Abstract: An ultrasonic flowmeter of the present invention includes: first and second ultrasonic transducers that send and receive an ultrasonic wave and are arranged so as to form a propagation path for the ultrasonic wave in a flow path of fluid; a transmission unit and a reception unit that drive the first ultrasonic transducer and the second ultrasonic transducer such that the ultrasonic wave is sent and received in two ways between the first ultrasonic transducer and the second ultrasonic transducer, and receive the ultrasonic wave; a zero-cross detection unit that measures a propagation time of the ultrasonic wave by subjecting a received signal generated by the ultrasonic wave received in the reception unit to zero-cross detection; and a correction unit that reduces an error in the zero-cross detection caused by noise superimposed on the received signal, in which the ultrasonic flowmeter calculates a flow volume of the fluid on the basis of the propagation time.

Abstract: A metering arrangement includes a meter housing, a source of energy signals, a source of gas flow signals, a source of temperature signals, and a processing circuit. The meter housing is securedly supported proximal to a facility receiving utility commodities. The processing circuit is disposed within the meter housing, and is operably connected to the source of energy signals, the source of gas flow signals, and the source of temperature signals. The processing circuit is operable to generate electrical energy consumption metering information from the energy signals. The processing circuit is further operable to generate corrected gas consumption information based on the received gas flow signals and the received temperature signals.

Abstract: A probe type acoustic transit-time flow sensor has paired transducers arranged to generate quasi-helical acoustic beams making a plurality of reflective contacts with a pipe's interior wall. The transducers in each pair are spaced apart along the flow axis so that transit-time measurements can be used both to measure the internal diameter of the pipe and to determine a flow rate. These measurements are combined to yield a volumetric flow rate. Various numbers of pairs of transducers can be put on a single probe or on multiple probes and used to provide a more accurate representation of a flow profile and therefore a more accurate volumetric flow determination.

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

Abstract: The present invention proposes an ultrasonic flow meter, comprising a conduit for measurement in which a liquid flows therein, and a pair of measurement sections which are provided in said conduit for measurement and are spaced apart by a certain interval along its longitudinal direction, and which obtains the flow velocity of said flowing liquid from the difference in the propagation time periods of ultrasonic in the two opposite directions between these measurement sections, and thereby measures the flow rate thereof; wherein a pair of fixing portions are provided which respectively support said conduit for measurement at the exterior side and also at the interior side in the longitudinal direction of said measurement sections.

Abstract: The present invention proposes an ultrasonic flow meter, comprising a conduit for measurement in which a liquid flows therein, and a pair of measurement sections which are provided in said conduit for measurement and are spaced apart by a certain interval along its longitudinal direction, and which obtains the flow velocity of said flowing liquid from the difference in the propagation time periods of ultrasonic in the two opposite directions between these measurement sections, and thereby measures the flow rate thereof; wherein a pair of fixing portions are provided which respectively support said conduit for measurement at the exterior side and also at the interior side in the longitudinal direction of said measurement sections.

Abstract: An acoustic time-of-flight size measuring device is added to the sensing head of an insertion probe sensor which may be used for measuring the flow of fluid in a pipe. The size-measuring device defines an acoustic beam making a plurality of reflective contacts with the pipe's interior wall. A time-of-flight measurement of this path length provides an accurate measurement of the internal diameter of the pipe. The magnitude of the transit time signal can also be used as an indicator of both insertion depth and angular orientation of the probe with respect to the pipe axis. In addition, the arrangement allows one to sense acoustic path attenuation caused by factors such as the buildup of deposits.

Abstract: A method and related ultrasonic meter identify and correct for transit time errors such as peak switch errors. The method includes calculating values for a set of diagnostics from measurements of the fluid flow, including transit time measurements. Based on the values for the diagnostics, and whether and how they fall outside of their respective ranges, the meter can identify a variety of problems with the meter or fluid flow, such as whether there has been an intermittent peak switch, a permanent peak switch, or the presence of noise, velocity pulsation in the fluid flow, temperature stratification, of other problem. In the event there is a problem with the meter, the meter self-tunes in order to minimize the chances of the problem happening again.

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

Abstract: In accordance with one embodiment, a flow meter of the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Abstract: A Doppler type ultrasonic flowmeter has an ultrasonic transmitting means for emitting ultrasonic pulses from an ultrasonic transducer into a fluid pipe, a flow velocity profile measuring means for receiving an ultrasonic echo reflected from a measurement region in the fluid pipe thereby to measure a flow velocity profile of a fluid to be measured, a fluid flow rate computing means for calculating the flow rate thereof on the basis of the flow velocity profile of the fluid to be measured, and a frequency selecting and setting means for automatically selecting a fundamental frequency of an ultrasonic wave that causes a resonant transmission phenomenon to take place from the ultrasonic transducer. The frequency selecting and setting means controls the operation of the ultrasonic transmitting means such that an ultrasonic wave of a selected optimum frequency is emitted from the ultrasonic transducer.

