Abstract: An ultrasound apparatus for measuring a fluid flow rate includes a processor which receives an analog signal from a receiver transducer then transforms it into a digitized signal used for determining the fluid flow rate. The processor includes a bandpass sigma-delta converter having a bandpass loop filter, and a digital-to-analog converter in a feedback loop.

Abstract: The invention concerns a device (10) for measuring calorific energy contained in a fuel gas transported in a pipe (16) comprising a gas meter (12) measuring a volume V in pressure conditions P and temperature conditions T of a gas circulating in said pipe and an apparatus (14;52;63) to determine the gas calorific power H. The invention is characterized in that said apparatus for determining calorific power measures at least one physical variable proportional to the number of molecules of the gas different constituents in a given volume and is placed as near as possible to the gas meter so as to determine the calorific power H(P,T) in similar pressure P and temperature T conditions as those wherein the gas volume V(P,T) is measured, said device then determining the calorific energy H(P,T) V(P,T) contained in the gas.

Abstract: The invention provides a fluid meter comprising ultrasound transducers, attenuation means for attenuating parasitic ultrasound waves of wavelength &lgr;, and constituted by at least one passage in which said waves propagate along a main direction corresponding to a longitudinal dimension a of said passage, said passage having a transverse dimension b perpendicular to a and much smaller than the wavelength &lgr; of the parasitic waves in the propagation medium, said passage comprising a plurality of consecutive passage portions each having a part presenting a reduction in transverse propagation section along the dimension b of the passage, the longitudinal dimension of each passage portion being substantially equal to &lgr;/2.

Abstract: The invention concerns a method for wavelength calibration of an electromagnetic radiation filtering device (16) included in an apparatus (10; 32) measuring spectral transmission of a propagating medium external to said apparatus and wherein said radiation flows through, said filtering device having spectral transmission tuneable on a wavelength range based on the value of a physical parameter. The invention is characterized in that it consists in: selecting at least one absorbing gaseous line which is always present in natural form in the propagation medium and whereof the corresponding wavelength is included in said filtering device tunability wavelength range; and in calibrating the filtering device with respect to said at least one absorbing gaseous line which is used as natural reference.

Abstract: The invention provides a fluidic oscillator that is symmetrical about a longitudinal plane of symmetry (P), comprising an enclosure defining an oscillation chamber and having an inlet opening and an outlet opening through which the fluid flows and which are in alignment in said plane (P) in a “longitudinal” first direction (A), said inlet opening being made in the form of a slot that is narrow in a second direction (B) extending transversely to said plane (P) and elongate in a third direction (C) parallel to said plane (P) and perpendicular to said longitudinal first direction (A), wherein said slot is provided in an insert which is removable from said enclosure.

Abstract: A method of communicating data in a system having a plurality of transmitters each adapted to transmit a radio signal, and a receiver situated at a distance from the transmitters to receive and process the signals transmitted by the transmitters, information for transmission being subdivided into N-bit symbols, the method consisting in: giving a numerical value to each symbol; and compressing the data using a CHIP encoding technique in which the values of the symbols are transposed to an encoded value having x digits in a base B, each digit subsequently being represented in the form of n chips, the base B, the number n of chips, and the number x of digits for an encoded value satisfying the following conditions: B≦2&ngr; and 2N≦B&xgr;  so that the total number of chips x.n representing the coded value is less than 2.N.

Abstract: The invention provides a liquid meter comprising a measurement chamber in which a spinner is caused to rotate about an axis and pivots, at least at low liquid flow rates, on a support in alignment with the axis. The pivoting motion takes place via a ball that is free to rotate between two concave surfaces each having a radius of curvature that is greater than the radius of curvature of the ball. One of the concave surfaces is tied to the spinner, whereas the other surface is secured to the support.

