Abstract: The present invention relates to a sensor for detecting the degree of deterioration of oil, and more particularly, provides an oil deterioration sensor which can detect the deterioration of oil and/or the liquid surface of oil by utilizing the fact that the sound velocity of ultrasonic waves change according to the alkalinity of the oil, the oil deterioration sensor for determining deterioration characteristics of oil by utilizing ultrasonic waves, which is characterized in that a deterioration sensor reflecting surface for reflecting ultrasonic waves transmitted from an ultrasonic wave transmitting portion is placed in oil so as to detect deterioration of the oil, and characterized by comprising: an oil deterioration detecting portion for evaluating a transmission velocity of an ultrasonic wave in the oil by receiving ultrasonic waves from the aforesaid deterioration sensor reflecting surface and for evaluating a degree of deterioration of oil from said transmission velocity of the oil.

Abstract: The present invention is an ultrasonic fluid densitometer that uses at least one pair of transducers for transmitting and receiving ultrasonic signals internally reflected within a material wedge. A temperature sensor is provided to monitor the temperature of the wedge material. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface and comparing a transducer voltage and wedge material temperature to a tabulation as a function of density.

Abstract: The present invention is an ultrasonic liquid densitometer that uses a material wedge having two sections, one with a liquid/wedge interface and another with a gas/wedge interface. It is preferred that the wedge have an acoustic impedance that is near the acoustic impedance of the liquid, specifically less than a factor of 11 greater than the acoustic impedance of the liquid. Ultrasonic signals are internally reflected within the material wedge. Density of a liquid is determined by immersing the wedge into the liquid and measuring reflections of ultrasound at the liquid/wedge interface and at the gas/wedge interface.

Abstract: In order to raise the measuring accuracy of a Coriolis-type mass flow rate meter in a cost-effective fashion, the latter comprises a measuring tube (4), a subcircuit measuring circuit and a subcircuit exciting circuit. Two vibration sensors (17, 18) and a vibration exciting (16) are arranged on the measuring tube. The vibration sensor (17) is assigned the amplifier (v1) in the subcircuit measuring circuit, and the vibration sensor (18) is assigned the amplifier (v2). Downstream of the two amplifiers are the summing stage (ss1) with a downstream integrating stage (ig), and the difference stage (ds). Downstream of the integrating stage (ig), the difference stage and the amplifier (v1) are the A/D converters (aw1, aw2, aw3), following which the digital processor (dp) is connected; it supplies the digital mass signal (m) and/or the digital density signal (d), as well as the gain control signal (v) for the amplifier (v2).

Abstract: Resonator sensors namely piezoelectric benders are used for sensing fluid viscosity and density. The benders are inserted into a liquid to be monitored. An input voltage is applied to the bender causing it to vibrate in the liquid at a resonant frequency. Output voltage amplitude or frequency are monitored to determine changes in viscosity and density, respectively. The device may be used as a liquid level sensor and to control alteration of the viscosity of the fluid as, for example, by connection with a supply of ink or solvent in an ink jet printing device.

Abstract: A vibration gas density meter provided with a cylindrical resonator, a cylinder block that incorporates the above cylindrical resonator concentrically and has one end of the cylindrical resonator fixed to itself, and a case which concentrically incorporates the above cylinder block and supports both ends of the cylinder block, further comprising first and second elastic elements which are provided between both end faces of the cylinder block and the case respectively, and through which the cylinder block is supported by the case in the direction of cylindrical axis, sealing the gaps between the cylinder block and the case as well, and third and fourth elastic elements which are provided between both parts of the outer cylindrical surface on both end face sides of the above cylinder block and the case respectively and through which the cylinder block is supported by the case in the radial direction, sealing the gaps between the cylinder block and the case as well.

Abstract: A device and a process for measuring resonant frequency and dissipation factor of a piezoelectric resonator are presented. After exciting the resonator to oscillation, the driving power to the oscillator is turned off after the decay of the oscillation of the resonator is recorded and used to give a measure of at least one of the resonators properties, such as dissipation factor, changes in the dissipation factor, resonant frequency and changes in the resonant frequency.

Abstract: A device for continuously measuring the quantity of coal inside a ball grinder including an ultrasound wave or electromagnetic wave emitter and a wave receiver. The emitter and the receiver are disposed so that the wave passes through at least part of the interior of the grinder. The receiver is associated with an electronic circuit for deducing the quantity of coal by comparing the signal received with data obtained from previous calibration measurements.

