| 摘要 |
PURPOSE:To minimize the draft loss and make possible the power for a primary fan to be controlled to its lowest possible level by setting the minimum hot air duct pressure relative to the mill load and controlling the inlet of the primary fan to satisfy said minimum pressure. CONSTITUTION:The system includes a differential pressure gauge 23 that measures the differential pressure between the mill inlet 21 and the mill outlet 22 and a pressure setting unit 26 that sets the pressure P in a hot air duct 3 by adding outputs DELTAP1, DELTAP2 of a converter 25 which computes the draft loss and further adding the draft loss DELTAP3 of a flow rate adjusting damper 6. It further includes a driving mechanism 29 that actuates the inlet vane 27 to the opening designated by a PI controller 28 which controls the opening of inlet vane 27 of the primary fan 1. The inlet vane 27 is controlled so that the primary fan 1 may generate the pressure P in the hot air duct 3. The way, the minimum required hot air duct pressure is set relative to the mill load, and so, the primary fan 1 does not generate an unnecessary power and the opening of the opening of the flow rate adjusting damper 6 can be maintained nearly constant. |
