| 摘要 |
<p>1. Process for determining the cloud point of a diesel or gas oil, i.e. the temperature below which appear crystals in the diesel or gas oil, which consists in focusing a light beam (24) through the said diesel or gas oil contained in a measuring cell (20), towards a large-diameter photoelectric detector (16), in interposing in front of the said detector (16) a light trap (15) having a smaller diameter than the detector, characterized in that the light beam (24) is focussed prior to causing it to pass through the diesel or gas oil sample maintained at a temperature higher than that of the cloud point, so that the beam (24), after having passed through the sample, is totally intercepted by the light trap (25), then in that the temperature of the sample is decreased until a part of the light scattered by the crystals formed in the sample passes round the light trap in order to reach the large-diameter detector (16), in that the appearance of an electric current (I) generated by the detector (16) is observed to signal the appearance of the trouble point of which the temperature is indicated by a thermo-electric sensor (59) and in that the current (I) generated by the detector is used to control the Peltier elements cycle (63, 64) for the cooling of the measuring cell (20).</p> |
