| 摘要 |
PURPOSE:To prevent the energy supplied to the primary air fan from being wasted by providing a means which modulates the delivery pressure of the primary air fan to meet the delivery pressure demanded by the mill at the time of load change in addition to a delivery pressure regulating means for the primary air fan for normal load operations of burning equipment. CONSTITUTION:Under normal load operating conditions, the delivery pressure at the standard load for normal operation is designated as a preliminary value by a function generator 18 in response to the load demand D of burning equipment. When the load changes, the load demand D is first inputted to a differentiator 5 to detect its change. Responding to the changing load demand D, a function generator 1D sets the required delivery pressure every time the load changes. It determines the final delivery pressure setting based on said required delivery pressure and the actual value which was fed back from a pressure signal generator 6, and the movable vanes 24 of the primary air fan are sequentially adjusted from the setting to follow the change of the load demand D. That is, when the load of the burning equipment changes, the actual delivery pressure of the primary air fan is modulated in a stepped manner in response to the required delivery pressure of the mill which changes in a stepped manner in response to said load change. |
