A method for detecting temperature at which a transition occurs in a material sample between a non-light scattering liquid phase and a light scattering phase, and capable of detecting wax appearance and disappearance temperatures of a transparent, translucent or opaque liquid, comprising:
- providing a sample path in and out of a sample receptacle having a receptacle opening to receive the sample for testing, providing a reflective bottom surface in the receptacle opening to reflect light that enters the receptacle opening, providing sides of the receptacle opening that are light absorbing;
- providing a transparent cover to seal an open top of the receptacle opening;
- purging the sample path and the receptacle opening to clean and dry the sample path and the receptacle opening;
- providing a viewing chamber above the transparent cover of the receptacle opening to view reflected light from a bottom of the receptacle opening, wherein the viewing chamber is surrounded by material that is light absorbing so as not to reflect light passing through the viewing chamber;
- purging the viewing chamber with a dried gas;
- inputting a sample through the sample path and filling the receptacle opening with the sample;
- providing a thermo device for heating and cooling of the sample contained in the receptacle opening, a thermometer to register current temperature of the sample in the receptacle opening, a light emitting device mounted to project light through the viewing chamber and the transparent cover such that the light enters the receptacle opening and reflects off the reflective bottom surface in the receptacle opening, and an image sensor that produces a signal change as light scattering intensity changes anywhere in said viewing chamber;
- inputting light into the view chamber which travels to the reflective bottom surface in the receptacle opening;
- changing the temperature of the sample using the thermo device;
- detecting changes in intensity of scattering of light reflected from the reflective bottom surface in the receptacle opening using the image sensor to sense appearance and disappearance of wax particles to determine wax appearance and disappearance temperatures of the sample.