Selective gas detection and measurement system
First Claim
1. A system for selectively detecting, measuring, and identifying a selected number of gases in an atmosphere comprising:
- a plurality of semiconductor sensors, greater or equal in number to the number of selected gases, each with a predetermined response characteristic which differs from the response characteristic of each of the other sensors in its response to at least one of the set of selected gases;
means, coupled to each of said sensors, for deriving a plurality of electrical signals, each of said signals representing the response to said atmosphere of a respectively different one of said sensors; and
electrical signal processing means, responsive to said plurality of derived signals, for developing respective indications of the concentrations of each of said selected gases as solutions of a set of equations, each of which is of the form ##EQU3## in which F(R) indicates a known and previously measured function of the response signal R of the particular sensor, j is a counter which indicates the gas type, M is the number of selected gases, [Gj ] represent the concentrations of the selected gases, nij are numerical constants of the particular sensor, Σ
is the symbol representing summation, i is a counter which distinguishes individual terms in the summation, L is the total number of terms in the summation, π
is the symbol representing products, and the Ki are previously measured numerical constants of the particular sensor.
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Abstract
A gas detecting system for determining the presence and concentrations of a number of selected toxic, combustible, or reducing gases in an atmosphere. The system includes a plurality of semiconductor gas sensors, each of which differs from each of the others in its response to at least one of the selected gases. The system includes a means of processing the responses of each sensor to produce an indication of each of the gas concentrations. The system may also produce indications of the measurement accuracy of each gas concentration, which can be used to determine the presence of gases not selected for detection.
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Citations
16 Claims
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1. A system for selectively detecting, measuring, and identifying a selected number of gases in an atmosphere comprising:
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a plurality of semiconductor sensors, greater or equal in number to the number of selected gases, each with a predetermined response characteristic which differs from the response characteristic of each of the other sensors in its response to at least one of the set of selected gases; means, coupled to each of said sensors, for deriving a plurality of electrical signals, each of said signals representing the response to said atmosphere of a respectively different one of said sensors; and electrical signal processing means, responsive to said plurality of derived signals, for developing respective indications of the concentrations of each of said selected gases as solutions of a set of equations, each of which is of the form ##EQU3## in which F(R) indicates a known and previously measured function of the response signal R of the particular sensor, j is a counter which indicates the gas type, M is the number of selected gases, [Gj ] represent the concentrations of the selected gases, nij are numerical constants of the particular sensor, Σ
is the symbol representing summation, i is a counter which distinguishes individual terms in the summation, L is the total number of terms in the summation, π
is the symbol representing products, and the Ki are previously measured numerical constants of the particular sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for selectively detecting a selected number of gases in an atmosphere, comprising:
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deriving from a plurality of sensors a plurality of electrical signals, each of said signals representing the response to said atmosphere of a respectively different one of said sensors, said plurality of sensors being greater or equal in number to the number of selected gases and each having a response characteristic which differs from the response characteristic of each of the other sensors in its response to at least one of the set of selected gases; and electrically processing said plurality of derived signals, for developing respective indications of the concentrations of each of said selected gases as solutions of a set of nonlinear equations, said set of nonlinear equations including terms proportional to products of powers of gas concentrations. - View Dependent Claims (16)
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Specification