| 摘要 |
<p>Thermostatic bath has a metal heating tube containing a bare resistance heating coil of large surface area, low thermal inertia and low surface heat flux. The bath contains a non-conducting medium, e.g. oil and a circulation of this through the tube is obtained by an impeller located below it. In the lower part of the tube is mounted a temp. probe which is thermally contacted to both the heating tube and the element. The arrangement of heater, sensor and impeller are connected via a transfer channel to the inlet part of the measurement cells which allows the medium to flow upwards through the cell. The cells are separated by insulating walls with openings at the base so that the oil has to flow down the outside of the cell, up past the heating tube and back past the heating element. The bath is esp. for use with Ubbelodde viscometers. Commonly used baths have the disadvantage of poor homogeneity in the bath so that it is difficult to carry out simultaneous checks on several cells in the same bath. The system claimed uses commonly available components to give the accuracy of plus-or-minus 005 degrees C. required.</p> |
