Digital flowmeter
First Claim
Patent Images
1. A controller for a flowmeter comprising:
- an input module operable to receive a sensor signal from a sensor connected to a vibratable flowtube, the sensor signal related to a fluid flow through the flowtube;
a signal processing system operable to receive the sensor signal, determine sensor signal characteristics, and output drive signal characteristics for a drive signal applied to the flowtube;
an output module operable to output the drive signal to the flowtube; and
a control system operable to modify the drive signal and thereby maintain oscillation of the flowtube during a time in which an apparent density of the fluid flow, as determined by the signal processing system based on the sensor signal characteristics, drops by more than ten percent in response to an introduction of gas within the fluid flow.
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Accused Products
Abstract
A flowmeter includes a vibratable conduit, a driver connected to the conduit and operable to impart motion to the conduit, and a sensor connected to the conduit and operable to sense the motion of the conduit. A control and measurement system is connected to the driver and the sensor. The control and measurement system includes circuitry to receive a sensor signal from the sensor, generate a drive signal based on the sensor signal, supply the drive signal to the driver, and generate a measurement of a property of material flowing through the conduit based on the sensor signal.
115 Citations
46 Claims
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1. A controller for a flowmeter comprising:
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an input module operable to receive a sensor signal from a sensor connected to a vibratable flowtube, the sensor signal related to a fluid flow through the flowtube;
a signal processing system operable to receive the sensor signal, determine sensor signal characteristics, and output drive signal characteristics for a drive signal applied to the flowtube;
an output module operable to output the drive signal to the flowtube; and
a control system operable to modify the drive signal and thereby maintain oscillation of the flowtube during a time in which an apparent density of the fluid flow, as determined by the signal processing system based on the sensor signal characteristics, drops by more than ten percent in response to an introduction of gas within the fluid flow. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for operating a flowmeter comprising:
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receiving a sensor signal from a sensor connected to a vibratable flowtube, the sensor signal related to a fluid flow through the flowtube;
processing the sensor signal to determine sensor signal characteristics, determining, based on the sensor signal characteristics, drive signal characteristics for a drive signal applied to the flowtube, the drive signal characteristics including a drive gain;
determining, based on the sensor signal characteristics, a flow transition characterized by the drive gain rising in conjunction with a reduction in an apparent density of the fluid flow; and
transitioning the flowmeter from a first state in which a substantially non-aerated fluid flow exists in the flowtube to a second state in which an aerated fluid flow exists in the flowtube, based on the flow transition. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A flowmeter comprising:
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a vibratable conduit conducting a fluid flow;
a driver connected to the conduit and operable to impart a motion to the conduit;
a sensor connected to the conduit and operable to sense the motion of the conduit; and
a control and measurement system connected to the driver and the sensor, the control and measurement system comprising circuitry to;
receive a first sensor signal from the sensor during a non-aerated fluid flow through the conduit;
generate, based on the first sensor signal and using digital signal processing, a first drive signal having a drive frequency, the first drive signal having a drive gain based on the first sensor signal;
receive a second sensor signal from the sensor upon introduction of gas to the fluid flow, the gas comprising more than five percent by volume of a total fluid flow;
generate a second drive signal based on the second sensor signal and using digital signal processing; and
update the drive gain in response to the introduction of the gas at a drive gain update rate, wherein the drive gain update rate is at least five percent of the drive frequency. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A controller for a flowmeter comprising:
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an input module operable to receive a sensor signal from a sensor connected to a vibratable flowtube, the sensor signal related to a fluid flow through the flowtube;
a signal processing system operable to receive the sensor signal, determine sensor signal characteristics using digital signal processing, and output drive signal characteristics for a drive signal applied to the flowtube, the drive signal characteristics including a drive gain to be applied to the drive signal;
a control system operable to modify the drive signal and thereby maintain oscillation of the flowtube at a determined oscillation frequency, wherein the drive gain is modified in response to a change in condition of the fluid flow, as necessary to maintain the oscillation of the flowtube, such that the drive gain incrementally changes at least once per forty cycles of the oscillation frequency; and
an output module operable to output the drive signal to the flowtube. - View Dependent Claims (26, 27, 28, 29, 30)
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31. A flowmeter comprising:
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a vibratable conduit;
a driver connected to the conduit and operable to impart a motion to the conduit;
a sensor connected to the conduit and operable to sense the motion of the conduit; and
a control and measurement system connected to the driver and the sensor, the control and measurement system comprising circuitry to;
receive a first sensor signal from the sensor at a first mass flow rate of fluid through the conduit;
generate, based on the first sensor signal, a measurement output characterizing a property of the fluid;
receive a second sensor signal from the sensor upon a change of the first mass flow rate to a second mass flow rate; and
update, based on the second sensor signal, the measurement output at an update rate that is at least five percent of an oscillation frequency of the conduit. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. A controller for a flowmeter comprising:
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an input module operable to receive a sensor signal from a sensor connected to a flowtube oscillating at an oscillation frequency, the sensor signal related to a flow of a fluid through the flowtube;
a signal processing system operable to receive the sensor signal, determine sensor signal characteristics using digital signal processing, and output a measurement output characterizing a property of the fluid flow; and
a control system operable to modify the measurement output in response to a change in condition of the fluid flow, to thereby obtain a modified measurement output, wherein a response time between the change in condition of the fluid flow and an outputting of the modified measurement output is less than 100 ms. - View Dependent Claims (41, 42, 43, 44, 45, 46)
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Specification