Abstract: In the particular embodiments described in the specification, a virtual sewer flow monitor detects flow rate and depth information periodically and supplies it to a scattergraph generator and a polynomial curve generator produces a polynomial curve corresponding to the scattergraph data. A filter eliminates polynomial curve portions corresponding to normal sewer flow conditions and an SSO detector responds to curve portions indicating a sewer overflow condition to generate an alarm.

Abstract: In the particular embodiments described in the specification, the velocity of a flowing liquid is measured by emitting acoustic signals from an acoustic signal unit into the flowing liquid and detecting signals reflected from solid particles moving with the liquid and a Fast Fourier Transform is performed on the Doppler frequency signals to produce a power signal spectrum. The resolution of the power signal spectrum is expanded at the high frequency end by taking the square root of the power signals and a least squares curve fitter produces a trend line from the data points at the upper end of the spectrum. The trend line is extrapolated to the zero amplitude axis to produce a signal representing the maximum velocity of the flowing liquid and an algorithm based on the shape of the conduit through which the liquid is flowing is used to produce a signal representing the average velocity of the liquid.

Abstract: A sonic-type fluid flow measuring system wherein reflections or echoes of an ultrasonic acoustic emitter (9) are sensed and typically comprise a number of frequencies representative of a number of discrete velocities of flow in a volume of fluid. As a sample, they simply appear as a voltage plot as a function of time and wherein the time width of a given signal excursion relates to the frequency of a given signal. 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. The highest frequency, velocity, signal from each of a rapid succession of samples is then obtained and stored in a memory (38). The highest and lowest of these are then discarded, and the remaining are averaged to obtain more likely representations of velocity.

Abstract: 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.

Abstract: A sewer flow monitoring system wherein the volume of flow is determined from the depth of fluid in a pipe together with the average velocity of flow through the pipe as determined by detecting the peak velocity from particles flowing in sewage at different velocities and then determining average velocity to be approximately 90% of the peak velocity.

Abstract: A sonic-type fluid flow measuring system wherein reflections or echoes of an ultrasonic acoustic emitter are sensed and typically comprise a number of frequencies representative of a number of discrete velocities of flow in a volume of fluid. As a sample, they simply appear as a voltage plot as a function of time and wherein the time width of a given signal excursion relates to the frequency of a given signal. 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. The highest frequency, velocity, signal from each of a rapid succession of samples is then obtained and stored in a memory. The highest and lowest of these are then discarded, and the remaining are averaged to obtain more likely representations of velocity.