Abstract: An ultrasonic flowmeter arranged to perform measurement with high accuracy has first and second ultrasonic transducers 1, 2 which transmit and receive ultrasonic waves, and which are placed so as to form a path for propagation of the ultrasonic waves in a flow passage 14 for a fluid, a transmitting section 3 which drives one of said first and second ultrasonic transducers 1, 2, a first matching section 5 which is connected to the transmitting section, and which adjusts the output impedance of the transmitting section, and a receiving section 6 which has an input impedance approximately equal to or lower than the adjusted output impedance, and which receives the ultrasonic wave reaching the other of the first and second ultrasonic transducers. The flow volume of the fluid is measured by detecting a bidirectional-propagation time difference between the ultrasonic waves propagating in the propagation path.

Abstract: An ultrasonic flow-measuring method measures the flow rate of a medium traveling through a measuring conduit by means of two ultrasound transducers which in the flow direction of the medium are offset relative to each other and both of which alternate in emitting ultrasonic pulses while the respective other ultrasound transducer receives the emitted ultrasonic pulses and the flow rate is determined as a function of the run times of the ultrasonic pulses received by the respective other ultrasound transducer. At least one correction parameter is established on the basis of the calculated sound propagation of the ultrasonic pulses traveling from one ultrasound transducer to the other, the calculation of the sound propagation of those pulses is made by taking into account a predefined frequency spectrum of the oscillations of the ultrasound transducers and the flow rate is calculated by applying the correction parameter established.

Abstract: In accordance with one embodiment, a flow meter of the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Abstract: An apparatus for measuring a gas concentration comprises a conduit through which an objective gas to be measured flows, a ultrasonic transmitting and receiving element fixed in a straight portion of the conduit and a reflecting plate fixed in the straight portion to face to the ultrasonic transmitting and receiving element. The apparatus further comprises a calibration gas source for supplying a calibration gas of which components and component ratio are preliminarily known, temperature sensors for measuring the temperature of the calibration gas flowing through the conduit, a propagation time calculating means for calculating the time period for propagation of the ultrasonic through the calibration gas in the conduit, a calibration means for calibrating the reference distance between the ultrasonic transmitting and receiving element and the reflecting plate based on the calculation results of the propagation time calculating means.

Abstract: A flow rate of fluid moving within a tube having a small diameter can be measured by the steps of: preparing a structure that has first and second oscillation wave generating-detecting means on a surface of a wall along the conduit; moving the fluid in the conduit; generating an oscillation wave in the first oscillation wave generating-detecting means, applying the wave onto the wall, and measuring a period of time required for transmitting the generated oscillation wave to the second oscillation wave generating-detecting means within the wall; generating an oscillation wave in the second oscillation wave generating-detecting means, applying the wave onto the wall, and measuring a period of time required for transmitting the generated oscillation wave to the first oscillation wave generating-detecting means in the wall; and comparing a difference of the periods of time of transmission and separately prepared calibration data.

Abstract: An ultrasonic flow-measuring method determines the flow rate of a medium flowing through a line is determined by measuring the runtime of an ultrasonic signal that travels from a first ultrasonic transducer to at least one other ultrasonic transducer. The runtime of the ultrasonic signal as it makes m passes in immediate succession through a predefined path over a predefined path length and at a predefined angle relative to the flow direction is measured, and the runtime of the ultrasonic signal as it makes n passes in immediate succession through the predefined path over the predefined path length at the predefined angle relative to the flow direction is measured, with m and n being mutually different integers, and the dead time of the ultrasonic flow-measuring process is determined on the basis of the measured runtimes. This ultrasonic flow-measuring method permits real-time compensation for the dead time during the actual measuring process, the result being highly accurate measurements.

Abstract: An ultrasonic sensor having a pair of ultrasound transducers adapted to be inserted in and being able to perform at a single site of introduction into a duct. The ultrasonic sensor measures a forward ultrasonic path transit time and a second reverse ultrasonic path transit time of ultrasound signals propagating in a fluid. The arrangement being such that a comparison of the signal associated with ultrasound travel in one direction with that of the signal associated with ultrasound travel in the opposite direction enables the flow rate of the fluid in the duct to be determined. The ultrasonic sensor may utilize a reflecting surface on the duct and a reflective surface of an ultrasonic sensor end cap to provide forward and reverse ultrasonic W-shaped paths. In addition, the ultrasonic sensor may also be used to measure the temperature, viscosity, and cavitation effects of a fluid.

