| 摘要 |
PURPOSE:To inhibit the discharge pressure of a primary draft fan to a minimum and hence reduce its power consumption by providing a required head arithmetic circuit which sets a discharge pressure conforming to an output command signal of a pulverized coal mill. CONSTITUTION:A mill 13 operates under the control of a mill control device 8 based on a signal transmitted from an output command oscillator 1. Every signal of the oscillator 1 is transmitted to a high output signal selector 7 where the highest signal is selected and output to a function generator 2. There an output pressure preset value of a preheater 10 conforming to the aforesaid value is output to a subtracter 3. A measured pressure value of an output detector 4 is input in the subtracter 3 where the setting value and the measured value are compared. Based on the deviation signal, a proportional plus integral controller 5 outputs a discharge pressure command signal of a primary draft fan 9 and control the performance. This construction makes it possible to produce a required minimum discharge pressure which properly reflects the mill output, and the number of the mills in operation and hence inhibit the power consumption of the primary draft fan 9 to a low value. |