Abstract: The invention relates to a fluidic oscillator that is symmetrical about a longitudinal plane of symmetry, the oscillator comprising an opening enabling a fluid to enter into an “oscillation” chamber in the form of a two-dimensional fluid jet oscillating transversely relative to said plane of symmetry, an obstacle occupying the major portion of said oscillation chamber and possessing a front wall provided with a cavity situated facing said opening and swept over by the fluid jet in oscillation, wherein two side walls extend on either side of the opening and form a nozzle inside the oscillation chamber extending towards the obstacle and having a longitudinal dimension that is less than the distance between the opening and the front wall of the obstacle.

Abstract: Measuring the propagation time of a sound signal between two spaced-apart transducers disposed in a fluid flow involves determining the zero-crossing of the signal. Each received sound signal is sampled and digitized, then for each period of the sampled and digitized signal the maximum amplitudes P− and P+ of the two lobes of the period under examination are determined. The ratio of the amplitudes are compared to an ideal amplitude ratio between the maximum amplitudes Pi− and Pi+ of two lobes of a first ideal characteristic period. The first zero-crossing of the characteristic oscillations of the signal is determined. And, as a function of the result of the comparison relative to a threshold value Gs, the period under examination is accepted or ignored as a characteristic period. The zero-crossing thereof is determined or not determined between the two lobes of the characteristic period.

Abstract: A cell for converting a differential pressure into an electric signal, which comprises two chambers and a sensor. The two chambers are filled with an incompressible fluid and each are closed by a respective membrane suitable for deforming under the action of an external pressure. The chambers are separated from each other by a rigid wall. The sensor associated with the wall and responsive to the pressure difference exerted across the wall, delivers an electric signal in response thereto. At least one passage is formed between the two chambers and possesses appropriate dimensions firstly for at least attenuating a parasitic pressure difference existing across the wall at a frequency that is low or zero, and secondly for allowing the sensor to detect the pressure difference exerted across the wall at higher frequencies.

Abstract: A gas volume concentration is determined. An electromagnetic radiation is emitted (state 1) through the gas volume. The radiation is filtered by temporally modulating the spectral transmission of said filter so as to obtain a temporal modulation of the energy of the radiation transmitted by the gas volume and this filter. This temporally modulated energy is detected and a signal E is extracted from it, the signal particularly depending on the concentration of the gas. The component Eac(1) of the time-variable signal and the component Edc(1) of the signal, which is not a time-variable signal are isolated. A radiation stops is emitted (state 0), and the component Eac(0) and the component Edc(0) of the signal received by the detector are isolated. The terms Eac(1)-Eac(0) and Edc(1)-Edc(0) are calculated, and the ratio (Eac(1)-Eac(0))/(Edc(1)-Edc(0)) is formed which then solely depends on the gas concentration c. From this, c is deduced.

Abstract: The invention concerns a fluid meter including a body comprising a fluid intake opening and a fluid evacuation opening aligned along a first direction A, a measuring unit formed of a fluid oscillator including at least one obstacle disposed into an oscillation chamber and which is provided with one fluid inlet and one fluid outlet, characterized in that the inlet and outlet of the fluidic oscillator are aligned along a second direction C approximately perpendicular to the first direction.

Abstract: A gas flow interrupter for a gas meter, the interrupter comprising a valve member that is movable relative to a valve seat which defines an opening for passing said gas flow, said valve member comprising firstly a membrane having a main surface including a "contact zone" portion that comes into contact with said valve seat when the interrupter is in its closed position, thereby closing said opening by means of the main surface of the valve member, and secondly a part that forms a mechanical support for the membrane and that co-operates with said membrane, wherein the metal part forming a support for the membrane has a continuous leakproof surface bounded by the contact zone so as to close the opening in the event of the membrane failing to provide sealing.

Abstract: A method for measuring a fluid flow rate between two points of a fluid flow according to which a measurement of the respective propagation times of two acoustic signals transmitted in opposite directions is combined with a measurement of acoustic phase shifts respectively induced in each signal. Each received signal is sampled and digitized and the corresponding acoustic phase shift is determined by synchronous detection. During successive iterations, a programmable phase shift dependent on the value of the acoustic phase shift obtained by synchronous detection in the previous iteration is determined for each iteration, so that the result of the synchronous detection step in the current iteration is as close as possible to zero, and the acoustic phase shift is therefore substantially the same as the last programmable phase shift.

