Abstract: A clamp-on ultrasonic measurement system for a gas or other fluid typically of low acoustic impedance such as low pressure steam or flare gas. The system includes a first ultrasonic signal transducer which clamps to the conduit, and a second ultrasonic signal transducer clamped on the conduit across from the first transducer. Each transducer is operated to transmit to, and receive from, the other along contrapropagation signal paths. The transducers generate a shear wave signal that skips within the conduit wall to coherently energize a region of the wall and launch ultrasonic signal energy at a defined angle across the direction of flow. The receiver is symmetrically arranged and positioned to respond to signal energy received along the path through the fluid.

Abstract: A clamp-on ultrasonic flowmeter has a pair of ultrasonic transmitting-receiving devices which are placed on a pipe in which a liquid flows. Each device is composed of a composite of a ultrasonic transducer and a ultrasonic propagating element which propagates ultrasonic wave transmitted by the transducer predominantly in the direction perpendicular to a plane of the transducer (which is arranged at an acute angle from the center line of the pipe), and a ultrasonic propagating layer placed between the ultrasonic propagating element and the pipe. The ultrasonic propagating layer has a viscosity of 0.5×10−3 to 3×10 Pa.sec at 25° C. and a rate of sonic propagation in terms of V1 at 25° C. satisfying the condition of 0.5<V1/V2<1.7 in which V2 represents a rate of sonic propagation of material of the pipe at 25° C. Otherwise, the ultrasonic propagating layer has a rate of penetration of needle in the range of 10 to 300 at 25° C.

Abstract: A low profile transducer (11, 12) is provided for use in flow meter for pipes of small diameter. The transducer (11, 12) has a transducer (18) or other form of transducer which transmits and receives electrical signals of three volts and 1 MHz and converts between these electrical signals and acoustic waves. In one embodiment, the transducer (18) produces surface acoustic waves (SAW), while in another embodiment the transducer (32) produces plate waves known as Lamb waves. These waves are converted to bulk acoustic waves (BAW) transmitted between the pair of transducers (11, 12).

Abstract: An ultrasonic fluid flow meter (50) measures the flow speed of a fluid by measuring the time, in each direction, for a sequence of ultrasonic pulses (55) to pass between two transducers (54A,54B) positioned in a measuring tube (52) in the fluid flow path. The second and subsequent transmit pulses of each sequence are caused to start by the arrival of its predecessor at the detector end of the measuring tube. A first transmit pulse calculates a delay (110) to a zero crossing which is used to identify a particular zero crossing at which the arrival of each pulse in the sequence is determined.

Abstract: The present invention provides an ultrasonic transducer having uniform characteristics. Because the characteristics of a pair of ultrasonic transducer are equalized with each other, measuring accuracy of an ultrasonic flowmeter can be improved. Electrical connection from an electrode surface 13 of a piezoelectric body 11 to an external electrode is achieved not by soldering but by an electroconductive elastic body 16. As a result, variations of the frequency characteristics due to thermal load on the piezoelectric body 11 can be reduced, and this makes it possible to obtain an ultrasonic transducer with uniform characteristics, and measuring accuracy of an ultrasonic flowmeter using a pair of the ultrasonic transducer can be improved.

Abstract: A multiphase flow meter is presented based on distributed sensors that provide data pertaining to temperature, pressure, phase fraction, speed of sound, and bulk velocity. The data is provided to a model that calculates the multiphase flow rates. The sensors are comprised of various combinations of temperature and pressure sensors combined with speed of sound and/or bulk velocity sensors and are distributed at various axial positions along an oil production pipe. In one embodiment the sensors comprise Bragg grating based optical sensors.

Abstract: An acoustic gas meter has an acoustic transmitter/receiver arrangement disposed within a gas flow conduit for transmitting and receiving acoustic energy along an acoustic path. A temperature probe has an elongate sensor region disposed relative to, preferably along, the acoustic path to provide a measure of a gas temperature indicative of an average gas temperature within the acoustic path.

