Patent ID: 8531669

Claim:
An air-driven shutter device for an optical analyzer, the optical analyzer including a measurement field to which a sample gas is supplied, a light-emitting unit configured to emit measuring light to the sample gas in the measurement field, a light-receptive unit configured to receive the measuring light that has passed through the sample gas, and a purge air supplying unit configured to supply a purge air, the air-driven shutter device comprising: a shutter provided between the measurement field and at least one of the light-emitting unit and the light-receptive unit, the shutter in a closed position being configured to block a flow of the sample gas in the measurement field toward the at least one of the light-emitting unit and the light-receptive unit; and a shutter opening and closing mechanism configured to open the shutter while a pressure of a gas supplied from the purge air supplying unit is higher than a predetermined level, and to close the shutter when the pressure of the gas supplied from the purge air supplying unit becomes lower than a predetermined level.