A DEVICE TO RECORD ULTRA-RAPID COOLING PROFILES

This work deals with the construction and performance of a measuring system capable of estimating temperature at sufficiently high speed (up to 1000 samples/sec). Due to its simple design and the utilization of standard materials, it could serve to recording the cooling profile of ultra-rapid procedures. An immersion device was also developed with the purpose of normalize the penetration speed of the sample in the LN2. The device allows also the comparative analysis of different cooling profiles. The system consists of an immersion device of the sample in the cooling agent, a temperature measurement system developed by Kleihans F and a laptop computer. To test the system, we recorded the cooling profiles of 10 pi, of distilled water and 6 M glycerol solution, obtaining a cooling rate of 8732 degrees C.min(-1) and 4441 degrees C.min(-1) respectively. Also we determine a cooling rate of 204.012 degrees C.min(-1) during the immersion of the thermocouple assembly in LN2. Although, the same device, with small technical modifications related to the handling of the sample, could be used to evaluate the recovery from LN2 temperature to room temperature (re-warming).