Abstract: Acoustic flow meters are used for the measurement of flow velocity of fluids. They have particular application in meters for gas and water in pipelines. The meter includes a tube fitted with three or more acoustic transducers distributed along its length and arranged to transmit wave packets up and down between at least two pairs of the acoustic transducers. The wave packets comprise a signal including zero crossings spaced apart by a packet period determined by a known packet frequency. The flow meter also includes measurement means associated with the transducers to make first measurements of received packets, from which the time of arrival of the zero crossings of a received packet can be determined relative to the time of transmission of the packet. A second measurement from which a particular zero crossing in the transmitted packet can be identified in the received packet. And calculation means to determine the velocity of fluid flow in the tube using the measurements.

Abstract: An ultrasonic flowmeter for measuring fluid flow are disclosed. The invention combines isolating conditioner technology with ultrasonic technology to determine flow velocity. The method and apparatus of the invention does not require the use of integration techniques or the prior determination of flow swirl or asymmetry to achieve accuracy. The performance of this novel flowmeter exceeds the performance of current ultrasonic flowmeters by an order of four to twelve times and offers significant savings in manufacturing and maintenance costs. The disclosed flowmeter also has self-diagnostic capabilities.

Abstract: Transmitting and receiving circuit for an ultrasonic flowmeter, comprising at least two ultrasonic transducers arranged for the transmission and receipt of ultrasonic signals in opposite directions across a measuring distance, a signal source for controlled production of electrical signals for transmission to the ultrasonic transducers and detection means for deriving transmission time measurements, used to calculate the flow, measuring of which is desired. The transmitting and receiving circuit includes an amplifier with a first inverting input terminal for connection to an ultrasonic transducer, a second non-inverting input terminal for connection to the signal source, an output terminal for connection with the detection means, and a feedback connection between the output terminal and the first input terminal.

Abstract: Illustrated and described is an ultrasonic flowmeter for flowing media, that operates according to the transit time method, with a measuring tube and at least one transmitting and/or receiving head, in connection with which the transmitting and/or receiving head has a housing and an ultrasonic transducer with which ultrasonic signals can be emitted into the flowing medium and ultrasonic signals can be received from the flowing medium. The ultrasonic flowmeter for flowing media is characterized in that a damping device with at least one damping element is arranged around the sides of the housing of the transmitting and/or receiving head and at least partly adjacent to it, and the damping device is provided in a recess of the measuring tube.

Abstract: An apparatus for measuring the discharge of a liquid, in particular urine, from a patient. The apparatus includes a measuring container (1), means (H) for applying a first acoustic signal to the liquid-empty part of the measuring container (1), means (H) for recording a second acoustic signal generated in the measuring container (1) in response to the first signal, means (45) for determining a current liquid amount in the measuring container (1) on the basis of the second acoustic signal. The measuring container (1) has a measuring pipe (5) defining a liquid-empty resonance chamber for generating the second acoustic signal.

Abstract: A time-of-flight flow sensor, of the type in which a measured phase difference between upstream and downstream acoustic propagations is representative of fluid flow rates, is operated at two distinct frequencies. Operation at a relatively low propagation frequency yields a first phase difference signal that is unambiguously representative of the rate of flow but that has a larger than desired measurement error. Operation at the higher frequency provides a lower measurement error, but may be ambiguous because of the modular nature of phase detectors. The low frequency phase difference signal can be used by a signal processor to determine a compensation term that can be combined with the higher frequency phase difference signal to remove the phase detector ambiguity, if one is present.

Abstract: An apparatus and process for using ultrasound to measure speed and acceleration in fluids is provided. Three preferred embodiments are disclosed. The first preferred embodiment measures fluid velocity, such as, for example, wind, under standard atmospheric pressure-temperature. The second preferred embodiment measures gas velocity, such as, for example, wind, affected by and automatically calibrates for pressure-temperature. The third preferred embodiment measures gas density, such as, for example, density altitude. Applications of the invention include wind direction and speed calculation in agriculture, aviation, hydraulics, and other industries. One of the advantages provided by the invention is there are no moving parts in making such measurements.

