Abstract: A Coriolis mass meter with two tube sections connected by a coupling extending between connection points of the tube sections wherein the coupling extends a distance between the connection points which exceeds the shortest perpendicular distance between the first and the second tube sections. The coupling facilitates less stiffness of the tubes against Coriolis oscillation and thus provides a mass meter with a stronger and potentially more reliable measuring signal.

Abstract: The invention concerns an ultrasonic transducer, which is assembled from several parts. These parts are a protecting plate, a piezoelectric disc and a housing. Joining of the parts for transducers are normally done by means of TIG welding or laser welding, but these are relatively costly processes, which also has an impact on the transducer, especially the piezoelectric disc, due to the heat. In order to reduce the heat load and simultaneously simplify manufacturing an ultrasonic transducer is suggested, in which the protecting plate and the housing consists of electrically conducting materials of different kinds and where joining of housing and plate is done by using a mechanical force influence and an electrical current which flows through plate and housing. Also, a method for joining the parts of an ultrasonic transducer is described.

Abstract: In a method for measuring flow by means of an ultra sonic flow meter, an ultra sonic signal is transmitted in an upstream and a downstream direction. This is measured upon receipt of an ultra sonic signal and the measurement stopped at a stopping point. A first series of transmissions is made, and the starting time of each transmission is incremented or decremented until a time difference between the upstream and downstream signal is inside a reference band. Flow is then calculated in accordance with the time measurements.

Abstract: A device having a first flow meter (2) and a second flow meter (3). The first and the second flow meters work according to a Coriolis principle. The first flow meter includes a first measuring tube (7). The second flow meter includes a second measuring tube (10). The first flow meter and the second flow meter are disposed in a common housing (4,5,6). The first flow meter and the second flow meters have different eigenfrequencies because of a first vibration-influencing device (18) attached to the first flow meter and a second vibration-influencing device (19) attached to the second flow meter.

Abstract: A transmitting and receiving circuit for an ultrasonic flowmeter. In such circuits, an ultrasonic transducer is typically used as both transmitter and receiver. This is obtained by using switching means, for example in the form of CMOS switches. However, problems arise with ringings of a transducer when having acted as a transmitter. This unwanted ringing makes the crystal of the transducer act as an additional signal generator, and the signal is coupled via parasitic capacitances in a switching means to the receiving ultrasonic transducer. This problem is solved by connecting one pole of a short circuit switch (S3, S4) to the ultrasonic transducer (TR1, TR2) or to the switching means (S1, S2) and the other pole of the short circuit switch to ground. Keeping the short circuit switch closed when the switching means is open, and open when the switching means is closed, creates a decoupling path for the unwanted signal, thereby improving the accuracy of the transmitting and receiving circuit.

Abstract: An insert for a measuring tube of an inductive flowmeter is disclosed, having a middle section and two end sections, in which at least one end section is of resilient construction and the middle section is of rigid construction. A flange constituting an earthing electrode is provided in a section B2B comprising electrically conductive elastomer. Integrally-formed electrodes 12 and 13 are also formed by electrically conductive elastomer.

Abstract: A method for testing an electromagnetic flowmeter and a flowmeter are described, the flowmeter having a measuring tube (2) and a coil arrangement (3, 4) for generating a magnetic field perpendicular to the direction of flow through the measuring tube (2), the current direction in the coil arrangement being periodically changed. In this connection, it is desirable for simple monitoring to be possible. For that purpose, after changing the current direction, at least one parameter of the current rise is determined and this is compared with a reference value. For this, the flowmeter has a testing device (20, 25) which, after a change-over of the current direction, determines at least one parameter (T) of the rise in the current in the coil arrangement (3, 4, 30) and compares it with a given value.

Abstract: A mass flow measuring apparatus (1) is described, having tube (2), which at a first position (P1) is coupled as regards oscillation to a first energy converter (4) and at a second position (P2) is coupled as regards oscillation to a second energy converter (5), and having an evaluating device, the first and the second position (P1, P2) being spaced (L) from one another, the energy converters (4, 5) each being operable as oscillation generator and oscillation detector and the energy converters (4, 5) working alternately as oscillation generators. A method can therefore be carried out in which the tube (2) is caused to oscillate alternately at the first position (P1) and at the second position (P2), signals being measured at the second and the first position (P2, P1). It is desirable to be able to achieve accurate measurements even in the case of a measuring apparatus of small construction.

Abstract: An optic fiber wavelength multiplexer-demultiplexer comprising a dispersing system (1) exhibiting a dispersing plane, at least one input fiber (2) with an output face, at least one output fiber (3) with an input face, and a device (4) for optic matching of the output face of the input fiber with the input face of the output fiber. The dispersing system and the matching means form an optic system with multiple transversal focuses (6) in the dispersing plane.

Abstract: A multiplexer, demultiplexer or router includes an input fiber and an output fiber, each fiber having a core and a sheath. At least one of the input fiber and the output fiber includes an intermediate ring having an optic index greater than the optic indexes of immediately adjacent portions of the core and the optic sheath and less than the optic index of the center axis of the core.

Abstract: A wavelength selective optical device includes a two-dimensional grating (6) and a device 11. The two-dimensional grating represents an intrinsic function. The device (11) is to change the complex amplitude of the electromagnetic field of the light wave, according to a filtering function, and is to expand the image spot into a monochromatic light in the direction of the spectral dispersion. An optical fiber wavelength multiplexer-demultiplexer includes a filter (11), a mirror (9) and a grating (6). The optical axis of the mirror passes through the plane of the grating and is parallel to the lines of the grating. The filter (11) is arranged in the vicinity of the mirror to control the intrinsic function of the multiplexer-demultiplexer.

