Abstract: A rheometer according to an embodiment includes a substrate on which an object to be measured is placed, a vibration unit configured to provide a vibration to the substrate, a plurality of probe units each including a quartz tuning fork and a contact member fixed to the quartz tuning fork, the contact member being able to contact the object, the plurality of probe units having different types of the contact members. Any one of the plurality of probe units is selected and contacts the object, and a controller configured to calculate a viscoelastic force of the object based on a vibration of the vibration unit and a vibration transmitted to the quartz tuning fork through the object from the vibration of the vibration unit.

Abstract: A method for determining a viscosity of a medium based on damping of an oscillation mode of a measurement tube comprises exciting oscillations of an oscillation mode; detecting a sequence of provisional damping measurement values for the measurement tube oscillation mode; and calculating target measurement values. The influence of the cross-sensitivity of the damping for the flow rate of the medium is corrected by determining rectified damping measurement values that correspond to damping when the medium is at rest and determining viscosity on the basis of the rectified damping measurement values, or correcting the influence of the cross-sensitivity of the damping for the flow rate of the medium by determining provisional intermediate values of a damping-dependent variable, determining rectified intermediate values that correspond to the intermediate values when the medium is at rest, and determining the target measurement values on the basis of the rectified intermediate values.

Abstract: A system (600, 700) for correcting a measured flow rate for viscosity effects of a fluid in a vibratory meter (5) is provided. The system (600, 700) includes a sensor assembly (10) and a meter electronics (20) communicatively coupled to the sensor assembly (10). The meter electronics (20) is configured to receive sensor signals from the sensor assembly (10), determine a non-viscosity correlation parameter based on the sensor signals, and correlate the non-viscosity correlation parameter to a viscosity of a fluid in the sensor assembly (10).

Abstract: A vibronic sensor for monitoring a flowable medium, comprising: an oscillator to which a medium surrounding the oscillator can be applied; at least one electromechanical transducer for exciting the oscillator to mechanical vibrations in accordance with driver signals and/or for outputting transducer signals that depend on vibrations of the oscillator; an operating and evaluating unit for providing the driver signals for driving the electromechanical transducer, for capturing the transducer signals, and for determining the presence, the density, and/or the viscosity of the medium in accordance with the transducer signals, wherein the operating and evaluating unit is designed to detect whether the medium in the pipe has a flow velocity above a limit value on the basis of time-varying modifications of the transducer signals.

Abstract: A rheometer for determining and/or monitoring the flow behavior of viscous fluids, in particular plastic melts and plastic solutions, includes a housing, in which at least one substantially rectilinear channel is formed between an inlet opening and an outlet opening, the channel having a rectangular cross section, and a plurality of pressure measuring devices which are arranged along the channel, wherein the channel is provided over its length with a cyclically narrowing and widening cross section.

Abstract: Multiple bulk acoustic wave (BAW) resonator structures are arranged along opposing surfaces of a fluidic passage arranged to receive a fluid. At least one resonator structure may be overlaid with functionalization (e.g., specific binding or non-specific binding) material to bind one or more analytes contained in the fluid. Combinations of BAW resonators providing dominant shear response for detection, and providing dominant longitudinal response for mixing or analyte movement, may be provided on one or more surfaces bounding a fluidic passage. Embodiments may reduce the footprint of multi-resonator fluidic device, enhance analyte binding rate, and/or enhance mixing of sample constituents.

Abstract: The present invention is seen to provide a new methodology, testing system designs and concept to enable in situ real time monitoring of the cure process. Apparatus, system, and method for the non-destructive, in situ monitoring of the time dependent curing of advanced materials using one or more differential ultrasonic waveguide cure monitoring probes. A differential ultrasonic waveguide cure monitoring probe in direct contact with the material to be cured and providing in situ monitoring of the cure process to enable assessment of the degree of cure or cure level in a non-cure related signal variances (e.g., temperature) independent calibrated response manner. A differential ultrasonic waveguide cure monitoring probe including a transducer coupled to a waveguide and incorporating correction and calibration methodology to accurately and reproducibly monitor the cure process and enable assessment of cure level via ultrasonic reflection measurements.

