| 摘要 |
<p>METHOD AND APPARATUS FOR DETERMINING THE SATURATION TEMPERATURE OF A SOLUTION Method and apparatus for determining the saturation temperature of a solution. In an optical measurement vessel, the temperature of a sample of the solution is gradually decreased until crystals are formed and subsequently gradually increased until the crystals dissolve. The temperature is measured continuously and the formation and dissolving of the crystals is detected optically by means of a beam of polarised light which is transmitted through the measuring vessel, and passed through an analyzer the direction of polarisation of which is normal to that of the beam of light, and detected by a photodetector behind the analysator. Only when a small amount of optically active crystals is present in the solution, in which the direction of polarisation of the light is rotated, the photodetector measures a certain light intensity. The moment the last crystals, upon heating, dissolve is detected by the drop of the measured light intensity to a minimum value. The temperature of the solution at that moment is the saturation temperature of the solution. Preferably the beam of polarized light is generated by means of a laser. For monitoring the transmitted beam, a beam splitter may be mounted in front of the analyzer, which casts part of the transmitted light onto a second photodetector.</p> |
