BOILER APPARATUS

PURPOSE:To provide a boiler apparatus having a forced draft fan and an induction ventilator and so controllable that a draft does not exceed a predetermined value width at the time of an abrupt load change. CONSTITUTION:When a boiler is stopped in emergency or solely operated in station, a flip-flop...

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Bibliographische Detailangaben
1. Verfasser: MISAWA KAZUYUKI
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:PURPOSE:To provide a boiler apparatus having a forced draft fan and an induction ventilator and so controllable that a draft does not exceed a predetermined value width at the time of an abrupt load change. CONSTITUTION:When a boiler is stopped in emergency or solely operated in station, a flip-flop 31 is operated, and an inducted draft fan exit damper is throttled to a specified opening. When it is detected by a level monitor 27, a proportional integrator 22 and an incomplete differentiator 24 are operated. Thus, an abrupt rise of a denitrification exit draft is collected by the differentiator 24, and the damper is rapidly opened to prevent an overrise of the draft. When an output of the differentiator 24 becomes again zero after a time or more of on-delay 35 is elapsed, an output of the incomplete differentiation is fixed to zero, and it is returned to a control of a normal state. When a ventilation system run-back occurs, a flip-flop 38 is operated, the differentiator 24 is operated, and the damper is switched to abrupt change of the draft immediately after the run-back occurs, thereby suppressing a variation width of the draft to a predetermined value or less.