Abstract: A technique, including a system and a method, for measuring a fluid property using a piezo-actuated fluid dispenser, is disclosed. The technique includes generating a pressure wave in a channel in the piezo-actuated fluid dispenser using a piezo element, detecting, using the piezo element, a residual pressure oscillation in the channel caused by the generating, obtaining a resonance frequency of the pressure oscillation, and determining, using the resonance frequency, the fluid property.

Abstract: Techniques for determining a wellbore fluid constituent concentration include depositing a portion of a hydraulic fracturing fluid that includes a base fluid on a quartz crystal microbalance, the base fluid including a constituent; measuring an oscillation frequency of the quartz crystal microbalance based on the constituent of the base fluid; determining, with the quartz crystal microbalance, a mass of the constituent in the deposited portion of the hydraulic fracturing fluid; and based on at least one of the determined mass or the measured frequency, determining a concentration of the constituent of the base fluid.

Abstract: The present invention provides a system and method for a milk measuring device for measuring the acoustic properties, such as acoustic damping and sound velocity in milk, in order to determine milk properties. The sound velocity in milk depends on temperature and composition. By carrying out, for example by means of a piezo element, a reference measurement on vibrations that have been directed by a second piezo element into a wire or the like of known material, which wire is strung in the measuring chamber which is filled with the milk to be tested, the milk temperature can be derived, so that other milk properties, in particular the fat/protein composition, can be determined in a more reliable manner.

Abstract: Disclosed herein is a property measurement apparatus including: a first plate installed in a state of being rotatable and/or vibratable; and a second plate placed to face the first plate and provided with an impedance measurement section, wherein a stress caused by a distortion generated by rotating or vibrating the first plate to serve as a distortion given to a sample provided in a gap between the first and second plates is measured, and at the same time, the impedance measurement section measures the impedance of the sample.

Abstract: To provide a sensing device that holds a piezoelectric sensor and a channel forming member placed on the sensor in a closely contacted state while maintaining a shape of space of a passage space formed inside the device. In a sensing device 1100 that senses a substance to be sensed based on a variation in an oscillation frequency caused by an absorption of the substance to be sensed in an absorption layer provided on a piezoelectric resonator 1720 of a piezoelectric sensor 1700, a holding member 1600 holds the piezoelectric sensor 1700 and a channel forming member 1730 that forms a passage space through which a sample fluid passes on an upper surface side of the sensor, in a vertically stacked state. A cover member 1510 is placed on the channel forming member 1730, and a pressing part 1350 which is raised/lowered by a first raising/lowering mechanism 1300 presses the cover member 1510 placed on the channel forming member 1730 downward with a previously set force.

Abstract: A resonator that includes an elastic tube defining an interior surface and a conductor threaded through the elastic tube. Solid material fills space between the conductor and the elastic tube interior surface, such that motion of the conductor is directly transferred to the elastic tube. In a preferred embodiment, the elastic tube 14 is electrically conductive and said solid material insulates said conductor from said elastic tube.

Abstract: A density and viscosity sensor for measuring density and viscosity of a fluid, comprises: a housing (4) defining a chamber (8) isolated from the fluid (3), the housing (4) comprising an area defining a membrane (9) separating the chamber (8) from the fluid (3); a resonating element (5) arranged to be immersed in the fluid (3) and mechanically coupled to the membrane (9); and an actuating/detecting element (6) coupled to the resonating element (5), the actuating/detecting element (6) being positioned within the chamber (8) and mechanically coupled to the membrane (9), the actuating/detecting element (6) comprising at least one piezoelectric element (10) comprising two sides (11, 12) substantially parallel to the membrane (9); The membrane (9) has a thickness enabling transfer of mechanical vibration between the actuating/detecting element (6) and the resonating element (5). One side (11) of the piezoelectric element (10) comprises a single conductive area (13).