Abstract: An ultrasonic-wave propagation-time measuring method and gas concentration sensor are disclosed in which a reception wave which has been transmitted and received by an ultrasonic element 5 is subjected to full-wave rectification in order to obtain a full-wave-rectified wave, which is then integrated by an integration circuit 37 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 threshold-level calculation section 21e sets a reference value on the basis of the peak value, and a point in time when the amplitude of a reception wave having undergone full-wave rectification is judged by a comparator 43 to have reached the reference value is regarded as an arrival time. Subsequently, a gas concentration is determined on the basis of a period between the emission time and the arrival time.

Abstract: The present invention provides fluidic devices and systems which have micromachined ultrasonic transducers integrated into microchannels. The ultrasonic transducers generate and receive ultrasonic waves. The transducers can be disposed and operated to measure fluid characteristics such as pressure, density, viscosity, flow rate and can also be used to mix and pump fluids.

Abstract: An ultrasonic sensor having a pair of ultrasound transducers adapted to be inserted in and being able to perform at a single site of introduction into a duct. The ultrasonic sensor measures a forward ultrasonic path transit time and a second reverse ultrasonic path transit time of ultrasound signals propagating in a fluid. The arrangement being such that a comparison of the signal associated with ultrasound travel in one direction with that of the signal associated with ultrasound travel in the opposite direction enables the flow rate of the fluid in the duct to be determined. The ultrasonic sensor may utilize a curved reflecting surface on the duct and a reflective surface of an ultrasonic sensor end cap to provide forward and reverse ultrasonic W-shaped paths.

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: Propagation time Tp of an ultrasound signal between two spaced-apart transducers constituting an emitter and a receiver is measured. The emitter transducer is subjected to an excitation signal of n successive pulses of period Te giving rise to an ultrasound signal being emitted towards the receiver transducer which receives the ultrasound signal generating and outputting a receive signal. A measurement of an intermediate propagation time Tint is started when the emitter transducer begins to be excited. The receive signal is detected and the oscillations in the receive signal are counted. Measurement of the intermediate propagation time Tint is stopped when an ith oscillation is detected. The propagation time Tp is determined by taking the difference Tint?i×Te. Advantageously, measurement of Tint is stopped for an ith oscillation of the receive signal that corresponds to the receive signal being at a maximum amplitude.

Abstract: For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

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: For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Abstract: Methods and apparatus for using ultrasound to measure speed and acceleration in fluids is provided. Three exemplary embodiments are disclosed. The first exemplary embodiment measures fluid velocity, such as, for example, wind, under standard atmospheric pressure-temperature. The second exemplary embodiment measures gas velocity, such as, for example, wind, affected by and automatically calibrates for pressure-temperature. The third exemplary 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: This ultrasonic flow meter is provided for measuring 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: A flow rate measuring apparatus capable of accurately measuring a flow rate of fluctuating fluid. A mode setting circuit selectively sets any one of a plurality of predetermined transmission modes different in transmission timing. The mode setting circuit sets any one of a first transmission mode which permits an ultrasonic wave to be transmitted at a predetermined timing for every period of a flow waveform of exhaust gas, a second transmission mode which permits an ultrasonic wave to be transmitted at a timing shifted by a predetermined time for every period of the flow waveform of the exhaust gas and a third transmission mode which permits an ultrasonic wave to be transmitted at predetermined intervals.

Abstract: It is an object of the present invention to provide an ultrasonic transducer, which is so configured as to reduce the variations in characteristics, thereby to enable the stabilization of the precision, as well as to enable the improvement of the durability, and the like, a method for manufacturing the ultrasonic transducer, and an ultrasonic flowmeter. In order to attain this object, in accordance with the present invention, the ultrasonic transducer is so configured as to include a piezoelectric element and an acoustic matching layer, wherein the acoustic matching layer is made of a dry gel of an inorganic oxide or an organic polymer, and a solid skeletal part of the dry gel has been rendered hydrophobic. With this configuration, it is possible to obtain the ultrasonic transducer having an acoustic matching layer 3 which is very lightweight and has a small acoustic impedance due to the solid skeletal part of the dry gel which has been rendered hydrophobic.

