| 摘要 |
The invention relates to an installation for providing a constant temperature during a chemical reaction which takes place in the presence of a solid catalyst in gaseous medium. According to the invention, the installation consists of a catalyst deposited on an electric heater and a circuit for automatically controlling the heater temperature, wherein the heater is a filament made of hardly fusible pure metal insulated with a thin layer of ceramic or glass material, the catalyst being deposited on the heater surface in a thin and uniform layer, so that the catalyst temperature is as close as possible to that of the filament, and the automatic temperature control circuit consisting of a bridge for measuring the filament resistance (R) which comprises some resistors (R, Rand R), where the first resistor (R) is adjustable and performs the calibration of the bridge when replacing a filament with another one, the third resistor (R) is also adjustable and sets the filament temperature, the bridge unbalanced voltage being applied on the inputs of an operational amplifier (AO) which controls, at the output, by means of a power transistor (T), the bridge supply voltage, thus carrying out the automatic balance thereof. |
