Schlumberger Industries, Sa

Enertec

Alain G Bazin

Michel Gervais

Denise Schang

Anthony J Ley

Lionel Beneteau

Roland Allesch

Robert De Vanssay

Jean Simon

Francedillaois Grasdepot

Juan Pedro Silveira

Antony Ley

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.

Method and device for determining a gas volume concentration

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.2 is determined that corresponds to the sum, over m consecutive periods, of the times elapsed between the instant at which the characteristic portion of each period appears and the instant at which the following signal CLS appears, the difference .vertline.t2-t1.vertline. is taken, and the flow rate is deduced therefrom.

Method and apparatus for measuring the flow rate of a flowing fluid

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.

Ultrasound apparatus for measuring the flow speed of a fluid

A signal processing circuit, including at least two stages of frequency modulation (25,20; 28, 31, 33) and demodulation of signals applied to or generated within that circuit, characterized in that the modulating and demodulating signal for each stage is an effective square wave and in that the ratio of the frequencies (F1, F2) of the modulating signals for the first and second stages corresponds substantially to the ratio of an even integer to an odd integer, or vice versa, such that there are substantially no common frequencies or harmonics between the first and second modulating signals.

Multiple stage frequency modulated circuit

A system for measuring the frequency of oscillation of the fluid in a fluid oscillator comprising detector means, a peak detector comprising a threshold device receiving a first signal from the detector means, means for storing the signal at the output of the threshold device and comparator means providing an output signal in accordance with the relative values of the first signal and the signal from the memory means.

System for measuring fluid oscillator signals

An electricity metering device including at least one sigma-delta converter (20) adapted to output a series of digital pulses, a digital counter means (21) for summing the output of the sigma-delta converter and a signalling means (32) to deliver an output signal (38) when the sum reaches a predetermined value, characterized in that the metering device further comprises a means (32, 33) for digitally adjusting the gain of the sigma-delta converter comprising programmable digital memory means (33) adapted to store a parameter representing the gain of the metering device, the value of the parameter being externally programmable, and a digital logic means (32) for logically combining the gain parameter with the digital sum stored in the counter means to determine the number of pulses required before the predetermined value is reached and an output pulse delivered.

Electricity meter with variable gain sigma-delta converter

A monostable circuit of a voltage-to-frequency converter supplies feedback pulses to balance the input signal to a first integrator. These same pulses are supplied to a second integrator where they are compared with reference pulses from a crystal-controlled clock. Any drift in the pulse-width of the feedback pulses is corrected by a control signal applied to the monostable circuit by the second integrator to vary its quasi-stable period appropriately. Thus the precision of the converter is improved without disturbing its asynchronous properties.

Voltage-to-frequency converters

A measurement shunt comprises a resistance provided with first and second voltage terminals and intended to provide a voltage representative of an electric current passing through it, and an inductance connected to at least the first of said voltage terminals to produce between first and second measurement terminals a voltage free of error voltages induced in said resistance, even in the presence of a variable magnetic field. The resistance is essentially constituted by a plate (12) of electrically conductive material, the first and second voltage terminals (26,28) are disposed on the same edge of the plate at spaced apart points thereon, and the inductance comprises at least one open loop (36a) at least partly formed from an electrically conductive material extending from its first and second ends respectively disposed in the vicinity of the first and second voltage terminals, towards the interior of the surface of the plate in a plane having, at least approximately the same direction as the plate.

Measurement shunt with compensation for induced error voltages

A device for measuring a quantity such as the electric power in a polyphase alternating current network including at least two phase conductors and a reference conductor, of the type comprising two measuring devices which are associated respectively with the two phases and the outputs from which are connected to a summation device. A supply circuit connected to one of the phases is associated with the corresponding measuring device, and a device connected to the other phase ensures the supply to the other measuring device and to the summation device, the supply circuit and the supply device being connected through a high-impedance tie circuit, the summation device being supplied if at least one of the phases is under voltage with respect to the reference conductor.

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Villejuif, France

Alain G Bazin