Abstract: A flow meter measures a flow rate of fluid flowing through a flow passage based on a duration of propagation of an ultrasonic wave along the flow passage. A signal of the received ultrasonic wave is then compared with a reference voltage to detect an arrival of the ultrasonic wave. A voltage setting unit determines the reference voltage to an appropriate level according to a signal output from a propagation measuring unit which measures a duration of propagation of the ultrasonic wave along the flow passage from the start of transmission of the ultrasonic wave to the output of a signal from a judging unit as the reference voltage being changed. The reference voltage is determined readily and accurately, the flow meter measures the flow rate with the appropriate reference voltage.

Abstract: An ultrasonic sensor having a pair of ultrasound transducers adapted to be inserted in and being able to perform at a single site of introduction into a duct. The ultrasonic sensor measures a forward ultrasonic path transit time and a second reverse ultrasonic path transit time of ultrasound signals propagating in a fluid. The arrangement being such that a comparison of the signal associated with ultrasound travel in one direction with that of the signal associated with ultrasound travel in the opposite direction enables the flow rate of the fluid in the duct to be determined. The ultrasonic sensor may utilize a reflecting surface on the duct and a reflective surface of an ultrasonic sensor end cap to provide forward and reverse ultrasonic W-shaped paths. In addition, the ultrasonic sensor may also be used to measure the temperature, viscosity, and cavitation effects of a fluid.

Abstract: An ultrasonic sensor having a pair of ultrasound transducers adapted to be inserted in and being able to perform at a single site of introduction into a duct. The ultrasonic sensor measures a forward ultrasonic path transit time and a second reverse ultrasonic path transit time of ultrasound signals propagating in a fluid. The arrangement being such that a comparison of the signal associated with ultrasound travel in one direction with that of the signal associated with ultrasound travel in the opposite direction enables the flow rate of the fluid in the duct to be determined. The ultrasonic sensor may utilize a curved reflecting surface on the duct and a reflective surface of an ultrasonic sensor end cap to provide forward and reverse ultrasonic W-shaped paths.

Abstract: An ultrasonic flow meter of the present invention includes: a measurement flow path 6 through which a fluid to be measured flows; ultrasonic transducers 8 and 9 provided respectively on an upstream side and a downstream side with respect to each other along the measurement flow path 6; an upstream aperture hole 11 and a downstream aperture hole 12, the aperture holes 11 and 12 for exposing the ultrasonic transducers 8 and 9 to the measurement flow path 6; a first influent suppressor 15 provided in a vicinity of at least the downstream aperture hole 12 for reducing inflow of the fluid to be measured into the aperture hole 12; a second influent suppressor 16 provided on an upstream side of the measurement flow path 6 with respect to the aperture holes 11 and 12 for reducing the inflow of the fluid to be measured into the aperture holes 11 and 12; a measurement control section 19 for measuring a propagation time of an ultrasonic wave between the ultrasonic transducers 8 and 9; and a calculation section 20 for ca

Abstract: Embodiments of the invention provide an algorithm for enhancing the transit time measurement of an ultrasonic wave through a fluid, and criteria for evaluating the suitability for various waveforms with regard to noise rejection. The transit time calculation provides a greater noise immunity and accuracy than techniques used in the prior art, and allows a measure of weighting of dispersed signals with different arrival times. The transit time calculation utilizes either the transmitted signal or the measurement of a reference system, the calculation of the squared convolution of this signal with the received signal, and the calculation of the transit time from the time-weighted squared convolution signal over a suitable interval defined by the minimums of the squared convolution signal. In the case of dispersion where the arrival times are symmetrically displaced around a mean transit time, or if asymmetric dispersion is suitably within the main lobe, the calculation properly weights the composite signal.

Abstract: Ultrasonic transducers for use in time-of-flight flow measurement are made by clamping a conformal material between a face of a piezoelectric element and a housing so as to efficiently acoustically couple the piezoelectric element to a flowing fluid wetting the housing. Both in-line and probe sensing heads are described, where the in-line sensor heads make use of side-looking transducers. Acoustic isolation arrangements are used to ensure that the transducer transmits and receives acoustic energy in a single, well-defined direction. Various pre-loading arrangements, such as metal springs that can be set by driving a wedge between the spring and the housing, are used to controllably force the piezoelectric element toward the housing.

Abstract: The invention relates to an apparatus for the measurement of the flow speed and/or of the molar mass of gases or gas mixtures in a medical application by means of ultrasonic transit time measurement with a graduated tube and two ultrasonic transducers which can be placed into this and which are separated from the interior space of the graduated tube via membranes. In accordance with the invention, the membranes are gas impermeable and are inserted into the graduated tube such that this forms a gas impermeable tubular connection. The ultrasonic transducers connected in a reseparable manner to the graduated tube contact the membranes in a flush manner.