Abstract: A densimeter is provided that is mounted on the side of a conduit carrying a fluid flow. The densimeter consists of an inlet and an outlet scoop which are immersed into the fluid flow through the conduit. A portion of the fluid flow enters into the first scoop and is directed into the densimeter where the fluid's density is measured and then exits through the exit scoop back into the fluid flow in the conduit.

Abstract: A vibration type measuring instrument measures at least one of density and mass flow rate of a fluid in a straight measurement pipe by vibrating the pipe. The vibration type measuring instrument comprises the pipe; a sensor for detecting the vibration of the pipe; and a signal processing circuit for obtaining the resonant angular frequency .omega. and axial force T based on the detection signal of the sensor, and obtaining the density .rho.w of the fluid flowing through the pipe using the obtained resonant angular frequency .omega. and axial force T. The density .rho.w is obtained by the following equation (E1). ##EQU1## (E: the Young's modulus of the pipe, I: a cross-sectional secondary moment of the pipe, Si: a cross-sectional area of the hollow portion of the pipe, .rho.

Abstract: An ultrasonic fuel-gauging system has a tank with several ultrasonic probes having reflectors spaced along their length. A vibrating cylinder densitometer is located at the bottom of the tank and provides an output to a control unit representative of fuel density at that location. The control unit calculates the speed of sound reflected from the reflector closest to the densitometer and uses this and the density measurement to calculate a fuel constant. The control unit calculates the density of fuel at different heights from the fuel constant and speed of sound measurements from other reflectors. From these density measurements the control unit calculates mean density and fuel mass.

Abstract: The present invention is an ultrasonic fluid densitometer that uses a material wedge and pitch-catch only ultrasonic transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.

Abstract: A resonator (1) is vibrating close to its resonance frequency. The vibration is excited by one or a first transducer (2) connected to an oscillator (11). The vibration is measured by the transducer (2) or a second transducer (3) and stabilized by a phase-locked feedback loop comprising a phase sensitive detector (33), a feedback controller (36), a phase shifter (17) and means (15) to evaluate the measured frequencies. In order to measure the damping of the resonator (1), the phase in the phase shifter (17) is alternately set to two different values. The difference between the frequencies corresponding to these two phase values is a measure for the damping of the system. One or more switches (19, 28, 27) and a gate generator (16) make sure that excitation and measurement do not occur at the same time. Thereby, any cross-talk between driving and sensing transducers is completely eliminated. Also, a single transducer can be used to both excite and measure the vibration.

Abstract: A system for measuring fluid parameters of one or more liquids by an ultrasonic method comprises a voltage controlled oscillator; an ultrasonic resonator comprising one or more resonator cells, each of the resonator cells comprising an electro-acoustical transmitting transducer, an electro-acoustical receiving transducer, and a sample cavity between the transducers, wherein the transmitting transducer is connected to the output terminal of the voltage controlled oscillator; and a phase locked loop circuit comprising one of the resonator cells.

Abstract: A method of compensating for at least one of pressure and density with a Coriolis meter, the meter having two modes of vibration impressed thereon, a fluid in the meter altering the modes of vibration to produce altered modes of vibration. The method includes the steps of: (1) measuring both the altered modes of vibration with a detector circuit at a selected working point and (2) simultaneously solving for the at least one of pressure and density, the at least one of pressure and density directly determined thereby to allow resulting flow-related signals produced by the meter substantially insensitive to a change in the at least one of pressure and density.

Abstract: An apparatus and method for nondestructively measuring a sample of material to determine changes in dynamic Young's Modulus, density, static viscosity, compressive strength and expansion or contraction of a material over a period of time and at substantially constant temperature and pressure. Samples of particular interest are cements and completions gels whose characteristic dynamic Young's Modulus, density, viscosity, compressive strength and expansion or contraction at down-hole conditions are particularly important to the petroleum industry.

Abstract: The precision of phase difference obtained by a phase difference calculating unit is improved by correction through outputs of a frequency ratio calculating unit and a temperature calculating unit considering that the phase or time difference of each output signal of a vibration sensor indicating the mass flow or density of a fluid is a function of the temperature and axial force on a measurement pipe, or that the axial force is a function of the ratio between two resonant frequencies.

Abstract: The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.

