Abstract: The invention provides a filter of the Fabry-Perot interferometer type for electromagnetic radiation having spectral density that is modified by a gas. The filter comprises a body which is transparent to said electromagnetic radiation, at least in its part through which the radiation passes. Said part comprises at least two portions possessing two facing surfaces that are mutually parallel and substantially plane. A "first" one of said portions is movable in a direction that is substantially perpendicular to the pair of facing surfaces. The filter further comprises: means for moving said facing surfaces between two extreme positions under the action of an electromagnetic field, and means for limiting adhesion between said surfaces in at least one of said positions in which said surfaces are at a distance apart which is small compared with the mean wavelength of the radiation passing through them.

Abstract: An ultrasonic measurement device measures a volume-related quantity of a fluid flowing from a first zone to a second zone of the device. The device includes two ultrasound transducers emitting and receiving ultrasound signals and each disposed in one of the zones to define between them an ultrasound measurement path in the fluid. The device also includes a measurement electronics block that drives emission and reception of ultrasound signals by transducers, measures a physical magnitude characteristic of the propagation speed of said signals in the fluid and deduces the volume-related quantity of the fluid from these measurements and the geometry of the device. This determines the volume-related quantity of the fluid on the basis of measurements of a physical magnitude that is characteristic of the propagation speed of ultrasound signals in the fluid.

Abstract: At least one live conductor and one neutral strap are provided for an electricity meter, the respective inlets and outlets of the live conductor and of the neutral strap being disposed inside the meter housing parallel to one another and being coplanar. A metal bar connected to neutral is disposed inside the meter housing in the vicinity of and at a short distance from the inlet and/or the outlet of the live conductor to define a gap in which a controlled arc between the live conductor and the metal bar can propagate in the event of a surge.

Abstract: An apparatus measures the flow rate of a fluid. The apparatus comprises a fluidic oscillator provided with an elongate slot in a direction Oz and suitable for forming a jet of fluid that oscillates in a plane Oxy perpendicular to the Oz direction, and an obstacle located upstream from the slot to modify the distribution of speeds in the flow. The obstacle is in the flow at least in the central portion thereof and is implemented in the form of a substantially plane plate.

Abstract: A fluidic oscillator is symmetrical about a longitudinal plane of symmetry in which a longitudinal fluid flow direction is contained. The oscillator generates a two-dimensional jet of fluid that oscillates transversely relative to said longitudinal plane symmetry. An ultrasound signal is generated in the fluid flow travelling from one transducer towards another. The ultrasound signal is received and modulated by the oscillations of the jet of fluid. The received signal is processed to determine a volume-related quantity concerning the fluid that has flowed through said fluidic oscillator. The tow ultrasound transducers are substantially in alignment with the longitudinal plane of symmetry.

Abstract: A method of analyzing a spatial series of waveforms, each waveform of which contains components arising from at least two substantially uncorrelated features, includes the steps of sorting the waveforms into groups or bins according to values of one or more of the features, determining a mean waveform for each group or bin, subtracting the mean waveform from each waveform in the group or bin, returning the waveforms to the original order of the series and determining a remaining feature. Binning, the process of sorting waveforms into groups based on values of features, can be performed for one feature determined from the waveform or for several features. All that is required is that the binning criteria are substantially uncorrelated with the feature of interest. An example of a binning criterion can be frequency or period of a component of the waveform. Also a value of a physical parameter calculated from the waveform can be used as a binning criterion.

Abstract: A protection device (70) for providing a drive system (60) for imparting rotary drive between two mechanical members (28, 44) about an axis by magnetic coupling with protection from an external magnetic field, said drive system including at least two axially magnetized elements (62a, 62b, 64a, 64b) each secured to at least one of said mechanical members and designed to interact with one another, said magnetized elements being axially offset, said protection device comprising two parts (72, 74; 92, 94; 96, 98) of magnetic material surrounding said drive system, each of said parts having a minimum radial extent greater than the radial extent of said magnetized elements, the protection device being characterized in that the two parts (72, 74; 92, 94; 96, 98) of magnetic material leave between them an axial space (76) so as to reduce the gradient of the external magnetic field at the drive system, and have an axial extent such that they encompass said drive system axially.

Abstract: An automated gas permeameter measures permeabilities of porous samples, such as rocks, ranging from 0.1 milliDarcys to 10 Darcys within 0.5% under dry and humid conditions. The automated gas permeameter includes a program for estimating a coarse permeablity value. The program uses the coarse value to determine settling time for pressure to reach steady state within 0.1% and optimal operating conditions, such as the setting of mass flow rates imposed on the sample. Operating conditions of the permeameter are set by the program according to the resolution and range of flow controllers, accuracy of a pressure transducer, and the limit of applicability of Darcy's law for a sample.

Abstract: The invention is a dial inbound MIU which includes only two elements, a transformer and an optoisolator, to couple timing and power signals to the meter whose data is being measured and to retrieve data from the meter.

Abstract: A vortex fluid meter (1) includes a pipe (2) having a maximum inside diameter D in which the fluid flows and having an internal profile comprising from the upstream end to the downstream end: a first pipe portion (4) progressively reducing the inside diameter of said pipe to a value D1 and having an inside wall (4a, 4b, 4c, 4d) at a continuously varying angle to the general direction of flow of the fluid; a second pipe portion (6) of constant diameter D1 in which is disposed at least one obstacle (8) adapted to generate oscillating fluid vortices; and a third pipe portion (20) returning the inside diameter of the pipe (2) to its original value D and adapted to separate the boundary layer of the fluid flow at a downstream end (6a) of said second pipe portion (6), and means (10, 12, 14, 16, 18, 200-221) for detecting the signal corresponding to the oscillations of the vortices and deducing the volume of fluid therefrom.

