Acoustic flowmeter
First Claim
1. An improvement in a monitoring circuit for an acoustic flowmeter of the type including a pair of ultrasonic transceivers at facing, longitudinally spaced locations along a conduit for producing alternating electrical output signals, each in response to the other, said electrical signals differing in phase by an amount corresponding to the rate of fluid flow in said conduit, oscillator means for feeding a predetermined alternating electrical input signal to said transceivers, said monitoring circuit being coupled to said transceivers for receiving the output signals produced thereby and for producing responsive output signals which correspond to the rate of fluid flow, the improvement comprising:
- a pair of phase responsive circuit means responsive respectively to the two transceivers output signals for producing pairs of pulse signals having a phase difference therebetween which corresponds in a predetermined fashion to the phase difference between said output signals from the respective transceivers, both of said phase responsive circuit means including phase shifting means for producing a pair of phase-shifted pulse signals having a predetermined minimum phase difference therebetween, even in response to a zero phase difference between the transceiver output signals, comparing means responsive to said pairs of pulse signals for producing a gating signal having a duration which corresponds to the difference in phase between said pairs of pulse signals and gating means coupled to said oscillator means and responsive to said gating signal for gating through a portion of said predetermined alternating signal corresponding in a predetermined fashion to the rate of fluid flow through said conduit means.
0 Assignments
0 Petitions
Accused Products
Abstract
An improvement in an acoustic flowmeter of the type utilizing a pair of longitudinally spaced transceivers mounted to a fluid-carrying conduit and an oscillator feeding predetermined alternating signals to the transceivers. The improvement lies in a novel monitoring circuit which comprises a phase responsive circuit for producing signals corresponding substantially only to the phase difference between the signals produced by the respective transceivers for developing an output signal which corresponds in a predetermined fashion to the rate of fluid flow through the conduit.
-
Citations
21 Claims
-
1. An improvement in a monitoring circuit for an acoustic flowmeter of the type including a pair of ultrasonic transceivers at facing, longitudinally spaced locations along a conduit for producing alternating electrical output signals, each in response to the other, said electrical signals differing in phase by an amount corresponding to the rate of fluid flow in said conduit, oscillator means for feeding a predetermined alternating electrical input signal to said transceivers, said monitoring circuit being coupled to said transceivers for receiving the output signals produced thereby and for producing responsive output signals which correspond to the rate of fluid flow, the improvement comprising:
- a pair of phase responsive circuit means responsive respectively to the two transceivers output signals for producing pairs of pulse signals having a phase difference therebetween which corresponds in a predetermined fashion to the phase difference between said output signals from the respective transceivers, both of said phase responsive circuit means including phase shifting means for producing a pair of phase-shifted pulse signals having a predetermined minimum phase difference therebetween, even in response to a zero phase difference between the transceiver output signals, comparing means responsive to said pairs of pulse signals for producing a gating signal having a duration which corresponds to the difference in phase between said pairs of pulse signals and gating means coupled to said oscillator means and responsive to said gating signal for gating through a portion of said predetermined alternating signal corresponding in a predetermined fashion to the rate of fluid flow through said conduit means.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
11. An improved monitoring circuit for an acoustic flowmeter of the type including a pair of ultrasonic transceivers at opposing, longitudinally spaced locations along a conduit and each producing an alternating electrical received signal, the two received signals differing in phase by an amount corresponding to the rate of fluid flow in said conduit and oscillator means for feeding a predetermined alternating electrical signal to be transmitted by each of said transceivers, said monitoring circuit comprising:
- phase responsive means responsive to the received signals for producing corresponding pulse signals having a phase difference therebetween which corresponds in a predetermined fashion to the difference in phase between said received signals, comparing means responsive to said pulse signals for producing a corresponding gating signal having a pulse width which corresponds to the phase difference between said pulse signals, gating means coupled to said oscillator means and responsive to said gating signal for gating through a portion of the alternating signal from the oscillator which corresponds to the rate of fluid flow through said conduit means, and wherein said comparing means further includes integrating circuit means for producing a gating signal which corresponds in a predetermined fashion to the integral of phase difference between a plurality of said pulse signals over a predetermined time interval.