Abstract: An ultrasonic-wave propagation time measuring method which enables determination of accurate propagation time, a gas-pressure measuring method, a gas-flow-rate measuring method, and a gas sensor. A reception wave which has been transmitted and received by an ultrasonic element 5 is shaped and integrated by an integration circuit 67 to obtain an integral value. A peak value of the integral value is held by a peak-hold circuit 39. As to detection of gas concentration, a resistance-voltage-division circuit 41 sets a reference value on the basis of the peak value, and a point in time when the integral value of the reception wave is judged by a comparator 43 to have reached the reference value is regarded as an arrival time. Subsequently, a gas concentration is detected on the basis of a period between the emission time and the arrival time.

Abstract: A procedure for detecting microparticles released by at least one dispenser, encompassing the following steps: (a) triggering the dispenser over an oscillation target (20) with a sensor material (21), so that at least one microparticle hits the sensor material (21) and excites an acoustic wave, (b) detecting the acoustic wave with at least one oscillation sensor (31) connected with the sensor material (21), which emits an electrical sensor signal when the acoustic wave arrives, and (c) evaluating the sensor signal to determine the impact of the microparticle. The procedure is aimed at detecting the impact and/or impact positions of microparticles on a target. A detector for executing the procedure is also described.

Abstract: A body for a flow meter for measuring the flow velocity and/or the volumetric through-flow of fluids. The flow meter body has a tubular center piece with connecting flanges for connection to a pipeline for fluids. On its exterior, the center piece has at least two substantially flat mounting surfaces (18, 20, 22, 24), each of which has at least one receptacle (32, 34; 38, 40, 42, 44) for mounting a probe (35). To enable the use of linearly emitting ultrasound probes in such flow meters, and to use the flow meter as a substitute for prior art flow meters without significant effort and cost, it is proposed to arrange the mounting surfaces (18 and 20; 22 and 24) diametrically opposite each other as a mounting surface pair (18-20; 22-24) so that the probes (35) in the opposing mounting surfaces (18 and 20; 22 and 24) define a measuring path (36, 46, 48). The mounting surfaces (18 and 20; 22 and 24) are parallel to each other and at an angle to a longitudinal axis (26) of center piece (12).

Abstract: Some techniques for monitoring health of a vessel include attaching a sensor suite of one or more sensors to an outer skin of the vessel and providing power for the sensor suite based on a temperature difference between a fluid temperature of a contained fluid inside the vessel and an ambient temperature outside the vessel. Some techniques include attaching a sensor suite by cinching a belt around the vessel and causing two ends of a strain gauge in the sensor suite to become rigidly attached to the outer skin of the vessel, for example, on opposite sides of a weld joining two sections of the vessel. These techniques allow a pipeline to be readily instrumented and monitored remotely which reduces manpower costs for performing manual inspections, reduces the risks of injury from performing manual inspections during hazardous weather conditions, and reduces the likelihood of undetected leaks.

Abstract: An ultrasonic flowmeter is disclosed that detects the speed, amount, and composition of a two-phase flow travelling through it. One or more ultrasonic paths corresponding to ultrasonic transducers are positioned to detect the velocity and speed of sound through one phase of the two-phase flow. A second ultrasonic path is positioned to travel through the one phase of the two-phase flow, but to reflect off the interface between of interface of the two phases. A third ultrasonic path is positioned to travel through the second phase of the two-phase flow, but once again reflects off the interface between the two phases. The information of transit times for ultrasonic signals along these ultrasonic paths provides the speed of the two-phase flows, the amount of the two-phase flows, and the compositions of the two-phase flows. A quality assurance check ensures that the measurements are accurate.

