| 摘要 |
PURPOSE:To enhance the controlling precision of heat insulation and to stably hold constant temp., by providing a heat source to the inside of an instrument main body wherein its inside is formed into a hollow part and packing sandy material in the hollow part in a state surrounding this heat source and forming the instrument for heating and heat insulation. CONSTITUTION:When a vessel 10 incorporated with a material to be heated is arranged in a recessing part 2a and an electric source is turned on, a nichrome wire 4 is heated and its heat is slowly spread to the circumference and conducted to glass sand 6 and furthermore conducted to the vessel 10 and the temp. of contents is raised. When the contents in the vessel 10 are reached to the set temp., the current allowed to flow through the nichrome wire 4 is reduced by operating a controller 5 and the calorific value of the nichrome wire 4 is controlled. Further when the temp. of the contents in the vessel 10 is reached to the temp. lower than the set temp., the controller 5 is operated again to increase the calorific value of the nichrome wire 4. The temp. of the contents in the vessel 10 is held at constant by such an operation.
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