System and method for a digital mass flow controller
July 10, 2019. Estimated 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.Patent ReferencesFlow controller-flow sensor assembly for gas chromatographs and the like Generation of a set point for process control Lubricating oil supply controller Self-diagnostic gel permeation/size exclusion chromatograph Flow regulation in gas chromatograph Flow controller, parts of flow controller, and related method Method of making a flow controller Flow controller, parts of flow controller, and related method Thermal mass flowmeter and mass flow controller, flowmetering system and method Patent #: 5911238 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 measurementExaminersPrimary: Bui, BryanAttorney, Agent or FirmForeign Patent References
International ClassesG01F 001/00G06F 019/00 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
Field of SearchFlow meteringPressure, resistive, or capacitive sensor Fluid measurement (e.g., mass, pressure, viscosity) Fluid or fluid flow measurement Weight Sensor or transducer Volume of flow, speed of flow, volume rate of flow, or mass rate of flow With signal processing, span or set point adjustment (e.g., zero correction) With pressure measurement or plural flowmeters With signal correction or processing Rate of flow Temperature Pressure With electrical computer or data processor control Responsive to change in rate of fluid flow Control by pressures across flow line valve Electrically actuated valve | |