Abstract: A viscometer provided with a transducer for converting a viscosity parameter of a fluid into an electrical signal. The transducer comprises a container, provided with a cavity for the fluid to be measured, a support element firmly connected thereto and an oscillatory device, which at one end is firmly attached to the support element and at the other end has an oscillatory body. An oscillation drive coil powered by alternating current and a constant magnetic field device for generating a constant magnetic field are provided for bringing and maintaining the oscillatory body in oscillation. The transducer is provided with a detection device for detecting the oscillation of the oscillatory body. The constant magnetic field device is arranged such that it is not able to come into contact with the fluid to be measured and the constant magnetic field lines generated by said device are directed towards the oscillatory body.

Abstract: A Coriolis effect densimeter which produces density output data of improved accuracy by embodying the principal that the natural frequency of a vibrating tube filled with material decreases with an increase in the material mass flow rate. High accuracy output data is achieved by measuring the density and the mass flow rate of material through the vibrating tube, correcting the measured density to compensate for the effect of the mass flow rate, and correcting the mass flow rate correction of the density measurement for changes due to temperature.

Abstract: The present invention is a method for the non-intrusive determination of average particle velocity and average particle mass density from the mass flux and RMS acceleration in a gas/particle transfer line. The method includes the steps of determining the RMS acceleration of the wall of the transfer line at one or more positions along the length of the transfer line, determining the average mass flux through the transfer line, and from both quantities determining the average particle mass density or the average particle velocity from the RMS acceleration and the average mass flux.

Abstract: A transducer measures density, viscosity, flowrate or suchlike of fluids or flowable solids using a resonator having two vibratile beam elements, one of which is disposed coaxially within the other. The outer element may be a closed tube which forms a chamber around the inner element. A drive and sensor may be disposed on a base which provides a common root for the beam elements.

Abstract: Methods and apparatus are provided for monitoring sliver and yarn characteristics. Transverse waves are generated relative to the sliver or yarn. At least one acoustic sensor is in contact with the sliver or yarn for detecting waves coupled to the sliver or yarn and for generating a signal. The generated signal is processed to identify the predefined characteristics including sliver or yarn linear density. The transverse waves can be generated with a high-powered acoustic transmitter spaced relative to the sliver or yarn with large amplitude pulses having a central frequency in a range between 20 KHz and 40 KHz applied to the transmitter. The transverse waves can be generated by mechanically agitating the sliver or yarn with a tapping member.

Abstract: A measurement system (45) includes a tank (46) having an inlet and outlet (47, 48) through which a sample (49) flows prior and subsequent to measurement. A stirrer (50) disposed near the base of tank (46) maintains a well mixed solution within the tank. Two immersion probes (52, 53) extend downwardly into the tank and include respective support tubes (54, 55) and sensor portions (56, 57). The sensor portions include respective gamma-ray transmission gauges and four pairs of ultrasonic transducers operating at different frequencies. Accordingly, probes (52, 53) allow the measurement of attenuation and velocity of high and low frequency ultrasound through the sample as well as measurement of attenuation of electromagnetic radiation through the sample. These measurements are utilized to derive an estimate of the solute concentration, particle size distribution, concentration of solids and suspension and the solute concentration of the sample.

Abstract: Volume of a working liquid in a sensing chamber is measured via a first mechanical resonance frequency. A second resonance may be measured to discriminate interacting volume and density effects, yielding corrected volume, density, and liquid mass. A probability of bubbles present in the liquid is indicated by an abnormal combination of first and second resonances. Determination of a frequency and an associated phase angle near a resonance may be used to discriminate interacting volume and viscosity effects, yielding corrected volume and viscosity. One boundary of the sensing chamber is a deformable plate, which may be rippled to increase the range of linear volumetric compliance. A second boundary paralleling the plate captures a thin variable-thickness fluid layer. Vibrations in the plate cause amplified fluid vibrations parallel to the plate surface, causing a high, thickness-sensitive fluid inertia that lowers plate resonance frequencies in a volume-sensitive manner.

Abstract: A sensor device has a quartz tuning fork and an analysis circuit arranged on a common board inside a common housing. The quartz tuning fork has its own, second housing within the common housing for acoustically decoupling the tuning fork from the analysis circuit. The second housing also has an opening for equalizing the pressure and temperature between the second housing and the rest of the common housing. The analysis circuit, which is connected via the electrical wires to the quartz tuning fork, performs linearization, signal amplification and elimination of environmental influences on the signals emitted by the quartz tuning fork. The signals processed by the analysis circuit are further transmitted via common housing's electrical contacts to external elements. Because of the physical proximity of the quartz tuning fork and the analysis circuit, interference attributable to electrical connections between the two elements is minimized.