Abstract: A process and device for measuring the velocity of flow of a fluid stream by measuring the difference between the respective traveltimes of acoustic pulses emitted by means of a generator (G) respectively between two points (PA, PB) spaced out along the fluid stream, according to whether they are propagated upstream or downstream in relation to the direction of flow, a difference that is indicative of the displacement velocity of the fluid stream. Measurement of this traveltime difference comprises using an acquisition unit (A) coupled to a processing unit (P) allowing determination of the frequency spectrum of each pulse and measurement of the phase lag affecting at least part of the frequency spectrum of each pulse, resulting from the traveltime thereof. Measurement of the velocity of flow of the fluid stream and of the resulting flow rate is very accurate. The process can be applied in chemical industries, chromatography, etc.

Abstract: A loop flow-path is formed by providing a partition in the path of flow of a fluid duct. An incoming flow-path and an outgoing flow-path are provided with the fluid duct through connecting ducts, and a gas G flows in the fluid duct. An ultrasonic sensor having two opposing surfaces for transmission and reception is disposed in a part of the loop flow-path so that ultrasonic waves to be transmitted and receive have vector components in the direction of the loop flow-path. The ultrasonic waves outputted from the two opposing surfaces of the ultrasonic sensor travel in opposite directions to each other in the loop flow-path, one ultrasonic wave with the flow of the gas and the other ultrasonic wave against the flow of the gas, and are received on the opposite surfaces of the sensor, respectively.

Abstract: The present invention relates to a method and a device for measuring volume flow rates of liquid phase components and gas and determination their volume concentrations in a multiphase mixture along a pipeline. Measurements are executed with an ultrasonic system which includes a set of local acoustic transducers arranged in the interior of the pipeline. Each pair of an emitter and a receiver of the transducer forms a sampling volume of a medium being under control. Volume concentrations of mixture components are determined by timing of passage of acoustic pulses through the sampling volume of the medium. Volume flow rates of the mixture components are calculated by measuring phase velocities and volume concentrations in two pipeline divisions with different cross-section areas located in series at a distance one from the other in flow direction.

Abstract: A clamp-on ultrasonic flowmeter has a pair of ultrasonic transmitting-receiving devices. Each device is composed of a ultrasonic propagating element in the form of wedge having a bottom surface and a slanting surface extending from one edge of the bottom surface at an acute angle, and a ultrasonic transducer attached on the slanting surface. The ultrasonic propagating element is composed of a plurality of sheet units in which each sheet unit is composed of plural high modulus fibers aligned in parallel in resinous material, whereby propagating ultrasonic wave emitted by the ultrasonic transducer onto the bottom surface at an angle perpendicular to the slanting surface.

Abstract: A meter includes a casing (1) with a fluid passage (2), in which two transducer mountings (3, 4) arranged at a distance (Lb) from each other support two transducers (5, 6) which are acoustically opposed to each other. Between the transducers (5, 6) there is a distance (Lu) over which they transmit and receive sound pulses through a fluid which in a direction (a) flows through the fluid passage (2). On the basis of the transit times of the sound pulses over the distance (Lu) both countercurrently with and countercurrently to the direction of flow (a), e.g. the velocity of the flow of the fluid is then calculated. A compensating device (8, 9) is arranged between at least one of the transducers (5, 6) and one of the transducer mounts (3, 4).

Abstract: Disclosed is a gas flowmeter comprising a transmit transducer for injecting sonic energy into gas; a receive transducer for receiving the sonic energy; and a spool of pipe having a metallic pipe wall and a liner having a lower sonic impedance than the sonic impedance of the metallic pipe wall, wherein the transmit and receive transducers are mounted on the spool.