Abstract: A siphon jet is attached to a dry hydrant which is in communication with a body of water to increase the flow of fluid to the dry hydrant and assist in overcoming the effects of atmospheric pressure and gravity in drawing the water. A pressurized fluid source can add fluid to the siphon assembly and this forces water from the body up the hydrant pipe. Also, the fluid from the pressurized fluid source can be added forward of a valve to fill the hydrant pipe which thus minimizes the duration of priming operations.

Abstract: The invention provides a method of monitoring variation in the current value of a rate of fluid flow through a fluid meter which includes a measurement unit and a rotary shaft connected to said measurement unit and suitable for rotating about its own axis when a volume of fluid passes through the measurement unit, the method consisting in detecting rotary movements rather than rotation of the shaft at a sampling frequency that is variable in application of a predetermined sampling relationship, said frequency being defined as a function of at least one predetermined fluid flow rate value, and in electronically processing bits corresponding to detection and to non-detection of a rotary movement of the shaft at said sampling frequency in order to determine the current value of the fluid flow rate over a continuum of flow rates and relative to the predetermined fluid flow rate value included in said continuum of flow rates.

Abstract: A method and apparatus for analyzing a sample to determine its mineral composition. The invention combines X-ray diffraction with Fourier transform infrared spectroscopy to provide a complete spectrum including molecular vibrations, probed by FTIR scans and lattice spacing measured by X-ray diffraction in a single representation. This FX spectrum provides a more complete and accurate mineralogy than either of the techniques alone. In addition, new techniques for independent X-ray diffraction analysis and FTIR analysis are described.

Abstract: A data collection system in which a number of remote terminals (RT) transmit data packets for reception by one or more fixed data collectors (FDC) or a portable data collector (PDC). Each remote terminal (RT) transmits data in two frequency sub-bands to which the fixed and portable data collectors are respectively tuned. Channel capacity is improved in at least the fixed data collector (FDC) sub-band by the use in the remote terminal of minimum shift keying (MSK) encoding and pseudo-random variation of a frequency error applied to the packet transmission frequency for successive packets. In the fixed data collectors dual fast-Fourier transform signal processing enables the interpretation of simultaneous packets with different error frequencies. The use of a single design of remote terminal (RT) in conjunction with portable data collectors (PDC) simplifies system set-up, with the portable collectors providing coverage for those areas where a fixed data collector (FDC) network has yet to be established.

Abstract: The instruments of a pulsed nuclear magnetic resonance (NMR) device are included in a drill collar for evaluating earth formations. The resulting tool makes NMR measurements while the formation is being drilled. Permanent magnets produce a static field in the earth formation. Shimming permanent magnets inside or outside the drill collar suppress the magnetic resonance of borehole fluids. The permanent magnets are manufactured from two magnetic materials, for example.

Abstract: An isolated current shunt transducer includes a current shunt that produces a voltage difference between the current shunt's first and second ends, with the voltage difference being related to a current flowing through the current shunt. The transducer also includes an isolation barrier positioned between the current shunt and a processing circuit to isolate the processing circuit from a voltage that is common to both ends of the current shunt. Two or more transducers may be included in a power meter for measuring power delivered to a load by a multiple phase power distribution circuit. In such a power meter, a processing circuit is connected to the current shunts through the isolation barriers and is operable to produce multiple phase power measurements based on the differences between the voltages at the first and second ends of the current shunts.

Abstract: An improved laminated ferromagnetic FIG. 8 power meter core is provided. The core is fabricated from a plurality of ferromagnetic plates and is formed in the general shape of a FIG. 8. The central leg of the core has a cross-sectional area that is larger than the cross-sectional area of other parts of the core. The core gap, in which a Hall-effect sensor is located, has gap faces with chamfered or rounded over edges to reduce fringing and bypassing effects. The core is formed without discontinuous corners that can result in local saturation and, in use, accommodates electrical power conductors in an over-under looping relationship through the openings of the core to provide a more homogeneous magnetic flux within the core and thus more reliable metering. The overall result is a core with a higher saturation point and thus a wider dynamic range than prior art cores.

Abstract: The present invention relates to a system for driving two mechanical members in rotation about an axis by magnetic coupling of the attractive type, the system comprises respective magnetic elements secured to each of said mechanical members, the two magnetic elements being concentric, one of them being made up of two identical magnetic rings of minimum radius R.sub.3 and of maximum radius R.sub.4, and the other one of them being made up of a magnetic ring having a minimum radius R.sub.1 and a maximum radius R.sub.2, with its midplane perpendicular to the axis of rotation being offset by a distance d from the midplanes of each of said two identical rings. Each ring possesses magnetization in a direction contained in a plane that is perpendicular to the axis of rotation. Each ring also possesses N magnetic poles uniformly distributed around said axis of rotation. The ratio 2d/.vertline.(R.sub.3 +R.sub.4)-(R.sub.1 +R.sub.2).vertline. lies in the range 0.2 to 0.8.

Abstract: A device for monitoring power in a wye power service having three phases includes a sampling element arranged and configured to sample a current value and a voltage value from each of the three phases. A processor, coupled to said sampling element, calculates power either (i) by using the current value and the voltage value for the at least one phase when the voltage value for the at least one phase is available, or (ii) by using the current value for the at least one phase and the voltage values for the other two phases if the voltage value for the at least one phase is unavailable.