Abstract: An apparatus for determining the density of liquids and gases from the length of a period of an oscillator filled with a test sample, an oscillation amplifier being provided for its excitation which excites the oscillator in its mechanical resonance frequency via one or a plurality of actuators and which emits a periodic electrical signal, the period of which corresponds with the period of the oscillator or a multiple thereof. To make highly accurate measurements possible it has been provided that the actuators are disposed between the installation site of the oscillator or the housing of the oscillator rigidly connected with the installation site, and a countermass. In an alternative embodiment, the oscillator housing is eliminated so that the actuator or actuators are interposed directly between the oscillator and the countermass. A thermostatically-controllable plate and thermostatically-controllable elements may be used as in the previous embodiment.

Abstract: Several Radial Mode Coriolis mass flow rate meter geometries and electronic circuits are described that may be made to be sensitive to pressure or density changes. In one embodiment, the meter comprises: (1) a flow conduit for containing a fluid having a physical characteristic, the fluid adapted to flow in the conduit at an unknown rate, (2) a drive circuit for creating a vibration in the flow conduit, the fluid altering the vibration as a function of the physical characteristic and the flow rate, (3) a detector circuit for measuring the altered vibration at a working point and producing a signal representing an uncompensated mass flow rate of the fluid and (4) a computation circuit for calculating a compensated mass flow rate of the fluid proportional to the uncompensated rate by 1/.OMEGA.1.sup.n, where .OMEGA.1 is a driven natural frequency of the flow conduit and n is a number chosen as a function of the working point, the compensated rate thereby reduced of effects of the physical characteristic.

Abstract: A density measuring device having a float with a marker provided therein that is connected by a pair of springs to each of the two supports which are on opposite sides of the float along a guide. A sonic waveguide arrangement is provided extending along this guide past at least one of the supports which can measure the relative positions of the float to thereby determine the effective buoyant force on the float and so the density of the fluid in which the float is submerged. Use of a further float permits determining fluid levels.

Abstract: An apparatus measures the mass of a tube and liquid contained in the tube. A stiff beam is fixed at one end and connected to the tube with a magnet thereon. An electric circuit generates a current pulse which vibrates the beam and tube and induces a natural response therein. Movement of the magnet on the beam induces a current in the circuit with the induced current having a frequency of oscillation equivalent to the natural frequency of vibration of the tube and liquid in the tube. The electric circuit includes a comparator and a counter, with the comparator receiving the current induced by movement of the magnet and supplying a pulse signal to the counter having a period equal to the period of oscillation of the beam and the tube. The counter triggers the generation of an additional current pulse after a predetermined number of cycles of the induced current are counted. The current pulses are generated at a frequency lower than the frequency of the natural vibratory response of the beam and the tube.

Abstract: A density sensor comprises a cavity arranged to receive the gas whose density is to be sensed. The cavity is divided into two chambers by a flexibly mounted diaphragm. A piezoelectric excitation device at one end of the cavity is used to excite the gas in the cavity into resonant vibration in a mode having an anti-node at the diaphragm, which causes the diaphragm to vibrate with the gas. Another piezoelectric device senses the vibration, whose frequency is a function of the known mass of the diaphragm and the density and speed of sound in the gas. This last parameter can be sensed by exciting the gas in the cavity into resonant vibration in a second mode having a node at the diaphragm, so that the diaphragm does not take part in the vibration. Alternatively, it can be sensed by providing a second cavity, also arranged to receive the gas but not having a diaphragm, and resonantly vibrating the gas in the second cavity.

Abstract: A fluid densitometer is constructed using loudspeaker technology. The loudspeaker diaphragm carries a fluid sample chamber. The increased mass loading causes a shift in resonant frequency of the loudspeaker when driven in positive feedback. With suitable calibration the shift in frequency provides a measure of the density of the fluid sample. In a modification, two loudspeakers are mounted back to back with the opposing diaphragms defining a sample chamber.

Abstract: An ultrasonic viscometer and method for measuring fluid viscosity are provided. Ultrasonic shear and longitudinal waves are generated and coupled to the fluid. Reflections from the generated ultrasonic shear and longitudinal waves are detected. Phase velocity of the fluid is determined responsive to the detected ultrasonic longitudinal waves reflections. Viscosity of the fluid is determined responsive to the detected ultrasonic shear waves reflections. Unique features of the ultrasonic viscometer include the use of a two-interface fluid and air transducer wedge to measure relative signal change and to enable self calibration and the use of a ratio of reflection coefficients for two different frequencies to compensate for environmental changes, such as temperature.

