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A sonic-type fluid flow measuring system wherein reflections or echoes of a burst 103 of ultrasonic energy from an ultrasonic acoustic emitter 9a are sensed and typically comprise a number of frequencies representative of a number of discrete velocities of flow in a volume of fluid. A receiver trans

A sonic-type fluid flow measuring system wherein reflections or echoes of a burst 103 of ultrasonic energy from an ultrasonic acoustic emitter 9a are sensed and typically comprise a number of frequencies representative of a number of discrete velocities of flow in a volume of fluid. A receiver transducer 13a is gated to receive echoes from a selected volume of fluid 104 a selected distance from transducer 13a. Thereafter, this time domain signal sample is converted to a frequency domain sample whereby the presence and magnitude of each frequency component, or velocity component, is isolated, this being typically done by what is known as a Fast Fourier Transform unit 42a, obtaining a frequency domain waveform representative of average flow velocity. A variable noise threshold stored in register 52a is subtracted from the waveform to remove electronic noise, and the result integrated by integrator unit 54a to compensate for the return echoes returning from a slightly curved plane of the outwardly propagating wavefront. Seven of these samples are stored, and averaged by averaging-velocity translator unit 58a to obtain an average result, which is applied to averaging-velocity translator unit 58a, which averages these stored velocities and applies the result to output unit 64a for disposition.

대표청구항 ▼

A sewer flow velocity measurement system comprising: acoustic emission means disposed within a sewer for transmitting broadly directed bursts of an acoustic signal, said bursts having a discrete duration and frequency, into a volume of moving fluid in the sewer; acoustic reception means including a

A sewer flow velocity measurement system comprising: acoustic emission means disposed within a sewer for transmitting broadly directed bursts of an acoustic signal, said bursts having a discrete duration and frequency, into a volume of moving fluid in the sewer; acoustic reception means including a transducer, and gated to receive a selected portion of Doppler shifted signals from fluid borne objects in a discrete volume of fluid at a discrete distance, said Doppler shifted signals comprising a plurality of time domain signals, frequency domain translation means responsive to said selected quantity of said time domain signals, for translating said time domain signals into a plurality of frequency domain signals; and velocity computation means responsive to said frequency domain translation means for providing as an output a signal representative of an average velocity of said fluid flow.