Abstract: An object is to measure a mechanical property of a fluid at a temporal resolution of at least 100 [?s]. Therefore, a method comprising: causing a droplet 21 to fly by ejecting a fluid to be measured from a nozzle 11a as the droplet 21; generating an electric field in a space around a flight path 22 of the droplet 21 by applying a voltage to an electrode arranged in the vicinity of the flight path 22; deforming the droplet 21 in a way of contactless deformation with a dielectric force induced by the electric field; and measuring a mechanical property of the fluid based on temporal variation of deformation state of the droplet 21 after deforming the droplet 21.

Abstract: Embodiments of the present invention are directed to resonating detection devices in which the sample flows through a conduit having a section in which the conduit is grouped or concentrated with the point of maximum movement. An exemplary device includes a primary conduit, at least one first flex section, at least one second flex section and at least one analysis section. The primary conduit cooperates with an energizer for inducing vibration and a programmed calculator for determining a resonant frequency to calculate a mass related parameter of the solution carried therein.

Abstract: A method for measuring an ultrasonic viscosity includes applying a driving voltage to a plurality of first piezoelectric transducers provided along an outer wall circumference of a pipe at constant intervals to generate a torsional wave on a surface of the pipe, receiving the torsional wave propagated along the surface of the pipe through a plurality of second piezoelectric transducers provided along the outer wall circumference of the pipe at constant intervals while being spaced from the first piezoelectric transducers at a certain distance in a longitudinal direction of the pipe to convert the torsional wave into a voltage signal, calculating an attenuation and a propagation velocity of the torsional wave based on the time for the propagation of the torsional wave and the converted voltage signal, and measuring viscosity of the fluid in the pipe based on the calculated attenuation and propagation velocity of the torsional wave.

Abstract: The present application provides apparatus and methods for determining the density of a fluid sample. In particular, it provides a sensor device which can be loaded with a fluid sample such as blood, and which further comprises at least one oscillating beam member or resonator. Exposure of the blood sample to clotting agents allows a clotting reaction to commence. The device allows the density of the sample fluid to be monitored with reference to the oscillation of the vibrating beam member, thus allowing the monitoring of the clotting of the fluid sample.

Abstract: A multivariable sensor for determining and/or monitoring a predetermined fill level and density and/or viscosity of a liquid in a container. The sensor comprises a measuring tube provided in the container. The measuring tube has at least a first oscillatable segment and a second oscillatable segment, wherein the oscillatable segments have a cross sectional area deviating from a circularly round shape and at least one straight side, wherein on an inner wall of the oscillatable segments, driver/receiving units are placed, which cause the oscillatable segments to execute resonant oscillations. At least one control/evaluation unit is provided, which evaluates frequency and/or phase and/or amplitude of the oscillations and determines therefrom reaching of the predetermined fill level and density and/or viscosity of the liquid.

Abstract: The oscillating velocity of an oscillating body in a fluid to be measured is positively fed back, so as to activate an actuator. The oscillating state of the oscillating body is monitored while making a velocity feedback gain increase. The velocity feedback gain when the oscillating body has oscillated is obtained as an oscillation limit gain at the oscillation limit, and this oscillation limit gain is used as a viscosity equivalent value representing viscosity of the measured fluid.

Abstract: A method and device for estimating a density value ?m indicative of a true density ? or for estimating a viscosity value ?m indicative of a true viscosity ? of a fluid is disclosed. For this, a first resonance frequency fR of a first mechanical oscillator in a reference volume and a second resonance frequency fF of a second mechanical oscillator in contact with the fluid are measured. The estimated value ?m or ?m is then derived using these resonance frequencies fR and fF. During this derivation, at least one fluid-temperature- or fluid-pressure-dependent parameter of the fluid is used. Additionally or alternatively, the first (i.e. reference) mechanical oscillator is arranged in contact with a reference fluid. Thus, fundamental errors in the derivation of the estimated value ?m or ?m are reduced and the estimated value becomes more reliable.

