Abstract: 22A temperature and/or pressure compensated microbalance is disclosed. Temperature compensation is achieved by applying heat to at least a part of the microbalance, measuring a temperature-dependent variable, and controlling the amount of heat applied to the microbalance to keep the temperature-dependent variable substantially constant. In one embodiment, the heat is applied to the microbalance by passing electrical current through a resistive element provided on or embedded in the oscillating element of the microbalance. Pressure compensation is achieved by taking into account the variation in the mass or density of fluid passing through the microbalance. Various materials and methods of construction are also disclosed, including micro-machining and electroforming.

Abstract: An ultrasound device having a transducer propagating and receiving sound signals to/from a blood vessel of a person being examined for caisson's disease where the blood vessel is at above normal surface atmospheric pressure and a controller determining onset of the caisson's disease by analyzing the received sound signals from the transducer to determine presence of naturally occurring bubbles in the blood vessel during decompression of the blood vessel.

Abstract: Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble.

Abstract: A bubble detector utilizes an ultrasonic transducer to sample bubbles as they pass the transducer. The envelope of the return signal is analyzed to determine the volume of each sampled bubble. If the total volume of bubbles sampled within a certain period of time exceeds a desired maximum volume, the bubble detector may initiate a system shut down. A bubble detector can be evaluated or calibrated by introducing bubbles into a conduit, detecting the bubbles introduced into the conduit using visual inspection or a bubble detector of known resolution and comparing the results with the examination of a bubble detector under evaluation.

Abstract: A method and an apparatus are provided for measuring the amount of entrained gases in a liquid sample. A conduit defining a volume is provided. The conduit has an inlet at a lower end thereof and an outlet at an upper end thereof. Liquid sample is made to flow into the inlet, through the conduit, and out of the outlet. The weight of the liquid sample in the conduit is determined during a flow of liquid sample through the conduit to obtain a first measurement. Thereafter, a difference between the first measurement and a predetermined weight value representing a weight of the same liquid sample flowing through the conduit but containing no entrained gases is determined to obtain a calculated weight of entrained gases in the liquid sample flowing through the conduit.

Abstract: A sealant stream anomaly detecting assembly for detecting anomalies such as gas bubbles in a high-pressure sealant stream. The assembly includes an ultrasonic transducer supported on a manifold defining a sensing chamber of a fluid channel. The transducer converts electrical voltage pulses into ultrasonic acoustic pulses and propagates the acoustic pulses through the manifold and into the sensing chamber. The transducer also receives resulting echo pulses from a back wall of the sensing chamber and converts the echo pulses into electrical output impulses. A control module including drive electronics is connected to the transducer. The module detects diminished and lost echo pulses by comparing the output impulse strength values for a given fluid passing through the sensing chamber to a known output impulse strength value for that same type of fluid having no anomalies.

Abstract: Volume measuring apparatus is used in a closed space as in the case of volume measurement of liquid in a container placed on an orbit of an artificial satellite and permits the volume measurement in a state without mixture with gas, liquid, or solid. A volume measuring apparatus is an apparatus for measuring the volume of liquid or solid under microgravity, which has two or more containers coupled to each other by a pipe, a device for separating or fixing a gas phase, a liquid phase, or a solid phase, a pressure fluctuation source, a pressure signal receiver, a pressure gage, and a thermometer, wherein the separating or fixing device, the pressure fluctuation source, the pressure signal receiver, the pressure gage, and the thermometer are placed in the containers and wherein the pressure fluctuation source, the pressure signal receiver, the pressure gage, and the thermometer are connected to a signal analyzing unit.

Abstract: A low voltage, low current apparatus for detecting discontinuities, such as bubbles, in a fluid stream, in which a tube is placed between a transducer transmitting successive bursts of ultrasonic energy and for receiving the bursts. The receiving transducer is connected to a low current transistor amplifier circuit of a signal processing circuit which keeps an output in a first state when signals are received corresponding to the presence of a fluid and in a second state when the bursts of energy are modified by the discontinuity.

Abstract: An air in-line sensor 10 for detecting air bubbles in a therapeutic solution flowing through a tube 12 utilizes a unitary type sensor having a channel 16 for receiving the tube 12. The channel 16 has a tube loading section 18. A signal emitting member 20 is positioned on one side of the tube 12 and a signal receiving member 22 is positioned on an opposite side of the tube 12. A first air baffle 24 is positioned between the signal emitting 20 and signal receiving members 22.

Abstract: A cavitation sensor includes an ultrasonically absorbent coating (20) disposed around a piezoelectric element (30) and a conduit (25). The conduit (25) includes a boundary delimited by the piezoelectric element (30), while the ultrasonically absorbent coating (20) is substantially transparent to acoustic driving field frequencies. The sensor is more accurate than prior art sensors.

