| 摘要 |
PURPOSE:To prevent the phenomenon of lifting of the combustion flame due to an excessive quantity of air or to prevent the red-flame combustion due to a shortage of air by a method wherein the quantity of combustion air is controlled on the base of the result of detection by a thermister for detecting the temperature of the open air so that the quantity of combustion air with respect to the variation of viscosity of a fuel oil due to the condition of the open air temperature is corrected. CONSTITUTION:The signal from an open air temperature detecting sensor is inputted to a central operation processing device 12 after it is subjected to an A/D conversion process (s) and is operated together with input signals from switches, those are changing quantity setting rotary switches 9, kind of grains setting rotary switches 10 and target amount of moisture setting rotary switches 11, so that the signal is set at a predetermined hot air temperature. Thus, when a drying switch is turned ON to start a required operation, an ON-time signal corresponding to the set air temperature is outputted to a fuel valve 14 from the central operation processing device 12. In this case, the ON-time pulse signal for the fuel valve 14 is shaped by a waveform shaping circuit, amplified by an amplifying circuit (h) through a switching circuit, an integrating smoothing circuit and a buffer circuit and is outputted as a r.p.m set voltage. However, when the open air temperature is low, the resistance on the thermister 2 increases to lower the output voltage while when the open air temperature is high, the resistance on the thermister 2 becomes small to increase the output voltage. As a consequence, it is possible to control the number of revolutions of a DC motor through a motor control circuit 1 in accordance with the open air temperature. |
