US3818757A — Dual path ultrasonic fluid flow metering system a…

Claim 1

Independent Claim 115 words

In a fluid flow metering system of the type including first and second transducers spaced in relative upstream-downstream positions in communication with the fluid to be metered, means for applying signals for alternate periods to said first and second transducers for transmission through the fluid, means for receiving transmitted signals sensed by the second and first transducers respectively during the alternate periods, a voltage controlled oscillator, means responsive to the transit time of said transmitted signals serving to generate a control voltage for controlling the frequency of said oscillator, and means for determining the difference in number of oscillator output cycles during upstream and downstream transmission periods and providing an output signal indicative of flow.

Claim 2

Dependent Claim 115 words

In a fluid flow metering system of the type including first and second transducers spaced in relative upstream-downstream positions in communication with the fluid to be metered, means for applying signals for alternate periods to said first and second transducers for transmission through the fluid, means for receiving transmitted signals sensed by the second and first transducers respectively during the alternate periods, a voltage controlled oscillator, means responsive to the transit time of said transmitted signals serving to generate a control voltage for controlling the frequency of said oscillator, and means for determining the difference in number of oscillator output cycles during upstream and downstream transmission periods and providing an output signal indicative of flow.

Claim 3

Dependent Claim 81 words

A fluid flow metering system as in claim 1 wherein said means for controlling the frequency of said oscillator comprises means for generating a reference signal after a predetermined number of output cycles from said oscillator following the transmission of a signal, and means for time comparing said transmitted and reference signals and using the result of the comparison to generate said control voltage to vary the frequency of said oscillator until said reference and transmitted signals are in time coincidence.

Claim 4

Dependent Claim 92 words

A system as in claim 2 wherein the means for generating a reference signal comprises a pulse divider, circuit means enabling said divider with a VCO pulse, first pulse generating means activated by output from said divider after a predetermined number of VCO pulses and producing a first pulse having a predetermined dwell time, and second pulse generating means activated by the end of the first pulse, whereby said second pulse is the reference signal delayed for the predetermined number of VCO output periods plus the dwell time of the first pulse.

Claim 5

Dependent Claim 108 words

A fluid flow metering system as in claim 2 wherein the means for time comparing said transmitted and reference signals comprises first circuit means responsive to the time of arrival of the transmitted signal, second circuit means generating a constant charge pulse, third circuit means to produce one polarity of constant charge for an early transmitted signal and the opposite polarity for a late transmitted signal, and integrating means connected to the VCO input to receive the constant charge pulses of varying polarity, whereby the VCO output frequency will rise as a result of an early transmitted signal and fall as a result of a late transmitted signal.

Claim 6

Dependent Claim 56 words

A fluid flow metering system as in claim 4 together with fail-safe alarm indication comprised of retriggerable circuit means responsive to change from early to late or late to early transmitted signal and having an output with a predetermined dwell time, whereby the output is maintained as long as a change occurs within the dwell time.

Claim 7

Dependent Claim 111 words

A fluid flow metering system as in claim 1 wherein said means for determining the difference in number of oscillator output cycles for upstream and downstream periods comprises a variable time base circuit providing a defined period of upstream and downstream counting, circuit means to disable said variable time base between periods, a decade register, a binary register, circuit means connected to said variable time base and said registers to disable said time base and change the transmit-receive modes of the transducers between periods and direct alternate up and down counting of cycles during alternate counting periods, whereby the difference in counted cycles is displayed as a calibrated indication of flow.

Claim 8

Dependent Claim 70 words

A fluid flow metering system as in claim 6 wherein said variable time base circuit comprises a crystal oscillator providing a clock frequency, a counting register providing an output when filled, having the clock frequency connected to the input, and a program to load said register with a predetermined initial count, whereby a predetermined period of time from beginning of count to output from the register when filled is obtained.

Claim 9

Dependent Claim 125 words

A fluid flow metering system as in claim 1 wherein said means for receiving transmitted signals sensed by the transducers comprises circuit means providing a push-pull form of said received transmitted signal, a low level detector connected to the push-pull output, circuit means providing automatic gain control to maintain the push-pull output at a desired level of amplitude, a differentiator set to operate at maximum slew rate with the detector signal input, a received pulse voltage comparator providing output with a time delay from the first sound point with the differentiator signal input, a pulse-shaper circuit, and circuit means responsive to the comparator output presenting a signal to said pulse-shaper, and circuit means connecting the shaped pulse to said means for controlling the VCO frequency.

Claim 10

Dependent Claim 56 words

A fluid flow metering system as in claim 8 wherein said circuit means responsive to the comparator output comprises a cross-over comparator in parallel with said detector and receiving the sensed transmitted signals, a gate enabled by said received pulse comparator and triggered by the cross-over comparator, whereby the pulse-shaper is fired by the gate output.

