In a flow meter device of the present invention, a unit measuring step is defined as a procedure for measuring ultrasonic sound wave propagation times by changing the direction in which an ultrasonic sound wave is transmitted and received between a first transducer and a second transducer, and a time measuring means measures a propagation time in a forward direction and a propagation time in a reverse direction in a unit measuring step. A time difference detecting means detects a difference between the propagation time in the forward direction and the propagation time in the reverse direction which are measured by the time measuring means. A determiner means determines whether or not there is a fluid flow based on the time difference. According to presence/absence of a fluid flow, the number of times the unit measuring step is performed is determined. Therefore, it can be determined whether or not there is a fluid flow quickly in real time. A responsiveness can be improved such that a measuring method can be switched to correspond to presence/absence of a fluid flow.

A respiratory flow therapy apparatus including a sensor module can measure a flow rate of gases or gases concentration provided to a patient. The sensor module can be located after a blower and/or mixer. The sensor module can include at least an ultrasonic transmitter, a receiver, a temperature sensor, a pressure sensor, a humidity sensor and/or a flow rate sensor. The receivers can be immersed in the gases flow path. The receivers can cancel delays in the transmitters and improve accuracy of measurements of characteristics of the gases flow. The receivers can allow for detection of a fault condition in a blower motor of the apparatus.

A method for detection of pipeline vibrations with a measuring instrument connected to a pipeline system through which a medium to be measured flows, the measuring instrument having at least one transducer for detection of an input variable and for output of an output variable and at least one evaluation unit. The method involves detecting the input variable, relaying of an output variable based on the input variable to the evaluation unit, determinating the measured value of the measured variable from the output variable. Monitoring of the operating state of a system is achieved in that the measured variable characterizes the medium located within the pipeline system, that the sampling rate for detection of the input variable is at least twice as high as the frequency of the pipeline vibration and a frequency analysis of the brief fluctuations of the measured variable is conducted.

A flow-rate measuring apparatus transmits a first measurement signal having at least one first frequency by a first transducer, and receives the first measurement signal by a second transducer through a fluid inside a pipe. The flow-rate measuring apparatus determines a second frequency based on the first measurement signal. The flow-rate measuring apparatus transmits a second measurement signal having the second frequency by a third transducer toward an interface between the pipe and the fluid, and receives the second measurement signal reflected at the interface by a fourth transducer. The flow-rate measuring apparatus calculates a flow rate of the fluid inside the pipe so as to reflect a viscosity of the fluid based on the first and second measurement signals.

An ultrasonic flowmeter includes a conduit for receiving a flow of a fluid and a flexible printed circuit board (FPC) including: a pair of ultrasonic transducers, wherein each transducer comprises a piezoelectric element divided into a plurality of segment electrodes and the FPC is bonded around the conduit; and a control circuit configured to sequentially activate the segment electrodes using a pulse train to cause at least one of the piezoelectric elements to emit a sonic signal. A delay time between activation of each successive segment electrode controls a phase velocity and an angle of emission of the corresponding sonic signal.

An ultrasonic flow meter is disclosed, including a switching unit for switching electrical transmission signals between a signal generator and at least two ultrasonic transducers and for switching electrical reception signal between the transducers and a receiver circuit, wherein the switching unit is coupled to an output terminal of an operational amplifier of the signal generator and to an inverting input terminal of an operational amplifier of the receiver circuit. Furthermore, a method for characterizing an ultrasonic transducer is disclosed, including the step of determining directly from one or more supply current signals for an active component of a signal generator one or more quantities useful for characterizing the transducer. Furthermore, a method for determining the time delay of an ultrasonic signal in a flow path of an ultrasonic flow meter is disclosed, including the step of comparing physically transmitted, delayed and received signals with simulated non-delayed signals.

Methods and systems for configuring a fluid flow meter include a processor obtaining a measurement signal recorded by the fluid flow meter. The processor can determine a whitening frequency band. The processor can then construct a whitening filter based on the measurement signal and the whitening frequency band. The processor can then generate a reference signal based on the whitening filter and the measurement signal. The processor can provide the whitening filter and the reference signal for use by the fluid flow meter to measure a time shift between the reference signal and another measurement signal.

The invention relates to an ultrasonic flowmeter for measuring the flow speed and/or the volumetric flow rate of a fluid. In order in particular to allow a simple and inexpensive calibration of a pressure sensor in the device, the device comprising a measurement sensor, at least two ultrasonic transducers, a pressure sensor, and a calibration connector.

The present application discloses a signal processing circuit (100), coupled to a first transducer (102) and a second transducer (104), wherein the first transducer and the second transducer have a distance greater than zero, and a fluid having a flow velocity flows sequentially through the first transducer and the second transducer, the signal processing circuit includes: a first transmitter (106), coupled to the first transducer; a first receiver (108), coupled to the first transducer; a second transmitter (110), coupled to the second transducer; a second receiver (112), coupled to the second transducer; and a control unit (114), coupled to the first transmitter, the first receiver, the second transmitter and the second receiver. The present application further provides a related chip, a flow meter and a method.

An ultrasonic transducer employing a meta slab includes a piezoelectric body configured to generate elastic waves; a meta slab connected to the piezoelectric body and configured to induce elastic wave mode conversion resonance with respect to the elastic waves incident on the meta slab; and a wedge connected to the meta slab, attached to an external surface of a pipe, and configured to transmit the elastic waves having passed through the meta slab to the pipe. The meta slab includes an anisotropic medium and a thickness of the meta slab satisfies the equation as follows: d=m.Math.n.sub.FS.Math.λ.sub.FS/4, d=m.Math.n.sub.SS.Math.λ.sub.SS/4, n.sub.SS/2−n.sub.FS/2=odd. Thus, highly-efficient flow velocity measurement is possible.