Abstract: A method for determining and/or monitoring the viscosity of a medium, wherein a mechanically oscillatable unit is excited to execute oscillations based on an exciter signal, and wherein oscillations are received from the mechanically oscillatable unit and transduced into a received signal. The eigenfrequency and/or resonance frequency of the mechanically oscillatable unit and/or phase relationship between the exciter signal and the received signal are/is ascertained and/or monitored, and from changes in the eigenfrequency and/or resonance frequency and/or phase relationship, a change in viscosity is deduced and/or, based on dependencies of the oscillations on the viscosity of the medium, from the eigenfrequency and/or resonance frequency and/or phase relationship, viscosity is ascertained. In a second variant of the method, decay behavior of the mechanically oscillatable unit is evaluated. An apparatus for determining and/or monitoring viscosity is also presented.

Abstract: A method for operating an apparatus which has an oscillatable unit. The oscillatable unit is excited to oscillate by means of a first frequency sweep within a predetermined frequency band with successive, discrete exciter frequencies of increasing or decreasing frequency. A first exciter frequency is ascertained, in the case of which, during the first frequency sweep, at least one predeterminable criterion is fulfilled. The oscillatable unit is excited by means of a second frequency sweep, wherein the frequency band, compared with the first frequency sweep, is run through in the opposite direction. A second exciter frequency is ascertained, in the case of which, during the second frequency sweep, the at least one predeterminable criterion is fulfilled. From the first exciter frequency and the second exciter frequency, via formation of an average, a measuring frequency for determining and/or monitoring at least one process variable is determined.

Abstract: A vibratory flow meter (5) for determining a viscosity of a flow material is provided according to the invention. The vibratory flow meter (5) includes a meter assembly (200) configured to generate a density (p) of a flow material, generate a first mass flow rate (m1) for a first flowtube (210a), and a second mass flow rate (m2) for a second flowtube (210b). The vibratory flow meter (5) further includes a restrictive orifice (252) located in the first flowtube (210a). The restrictive orifice (252) ensures that a first flow rate of the flow material in the first flowtube (210a) is less than a second flow rate of the flow material in the second flowtube (210b).

Abstract: A method for determining and/or monitoring the viscosity of a medium, wherein a mechanically oscillatable unit is excited to execute oscillations based on an exciter signal, and wherein oscillations are received from the mechanically oscillatable unit and transduced into a received signal. The eigenfrequency and/or resonance frequency of the mechanically oscillatable unit and/or phase relationship between the exciter signal and the received signal are/is ascertained and/or monitored, and, from changes in the eigenfrequency and/or resonance frequency and/or phase relationship, a change in viscosity is deduced and/or, based on dependencies of the oscillations on the viscosity of the medium, from the eigenfrequency and/or resonance frequency and/or phase relationship, viscosity is ascertained. In a second variant of the method, decay behavior of the mechanically oscillatable unit is evaluated. An apparatus for determining and/or monitoring viscosity is also presented.

Abstract: A method of measuring properties of a fluid that uses a conductor electrically connected to a current source. A magnetic field is created about the conductor and the conductor is introduced into the fluid medium. A current waveform, having a frequency, is periodically passed through the conductor, so as to cause the conductor to move, due to force exerted on the conductor from interaction of the current and the magnetic field. The conductor movement is sensed, producing a sense signal that is amplified into an amplified sense signal. The phase relationship between the current waveform and the amplified sense signal is measured and the current waveform frequency is adjusted to create a phase lock loop. The frequency when the phase lock loop is in lock state is measured as the phase between the excitation and the measured sense signal is varied, and fluid properties are calculated from the measured frequencies.

Abstract: The present invention provides a method for the real-time continuous monitoring of a change or density and/or viscosity within a test sample. Such methods can be used to determine the occurrence of a chemical reaction within a test sample where the same causes and increase or decrease in the density and/or viscosity of the sample due to, for example, a gelation, precipitation or coagulation occurring within the test sample. There is further provided a multi-resonator apparatus for use in measuring the density and/or viscosity of a test sample in which the multi-beam resonator is immersed.

Abstract: Disclosed is a micro viscometer comprising a substrate having a first chamber and a second chamber that are positioned at intervals; a thin film disposed on the substrate to cover the first chamber and the second chamber; an actuating part that disposed on the thin film corresponding to the first chamber; and a sensing part that disposed on the thin film corresponding to the second chamber, wherein at least one main trench is formed in between the first chamber and the second chamber.

