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: 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: The invention relates to a device for measuring the fluid consumption of a user over a given measurement time, including a volumetric meter (26) connected to a central information processing unit (28). This unit is designed to take a series of readings at successive intervals in said measurement time, so as to compare each reading with a reference value that corresponds to a predetermined nominal consumption threshold and thus from this deduce the quantity consumed over said measurement time corresponding to consumption with a flow rate higher than the nominal consumption threshold.

Abstract: An ultrasonic flow measuring method comprises steps of selecting a section area in a right angle to an ultrasonic transit trajectory line for measuring a flow velocity as a section area necessary for a flow measurement; and multiplying a flow velocity component of a direction corresponding to an ultrasonic transit trajectory, which is directly measured by an ultrasonic wave, by the section area thereby to compute a flow or flowrate, so that a flow measuring error and a measuring error of a section area can be significantly reduced, thereby enhancing the accuracy of the flow measurement.

Abstract: The invention concerns, according to the first teaching, a sound damper for ultrasonic waves in a gas flow, with at least one damping element (3) that can be inserted into a line for the gas flow. In accordance with the invention, the sound damper for ultrasonic waves is characterized by the fact that at least one scattering unit (5, 6, 7) having a number of small reflective surfaces is located in the damping element (3).

Abstract: An ultrasonic flowmeter using ultrasonic pulses transmitted within a pipe containing flowing fluid determines values, including flow rate or fluid velocity of the flowing fluid. The ultrasonic flowmeter transmits trains of ultrasonic pulses having velocity components either in the upstream or downstream direction. The ultrasonic flowmeter includes the transducer placed downstream external to the pipe and a transducer placed upstream external to the pipe. Time measurements are made to determine a time, TU, required for a pulse train to travel from the downstream transducer to the upstream transducer and the time, TD, required for a pulse train to travel from the upstream transducer to the downstream transducer. The ultrasonic flowmeter is configured to have consistent triggering of the pulses of the pulse train to reduce error. Also, the electronics are simplified to allow for lower timing resolution requirements.

Abstract: A flowmeter for a medium includes two transducers displaced from each other in the direction of flow of the medium. The flowmeter contains an emitting device which emits acoustic signals in both directions through the medium using the transducer. The flowmeter also contains a processing device for determining information via the flow of the medium by monitoring the travel times of the acoustic signals received by the transducers. A part of the space between the transducers defines a flow path which includes a flow structure with at least one medium flow passage extending axially in the direction of the flow of the medium. The medium flow passage has damping devices which are located so that at least one asymmetrical noise propagation mode is damped. The damping device has a damping structure which extends substantially across the whole length of the media flow passage.

Abstract: An ultrasonic system employs a path through a fluid to determine fluid density by a differential reflection coefficient measurement of fluid impedance Z and a fluid sound speed c. Preferred configurations use clamp-on (external) transducers and combine ultrasonic measurements of flow velocity V over one or more paths, to obtain the mass flow rate. Z is determined by comparing reflections from a reference target, which may be totally reflective, with reflections from a sensor target having an effectively lower Z, which may be close to that of the fluid. Both targets are preferably located to be cleaned by the natural flow of the fluid. The low-Z target is interrogated at least once. Vee blocks provide a compact combination of reference and sensor targets that can be integrated with a velocity-sensing flowcell. Folded-path flow cells compactly measure V alone or in combination with density.

Abstract: A method and device (60) is described which measures the speed of a flowing fluid (F) by measuring the difference in time taken for an ultrasonic signal to travel first upstream and then downstream in the fluid. In each direction the device (60) calculates the time taken for an ultrasonic wave packet emitted by one ultrasonic transducer (62) to be received by another (63). The method used consists of the digitisation (85) of the received waveform and the subsequent identification of waveform features by comparison with a standard template of the waveform. The position in time of these features is then determined with respect to a high speed clock (70). The results are then used in a weighted computation to determine the time of arrival of the waveform at the transducer (63).

Abstract: An ultrasonic measurement system performs a signal path measurement by directing ultrasonic signals through a gaseous material in a conduit, and processing the detected signals to determine sound speed and to derive the average molecular weight of an unknown hydrocarbon mixture present in the material. The processor includes a plurality of stored tables of critical constants of hydrocarbon mixtures as a function of the average molecular weight of the mixture, and is configured to iteratively set a hypothetical molecular weight, determine the corresponding critical properties, and compute a predicted sound speed. If the two speeds differ, a new weight is set and the procedure is repeated until the predicted sound speed matches the measured speed, indicating that the current estimate is the correct average molecular weight.

Abstract: An apparatus and related method for measuring the properties and individual flow rates of a two-phase flow comprising a gas and a liquid is disclosed. This apparatus and related method also can determine whether the liquid is travelling in primarily a mist or stratified flow. More precisely, one embodiment of the disclosed invention uses measured parameters such as gain, standard deviation in upstream and downstream travel times for an ultrasonic signal, measured speed of sound, noise, signal quality, batch failure rate, and velocity profile to infer the amount of liquid in the gas flow, and in what form the liquid is travelling. For a horizontal two-phase flow, an internal measurement can be used as a dry gas reference, although the invention is also applicable to a vertical flow. For increased confidence, these determinations may be corroborated by the disclosed liquid level measurement device.

Abstract: A transit time ultrasonic fluid flow sensor is configured as a self contained modular unit that does not rely on acoustic transmissions through or reflected by a pipe for operation. A highly efficient transducer assembly transmits and receives signals which are well isolated from each other and which enables simplification of the supporting electronics. Continuous wave transmission and reception of the acoustic signals, and provision for acoustic path and electronic drifts enable the sensors to be physically small and yet to exhibit high sensitivity and measurement precision. Some versions of the apparatus sense flow along two orthogonal axes. In addition, electrolytic cleaning is provided for some versions of the sensor.