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US Patent 6389364 - System and method for a digital mass flow controller
US Patent Issued on May 14, 2002
Estimated Patent Expiration Date:
July 10, 2019Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
Estimated Patent Expiration Date:
July 10, 2019Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.AbstractA method for controlling the gas flow within a digital mass flow controller. The method calculates a digitally enhanced flow rate signal that more accurately represents an actual flow rate through the digital mass flow controller. The digitally enhanced flow rate is calculated using a sensed flow rate signal output from a flow sensor, a scaled first derivative of the sensed flow rate signal, and a scaled, filtered second derivative of the sensed flow rate signal. A set-point signal is compared to the digitally enhanced flow rate signal to generate a digital error signal. The digital error signal is provided to a digitally realized PI (proportional integral) controller. The PI controller generates a digital control signal which is used to control a valve in the digital mass flow controller.Other References
| InventorAssigneeApplicationNo. 351120 filed on 07/10/1999US Classes:702/45, Flow metering73/1.34, With signal processing, span or set point adjustment (e.g., zero correction)137/486, Responsive to change in rate of fluid flow702/100Fluid or fluid flow measurementField of Search702/45, Flow metering702/47, Pressure, resistive, or capacitive sensor702/50, Fluid measurement (e.g., mass, pressure, viscosity)702/100, Fluid or fluid flow measurement702/101, Weight702/104, Sensor or transducer73/1.16, Volume of flow, speed of flow, volume rate of flow, or mass rate of flow73/1.34, With signal processing, span or set point adjustment (e.g., zero correction)73/1.35, With pressure measurement or plural flowmeters73/1.59, With signal correction or processing73/23.24, Rate of flow73/23.25, Temperature73/23.27, Pressure73/23.36, With electrical computer or data processor control137/486, Responsive to change in rate of fluid flow137/487, Control by pressures across flow line valve137/487.5Electrically actuated valveExaminersPrimary: Bui, BryanAttorney, Agent or FirmUS Patent References4096746, Flow controller-flow sensor assembly for gas chromatographs and the likeIssued on: 06/27/1978 Inventor: Wilson , et al.4543637, Generation of a set point for process control Issued on: 09/24/1985 Inventor: Smith , et al.4632085, Lubricating oil supply controller Issued on: 12/30/1986 Inventor: Misawa , et al.4674323, Self-diagnostic gel permeation/size exclusion chromatograph Issued on: 06/23/1987 Inventor: Rulf , et al.5545252, Flow regulation in gas chromatograph Issued on: 08/13/1996 Inventor: Hinshaw, et al.5660207, Flow controller, parts of flow controller, and related method Issued on: 08/26/1997 Inventor: Mudd5765283, Method of making a flow controller Issued on: 06/16/1998 Inventor: Mudd5850850, Flow controller, parts of flow controller, and related method Issued on: 12/22/1998 Inventor: Mudd5911238Thermal mass flowmeter and mass flow controller, flowmetering system and method Issued on: 06/15/1999 Inventor: Bump, et al. Foreign Patent References
International ClassesG01F 001/00G06F 019/00 |
