Patent ID: 8705037

Claim:
A liquid component concentration meter comprising: a liquid supply tube adapted to be supplied with a liquid, the liquid supply tube having a light transmission unit which is disposed midway through the liquid supply tube; a light emission unit for irradiating measurement light to the light transmission unit; a light reception unit for receiving measurement light passed through the light transmission unit; a support member adapted to movably support the light emission unit and the light reception unit in such a way that a measurement position is moved along the light transmission unit, wherein the measurement position is a position at which light is irradiated to the light transmission unit and, also, is a position at which the light passed through the light transmission unit is received by the light reception unit; a measurement-position moving mechanism for moving the support member in such a way that the measurement position is moved within a predetermined area in the light transmission unit; and a data processing unit adapted to acquire data of intensities of light received by the light reception unit at a plurality of the measurement positions and to calculate the concentration of the liquid flowing through the liquid supply tube, based on the plural data of light intensities, wherein the measurement-position moving mechanism comprises a pneumatic actuator, the pneumatic actuator comprising a space which encloses an entirety of the support member, and at least one air-driving pipe connected to the space enclosing the support member, and wherein the measurement-position moving mechanism is adapted to move the entirety of the support member within the space by supplying air into the space.