| 摘要 |
PURPOSE:To ignite the air-hydrogen flame of a detector securely by using the temperature change of a filament arranged in the upper part of the collecting tube of the detector. CONSTITUTION:Using the change of resistance corresponding to the temperature change of a filament 38 and operating a switching transistor Q3 via an amplifier 70 and a comparator 85, a current to relay winding 90 is switched on and off and an air sypply valve V is controlled. First, the valve V is set in a full line position and air alone is supplied from a supply soruce 24 to a mixing chamber 22, then hydrogen is supplied from a supply source 16 to a mixing chamber 14 and the combustion of an air-hydrogen flame is started on the upper end of a collecting tube 30. Owing to the combustion, the temperature of a filament 38 rises and its resistance increases, the valve V is changed to a dotted line position by said control system, air is supplied only from an accumulator 26 decreasing gradually, the flame goes down gradually and burns at the upper end of a nozzle 18. Next, the temperature (accordingly resistance) of the filament 38 decreases and the valve V returns to the full line position, the quantity of air supply is increased and the flame enters a steady combustion state. |
