# US 11,906,984 B2 · Concentration control system, concentration control method and program for a concentration control system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,984 B2 - Document ID: US11906984B2 - Status: Granted - Kind: B2 - Application number: 17/454,608 - Filed: 2021-11-11 - Published: 2022-05-12 - Granted: 2024-02-20 - Earliest claimed: 2020-11-11 - Assignees: HORIBA STEC, Co., Ltd. - Applicants: HORIBA STEC, Co., Ltd. - Inventors: Kotaro Takijiri; Ojiro Takamune - Web page: https://patentgrep.com/patent/US11906984B2 ## CPC - G05D 11/138: {by sensing the concentration of the mixture, e.g. measuring pH value} - G05D 21/02: characterised by the use of electric means - C23C 16/4401: {Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber} - C23C 16/4408: {by purging residual gases from the reaction chamber or gas lines} - C23C 16/448: characterised by the method used for generating reactive gas streams, e.g. by evaporation or sublimation of precursor materials - G01N 21/3504: for analysing gases, e.g. multi-gas analysis - G05B 17/02: electric - G05D 11/132: {by controlling the flow of the individual components (G05D11/133 takes precedence)} - G05D 11/135: {by sensing at least one property of the mixture (G05D11/139 takes precedence)} - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract Provided is a concentration control system that has only a small time delay, obtains accurate estimated values, and also enables partial pressure control having improved responsiveness and accuracy. The system includes a flow rate control device provided on a supply flow path that supplies gas to a chamber, and controls a flow rate of a gas in the supply flow path to match a set flow rate, a partial pressure measurement device for a gas inside the chamber, an observer having a model which estimates a state of the gas inside the chamber, where a flow rate of the gas flowing into the chamber and measured partial pressures are input into the model, and an estimated partial pressure of the gas within the chamber is output, and a controller that, based on a set partial pressure and on the estimated partial pressure, sets the set flow rate. ## Claims ### Claim 1 A concentration control system comprising: a flow rate control device that is provided on a supply flow path that supplies gas to an interior of a chamber, and performs control such that a flow rate of a gas flowing through this supply flow path matches a set flow rate that has been input; a partial pressure measurement device that measures a partial pressure of a gas inside the chamber; an observer that is equipped with a model which estimates a state of the gas inside the chamber, and that is formed such that an inflow flow rate of a gas flowing into the chamber and measurement partial pressures from the partial pressure measurement device are input into the model, and an estimated partial pressure of the gas within the chamber is output; and a controller that, based on a set partial pressure and on the estimated partial pressure of the gas within the chamber output by the observer, sets the set flow rate in the flow rate control device. ### Claim 2 (depends on 1) The concentration control system according to claim 1, wherein the model simulates a conductance of an exhaust flow path that expels gas from within the chamber, and the conductance is set to a constant value. ### Claim 3 (depends on 2) The concentration control system according to claim 2, wherein an exhaust valve whose valve opening is able to be controlled is provided on the exhaust flow path, and the exhaust valve is fixed at a predetermined valve opening. ### Claim 4 (depends on 2) The concentration control system according to claim 2, wherein the estimated partial pressure is a column vector formed by: a first estimated partial pressure obtained by estimating the actual partial pressure; and a second estimated partial pressure obtained by estimating the measurement partial pressure from the partial pressure measurement device, and wherein the observer is further equipped with an observer gain H which is a row vector whose elements are h1 and h2, and the element h2 is set to the same value as the conductance. ### Claim 5 (depends on 1) The concentration control system according to claim 1, wherein the partial pressure measurement device is an NDIR analyzer, and the model simulates a delay in the measurement partial pressure output by the NDIR analyzer relative to the actual partial pressure as a first order delay. ### Claim 6 (depends on 1) The concentration control system according to claim 1, wherein the estimated partial pressure is a row vector formed by: a first estimated partial pressure obtained by estimating the actual partial pressure; and a second estimated partial pressure obtained by estimating the measurement partial pressure from the partial pressure measurement device, and wherein the controller is formed such that deviations between the set partial pressure and the first estimated partial pressure are integrated. ### Claim 7 A concentration control method that utilizes a concentration control system that comprises a flow rate control device that is provided on a supply flow path that supplies gas to an interior of a chamber, and performs control such that a flow rate of a gas flowing through this supply flow path matches a set flow rate that has been input, and a partial pressure measurement device that measures a partial pressure of a gas inside the chamber, in which an inflow flow rate of a gas flowing into the chamber and a measurement partial pressure from the partial pressure measurement device are input into a model which estimates a state of the gas inside the chamber, and an estimated partial pressure of the gas within the chamber is estimated, and in which, based on a set partial pressure and on the estimated partial pressure of the gas that has been estimated, the set flow rate is set in the flow rate control device. ### Claim 8 A program recording medium on which is recorded a program that is used in a concentration control system comprising: a flow rate control device that is provided on a supply flow path that supplies gas to an interior of a chamber, and performs control such that a flow rate of a gas flowing through this supply flow path matches a set flow rate that has been input; and a partial pressure measurement device that measures a partial pressure of a gas inside the chamber, and that is characterized in causing a computer to perform functions of: an observer that is equipped with a model which estimates a state of the gas within the chamber, and that is formed such that an inflow flow rate of a gas flowing into the chamber and a measurement partial pressure from the partial pressure measurement device are input into the model, and an estimated partial pressure of the gas within the chamber is output; and of a controller that, based on a set partial pressure and on the estimated partial pressure of the gas within the chamber output by the observer, sets the set flow rate in the flow rate control device.