Claim 11

Dependent Claim 42 words

A fluid flow metering system as in claim 8 wherein said circuit means responsive to the comparator output comprises a switch connecting said received pulse comparator to said pulse-shaper, whereby error induced by excessive phase noise in the transmitted pulse is eliminated.

Claim 12

Dependent Claim 129 words

Apparatus as in claim 8 wherein the low level detector comprises first and second junction FET''s, a capacitor coupling between the gate of the first FET and the drain of the second FET, a capacitor coupling between the gate of the second FET and the drain of the first FET, a positive voltage supply, first and second resistances between the positive voltage and the drains, an inverted signal applied to the gate of the first FET, a non-inverted signal applied to the gate of the second FET, an emitter follower, a common connection between the sources of the first and second FET''s and the base of the emitter follower, whereby all the pulses from the inverted and the non-inverted signals of one polarity appear at the emitter follower output.

Claim 13

Dependent Claim 123 words

Apparatus as in claim 8 wherein the low level detector comprises a first junction FET and a second junction FET, a common connection between the gates of the first and second junction FET''s, an inverted signal capacitor coupled to the drain of the first junction FET, a non-inverted signal capacitor coupled to the drAin of the second FET, a potential placed on the gates at the signal ground, an emitter follower, a negative voltage supply, a resistance between the negative voltage and the emitter, a common connection between the sources of the first and second junction FET''s and the base of the emitter follower, whereby all the pulses from the inverted and non-inverted signals of one polarity appear at the emitter follower output.

Claim 14

Dependent Claim 95 words

A fluid flow metering system as in claim 8 wherein the means for applying signals for alternate periods to said first and second transducers comprises circuit means generating a transmit pulse actuated by a VCO pulse, a transmit pulse amplifier, circuit means providing automatic gain control for said transmit amplifier responsive to the signal from said push-pull amplifier automatic gain control, and an alarm comparator responsive to said transmit amplifier output, whereby the transmit amplifier gain is held high enough to provide adequate received signal and alarm indication when the amplifier gain is at maximum.

Claim 15

Dependent Claim 233 words

A fluid flow metering system for measuring fluid flow, comprising first and second transducers spaced generally in relative upstream-downstream positions in communication with the fluid, a voltage controlled oscillator to provide a continuous series of output pulses, a divider adjusted to receive said oscillator pulses and provide a delayed output pulse after a predetermined number of pulses are received from the oscillator, a transmit pulse generator, a control circuit connected to simultaneously initiate the divider and transmit pulse generator, circuit means to connect the transmit pulse to the first transducer during the period transmission is upstream and to the second transducer during the period transmission is downstream, a received signal processing circuit, circuit means to conduct the received pulse to the received signal processing circuit from the second transducer during the period transmission is upstream and from the first transducer during the period transmission is downstream, a time of arrival circuit connected to receive the received signal and delayed pulse and provide an output signal which is a function of the time of arrival of the pulses, means connecting the time of arrival output to the VCO to alter the VCO output frequency and cause the delayed pulse to assume time coincidence with the received pulse, and a data count circuit to determine the difference between the VCO output pulses for predetermined periods of time within the period of transmission upstream and downstream.

Claim 16

Dependent Claim 233 words

A fluid flow metering system for measuring fluid flow, comprising first and second transducers spaced generally in relative upstream-downstream positions in communication with the fluid, a voltage controlled oscillator to provide a continuous series of output pulses, a divider adjusted to receive said oscillator pulses and provide a delayed output pulse after a predetermined number of pulses are received from the oscillator, a transmit pulse generator, a control circuit connected to simultaneously initiate the divider and transmit pulse generator, circuit means to connect the transmit pulse to the first transducer during the period transmission is upstream and to the second transducer during the period transmission is downstream, a received signal processing circuit, circuit means to conduct the received pulse to the received signal processing circuit from the second transducer during the period transmission is upstream and from the first transducer during the period transmission is downstream, a time of arrival circuit connected to receive the received signal and delayed pulse and provide an output signal which is a function of the time of arrival of the pulses, means connecting the time of arrival output to the VCO to alter the VCO output frequency and cause the delayed pulse to assume time coincidence with the received pulse, and a data count circuit to determine the difference between the VCO output pulses for predetermined periods of time within the period of transmission upstream and downstream.

Claim 17

Dependent Claim 146 words

In a fluid flow measuring system of the type including first and second transducers spaced in the direction of fluid flow in communication with the fluid to be metered, means for applying input signals alternately to said first and second transducers for a predetermined period of time to transmit signals through said fluid alternately in an upstream and downstream direction from one transducer towards the other to develop output signals in said other transducer, means responsive to the time between said input and output signals for generating control voltages representative of an upstream and downstream transit time of said signals, a voltage controlled oscillator connected to receive said control signals and oscillating at first and second frequencies representative of the upstream and downstream transit times, and means for measuring the difference in oscillation frequency for upstream and downstream transmission to provide an output indicative of flow.

