| 摘要 |
PURPOSE:To obtain control characteristics having a little overshooting, by approaching a temperature to a set value at either the maximum combustion or the minimum combustion when a temperature difference between a set temperature and a load temperature becomes more than a fixed value under a normal state. CONSTITUTION:A gas combustor is constituted with a gas burner 1, a gas proportional valve 2 which controls gas quantity to the gas burner 1 continuously, a temperature sensing element 3 which detects a load temperature, a control circuit 4 which increases or decreases a proportional valve current according to a difference between a set temperature and the load temperature, a timer and a memory circuit which stores a value of the proportional valve current. In this device, a value of a proportional control valve current is stored in a memory circuit when the temperature difference becomes more than a fixed value, the proportional valve current is set to a current value at the time of either the maximum gas combustion or the minimum gas combustion according to a positive or negative temperature difference, and when the temperature difference becomes less than the fixed value a current value corresponding to a period required till that time is added to or deducted from a current value stored in the memory circuit for a new current value. |