Abstract: A clamp-on ultrasonic flowmeter has a pair of ultrasonic transmitting-receiving devices. Each device is composed of a ultrasonic propagating element in the form of wedge having a bottom surface and a slanting surface extending from one edge of the bottom surface at an acute angle, and a ultrasonic transducer attached on the slanting surface. The ultrasonic propagating element is composed of a plurality of sheet units in which each sheet unit is composed of plural high modulus fibers aligned in parallel in resinous material, whereby propagating ultrasonic wave emitted by the ultrasonic transducer onto the bottom surface at an angle perpendicular to the slanting surface.

Abstract: An ultrasonic flowmeter includes a fluid duct including therein first and second flow-paths separated by a partition and an ultrasonic sensor provided at one end of the fluid duct. A reflecting plate provided at the other end of the fluid duct reflects ultrasonic waves generated by the ultrasonic sensor and reaching the reflecting plate through the first and second flow-paths, and returns the ultrasonic waves to the ultrasonic sensor through the second and first flow-paths, respectively, which are different from the first and second flow-paths, respectively, through which the ultrasonic waves have reached the reflecting plate. The ultrasonic flowmeter also includes first and second connecting flow-paths communicating with the first flow-path at the vicinity of one end and the other end, respectively, of the fluid duct.

Abstract: A transmitting and/or receiving head for a sonic flowmeter measuring moving fluids by the runtime method, with an enclosure, an ultrasonic transducer transmitting ultrasound signals into and/or receiving ultrasound signals from the moving fluid and with an ultrasound waveguide by way of which the ultrasound signals are injected into and/or extracted from the moving fluid. The transmitting and/or receiving head is particularly well suited to utilization in a sonic flowmeter for very hot fluids, especially hot gases, by virtue of the fact that it employs an ultrasound waveguide in the form of an elongated sonic funnel offering high thermal conduction resistance.

Abstract: A transit time ultrasonic flow sensor uses a pair of transducers that alternate between transmitting and receiving operational states, the operating frequency of a reference oscillator driving the transmitting transducer is controllably varied so as to maintain a constant phase relationship between the transmitted and received signals. A second oscillator is slaved, in frequency to the reference oscillator just before the alternation in operational states takes place and retains that frequency for most of the next operational state, and so forth. Fluid flowing along a line between the two transducers causes one of the two oscillators to swing to a higher frequency, and the other to swing low with respect to each other. A difference frequency between the two oscillators is detected and used as a basis for calculating the rate of fluid flow. In preferred versions of the invention the pair of transducers and an acoustic reflector are configured as a probe that can be inserted into the flowing fluid.

Abstract: A method and device for making measurements of the characteristics of a fluid, particularly the milk, which flows in pulsations in a conduit. The device has a measuring region wherein at least one characteristic of the fluid is determined. The measurement is made during an optimal measuring window which constitutes a time interval while a pulsation of the fluid is received in the measuring region which contains a sensor or sensors for measuring one or more selected characteristics of the fluid, such as color, conductivity or acoustic qualities. The measuring region may be in a bypass passageway in the conduit which may be incorporated in a teat cup. The pulsations in the teat cup may be used to define an optimal measuring window for measuring one or more characteristics of the fluid as it flows in pulsations through the conduit. The sensed entry or approach of a pulsation into the measuring region may also be used to define the optimal measuring window.

Abstract: A method for measuring fluid flow are disclosed. The invention combines isolating flow conditioner technology with ultrasonic technology to determine flow velocity. The method and apparatus of the invention does not require the use of integration techniques or the prior determination of flow swirl or asymmetry to achieve accuracy. The performance of this novel flowmeter exceeds the performance of current ultrasonic flowmeters by an order of four to twelve times and offers significant savings in manufacturing and maintenance costs. The disclosed flowmeter also has self-diagnostic capabilities.