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
-
20. A monitoring circuit for an acoustic flowmeter of the type including a pair of ultrasonic transceivers at facing, longitudinally spaced locations along a conduit for producing alternating electrical output signals one in response to the other, said electrical signals differing in phase by an amount corresponding to the rate of fluid flow in said conduit, oscillator means for feeding a predetermined alternating electrical input signal to said transceivers, said monitoring circuit being coupled to said transceivers for receiving the output signals produced thereby and for producing responsive output signals which correspond to the rate of fluid flow;
- said monitoring circuit comprising;
phase responsive means for producing pairs of pulse signals having a phase relationship therebetween which corresponds in a predetermined fashion to the phase relationship between said output signals from the respective transceivers, comparing means responsive to said pairs of pulse signals for producing a gating signal having a duration which corresponds to the difference in phase between said pairs of pulse signals, gating means coupled to said oscillator means and responsive to said gating signal for gating through a portion of said predetermined alternating signal corresponding in a predetermined fashion to the rate of fluid flow through said conduit means, zeroing circuit means selectable at predetermined times for substituting said oscillator signal for said transceiver output signals at said phase responsive means, and producing a zeroing signal corresponding in a predetermined fashion to the phase difference between said pairs of pulse signals produced in response to said oscillator signal, said phase responsive means being further responsive at times other than said predetermined time to the zeroing signal thus established for modifying the phase difference between said pairs of pulse signals in accordance therewith, thereby modifying said gating signal by a corresponding amount so as to reference said gating signal against a signal representing zero flow, temperature sensor means mounted to said conduit for producing a temperature signal corresponding to the temperature of the fluid flowing through said conduit, and temperature compensation circuit means coupled with said comparing means and responsive to said temperature signal for modifying said gating signal in a predetermined fashion to compensate for the difference in the temperature of said fluid from a predetermined reference temperature.
- said monitoring circuit comprising;
-
21. An improvement in a monitoring circuit for an acoustic flowmeter of the type including a pair of ultrasonic transceivers at facing, longitudinally spaced locations along a conduit for producing alternating electrical output signals, each in response to the other, said electrical signals differing in phase by an amount corresponding to the rate of fluid flow in said conduit, oscillator means for feeding a predetermined alternating electrical input signal to said transceivers, said monitoring circuit being coupled to said transceivers for receiving the output signals produced thereby and for producing responsive output signals which correspond to the rate of fluid flow, the improvement comprising:
- a pair of phase responsive circuit means responsive respectively to the two transceivers output signals for producing pairs of pulse signals having a phase difference therebetween which corresponds in a predetermined fashion to the phase difference between said output signals from the respective transceivers, at least one of said phase responsive circuit means including phase shifting means for producing a predetermined minimum phase difference between said pulse signals in response to a zero phase difference between the transceiver output signals, comparing means responsive to said pairs of pulse signals for producing a gating signal having a duration which corresponds to the difference in phase between said pairs of pulse signals, gating means coupled to said oscillator means and responsive to said gating signal for gating through a portion of said predetermined alternating signal corresponding in a predetermined fashion to the rate of fluid flow through said conduit means, and zeroing circuit means selectable at predetermined times for substituting said oscillator signal for said transceiver output signals at both of said phase responsive circuit means and producing a zeroing reference signal corresponding to the phase difference between the pairs of pulse signals produced in response to said oscillator signals, said phase shifting means being further responsive at times other than said predetermined times to said zeroing signal thus established for modifying said predetermined minimum phase difference between said pairs of pulse signals in accordance therewith, thereby modifying said gating signal by a corresponding amount so as to reference said gating signal against a signal representing zero flow.
Specification