Abstract: A system and method of fluid analysis in a hydrocarbon borehole is disclosed. Acoustic energy is emitted into the production fluid downhole at a level which causes a phase transition in the fluid. The pressure associated with the phase transition is determined using the level of emitted acoustic energy. Advantageously, the determination of the phase transition pressure need not rely on mechanical means to substantially alter the volume of a sample of the fluid. An acoustic transducer can be installed either semi-permanently or permanently downhole in the well. The bubble point or the dew point can be detected. In the case of bubble point detection, the bubbles in the fluid can be detected by sensing variations in impedance of the acoustic transducer, and the level of emitted acoustic energy can determined by measuring the electrical energy used to drive the transducer. A control system for a hydrocarbon well is also disclosed.

Abstract: Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble.

Abstract: Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble.

Abstract: Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble.

Abstract: A bubble detector utilizes an ultrasonic transducer to sample bubbles as they pass the transducer. The envelope of the return signal is analyzed to determine the volume of each sampled bubble. If the total volume of bubbles sampled within a certain period of time exceeds a desired maximum volume, the bubble detector may initiate a system shut down. A bubble detector can be evaluated or calibrated by introducing bubbles into a conduit, detecting the bubbles introduced into the conduit using visual inspection or a bubble detector of known resolution and comparing the results with the examination of a bubble detector under evaluation.

Abstract: The ultrasonic sensor comprises an ultrasonic transmitter (11) and an ultrasonic receiver (12) between which an accommodating device (13) for a hose (14) is arranged. The hose is flattened between stamps (21, 22) thus being pressed against rigid concave forming areas (15, 16) where the hose bears in a gap-free manner upon the housing wall (17). The sound velocity in the housing (10) is approximately as large as in the material of the hose (14). In the liquid contained in the hose the sound velocity is considerably smaller. Parallel sound waves are refracted at the interface between hose material and liquid such that the sound waves converge. By concentrating the sound energy into the hose and onto the ultrasonic receiver (12) a high-energy received signal is generated. When air bubbles exist in the liquid, the received signal is attenuated.

Abstract: Method and apparatus are provided for a non-invasive bubble measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as bubbles over a selectable range of bubble sizes of interest. A selected measurement volume in which bubbles may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite bubbles to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which bubbles may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant bubble.

Abstract: A method is provided for analyzing suspended particulate and liquid medium in a fluid stream by transmitting acoustic signals into the fluid, detecting scattered acoustic energy, and determining a parameter related to the density and compressibility of the fluid. In one embodiment, the fluid analysis tool comprises two transmitting transducers intermittently emitting acoustic signals, and two receiving transducers being differently azimuthally positioned with respect to the transmitters. The ratio of the amplitude of scattered signals measured by the two receivers as a result of emission from the first and second transmitters are used to calculate the parameter. In another embodiment, a tool comprising one transmitter and at least three receivers with azimuthal angles in both forward and backward scattering regions with respect to the incident wave is disclosed. The scattering signal amplitudes normalized by the amplitude from one of the receivers is used to identify and monitor the system.

Abstract: There is provided a double-headed mass sensor (25) in which between a first connecting plate (22A) joined to a first diaphragm (21A) at respective sides and a second connecting plate (22B) joined to a second diaphragm (21B) at respective sides, a first sensing plate (41A), on which a main element (44) is provided on at least one plane surface, is bridged, and a resonating portion comprising the diaphragms (21A), (21B), the connecting plates (22A), (22B), the first sensing plate (41A) and the main element (44) is joined to a sensor substrate (27). Change in the mass of each of the diaphragms (21A), (21B) is measured by measuring change in the resonant frequency of the resonating portion accompanying the change in the mass of the diaphragms (21A), (21B). The mass sensor of the present invention enables the easy and highly accurate measurement of a minute mass of a nanogram order including microorganisms such as bacteria and viruses, chemical substances, and the thickness of vapor-deposited films.

Abstract: Provided are a measurement apparatus and a measurement system comprising sample and reference microresonators, such as sample and reference quartz crystal microbalances; sample and reference heat flow sensors; and a heat sink coupled thermally to the heat flow sensors. These may be used to measure changes in one or more properties, such as mass, due to a liquid sample on a surface of a sample microresonator and also to measure heat flows from the sample on the surface of the sample microresonator by utilizing the heat flow sensors, which are coupled thermally to the corresponding sample or reference microresonators. Also provided is a method for measuring one or more properties, such as mass, of a liquid sample and the flow of heat from the sample to the heat sink by utilizing such apparatus.

