Method and apparatus for determining a change of the flow state of flowable substances from its static state to its flowing state or vice verse
First Claim
1. A method of determining a change of the flow state of a flowable substance, comprising the steps of:
- transmitting ultrasonic waves of substantially constant frequency to a spatial region of the substance;
receiving ultrasonic waves backscattered by the substance;
transforming the backscattered ultrasonic waves into a primary signal which is amplitude and phase modulated in accordance with the backscattering;
demodulating the primary signal to obtain a modulation signal which can be subdivided into a spectrum of signal components of different frequencies and possessing pseudo periods which are defined as the time spacing between successive mutually corresponding momentary values of the signal modulation;
determining at least one time point at a mean value of the psuedo periods having a monotonous variation with time which entails a monotonous variation with time of the time duration of a predetermined number of pseudo periods;
comparing a time duration corresponding to a predetermined number of pseudo periods with a predetermined time duration; and
whereinthe time duration of the predetermined number of pseudo periods traverses the predetermined time duration in the course of its monotonous variation with time.
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Abstract
A method and apparatus for determining a change of the flow state of a flowable substance by transmitting ultrasonic or ultrasound waves of constant frequency to a spatial region of the substance, receiving ultrasonic waves backscattered by the substance, converting the backscattered ultrasonic waves into a primary signal which is amplitude- and phase-modulated in accordance with the backscattering and demodulating the primary signal in order to obtain a modulation signal. This modulation signal can be divided into a spectrum of signal components of different frequency and possessing pseudo periods which are defined as the time intervals between successive momentary values of the modulation signal, such momentary values corresponding to one another. The time duration corresponding to a predetermined number of pseudo periods is compared with a predetermined time duration.
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Citations
18 Claims
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1. A method of determining a change of the flow state of a flowable substance, comprising the steps of:
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transmitting ultrasonic waves of substantially constant frequency to a spatial region of the substance; receiving ultrasonic waves backscattered by the substance; transforming the backscattered ultrasonic waves into a primary signal which is amplitude and phase modulated in accordance with the backscattering; demodulating the primary signal to obtain a modulation signal which can be subdivided into a spectrum of signal components of different frequencies and possessing pseudo periods which are defined as the time spacing between successive mutually corresponding momentary values of the signal modulation; determining at least one time point at a mean value of the psuedo periods having a monotonous variation with time which entails a monotonous variation with time of the time duration of a predetermined number of pseudo periods; comparing a time duration corresponding to a predetermined number of pseudo periods with a predetermined time duration; and
whereinthe time duration of the predetermined number of pseudo periods traverses the predetermined time duration in the course of its monotonous variation with time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for determining a change of the flow state of a flowable substance, comprising:
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a signal generator for producing a reference signal of substantially constant frequency; said signal generator having an output side; an ultrasonic transmitter arranged in circuit with the output side of the signal generator for transmitting ultrasonic waves corresponding to the reference signal to a spatial region of the substance; an ultrasonic receiver for receiving ultrasonic waves which are backscattered at the substance and for converting such backscattered ultrasonic waves into a primary signal which is amplitude and phase modulated in accordance with the backscattering; a demodulator for obtaining a modulation signal from said primary signal; an analyser for detecting signal components of the modulation signal; said analyser being structured to comprise a detector which delivers a detector signal upon the presence of a predetermined momentary value of the modulation signal; said detector having an output side; a pulse generator connected with the output side of said detector; said pulse generator delivering a predetermined pulse upon reception of a detector signal; said pulse generator having an output side; said analyser further comprising at least one analysis device connected in circuit with the output side of said pulse generator; said analysis device comprising an integrator having an output side and possessing charging and discharging time constants and a comparator connected at the ouput side of the integrator; and said analysis device serving for the integration of a pulse train formed from the pulses, for the comparison of the result of the integration with a predetermined threshold value and for delivering an analysis signal upon the presence of a predetermined result of the comparison. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An apparatus for determining a change of the flow state of a flowable substance, comprising:
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a signal generator for producing a reference signal of substantially constant frequency; said signal generator having an output side; an ultrasonic transmitter arranged in circuit with the output side of the signal generator for transmitting ultrasonic waves corresponding to the reference signal to a predetermined region of the substance; an ultrasonic receiver for receiving ultrasonic waves which are backscattered at the substance and for converting such backscattered ultrasonic waves into a primary signal which is modulated in accordance with the backscattering; a demodulator for obtaining a modulation signal from said primary signal; an analyser for detecting signal components of the modulation signal; said analyser comprising a detector which delivers a detector signal upon the presence of a predetermined momentary value of the modulation signal; said detector having an output side; a pulse generator connected with the output side of said detector; said pulse generator delivering a predetermined pulse upon reception of a detector signal; said pulse generator having an output side; said analyser further comprising at least one analysis device connected in circuit with the output side of said pulse generator; said analysis device containing an integrator having charging and discharging time constants and a comparator connected to the output side of the integrator; and said analysis device serving for the integration of a pulse train formed from the pulses, for the comparison of the result of the integration with a predetermined threshold value and for delivering an analysis signal upon the presence of a predetermined result of the comparison.
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Specification