Abstract: An instrument for the detection or measurement of attributes of a material comprises at least one vane which is mounted on a support that allows the vane to vibrate, a drive transducer which is disposed relative to the vane to stimulate vibration therein and at least one sensing transducer disposed to sense the vibrations.

Abstract: An apparatus for determining the time taken for sound energy to cross a body of fluid in a pipe uses a modified pipe in which flat members seal apertures in the pipe and two transducers are attached to respective fiat members, wherein the material around each aperture curves away from the centre of the pipe towards the periphery of the aperture and contacts the respective flat member along the entire periphery of the aperture.

Abstract: The specific gravity or solute concentration of a process fluid solution located in a selected structure is determined by obtaining a resonance response spectrum of the fluid/structure over a range of frequencies that are outside the response of the structure itself. A fast fourier transform (FFT) of the resonance response spectrum is performed to form a set of FFT values. A peak value for the FFT values is determined, e.g., by curve fitting, to output a process parameter that is functionally related to the specific gravity and solute concentration of the process fluid solution. Calibration curves are required to correlate the peak FFT value over the range of expected specific gravities and solute concentrations in the selected structure.

Abstract: A sensing element and system for determining the density of fuel housed in the tank of an aircraft, includes sensing element (10). The sensing element has a disc shaped member (20) extending through a wall (16) of the sensor body. The sensor body also encloses a chamber (14) containing dry nitrogen at a pressure of one atmosphere. Electromagnetic driving coils (24) are electrically actuated to cause member 20 to vibrate in its resonant frequency in four quadrants with a node along an axis (22) corresponding to the wall of the sensor and a second node axis (42). Pickup coils (26) in the sensor body sense displacement of the disc shaped member in a location of maximum displacement. Fluid surrounding the sensing element causes mass loading of the exposed portion of the disc shaped member and changes its resonant frequency. The changes in resonant frequency along with values determined through calibration are used by a processor (44) to calculate the density of the fluid.

Abstract: A device for determining the density of liquids and gases uses an actuator to physically excite a sample of the material being tested. The oscillations induced by this excitation are detected by a sensor and amplified by an oscillation amplifier, and the amplified signal is used to drive the actuator in a closed-loop fashion. To compensate for errors in the density measurement process arising from non-ideal viscous effects of the sample, a phase change circuit or inverter may be shunted into the amplifier circuit to change the phase of the excitation signal. By observing the effects of the excitation phase change on the oscillation frequency of the sample, the sample's viscosity can be measured, and the system can compensate for its effects.

Abstract: An aerosol sampler comprises at least one U-tube whose ends are fixed to a support, and through which the aerosol is caused to flow. Means are provided to set the tube vibrating, and to measure its resonant frequency. The bend of the U-tube acts as an impactor so aerosol particles larger than a cut-off size are trapped, causing a change in the measured frequency. A sampler may include a number of such U-tubes in series, with steadily decreasing cut-off sizes, so the aerosol particulate size distribution can be determined.

Abstract: A sensor, for use in determining physical properties of fluid, comprises a flexible diaphragm having a plane. Two tines depend from the diaphragm substantially at right angles to the plane. First and second substantially planar transducers are each bonded to the diaphragm so that the plane of the transducers are parallel to that of the diaphragm. A first one of the transducers is operative, in use, to flex between in its plane and to couple an alternating driving force into the plane of the diaphragm such that the tines vibrate in an oscillatory motion. Second of the transducers is operative to detect vibrations of the diaphragm.

Abstract: A Coriolis effect densimeter which produces density output data of improved accuracy by embodying the principal that the natural frequency of a vibrating tube filled with material decreases with an increase in the material mass flow rate. High accuracy output data is achieved by measuring the natural frequency of the tube as material flows therethrough, correcting the measured frequency to compensate for the decrease in natural frequency caused the material flow (mass flow rate) and using the corrected natural frequency in the material density computation.