Abstract: The flow rate of a fluid can be measured using an ultrasonic flow meter according to the present invention with a higher measuring accuracy and a lower cost. The feature of the invention consists in an ultrasonic flow meter comprising a measurement tube for flowing a fluid to be subjected to measurement, a first oscillator fitted to the outer circumference of the measurement tube, a second oscillator fitted to the outer circumference of the measurement tube at a predetermined interval along the flow of the fluid from the first oscillator and an acoustic filter fitted to the measurement tube for cutting high frequency range of the oscillating wave propagating through the oscillating tube, in which the flow rate of a fluid is measured based on a time difference between a time required when the ultrasonic wave from the upstream oscillator reaches the downstream oscillator and another time required when the ultrasonic wave from the downstream oscillator reaches the upstream oscillator.

Abstract: A system for determining the density, flow velocity, and mass flow of a fluid comprising at least one sing-around circuit that determines the velocity of a signal in the fluid and that is correlatable to a database for the fluid. A system for determining flow velocity uses two of the inventive circuits with directional transmitters and receivers, one of which is set at an angle to the direction of flow that is different from the others.

Abstract: An ultrasonic flow velocity measuring method using a transit time difference of continuous sine waves without transmitting/receiving an ultrasonic pulse comprises steps of amplitude-modulating a continuous ultrasonic sine wave carrier into a lower frequency and transiting the amplitude-modulated signal, whenever the ultrasonic transit time is measured; demodulating the amplitude-modulated signal; detecting or discriminating the amplitude-modulated signal from the demodulated signal and measuring a time interval from the moment that the ultrasonic sine wave is amplitude-modulated till the amplitude-modulated signal is demodulated.

Abstract: Flow is described by first variables related to a coordinate system, and by at least one second flow-related variable such as friction factor or Reynolds number unrelated to the coordinate system, wherein the first variables are separable or substantially separable from the second variables. The method includes determining average velocities of the fluid on two paths, or taking a first path measurement and at least one point measurement, selected such that combining the first path measurement and the second measurement forms an expression independent of the second variable. In one embodiment, first and second path measurements are combined in accordance with the velocity relationships given by the Pao equation to produce a flow measurement which is independent of the friction factor. A single calibration then allows the meter to be used on diverse conduits with different wall roughness or friction factor. The system also yields a non-invasive measure of the friction factor.

Abstract: A clamp-on ultrasonic flowmeter has a pair of ultrasonic transmitting-receiving devices which are placed on a pipe in which a liquid flows. Each device is composed of a composite of a ultrasonic transducer and a ultrasonic propagating element which propagates ultrasonic wave transmitted by the transducer predominantly in the direction perpendicular to a plane of the transducer (which is arranged at an acute angle from the center line of the pipe), and a ultrasonic propagating layer placed between the ultrasonic propagating element and the pipe. The ultrasonic propagating layer has a viscosity of 0.5×10−3 to 3×10 Pa.sec at 25° C. and a rate of sonic propagation in terms of V1 at 25° C. satisfying the condition of 0.5<V1/V2<1.7 in which V2 represents a rate of sonic propagation of material of the pipe at 25° C. Otherwise, the ultrasonic propagating layer has a rate of penetration of needle in the range of 10 to 300 at 25° C.

Abstract: An ultrasonic transit time flow sensor detects a signal corresponding to the phase difference between signals from two transducers during the interval of an acoustic transmission, and uses this signal to adjust an output flow rate signal in order to compensate for circuit errors inherent in the flow sensor. An Exclusive-Or phase detector detects the difference in phase between the signals resulting from the difference in propagation transit time of the flowing fluid. This measured difference includes a phase shift due to the electrical circuits of the flow sensor. In order to compensate for the circuit-induced phase shift, when the transducers are transmitting bursts of acoustic energy, the corresponding electrical signals are routed to the Exclusive-Or phase detector in order to generate a common mode DC signal representative only of the phase shift of the electrical circuits of the flow sensor.