Abstract: Disclosed is a micro viscometer comprising a body including an inlet where a fluid flows in, an outlet where the fluid flows out, a first chamber and a second chamber that is connected to the inlet and the outlet, respectively, a substrate and a cover that partition multiple micro channels that connect the first chamber and the second chamber; a first thin film that vibrates with the fluid within the first chamber and locates on the side of the first chamber; a second thin film that vibrates with the fluid within the second chamber and locates on the side of the second chamber; an actuating part that applies vibration onto the fluid within the first chamber by conducting vibration through the first thin film; a sensing part that senses vibration or pressure onto the fluid that transfers through the micro channels to the second thin film through vibration of the first thin film.

Abstract: A viscometer for measuring the viscosity of fluid. The viscometer includes: a first chamber and a second chamber separated from the first chamber; a micro channel connecting the first chamber to the second chamber; a first thin film disposed over the first chamber and a second thin film disposed over the second chamber; and a first piezoelectric film disposed over the first thin film and a second piezoelectric film disposed over the second thin film. At least one of the first and second piezoelectric films has a hexagonal shape if a longest distance between a center and an edge of the piezoelectric film is longer than a threshold range and a circular shape if the distance is shorter than the threshold range.

Abstract: Disclosed is a micro viscometer comprising a first chamber and a second chamber positioned with an interval; a micro channel that connects the first chamber and the second chamber; and a first thin film and a second thin film arranged on top of the first chamber and the second chamber, respectively, wherein a height of the first chamber and second chamber are substantially identical to a half wavelength corresponding a first resonant frequency of the first thin film and the second thin film, respectively, and a width of the first chamber and the second chamber are narrower than the height of the first chamber and the second chamber.

Abstract: An ultrasonic or acoustic viscosity sensor or viscometer is provided that can be used to accurately measure viscosity for fluid samples of less than 1 ?l in volume. Methods for measuring viscosity for fluid samples of less than 1 ?l in volume are also provided. The viscosity sensor and methods based thereon enable simultaneous measurement of bulk and dynamic (shear-rate dependent) viscosity of a non-Newtonian fluid. Bulk and dynamic viscosity of the non-Newtonian fluid can be measured simultaneously without separating constituents of the fluid, and thus distinguishing the effect of constituents on the viscosity. Dynamic viscosity of the non-Newtonian fluid can be estimated at varying shear rates, to study the deformability of the constituents of the fluid as a function of shear rate.

Abstract: Disclosed herein are devices for measuring, at one or more time points, one or more properties or changes in properties of a fluid sample. The devices may comprise a chamber defining an internal volume of the device suitable for receiving and retaining the fluid sample; a plurality of layers, the plurality comprising at least a first layer below the chamber, at least a second layer above the chamber, and a substrate layer between the first and second layers, wherein: the substrate layer is linked to at least one suspended element located within the chamber; the suspended element is linked to the substrate layer by at least two compliant structures located within the chamber; and the suspended element is configured to oscillate upon application of an actuating signal to at least one electrically conductive path, which runs across at least two of the compliant structures and the suspended element. Related methods and uses are also disclosed.

Abstract: Vibrating wire viscometers are disclosed herein. An example viscometer includes a housing defining a chamber and a wire holder disposed in the chamber. The wire holder has an elongated, electrically insulating body and a channel extending along a length of the body. A wire is at least partially disposed in the channel and coupled to the wire holder at opposing ends of the wire holder to tension the wire and electrically isolate the wire from the housing.

Abstract: A fluid properties measurement device includes a symmetric resonant element having a first mass and a second mass, balanced to the first mass and coupled to the first mass by a torsional spring, having a nodal support between the first mass and the second mass. Also, a chamber having at least one opening accommodates the first mass, free of mechanical constraint and a driving and sensing assembly, is adapted to drive the first mass in torsion and sense resulting torsional movement of the first mass. The torsional spring passes through the opening which is sealed about the torsional spring at the nodal support and the second mass is free to be placed into a fluid, for fluid property measurements.

