Improvements in and relating to Economisers for Internally Fired Steam Boilers with One or More Large Flues.

摘要

9578. Nicolson, J. T. April 25. Heating water.-Feedwater-heaters to be placed in the furnace flues of Cornish and like boilers, and constructed in accordance with the principles set forth in Specification No. 5140, A.D. 1907, comprise a double-walled cylinder or its equivalent placed concentric with the flue tube and enclosing elements forming narrow passages for the feedwater and the flue gases. In the construction shown in Fig. 1, the double-walled cylinder a provided with helically-disposed angle-irons h encloses a number of feed-heaters each consisting of concentric tubes k, l connected respectively to headers n, m. The feed-water enters at m, flows to the header n through the elements, passing along first the inner and then the outer surfaces of guide-tubes o, and finally by way of the pipe n' enters the drum a, which it traverses before reaching the water space of the boiler. The flue gases pass along the outer and inner surfaces of the drum and through the tubes l to the passage e ; dust, ashes, &c. thrown off at the sharp turns of the gases are received in spaces provided for the purpose. The dampers i, j are opened when a through draught is desired. In the form shown in Fig. 3, the drum a contains two series of smoke-tubes t, u, the latter being surrounded by water-tubes w connecting headers m, n. The feed-water enters the header m, flows through the tubes w to the header n, and thence, through guide-tubes r surrounding the smoke-tubes t, to the outer annular space of the drum a and so to the boiler. The flue gases turn twice as before, flowing through the tubes t, u in succession. In the arrangement shown in Fig. 4, the water flows from the header x to the header y through tubes v and thence to the drum a, while the combustion products pass around the latter and through the tube w surrounding the tubes v. The header y con-, tains granite chippings, coke, or the like to take up the sediment deposited from the hot feed-water. A damper. 2 permits the furnace gases to escape direct to the passage z without traversing the tube w. Water may be withdrawn from the boiler and passed with the feed-water through the feedheaters, for example as shown in Fig. 4, by means of a pump 4 and pipes 5, 6. The Provisional Specification describes a modification in which three or more double-walled concentric drums are placed within the flue tube, the gases passing in the same devious manner among the drums ; or one outer drum and several such sets of concentric drums arranged within it may be employed. Moreover, the dust and ashes collected in a space at the rear of the flue may be removed by opening the space to the fan suction.