Method and apparatus for monitoring cloud point or like transition temperature

Apparatus for measuring the temperature at which a transition occurs in a material between a transparent or translucent liquid phase and a light scattering phase, comprising:

• a generally light proof chamber having lightabsorbing internal surfaces;
• a liquid sample-receiving receptacle within said chamber having a bottom formed of a heat conductive material with an upper surface which is non-light scattering;
• a removable, transparent top adapted to fit over the receptacle;
• means allowing access to the chamber for placing a sample of the material in said receptacle and allowing removal of the material from the receptacle at the termination of the test;
• means in thermal contact with said bottom for changing the temperature of said bottom and means for determining the temperature of said bottom in thermal contact therewith;
• a light beam source located to direct a beam of light towards said surface at an incident angle so that light from the beam is largely reflected or absorbed by said surface;
• and
• scattered light detection means arranged so as to detect light scattered by said sample and changes in intensity of the scattered light and connected into circuit means capable of registering a change in light scattered from the said sample as said surface is heated or cooled.