Impulse analysis for flow sensor-based fluid control system
First Claim
1. A flow sensor for a flow control system for controlling flow of a liquid, the flow control system having a flow passageway, the flow sensor comprising:
- a sensor element movably positioned in the flow passageway, wherein a position of the sensor element in the flow passageway is responsive to a flow rate of the liquid in the flow passageway and to a viscosity of the liquid, and further wherein the flow rate is responsive to a fluid driving pressure and a systemic flow resistance in the flow control system;
a sensor for generating a signal representative of a position of the sensor element in the flow passageway;
a processor coupled to the sensor for receiving the signal from the sensor before and after an abrupt change in the fluid driving pressure to calculate any one or more of;
the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure;
the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure;
a change in position of the sensor element in the flow passageway;
a rate of change in position of the sensor element in the flow passageway;
the flow rate before the abrupt change in the fluid driving pressure;
the flow rate after the abrupt change in the fluid driving pressure;
a change in the flow rate;
the viscosity of the liquid; and
the systemic flow resistance;
said processor calculating one or both of an axial distance between the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure and a rate of change of position of the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure; and
said processor correlating one or both of said axial distance between the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure and said rate of change of position of the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure with a viscosity.
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Abstract
A fluid flow control system using flow rate changes to extract additional information from an in-line flow sensor. The system provides the ability to determine a position of a movable flow sensor element of a flow sensor by illuminating a photosensitive pixel array with a light source to create a first set of pixel intensity values introducing an abrupt change to the fluid driving pressure, illuminating the photosensitive pixel array with a light source to create a second set of pixel intensity values, and calculating the difference between the first and second sets of pixel intensity values as a function of pixel position.
65 Citations
13 Claims
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1. A flow sensor for a flow control system for controlling flow of a liquid, the flow control system having a flow passageway, the flow sensor comprising:
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a sensor element movably positioned in the flow passageway, wherein a position of the sensor element in the flow passageway is responsive to a flow rate of the liquid in the flow passageway and to a viscosity of the liquid, and further wherein the flow rate is responsive to a fluid driving pressure and a systemic flow resistance in the flow control system; a sensor for generating a signal representative of a position of the sensor element in the flow passageway; a processor coupled to the sensor for receiving the signal from the sensor before and after an abrupt change in the fluid driving pressure to calculate any one or more of; the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure; the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure; a change in position of the sensor element in the flow passageway; a rate of change in position of the sensor element in the flow passageway; the flow rate before the abrupt change in the fluid driving pressure; the flow rate after the abrupt change in the fluid driving pressure; a change in the flow rate; the viscosity of the liquid; and the systemic flow resistance; said processor calculating one or both of an axial distance between the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure and a rate of change of position of the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure; and said processor correlating one or both of said axial distance between the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure and said rate of change of position of the position of the sensor element in the flow passageway before the abrupt change in the fluid driving pressure and the position of the sensor element in the flow passageway after the abrupt change in the fluid driving pressure with a viscosity. - View Dependent Claims (9, 10, 11, 12, 13)
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2. A method for determining flow information in a flow control system, the flow control system for controlling flow of a liquid, the flow control system having a flow passageway, a sensor element movably positioned in the flow passageway, and a sensor for generating a signal representative of a position of the sensor element in the flow passageway, wherein a position of the sensor element in the flow passageway is responsive to a flow rate of the liquid in the flow passageway and to a viscosity of the liquid, and further wherein the flow rate is responsive to a fluid driving pressure and a systemic flow resistance in the flow control system, the method comprising:
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introducing an abrupt change in fluid driving pressure; prior to introducing the abrupt change in fluid driving pressure, sampling the signal from the sensor to obtain a first measurement of sensor element position; after introducing the abrupt change in fluid driving pressure, sampling the signal from the sensor to obtain a second measurement of sensor element position; determining a difference between the first measurement and the second measurement; calculating one or both of an axial distance between the first measurement of sensor element position and the second measurement of sensor element position and a rate of change of position of the sensor element between the first measurement of sensor element position and the second measurement of sensor element position; and correlating one or both of said axial distance between the first measurement of sensor element position and the second measurement of sensor element position and said rate of change of position of the sensor element between the first measurement of sensor element position and the second measurement of sensor element position with a viscosity. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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Specification