| 摘要 |
1,124,327. Controlling air supply. COMBUSTION ENG. Inc. 3 Dec., 1965 [29 Dec., 1964], No. 51492/65. Heading F4B. In a pulverulent fuel fired furnace, the heater 3 for the secondary air fed to the furnace and the heater 9 for the primary air fed to the pulverizers 18 are arranged in parallel in a gass pass 7. The proportion of hot and cold primary air fed to each pulverizer 18 and the total air flow through each pulverizer are controlled by dampers 25, 24 and 32 and a selecting controller 35 adjusts the total primary air damper 39 to maintain the most nearly open pulverizer damper 32 in a preselected nearlyopen position. A damper 12 controlling the amount of flue gas flow through the primary air heater 9 is adjusted by a selecting controller 43 to maintain the most nearly closed cold primary air damper 25 in a predetermined nearly closed position. The mean of the cold primary air temperature and the cooled flue gas temperature at the exit of air heater 9 is used to regulate the operation of heater 9 to prevent corrosion by passing steam through a heating coil 54 in the primary air heater supply conduit, or by feeding part of the primary stream through an air heater by-pass to mix with the hot primary air stream, or by changing the preselected position of the chosen pulverizer cold air damper 25 to enable hotter primary air to be used. |