Abstract: A method of and system for analyzing the mass flow rate of a fluid flowing in a conduit wherein ultrasonic energy is transmitted along multiple v paths in multiple parallel quadrature planes through the fluid, the transit time of the ultrasonic energy through the fluid with and against the flow direction of the fluid is measured, and the flow velocity of the fluid in each quadrature plane is calculated based on the transit time in each quadrature plane. The density of the fluid in each quadrature plane is then determined and quadrature integration of the product of the fluid density and fluid velocity in each quadrature plane is performed to calculate the total mass flow rate of the fluid more accurately by eliminating errors associated with assuming that the density of the fluid in the conduit is uniform.

Abstract: A gas leakage detection system includes a flow path, a dual mode valve disposed in the flow path, an ultrasonic measuring section including a pair of ultrasonic transducers, disposed in the flow path upstream from the dual mode valve, a flow rate calculation section for computing a flow rate based on a signal from the ultrasonic measuring section, and a control section for controlling the dual mode valve. The control section closes or opens the dual mode valve instantaneously, and the flow rate calculation section computes a flow rate when the dual mode valve is closed. Thus, gas leakage can be decided substantially without stopping a gas flow when a user is using the gas.

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: 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.

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 method of and system for analyzing the mass flow rate of a fluid flowing in a conduit wherein ultrasonic energy is transmitted along multiple v paths in multiple parallel quadrature planes through the fluid, the transit time of the ultrasonic energy through the fluid with and against the flow direction of the fluid is measured, and the flow velocity of the fluid in each quadrature plane is calculated based on the transit time in each quadrature plane. The density of the fluid in each quadrature plane is then determined and quadrature integration of the product of the fluid density and fluid velocity in each quadrature plane is performed to calculate the total mass flow rate of the fluid more accurately by eliminating errors associated with assuming that the density of the fluid in the conduit is uniform.

Abstract: Disclosed is a method and apparatus for measuring flow velocity and flow rate of a fluid in a tube member or the like with high precision. A flow vel0ocity measuring method has: a step of allowing a signal sound of ultrasound to propagate through a fluid in a tube member or the like and detecting a phase difference between the signal sound and an original signal; a step of eliminating a phase difference detected in the step to obtain synchronism; a step of detecting time or oscillation frequency required to complete the phase synchronization in the step; and a step of, on the basis of the time or oscillation frequency required to complete phase synchronization in the step, calculating flow velocity by referring to flow velocity which is preset in a table in correspondence with the time or frequency. In the table, flow velocities corresponding to changes in temperature, pressure, and kind of a fluid may be preset together with the time or oscillation frequency.

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.

Abstract: A transit-time difference type ultrasonic flowmeter comprises a pair of ultrasonic transducers mounted on a flow tube at an upstream side and a downstream side respectively, a switching device for switching the operational mode of each of the transducers alternatively to its transmitting or receiving mode, an amplifier for amplifying the signal received by the transducer of the receiving side, and a data reduction equipment includes an analog-digital converter and a digital signal processor; the converter converts the waveform into a plurality of voltage-time data sets; and the processor picks up an object peak of the voltage-time data sets on the basis of the time, or the data on the voltage, or determines the peaks of maximum voltage included within the waveform of the voltage-time data sets as an object peak, estimates at least one zero-cross point confined by the object peak or a peak adjacent to the object peak through the calculation made on the plurality of voltage-time data sets distributing along the

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: A flow rate measurement apparatus includes: a plurality of flow paths 13 provided between an inflow port 11 and an outflow port 12; opening/closing sections 14 for opening/closing the plurality of flow paths 13; measurement sections 15 for measuring a flow rate of fluid flowing through at least one of the plurality of flow paths 13; and a control section 17 for controlling the opening/closing sections 14 and the measurement sections 15; The control section 17 includes a gain adjustment section 16 for correcting a gain of the measurement section 15 in a flow path which is closed by the opening/closing section 14.

Abstract: A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.

Abstract: A zero crossing detector has an analyzer which determines a zero level crossing of a currently input electrical pulse packet and which emits a trigger signal indicative of a determination having been made, and a pre-trigger unit which monitors variations in the amplitude of the current input pulse packet to detect a crossing of a pre-trigger level. The detector further includes a control unit operably connected to the pre-trigger unit which compares the amplitude of the pre-trigger level with any amplitude of a signal derived from the current or a previous input electrical pulse packet, and which automatically controls the amplitude of the pre-trigger level to maintain a working difference therebetween.