Abstract: A method and apparatus for non-intrusively identifying a property of a fluid in a container or pipe. The method includes propagating, from a transmitter, sonic energy into the fluid in the container; receiving the sonic energy at a reception site after a defined time delay determined by the nature of the fluid in the container; determining the time for the sonic energy to propagate from the transmitter to the reception site; determining the sonic propagation velocity of the sonic energy in the fluid from the determined time and from knowledge of the distance from the transmitter to reception site; determining the temperature of the fluid in the container; and determining the fluid property from the relationship between the sonic propagation velocity in the fluid and temperature. The properties determined may include viscosity and density, and if the fluid is known, pressure. Additionally, if the fluid is unknown, but known to be one of a number of fluids, the identity of the fluid can also be determined.

Abstract: A density measuring device having a float with a marker provided therein that is connected by a pair of springs to each of the two supports which are on opposite sides of the float along a guide. A sonic waveguide arrangement is provided extending along this guide past at least one of the supports which can measure the relative positions of the float to thereby determine the effective buoyant force on the float and so the density of the fluid in which the float is submerged. Use of a further float permits determining fluid levels.

Abstract: A mass flow meter for flow media which works primarily on the Coriolis Principle has a pipe inlet, a straight pipe carrying the flow medium, a pipe outlet, an oscillation generator operating on the pipe and two transducers detecting preferably Coriolis forces and/or Coriolis oscillations affecting Coriolis forces. The flow meter has a relatively low natural frequency at a certain layout length or a relatively short layout length at a certain natural frequency, and in this way, the oscillation generator engages the pipe via an articulated arm so that the conduit is excited to torsional and bending vibrations.

Abstract: A process for monitoring fluid density by use of a fluidic jet oscillator (26) absent the necessity for a high-precision pressure regulator. Fluid is delivered to the fluidic oscillator (26) via a pressure divider (28). As the fluid flows through the oscillator the latter generates a pressure wavetrain at a frequency which is indicative of the density of the fluid, but is inaccurate to the extent that the pressure difference across the oscillator varies from a predetermined value. A differential pressure transducer (30) senses the pressure difference. Accordingly, the process is adapted for use with a gated sampling and control system (84) which operatively responds to the oscillator output only when the differential pressure is substantially in accord with a predetermined value thereof.

Abstract: A flexural acoustic wave sensing method and efficient, simple, miniature and economical ultrasonic devices using thin rods are presented. The diameter of the thin rod is less than one acoustic wavelength. The lowest order flexural acoustic wave, F.sub.11 mode, propagating along such thin rods is used. The thin rod materials can be metals, glasses, ceramics, polymers and single crystals. Any external disturbance which can alter the propagation characteristics of F.sub.11 mode may be monitored by recording such variation. Fiber acoustic interferometers, which are built by jointing two thin rods, can offer high sensitivity. These devices are primarily used for sensors.

Abstract: A measuring apparatus uses a fixed frequency oscillator to measure small changes in the phase velocity ultrasonic sound when a sample is exposed to environmental changes such as changes in pressure, temperature, etc. The invention automatically balances electrical phase shifts against the acoustical phase shifts in order to obtain an accurate measurement of electrical phase shifts.

Abstract: A method, using a quartz crystal microbalance, to obtain simultaneous measurement of solid mass accumulation and changes in liquid density-viscosity product. The simultaneous real-time measurements of electrical parameters yields that changes in surface mass can be differentiated from changes in solution properties. Two methods to obtain the admittance/frequency data are employed.

Abstract: A viscosity measuring transducer especially useful for process control of fluids. The transducer oscillates an immersed blade sensor in the direction of the plane of the blade in order to maximize generation of shear waves and to minimize generation of compression waves. The transducer includes a bar which penetrates and is secured and peripheral sealed to an isolation plate which serves to protect the oscillation driver and pickup adjacent one end of the bar from the sensor blade to be immersed in a fluid adjacent the other end of the bar. Either the bar is relatively rigid and the isolation plate is relatively compliant, or vice versa. In the former case the isolation plate acts as an intrinsic flexible member of the oscillating system of the transducer; and in both cases the isolation plate constitutes a strong impermeable seal between the fluid and the driver/pickup mechanism.

Abstract: Solid-state acoustic sensors for monitoring conditions at a surface immersed in a liquid and for monitoring concentrations of species in a liquid and for monitoring electrical properties of a liquid are formed by placing interdigital input and output transducers on a piezoelectric substrate and propagating acoustic plate modes therebetween. The deposition or removal of material on or from, respectively, a thin film in contact with the surface, or changes in the mechanical properties of a thin film in contact with the surface, or changes in the electrical characteristics of the solution, create perturbations in the velocity and attenuation of the acoustic plate modes as a function of these properties or changes in them.