Abstract: A surface acoustic wave device sensor configured so as to have at least two different modes of operation. An acoustic response is obtained from each of the different modes of operation. The different modes of operation are a combination of a temperature effect and a measurand effect. The measurand effect is caused by the absorption and/or adsorption of a substance into a selective coating on the piezoelectric substrate. The two different modes of operation are effected differently by the temperature effect and therefore can be used to effectively eliminate the temperature effect by simultaneously solving equations representative of the different modes of operation. The present invention eliminates the need to provide other relatively more complicated temperature compensating structure or to maintain the device at a predetermined constant temperature. The present invention can be used to detect different chemicals or substances.

Abstract: An apparatus for detecting gas bubbles, in a liquid flow, comprises a one-piece housing (1) of a material that is transmissive to ultrasound, a liquid passage (2) extending through the housing (1), inlet and outlet means on the housing (1) for connecting the liquid passage (2) to the liquid flow, and ultrasonic transducer means (3, 4) on the housing on each side of the liquid passage (2), one transducer means being arranged as sender and the other transducer means being arranged as receiver, with the liquid passage (2) positioned in the sound transmission path between the sender and the receiver, whereby inhomogeneities in the liquid flow can be detected based on the emitted ultrasound energy that is received by the receiver. The housing (1) has two opposed recesses (6, 7), one on the sender side of the liquid passage (2) and one on the receiver side thereof, which recesses in a direction perpendicular to the sound transmission path as well as to the liquid passage.

Abstract: Provided are a measurement apparatus and a measurement system comprising sample and reference microresonators, such as sample and reference quartz crystal microbalances; sample and reference heat flow sensors; and a heat sink coupled thermally to the heat flow sensors. These may be used to measure changes in one or more properties, such as mass, due to a liquid sample on a surface of a sample microresonator and also to measure heat flows from the sample on the surface of the sample microresonator by utilizing the heat flow sensors, which are coupled thermally to the corresponding sample or reference microresonators. Also provided is a method for measuring one or more properties, such as mass, of a liquid sample and the flow of heat from the sample to the heat sink by utilizing such apparatus.

Abstract: Apparatus and method for detecting the dew point or bubble point phase transition in fluid. The apparatus used comprises a piezoelectric crystal sensor and a signal analyser. The phase transition of the fluid is measured by monitoring, directly or indirectly, change in the resonant frequency of the piezoelectric crystal sensor while said one of the temperature and pressure is varied, so as to detect a substantial change in said resonant frequency and/or in the rate of change in resonant frequency with change in the varying one of the temperature and pressure.

Abstract: An ultrasonic transmitter, particularly for an air bubble detector, having a transmitting stage and an ultrasonic crystal. The transmitting stage includes a multivibrator having a time-base circuit with two stable output states. A timing element is interconnected in the feedback loop of the time-base circuit. An ultrasonic crystal is interconnected with the feedback loop of the time-base circuit so that the electrical circuit oscillates at or near a resonance frequency of the ultrasonic crystal. The ultrasonic crystal may be disconnected so that the multivibrator oscillates automatically at its own natural frequency.

Abstract: Provided is a mass and heat flow measurement apparatus comprising sample and reference microresonators, such as sample and reference quartz crystal microbalances; sample and reference heat flow sensors, such as sample and reference isothermal heat conduction calorimeters; and sample and reference heat sinks coupled thermally to the heat flow sensors. The apparatus may be used to measure changes in mass due to a sample on a surface of the sample microresonator and also to measure heat flows from the sample on the surface of the sample microresonator by utilizing the heat flow sensors, which are coupled thermally to the corresponding sample or reference microresonators. Also provided is a method for measuring the mass of a sample and the flow of heat from the sample to the heat sink by utilizing such apparatus.

Abstract: A vapor recovery system is disclosed that utilizes a crystal oscillator for sensing the presence of hydrocarbon in the vapor emissions emanating from a fuel tank during refueling. The crystal oscillator is coated with a layer of material having a sensitivity for hydrocarbon. In response to any interaction between the coating layer and hydrocarbon, the crystal oscillator experiences a shift in its oscillation frequency relative to the fundamental resonance frequency. The frequency shift is representative of the hydrocarbon concentration in the vapor emissions. A control signal based on the frequency shift is generated and then used to adjust the operating speed of the vapor pump.

Abstract: An improved method of fluid analysis in the borehole of a well. A fluid sampling tool is fitted with a pumpout module that can be used to draw fluids from the formation, circulate them through the instrument, and then expel this fluid to the borehole. It has been determined that certain measurements would be most valuable to implement down hole, such as the formation fluid bubble point and dew point. Accurate bubble point and dew point measurements are made by forming bubbles or a liquid drop in a measured sample, and detecting same.