detection unit including a closed housing (1) delimited by two cups (2, 3) resting against each other, each one being provided with a flexible diaphragm (4) and at least two piezoelectric sensitive elements (6, 8) associated each with electrodes (7, 9), one outside the housing, the other inside the housing. The two sensitive elements are preferably different in size, notably with different diameters. Electrodes (7a, 9a) of the sensitive elements that are not in contact with cups (2, 3) are electrically interconnected and the electrodes in contact with cups (2, 3) are also electrically interconnected. Each detection unit is preferably included in a protective assembly (not shown). The hydrophone can be used for marine seismic monitoring or prospecting for example.

Abstract: The hydrophone according to the invention comprises at least one detection unit (1) comprising a casing made up of two cups (2a, 2b) resting on each other by a peripheral rim (3), each one of them being provided with a flexible central part, and a sensitive element (4) associated with electrodes, that is fastened to the central part of the cups, on the outer face thereof, a hollowed flat centering element (6) made of a deformable material, into which at least one casing is fitted, intended to be inserted into a tube (9) along an axial plane thereof, this centering element being provided for example with an inner slot (8) for fitting in the peripheral rim of the two cups (2a, 2b) of the casing, and a sealed protective coating (11) sheathing detection unit (1), and a part of the inner face of tube (9).