tailieunhanh - flame safeguard control phần 2

giữ cho giường nhiên liệu xốp. Bán phá giá vỉ atlhe phía sau thoát khỏi tro. Nhiều retorl giải khát là một phần mở rộng nalural của relor duy nhất! ý tưởng. HOWElWJr, pq của nó: l'Jlarily đã suy yếu 10 lhe poinl kiểm tra một thất bại f1ame-simulaling trước khi | .Burner6 Alld Bolte rs SECTIONAL VIEW OF A SINGLE-RETORT FIG. 59 SECTIONAL VIEW OF A SINGLERETORT STOKER WITH UNDULATING GRATES. Courtesy of Detroit Stoker Company Monroe Michigan. STOKER WITH STATIONARY GRATES. Courtesy of Detroit Stoker Company Monroe Michigan. FIG. 60 MULTIPLE-RETORT STOKER SECTIONAL VIEW OF 1 RETORT . lively thin sections of fuel bed over the tuyere zones where the air is entering. The valleys form aseries of parallel active burning lanes down the length of the stoker. The reciprocating grate is built in sections. Adjacent sections move in opposite directions to cause stroking action when one section Is moving forward the other is moving backward. This reciprocating movement distributes coal over the grate surface and at the same time keeps the fuel bed porous. Dumping grates at the rear get rid of the ash. The multiple-re tort stoker was a natural extension of the single-retori idea. However its popularity has waned to the point where only one or two are sold each year throughout the entire industry. The multiple-retort stoker was used extensively for burning caking coals for which it is well adapted. Recent successes in this same area by 33 71-97558-1 overfeed stokers which are much less costly to maintain have just about obsoleied multiple-retort stokers. SUSPENSION FIRING In suspension firing pulverized powdered coal is transported to the furnace in an air stream and injected into the combustion chamber along with primary air through a nozzle. The nozzle is usually horizontal and is surrounded by an air register through which secondary air Is admitted. . Within a fraction of a Sfecbnd after a fine panicle of powdered coal enters the combustion chamber the heat present raises Ils temperature and distills off the volatile matter. The volatiles mostly hydrocarbons Ignite more easily than the carbon component erf the coal. While the volatiles bum they heat the remaining carbon particles to incandescence. Secondary air sweeps past and .