Claim 18

Dependent Claim 146 words

In a fluid flow measuring system of the type including first and second transducers spaced in the direction of fluid flow in communication with the fluid to be metered, means for applying input signals alternately to said first and second transducers for a predetermined period of time to transmit signals through said fluid alternately in an upstream and downstream direction from one transducer towards the other to develop output signals in said other transducer, means responsive to the time between said input and output signals for generating control voltages representative of an upstream and downstream transit time of said signals, a voltage controlled oscillator connected to receive said control signals and oscillating at first and second frequencies representative of the upstream and downstream transit times, and means for measuring the difference in oscillation frequency for upstream and downstream transmission to provide an output indicative of flow.

Claim 19

Independent Claim 135 words

The method of measuring fluid flow which comprises transmitting signals through the fluid for alternate periods upstream and downstream of the flow, initiating a reference signal at the same time as the transmitted signal, delaying the reference signal for a predetermined period of time, receiving the transmitted signal, comparing the times of the received and delayed signals, generating a control signal determined by the time comparison, varying the frequency oF a single voltage controlled oscillator responsive to the control signal for upstream and downstream received signals during said alternate periods, accumulating a number of oscillator cycles for a predetermined time during the downstream transmission period, subtracting a number of oscillator cycles for the predetermined time during the upstream transmission period, and scaling the remaining number of oscillator cycles to provide an indication of fluid flow.

Claim 20

Independent Claim 135 words

The method of measuring fluid flow which comprises transmitting signals through the fluid for alternate periods upstream and downstream of the flow, initiating a reference signal at the same time as the transmitted signal, delaying the reference signal for a predetermined period of time, receiving the transmitted signal, comparing the times of the received and delayed signals, generating a control signal determined by the time comparison, varying the frequency oF a single voltage controlled oscillator responsive to the control signal for upstream and downstream received signals during said alternate periods, accumulating a number of oscillator cycles for a predetermined time during the downstream transmission period, subtracting a number of oscillator cycles for the predetermined time during the upstream transmission period, and scaling the remaining number of oscillator cycles to provide an indication of fluid flow.

Claim 21

Independent Claim 242 words

A method for measurement of fluid flow utilizing at least one pair of first and second ultrasonic energy transducers capable of functioning as transmitters and receivers in communication with the fluid which comprises generating an energy pulse at the otput of a voltage controlled oscillator, transmitting the energy pulse through the medium for which the flow is to be measured first in a generally upstream direction and then in a generally downstream direction, providing a delayed pulse responsive to the energy pulse and to a predetermined number of cycles of said oscillator, receiving the energy pulse which has been transmitted through the medium, processing the received pulse to provide a pulse representing the received pulse time of arrival, comparing the processed-received pulse time of arrival with the time of arrival of the delayed pulse, generating a control voltage from the comparison, applying the control voltage to the voltage controlled oscillator driving the oscillator output to a higher frequency for an early processed-received pulse and to a lower frequency for a late processed-received pulse, counting the number of cycles produced by said oscillator when the processed-received pulse and the delayed pulse substantially coincide in time for both upstream and downstream transmissions, obtaining a difference between the upstream count and the downstream count, and calibrating the count by predetermining the amount of time the count should be accumulated both upstream and downstream so that the difference will directly represent desired units of flow measurement.

Claim 22

Independent Claim 242 words

A method for measurement of fluid flow utilizing at least one pair of first and second ultrasonic energy transducers capable of functioning as transmitters and receivers in communication with the fluid which comprises generating an energy pulse at the otput of a voltage controlled oscillator, transmitting the energy pulse through the medium for which the flow is to be measured first in a generally upstream direction and then in a generally downstream direction, providing a delayed pulse responsive to the energy pulse and to a predetermined number of cycles of said oscillator, receiving the energy pulse which has been transmitted through the medium, processing the received pulse to provide a pulse representing the received pulse time of arrival, comparing the processed-received pulse time of arrival with the time of arrival of the delayed pulse, generating a control voltage from the comparison, applying the control voltage to the voltage controlled oscillator driving the oscillator output to a higher frequency for an early processed-received pulse and to a lower frequency for a late processed-received pulse, counting the number of cycles produced by said oscillator when the processed-received pulse and the delayed pulse substantially coincide in time for both upstream and downstream transmissions, obtaining a difference between the upstream count and the downstream count, and calibrating the count by predetermining the amount of time the count should be accumulated both upstream and downstream so that the difference will directly represent desired units of flow measurement.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-06-24	1977-12-24	1978-06-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-06-24	1981-12-24	1982-06-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-06-24	1985-12-24	1986-06-25	$7700.00	Window Closed / Lapsed

Dual path ultrasonic fluid flow metering system and method

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag