| 摘要 |
1,218,131. Monitoring solution concentration. SIEMENS A.G. May 16, 1968 [May 26, 1967], No. 23453/68. Heading G1A. [Also in Division G3] In a method and apparatus for monitoring the concentration of a liquid solution 2, the solution is brought into contact with a surface portion of a light permeable wall 5, a light beam 3 is directed through a first chamber 1 containing a reference solution to strike the surface portion obliquely and to pass through into the solution under test and a photo-electric transducer which may comprise one or two photo-cells is positioned to detect a change in the refractive index of the solution by responding to a consequent change in the direction of travel of the beam. Two cells may be spaced to be within the beam, to touch the outside of the beam or to be spaced either side of the beam. The solution may be a potassium hydroxide solution from a fuel cell 13 and may be regulated in a concentrator or deconcentrator 11 by a control switching device 10. The transducer may be photo-voltaic photoresistive or a photo-transistor. |