Abstract: A pipe 16 having a produced fluid 18 (liquid an/or gas) and at least two acoustic pressure sensors 20-24, is provided with a cylindrical sleeve 30 attached to the pipe 16 at two locations around a sensing region where the sensors 20-24 are located, the sleeve forming a closed cavity 32 filled with a fluid (or material) having an acoustic impedance (&rgr;c2) that is much less than the acoustic impedance (&rgr;c1) of the produced fluid 18 in the pipe 16 (i.e., &rgr;c2<<&rgr;c1), which causes the sleeve 20 to isolate the acoustic sensors 20,22,24 from being affected by acoustic properties of the cavity 32 and the acoustic properties outside the pipe 16. For most effective acoustic, the cavity 32 may be evacuated.

Abstract: An ultrasonic flow velocity measuring apparatus measures a transit time under the condition a synchronization of an ultrasonic signal having a modulated frequency by PN (pseudo noise) code of a diffusion band at a transmitting side is locked at a receiving side, and prevents an excessive measurement error exceeding allowable error range. If the installation positions of the ultrasonic transducers of upper and lower stream sides are moved, an ultrasonic transit time can be precisely measured by using a different signal series PN code without changing an electronic component and a program. In addition, the ultrasonic flow velocity measuring apparatus installs a plurality of ultrasonic transducers according to various distances from the bottom of a fluid passage, and accurately measures average flow velocity which is variable in response to the height in a curved fluid passage.

Abstract: A method for detecting a phase difference is provided. The method includes selecting first and second input signals from a plurality of pairs of input signals. The method further includes modulating a duty cycle of first and second intermediate signals from a first duty cycle based on a phase difference between the first and second input signals. The method also includes creating a differential signal based on the modulated duty cycles of the first and second intermediate signals that is related to the phase difference between the first and second input signals.

Abstract: A clamp-on ultrasonic flowmeter has a pair of ultrasonic transmitting-receiving devices. Each device is composed of a ultrasonic propagating element in the form of wedge having a bottom surface and a slanting surface extending from one edge of the bottom surface at an acute angle, and a ultrasonic transducer attached on the slanting surface. The ultrasonic propagating element is composed of a first ultrasonic propagating member having on its bottom surface a number of planes aligned in parallel with the slanting surface on which the ultrasonic transducer is attached and a second ultrasonic propagating member of elastic or plastic material, so as to propagate ultrasonic wave emitted by the ultrasonic transducer onto the bottom surface of the ultrasonic propagating element at an angle perpendicular to the slanting surface.

Abstract: The present invention provides an ultrasonic flow meter that measures flow volume by determining the flow rate of a liquid from the difference in propagation times of ultrasonic waves in both directions between measuring units by providing measuring units having transducer at an interval in the lengthwise direction on a measuring pipe through which liquid flows. A pair of mounting members are provided in a lower case of a case serving as a base at an interval wider than that of measuring units. The measuring pipe is held by respective retaining indentations to the outside in the axial direction of measuring units by facing a left mounting member and a right mounting member that compose the mounting members. In addition, an insulating material is filled into the case so as to cover the measuring units and the measuring pipe.

Abstract: The ultrasonic flow meter of the present invention comprising a measuring pipe through which liquid flows, and two measuring units provided at an interval in the lengthwise direction on measuring pipe. A tightly adhered tube having elasticity is attached to an attaching indentation formed in the measuring pipe over the peripheral direction, and its inner peripheral surface is tightly adhered to the outer peripheral surface of measuring pipe. A transducer is arranged on the outer peripheral surface of tightly adhered tube in the state in which it is pressed against the outer peripheral surface of the tightly adhered tube. In this ultrasonic flow meter, the transmission of vibrations between the transducer and fluid inside the measuring pipe can be carried out uniformly.

