摘要:
A wedge unit according to the present invention is used for an ultrasonic Doppler flow meter, being mounted on the outer wall of a pipe in which a fluid flows, supplying an ultrasonic wave to the fluid, receives the reflected wave and supplies the reflected wave to a flow rate calculation unit, comprises a wedge with one surface thereof being mounted on a part of the outer circumference of the pipe and on another surface thereof being equipped with an ultrasonic oscillator that generates the ultrasonic wave in response to an electric signal and receives the reflected wave; and an ultrasonic wave attenuation unit being mounted on the outer circumference of the pipe so as to include a position where an ultrasonic wave injected from the ultrasonic oscillator into the pipe by way of the wedge first reaches the outer wall of the pipe after being reflected by the inner wall thereof.
摘要:
A wedge unit according to the present invention is used for an ultrasonic Doppler flow meter, being mounted on the outer wall of a pipe in which a fluid flows, supplying an ultrasonic wave to the fluid, receives the reflected wave and supplies the reflected wave to a flow rate calculation unit, comprises a wedge with one surface thereof being mounted on a part of the outer circumference of the pipe and on another surface thereof being equipped with an ultrasonic oscillator that generates the ultrasonic wave in response to an electric signal and receives the reflected wave; and an ultrasonic wave attenuation unit being mounted on the outer circumference of the pipe so as to include a position where an ultrasonic wave injected from the ultrasonic oscillator into the pipe by way of the wedge first reaches the outer wall of the pipe after being reflected by the inner wall thereof.
摘要:
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.
摘要:
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.
摘要:
A clamp-on type acoustic Doppler current profiler eliminates, among ultrasound echoes caused by two measurement lines of a longitudinal wave and a shear wave propagating in a piping, the ultrasound echo based on the longitudinal wave, thereby providing the measurement of a flow rate profile and/or a flow rate with a higher accuracy. The profiler includes a wedge mounted to the piping. The wedge includes an inclined surface at which an ultrasonic transducer can be mounted. The inclination is such that the ultrasound transducer receives only the ultrasound echo from the reflection of a shear wave component off the reflectors in the fluid.
摘要:
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.
摘要:
In a doppler type ultrasonic flow meter 1 for measuring the volumetric flow of a measurement object fluid 10 using doppler shift of ultrasound, 1 pair of ultrasonic transducers 3a, 3b perform transmission of ultrasound and reception of an ultrasound echo resulting from the ultrasound being reflected. The 1 pair of 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.
摘要:
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. The values serving as an index of the reliability of the reception wave may be the amplitude of the reception wave, the ratio of the amplitude of the reception wave against a predetermined measurable amplitude value, the ratio of the power spectrum against a predetermined power value, the ratio of transmission wave amplitude against the maximum amplitude of the reception wave, the ratio of the power spectrum of the transmission frequency included in the reception wave and obtained by Fourier transform of the reception wave against a predetermined power value, and the like.
摘要:
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).
摘要:
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.