Abstract: A viscoelastic property of tissue is measured in vivo. To collect more information and/or estimate viscosity, shear modulus, and/or other shear characteristics, an amplitude and phase modulated waveform is transmitted to the tissue. The displacement caused by the waveform over time includes displacements associated with response to different frequencies. By examining the displacement in the frequency domain, one or more viscoelastic properties may be calculated for different frequencies. The frequency response may indicate the health of the tissue.

Abstract: A method of measuring properties of a fluid that uses a conductor electrically connected to a current source. A magnetic field is created about the conductor and the conductor is introduced into the fluid medium. A current waveform, having a frequency, is periodically passed through the conductor, so as to cause the conductor to move, due to force exerted on the conductor from interaction of the current and the magnetic field. The conductor movement is sensed, producing a sense signal that is amplified into an amplified sense signal. The phase relationship between the current waveform and the amplified sense signal is measured and the current waveform frequency is adjusted to create a phase lock loop. The frequency when the phase lock loop is in lock state is measured as the phase between the excitation and the measured sense signal is varied, and fluid properties are calculated from the measured frequencies.

Abstract: A drive device for operating an electromagnetic oscillator includes an OP amplifier for amplifying an analog input signal from an electromagnetic pick-off and an A/D converter for converting an analog signal output from the OP amplifier into a digital signal. The drive device also includes a D/A converter for converting, after digital processing performed by a DSP on the digital signal output from the A/D converter based on phase detection, a digital signal having a processed data amount into an analog signal, and a D/A converter for converting, after the digital processing performed by the DSP on the digital signal output from the D/A converter based on the phase detection, a digital signal having a processed data amount into an analog signal.

Abstract: An apparatus for determining and/or monitoring at least one process variable of a medium. The apparatus includes: at least one mechanically oscillatable unit; at least one transducer unit, which excites the mechanically oscillatable unit to mechanical oscillations based on an exciter signal and which receives the mechanical oscillations of the mechanically oscillatable unit and converts such to a received signal. The transducer unit has at least one piezoelectric element. The apparatus further includes: at least one electronics unit, which supplies the transducer unit with the exciter signal and which receives the received signal from the transducer unit; and at least one compensation element, which supplies the exciter signal to the electronics unit and from which the electronics unit receives a compensation signal. The invention provides that the compensation element has at least one at least element made at least partially of a piezoelectric material.

Abstract: A torsional sensor including a high-pressure sealing mechanism for sensing at least one parameter of a high-pressure fluid. The torsional sensor includes a torsional portion including a torsional rod sensor, a reference portion coupled to the torsional portion and including a transducer device and a high-pressure sealing mechanism coupled to the reference portion and the torsional portion and in sealing arrangement therewith. The high-pressure sealing mechanism is configured to provide for sealing therein the transducer device and allow for protrusion therethrough of a torsional rod sensor. At least a portion of the torsional sensor is mountable for immersion in the high-pressure fluid and operable to propagate a torsional wave that interacts with the high-pressure fluid along the at least portion of the torsional sensor so as to affect propagation of the torsional wave in a manner dependent on the at least one parameter of the high-pressure fluid.

Abstract: Various embodiments include apparatus and methods of determining the viscosity of a fluid downhole in a well. A parameter of a response signal, obtained from driving a tube containing a fluid with an excitation signal for vibrating the tube, can be collected while maintaining the tube in a vibrating mode. The parameter can be evaluated to measure the viscosity of the fluid. In various embodiments, the fluid viscosity may be measured in-situ downhole in the well.

Abstract: An apparatus for determining and/or monitoring at least one process variable, especially a fill level, a density or a viscosity, of a medium in a container, including: a mechanically oscillatable structure protruding into the container during operation, with at least one oscillatory characteristic dependent on the process variable; an electromechanical transducer; and electronics, for producing an exciter signal connected to the input side of the transducer, which has a first filter, wherein the first filter filters out a wanted signal from the received signal; and which determines and/or monitors the process variable based on the wanted signal.