Abstract: A modified concentric spectrograph for diffracting light with high stray light rejection without astigmatism is provided. The modified spectrograph includes a grating, a lens, and at least one entrance port and one exit port. The grating has a concave surface and a meridian plane with a first side and a second side. The lens has a substantially planar surface and a convex surface. Preferably, the convex and concave surfaces are substantially concentric. The ports are substantially located on different sides of the meridian plane near a focal plane of the spectrograph. The position of a focal plane may be modified using an optically transmissive triangular prism with a reflective surface, and an optically transmissive block. The position of a focal plane may further be modified with one or more optically transmissive plates. Methods for using the spectrograph are also provided.

Abstract: An optic dispersing system, designed for usage in a wavelength field of a beam, includes a network or grating (1) carried by a support (2) with a dilatation coefficient .epsilon.. The system suggested is temperature-stabilized. To do so, it contains a front blade or optical element (3), or refractive index n.sub.1, transparent in the concerned wavelength field. .epsilon.+1/n.sub.1 .times.dn.sub.1 /dt is small and, advantageously, dn.sub.1 /dt and .epsilon. are of opposite signs. This device enables the manufacture of a multiplexer-demultiplexer or a fiber optic wavelength router, which is temperature-stabilized.

Abstract: A system for introducing a liquid sample (1) for analytical atomic spectrometry includes a nebulizer (20) and separator (27) at the exit (23) of the nebulizer. The system also includes at least one drain (30) fitted with evacuator (16, 17) for evacuating residual liquid (8) in a constricted and controlled flow, and reagent supplier (12, 13) for supplying drain (30) with a reagent (2) to generate hydride.

Abstract: Device and method for three-dimensional measurements and observation of a surface layer of a thin-film structure, comprising a monitoring unit 4 which includes a video camera 12, a wide-beam illumination source 14, a narrow-beam illumination source, 20, an operation and control unit and a table for horizontal movement. The device comprises a Wollaston prism 24 arranged on the optical path of the narrow light beam, in order to obtain two narrow light beams whose polarization states are linear and mutually orthogonal, a polarizer 27 arranged on the optical axis of the Wollaston prism 24 so that the reflected narrow light beam passes through it after its travel through the Wollaston prism 24, and a detection cell 28.

Abstract: A photodetection system that analyzes a luminous flux (15) received on a line (10). The photodetection system includes an opaque mask (4) provided with at least one aperture (6), placed in the vicinity of the line, driver (7) designed to rotate the mask, detector (8, 9) of an angular position of reference of the mask, a field lens (12) concentrating the luminous flux (16) crossing the line onto a photodetector (1), and a processing unit (3) connected to the photodetector, for analyzing the luminous flux to yield values for several points on the line.

Abstract: There is provided a method and apparatus for controlling the carrier gas flow through a gas chromatographic apparatus with capillary column subjected to variations in temperature, through control of feeding pressure achieved following computerized processing of the equation of the carrier flow rate as a function of inlet pressure, column temperature and system structural parameters, including preliminary determination of the system parameters through detection of pressure, temperature and flow rate values in stabilized conditions of carrier passage through apparatus and calculation of a constant representing said parameters on the basis of values detected and in application of the aforesaid equation; storage of aforesaid constant; utilization of constant in the mentioned equation for controlling carrier flow rate through calculation and control of its feeding pressure during utilization of the gas chromatographic apparatus.

Abstract: An N.times.N wavelength router (1) includes n m.times.m couplers (10, 15, 20, 25), N being equal to n.times.m, and the N inputs (11, 12, 16, 17, 21, 22, 26, 27) of the couplers being the inputs (E1-E8) of the N.times.N router. The N.times.N router also includes m n.times.n routers (30, 40) capable of switching an optical signal having a wavelength, from any one of its n inputs (31-34, 41-44) to any one of its n outputs (35-38, 45-48), according to the wavelength of the signal. The inputs of the n.times.n routers are connected to the outputs of the m.times.m couplers, and the outputs of the n.times.n routers are the outputs (S1-S8) of the N.times.N routers. The transmission spectra of the n.times.n routers have the form of a series of peaks, each of the series being different one from another.

Abstract: The present invention relates to a multiplexer-demultiplexer for optical wavelengths comprising:endpoints of input-output lines (22.sub.1, 22.sub.2, . . . ,22.sub.n),an endpoint of a transmission line (23),a diffraction network with a diffraction plane and,an optical system ensuring the optical conjugation between the input-output lines (22.sub.1, 22.sub.2, . . . ,22.sub.n) and the endpoint of the transmission line (23),The endpoints of the input-output lines (22.sub.1, 22.sub.2, . . . ,22.sub.n) are aligned along a straight line parallel to the diffraction plane and the endpoint of the transmission line (23) is offset transversally with respect to said straight line.

Abstract: A grating drive apparatus for use in a multiple-grating spectrometer is provided. The spectrometer has an entrance slit, an exit port, an optical path between the entrance slit and the exit port, and a plurality of diffraction gratings. Each of the gratings is rotatable about a respective preferred axis for selecting a wavelength during spectrometer operation. The grating drive apparatus includes a turret having a plurality of gratings mounted on it, a mechanical stop assembly, and a drive assembly. The drive assembly causes the turret to engage the stop assembly to rotate the turret and select a grating. The drive assembly also rotates the selected grating to select an operational wavelength.