Patent ID: 8485219
Filing Date: 2013-07-16
Classification: F17D,G01F,G05D,Y10T

Abstract:
1. A method for controlling flow rate of a gas flowing on a flow path, comprising the steps of: (a) providing a flow rate control device configured to perform feedback control of a gas flow rate for a gas flowing on a flow path based on a target flow rate and a sensed flow rate, wherein the target flow rate is a target value for an intended mass flow rate of the gas flowing on the flow path wherein the sensed flow rate is a sensed mass flow rate of gas flowing on the flow path; (b) providing control data that includes a plurality of control parameters respectively associated with mutually different mass flow rates wherein the control data is associated with a type of the gas flowing on the flow path, and said providing of the control data comprising the steps of: (b1) providing first characteristic data that includes a plurality of first characteristic parameters associated with flow characteristics of a standard gas through the flow rate control device, wherein the first characteristic parameters are associated with mutually different mass flow rates for the standard gas through the provided flow rate control device, wherein the first characteristic parameters reflect differences of flow rates of the standard gas in the flow rate control device and flow rates of the standard gas in a benchmark flow rate control device, wherein the first characteristic data is saved to a first storage unit of the flow rate control device; (b2) providing second characteristic data that includes a plurality of second characteristic parameters associated with flow characteristics of an actual gas through a benchmark flow rate control device, wherein the second characteristic parameters are associated with mutually different mass flow rates for the actual gas through the benchmark flow rate control device, wherein the second characteristic parameters reflect differences of flow rates of the actual gas in the benchmark flow rate control device and flow rates of the standard gas in the benchmark flow rate control device, wherein the second characteristic parameters are saved to a second storage unit on which data can be swapped or updated more easily than that on the first storage unit of said flow rate control device; and (b3) reading the first characteristic data from the first storage unit; reading the second characteristic data from the second storage unit; and generating the plurality control parameters based on the first and second characteristic parameters thereby generating the control data; and (c) controlling the flow rate of the gas flowing on the flow path the flow rate control device using the target flow rate, the sensed flow rate, and a control parameter that is determined based on at least one of the target flow rate and the sensed flow rate from among the plurality of control parameters of control data, and generating a corrected target flow rate based on the target flow rate and the plurality of control parameters; and performing feedback control of the flow rate of gas flowing through the flow path by generating output signal for controlling a flow rate modifying unit that controls the flow rate of gas flowing through the flow path, based on the corrected target flow rate and the sensed flow rate.