Abstract: Disclosed is a micro viscometer comprising a body including an inlet where a fluid flows in, an outlet where the fluid flows out, a first chamber and a second chamber that is connected to the inlet and the outlet, respectively, a substrate and a cover that partition multiple micro channels that connect the first chamber and the second chamber; a first thin film that vibrates with the fluid within the first chamber and locates on the side of the first chamber; a second thin film that vibrates with the fluid within the second chamber and locates on the side of the second chamber; an actuating part that applies vibration onto the fluid within the first chamber by conducting vibration through the first thin film; a sensing part that senses vibration or pressure onto the fluid that transfers through the micro channels to the second thin film through vibration of the first thin film.

Abstract: Disclosed is a micro viscometer comprising a first chamber and a second chamber positioned with an interval; a micro channel that connects the first chamber and the second chamber; and a first thin film and a second thin film arranged on top of the first chamber and the second chamber, respectively, wherein a height of the first chamber and second chamber are substantially identical to a half wavelength corresponding a first resonant frequency of the first thin film and the second thin film, respectively, and a width of the first chamber and the second chamber are narrower than the height of the first chamber and the second chamber.

Abstract: Disclosed is a micro viscometer comprising a substrate having a first chamber and a second chamber that are positioned at intervals; a thin film disposed on the substrate to cover the first chamber and the second chamber; an actuating part that disposed on the thin film corresponding to the first chamber; and a sensing part that disposed on the thin film corresponding to the second chamber, wherein at least one main trench is formed in between the first chamber and the second chamber.

Abstract: Vibrating wire viscometers are described. Some example vibrating wire viscometer housings include a flowline through the housing to expose a first wire to a downhole fluid, a cavity in the housing to hold a magnet and to conduct one or more additional wires from the flowline to a signal generator, first and second electrically conductive posts mechanically coupled to the housing to hold the first wire in tension within the flowline, and a seal mechanically coupled to the housing to prevent access to the magnet by the downhole fluid.

Abstract: The oscillating velocity of an oscillating body in a fluid to be measured is positively fed back, so as to activate an actuator. The oscillating state of the oscillating body is monitored while making a velocity feedback gain increase. The velocity feedback gain when the oscillating body has oscillated is obtained as an oscillation limit gain at the oscillation limit, and this oscillation limit gain is used as a viscosity equivalent value representing viscosity of the measured fluid.

Abstract: Apparatus for inspection of a fluid comprising: a channel portion, the channel portion having a channel inlet and a channel outlet separate from the channel inlet; a piezoelectric sensor element provided at a sensor position of the channel and arranged to contact fluid flowing through the channel portion from said channel inlet to said channel outlet, the apparatus being configured to determine a difference value being a value corresponding to a difference between a resonant frequency of oscillation of said piezoelectric element at a given moment in time and a reference resonant frequency.

Abstract: Vibrating wire viscometers are disclosed. An example vibrating wire viscometer includes first and second electrically conductive tubes, where the first tube is at least partially inserted into the second tube, and where the first and second tubes are coupled via an electrically insulating bonding agent. The example viscometer further includes first and second electrically conductive pins inserted into respective ones of the first and second tubes, and an electrically conductive wire fastened to the first and second pins to vibrate in a downhole fluid to determine a viscosity of the downhole fluid.

Abstract: A method for operating an apparatus which has an oscillatable unit. The oscillatable unit is excited to oscillate by means of a first frequency sweep within a predetermined frequency band with successive, discrete exciter frequencies of increasing or decreasing frequency. A first exciter frequency is ascertained, in the case of which, during the first frequency sweep, at least one predeterminable criterion is fulfilled. The oscillatable unit is excited by means of a second frequency sweep, wherein the frequency band, compared with the first frequency sweep, is run through in the opposite direction. A second exciter frequency is ascertained, in the case of which, during the second frequency sweep, the at least one predeterminable criterion is fulfilled. From the first exciter frequency and the second exciter frequency, via formation of an average, a measuring frequency for determining and/or monitoring at least one process variable is determined.