Importance

Loading Importance Indicators...

Abstract

In a power plant, a solid state sequence is provided for starting an FD or ID fan, or for changing the fan speed in response to the position of the fan inlet vanes. The sequential process is self-calibrated since process events control the stepping operation of the sequencer. At the operating fan speed, boiler air flow and pressure are controlled by fan inlet vane position in accordance with plant load demand. When the fan speed is changed, a multiplier circuit causes the fan inlet vanes to reposition so as to minimize air flow changes as the fan speed changes. When one of multiple FD fans or multiple ID fans has its speed changed at a time a fan balancer control, which normally equalizes air flow, is biased to permit different fan flows through the different speed FD or ID fans.

Loading the Abstract Image...

First Claim