Abstract: In a doppler type ultrasonic flow meter (1) for measuring the volumetric flow of a measurement object fluid (10) using doppler shift of ultrasound, a pair of ultrasonic transducers (3a, 3b) perform transmission of ultrasound and reception of an ultrasound echo resulting from the ultrasound being reflected. The ultrasonic transducers (3a, 3b) are disposed on an extension line of a measurement line ML for performing measurement of doppler shift, symmetrical about the center axis (5) of a pipe (2) with a measurement object fluid (10) flowing through its inside, and on the outside of the pipe (2). A flow profile for the side opposite, with respect to the center axis (5) of the pipe (2), the side on which the respective ultrasonic transducer (3a, 3b) is disposed is used for the calculation of the volumetric flow of the measurement object fluid (10).

Abstract: In a Doppler ultrasonic flowmeter, to obtain a precise flow rate a flow rate calculation equation that corrects a quantization error occurring to a spatial resolution is used. An ultrasonic transducer transmits/receives ultrasonic pulses, and subject the resulting received signals to A/D conversion after a predetermined process is applied thereto. A computation control section calculates the flow velocity distribution. Then, the flow rate is calculated based on the flow rate calculation equation, which corrects the quantization error occurring to the spatial resolution.

Abstract: A flowmeter includes: a transit time method unit having a sensor and a reception signal amplification control unit and a flow rate calculation unit which are connected to the sensor via a sensor selector switch; a pulse Doppler method having a reception signal amplification control unit and an integration calculation unit which are connected to the sensor; a transmission/reception timing control unit common to them; a measurement method selection control unit for controlling switching between the transit time method unit and the pulse Doppler method unit, and parallel operation; and a measurement value output selector switch for selecting the output of the transit time method unit and the pulse Doppler method unit. That is, the single flowmeter can perform flow rate measurement by the transit time method having no restriction on the measurement range as well as by the pulse Doppler method having an upper limit of the measurement range but enabling a highly accurate measurement.

Abstract: An apparatus and method for measuring a flow velocity profile of fluid traveling in a pipe or conduit uses an ultrasonic wave transmitted from an ultrasonic wave transducer mounted at an angle on the outside of a pipe using a wedge, and made incident onto the fluid in the pipe to measure the fluid flow velocity profile, using the principle that a frequency of an ultrasonic wave, reflected by a reflector existing in the fluid, is changed depending on a flow velocity due to Doppler effect. The transmission frequency and the angle of incidence onto the pipe can be selected to suppress frequency dependence of a measured value due to Lamb wave and allow the flow velocity or flow rate of fluid to be measured with a greater accuracy.

Abstract: A flowmeter includes: a transit time method unit having a sensor and a reception signal amplification control unit and a flow rate calculation unit which are connected to the sensor via a sensor selector switch; a pulse Doppler method having a reception signal amplification control unit and an integration calculation unit which are connected to the sensor; a transmission/reception timing control unit common to them; a measurement method selection control unit for controlling switching between the transit time method unit and the pulse Doppler method unit, and parallel operation; and a measurement value output selector switch for selecting the output of the transit time method unit and the pulse Doppler method unit. That is, the single flowmeter can perform flow rate measurement by the transit time method having no restriction on the measurement range as well as by the pulse Doppler method having an upper limit of the measurement range but enabling a highly accurate measurement.

Abstract: The reliability of a reception wave from a transducer is checked and when the reliability is determined to be insufficient, a method different from the current method is selected. The reliability is judged by calculating a value serving as an index of the reliability of the reception wave and checking whether the value is smaller than a predetermined set value. When the value is smaller than the set value, the reliability is judged to be insufficient.

Abstract: An apparatus and method for measuring a flow velocity profile of fluid traveling in a pipe or conduit uses an ultrasonic wave transmitted from an ultrasonic wave transducer mounted at an angle on the outside of a pipe using a wedge, and made incident onto the fluid in the pipe to measure the fluid flow velocity profile, using the principle that a frequency of an ultrasonic wave, reflected by a reflector existing in the fluid, is changed depending on a flow velocity due to Doppler effect. The transmission frequency and the angle of incidence onto the pipe can be selected to suppress frequency dependence of a measured value due to Lamb wave and allow the flow velocity or flow rate of fluid to be measured with a greater accuracy.

Abstract: In a Doppler ultrasonic flowmeter, to obtain a precise flow rate a flow rate calculation equation that corrects a quantization error occurring to a spatial resolution is used. An ultrasonic transducer transmits/receives ultrasonic pulses, and subject the resulting received signals to A/D conversion after a predetermined process is applied thereto. A computation control section calculates the flow velocity distribution. Then, the flow rate is calculated based on the flow rate calculation equation, which corrects the quantization error occurring to the spatial resolution.