Abstract: The invention relates to a method of measuring the flow rate of a flowing fluid on the basis of two ultrasonic signals transmitted consecutively in mutually opposite directions between two ultrasonic transducers. In the method, n clock signals CK.sub.i, where i=1 to n, that are at mutual phase offsets of 2.pi./n are formed, the first clock signal, referenced CLS, that occurs immediately after a characteristic portion the first received ultrasonic signal SIG.sub.1 appears is identified and stored, the time t.sub.1 is determined that corresponds to the sum, over an integer number m of consecutive periods, of the times elapsed between the instant at which the characteristic portion of each of the m periods of the signal SIG.sub.1 appears, and the instant at which the following signal CLS appears, likewise, for the signal SIG.sub.2 received in the opposite direction, the time t.sub.

Abstract: A single-jet liquid meter comprises a body in which a measurement chamber of substantially cylindrical shape is disposed. The chamber is fitted with a spinner having a longitudinal axis XX' and provided with blades, a liquid feed tube and a liquid discharge tube connected to the body and in alignment on an axis YY' that intersects axis XX' perpendicularly. A housing is disposed in the body around the periphery of the spinner and includes at least two slots respectively facing the feed tube and the discharge tube. The slots are designed to inject and eject the liquid flow in an inclined manner relative to the alignment axis of the tubes. At least one slot faces the feed tube and presents, to the flow of liquid coming from said tube, a shaped surface that progressively increases the speed of the flow.

Abstract: A device for detecting meter opening, the meter including at least a first structural element and a second structural element that are in a given position relative to each other when the meter is closed, said device comprising: a moving member connected to the first element and organized to take up a stable state or an unstable state as a function of the displacement of one of the structural elements relative to the other; holding means connected at least to the second element and co-operating with the moving member as a function of the displacement of one of the structural elements relative to the other, so as to hold said moving member in its unstable state and so as to enable it to go to its stable state; and detection means suitable for determining the state of the moving member and for emitting an opening signal when the moving member is in a predetermined state.

Abstract: An electronic switch comprising at least one switching device 70,72, a reference frequency source 58, a microprocessor 50 and means for applying to the microprocessor inputs representative of at least the current time and date and the latitude at which the time switch is to be used 31-36, the microprocessor being 50 responsive to the reference frequency source 58 and the current time and date inputs to implement a real time clock and calendar 62, and being arranged to calculate from the date provided by said real time clock and calendar and from the latitude input the respective times of at least one of sunrise and sunset at said location on each of a plurality of days, and to operate the switching device 70,72 at respective switching times dependent upon the calculated times.

Abstract: The invention relates to ultrasound apparatus for measuring the flow speed of a fluid, the apparatus comprising first and second ultrasound transducers disposed at points that are spaced apart in the direction of fluid flow, a transmitter module, a receiver module, and switch means organized so that each of the first and second transducers operates alternately as a transmitter and as a receiver. The transmitter module includes at least one transmission signal generator whose output is permanently connected via two logic gates each followed by a respective resistive divider bridge to a respective first terminal of the first and second transducer, and in that the first and second switch means are interposed respectively between the first terminals of said first and second transducers and the receiver module.

Abstract: A vortex fluid meter (1) includes a pipe portion (2) of constant inside diameter in which the fluid flows, at least two obstacles disposed in the middle of the flow of the fluid in said pipe portion (2) each having a generally elongate shape with longitudinal and transverse dimensions perpendicular to the direction of flow of the fluid, and adapted to generate oscillatory fluid vortices, an upstream obstacle (4) having a substantially uniform trapezoidal transverse section and a downstream obstacle (6) having a generally T-shape transverse section, and means (10, 12, 14) for detecting the signal corresponding to the oscillations of said vortices and for deducing therefrom the fluid volume or flowrate.