Abstract: The flow rate of a fluid can be measured using an ultrasonic flow meter according to the present invention with a higher measuring accuracy and a lower cost. The feature of the invention consists in an ultrasonic flow meter comprising a measurement tube for flowing a fluid to be subjected to measurement, a first oscillator fitted to the outer circumference of the measurement tube, a second oscillator fitted to the outer circumference of the measurement tube at a predetermined interval along the flow of the fluid from the first oscillator and an acoustic filter fitted to the measurement tube for cutting high frequency range of the oscillating wave propagating through the oscillating tube, in which the flow rate of a fluid is measured based on a time difference between a time required when the ultrasonic wave from the upstream oscillator reaches the downstream oscillator and another time required when the ultrasonic wave from the downstream oscillator reaches the upstream oscillator.

Abstract: An ultrasonic transit time flow sensor employs two transducers spaced out along a direction of fluid flow. A variable frequency acoustic signal is simultaneously transmitted by both transducers in a burst. After an interval corresponding to the expected transit time between transducers, both transducers are switched to their respective receiving states and a phase difference between their received signals is used as measure of the fluid rate. The invention also provides a feedback arrangement for controlling the acoustic frequency to maintain stable operation under a variety of operating conditions.

Abstract: The present invention includes a clamp-on housing for encapsulating or confining a flexible tube or pipe. The housing includes transducers therein for transmitting and receiving sonic energy. A sonically matched plate is provided to function as a waveguide for the sonic energy to form a coherent wide beam such that flow characteristics may be measured in the flexible tube. An apparatus for measuring flow in flexible tubes, in accordance with the present invention, includes a housing including a first portion configured and dimensioned for receiving a first transducer and a second transducer therein and a second portion adapted to attach to the first portion to encapsulate a flexible tube between the first and second portion without cutting off flow within the tube. A plate is disposed within the housing in contact with the tube.

Abstract: A fluid property monitor includes a transducer assembly to impart multiple frequency energy to a conduit in one or more modes and to receive resonant frequency energy from the conduit. The resonant frequency energy is responsive to the imparted energy, the conduit and a fluid in the conduit. The fluid property monitor can also be defined as including: a frequency signal generator connected to cause multiple frequency energy to be transferred to a conduit having a fluid to be monitored; and a spectral analysis signal processor connected to receive and process electrical signals generated in response to vibrations propagated through the conduit and the fluid in the conduit in response to transferred multiple frequency energy. Particular implementations can be adapted as a densitometer, a coherent flow detector, and other particular fluid parameter detectors.

Abstract: An improved clamp-on arrangement having a first sensor assembly (2, 2′) and a second sensor assembly (3, 3′) usable for different nominal diameters of pipes. The sensor assemblies can be positioned either along a single straight surface line (11) or along diametrically opposed straight surface lines (11′, 11″) of the pipe. The arrangement contains replaceable components, so that in the event of a malfunction, only faulty components need to be replaced. The assemblies (2, 2′; 3, 3′) are attached by means of pipe straps (4, 4′); (5, 5′) and wherein the assemblies are identical in construction. Each assembly has a flat bracket (6) adjacent to the pipe and having a longitudinal center line (61) and a tubular portion (62) integrally formed thereon. A sensor inset (63) is longitudinally guided in the tubular portion (62) and contains an ultrasonic transducer (64) with a transducer element (644).

Abstract: A transit time ultrasonic fluid flow sensor is configured to compensate for circuit related drifts in the flow rate output signal. During acoustic transmission some of the transmitting signal is also routed through the receiving circuits from which a reference signal is derived to provide the compensating signal. In an alternate configuration, compensation or flow sensor drift is derived from reception of the round-trip signals between a pair of transducers.

Abstract: An ultrasonic flowmeter of the present invention has a pipe (2) through which a fluid to be measured flows, and measurement portions (3) separated on the pipe by a predetermined distance along the longitudinal direction of the pipe. The measurement portions each comprises a transducer fixing member (4) having an arc shaped indentation (6) into which a part of the pipe can be fitted, and a piezoelectric transducer (5) fixed to the transducer fixing member. The pipe and the arc shaped indentation are closely fixed to each other by an adhesive (7) by fitting and pressing the pipe into the arc shaped indentation via the adhesive.