Ultrasonic Flow Meter
AssigneeApator Miitors ApS
InventorJens Drachmann
Life of this patent
Estimating the term…
Abstract
A method for estimating and correcting or at least reducing phase errors in received ultrasonic signals in an ultrasonic flow meter is disclosed, the method including the steps of: measuring one or more signals in the ultrasonic flow meter, which one or more signals depend on characteristics of one or more ultrasonic transducers in the ultrasonic flow meter, using the one or more measured signals for calculating an estimated phase error value, and using the estimated phase error value for correcting transmission times measured by the ultrasonic flow meter.
Claims18
A method for estimating and correcting or at least reducing phase errors in received ultrasonic signals in an ultrasonic flow meter, said method comprising the steps of:
- measuring one or more signals in the ultrasonic flow meter, which one or more signals depend on characteristics of one or more ultrasonic transducers in the ultrasonic flow meter,
- using the one or more measured signals for calculating an estimated phase error value, and
- using the estimated phase error value for correcting transmission times measured by the ultrasonic flow meter.
A method for determining an absolute transit time of an ultrasonic signal in a flow path of an ultrasonic flow meter comprising two ultrasonic transducers, said method comprising the steps of:
- monitoring a current to an active component of a signal generator driving a transducer from one or more voltage supplies during and after a feeding of an input signal to the signal generator, thus obtaining a supply current signal for the transducer,
- emulating a flow meter response similar to an output signal from a receiver circuit of the flow meter as the output signal would be, if there was no time delay in a transmission of an ultrasonic signal between the two ultrasonic transducers,
- comparing the emulated flow meter response to a measured flow meter response actually received by the receiver circuit, and
- calculating the absolute transit time as a time difference between the emulated flow meter response and the measured flow meter response.
An ultrasonic flow meter comprising
- at least one ultrasonic transducer and
- a signal generator for generating electrical signals to the transducer, the signal generator comprising an active component, wherein
- the flow meter further includes a current measuring arrangement for measuring one or more power supply currents to the active component of the signal generator.
A method for characterizing an ultrasonic transducer, said method comprising the steps of:
- feeding a pulsating input signal to a signal generator driving the transducer, said signal generator comprising an active component,
- monitoring a current to the active component from one or more voltage supplies during and after a feeding of the input signal to the signal generator, thus obtaining one or more supply current signal, and
- determining directly from the obtained one or more supply current signal or from one or more resulting signals derived from the one or more obtained supply current signal one or more quantities useful for characterizing the transducer.
A method for determining a time delay of an ultrasonic signal in a flow path of an ultrasonic flow meter, said method comprising the steps of:
- characterizing two transducers of the flow meter by determining characteristic quantities, such as an angular frequency ωD and a damping coefficient α of dampened oscillations of the transducers,
- using the determined characteristic quantities of the transducers for finding an equivalence model of the transducers and establishing a numerical simulation model of the transducers and one of
- electronic circuits of a signal generator;
- a receiver circuit of the flow meter;
- and
- electronic circuits of a signal generator and a receiver circuit of the flow meter.
- simulating the flow meter system by entering an input signal function or a sampled version of a physical transmission signal reaching a first transducer of the transducers into the numerical simulation model, thereby obtaining a simulation model response corresponding to an output signal from the receiver circuit as it would be according to the model, if there was no time delay in a transmission of an ultrasonic signal between the two transducers,
- recording a physical flow meter response actually received by the receiver circuit, and
- calculating an absolute transit time by determining a time delay of the physical flow meter response as compared to the simulation model response.
An ultrasonic flow meter comprising
- at least one ultrasonic transducer and
- a signal processing unit for processing electrical signals received from the at least one ultrasonic transducer,
- wherein
- the signal processing unit is arranged to digitalize a continuous signal from the transducer at a sample frequency of less than twice a resonance frequency of the at least one ultrasonic transducer.
An ultrasonic flow meter comprising
- a flow path for fluid flow,
- at least two ultrasonic transducers acoustically coupled to the flow path, one transducer of the at least two transducers arranged upstream of the another transducer of the at least two transducers along the flow path,
- a signal generator for generating electrical transmission signals to the transducers, the signal generator comprising a negative feedback coupled operational amplifier,
- a receiver circuit for receiving electrical reception signals from the transducers, the receiver circuit comprising a negative feedback coupled operational amplifier,
- a switching unit for switching electrical transmission signals between the signal generator and the transducers and for switching electrical reception signal between the transducers and the receiver circuit,
- a signal processing unit for providing an output indicative of a flow rate in the flow path based on the electrical reception signals,
- wherein
- the switching unit being coupled to an output terminal of the operational amplifier of the signal generator and
- the switching unit being coupled to an inverting input terminal of the operational amplifier of the receiver circuit.
Dependencies are inferred from the claim text.