| 摘要 |
PURPOSE:To make a responsive property for the concentration of suspension linear and not to cause an error for the color change of sludge, by regulating an angle formed by mutual central axes of a pair of light projecting and receiving parts with respect to water to be inspected to below a specific angle. CONSTITUTION:A light projecting element 1 consisting of a near infrared ray emitting diode having the directivity which is projecting light through a light projecting window glass 11 and a photodetecting element 15 receiving scattered light through a photodetecting window glass 14, are arranged so that central axes cross at right angles and a space contributing to the scattered light entering the element 15 is limited. Also, a distance (a) between the tip end part of the light projecting element side and the central axis of the vacant space is made so small as 5mm., into 5mm. and a distance (b) between the tip end part of the photodetecting element side and the central axis of the vacant space is made so small as 5mm. also into 5mm. and thus, the multiplex scattering and absorption in the vacant space are not produced. |
