GB191419678A - Improvements in or relating to Furnace Grates. - Google Patents

Abstract

19,678. Brams, H. Sept. 11. Fire-bars and grates. - A furnace grate is formed of rotary bars comprising an inner straight tube and one or more helically wound outer tubes, means being provided for the circulation of water through the tubes for cooling purposes. The driving-mechanism for the bars may be so arranged that (a) all the inner tubes remain fixed while the water tubes rotate in the same direction, (b) all the inner tubes remain fixed while the outer tubes rotate alternately in opposite directions, in which case the helical tubes on adjacent bars are wound in a right-handed and left-handed manner, (c) all the inner tubes and the outer tubes rotate in the same direction, (d) the inner and outer tubes of each bar turn in the same direction but those of adjacent bars turn in opposite directions, and (e) all the inner tubes rotate in one direction while the outer tubes rotate in the oppositedirection. Fig. 1 shows the arrangement last referred to. The fire-bars comprise inner tubes 1 communicating with a water-chamber 17 extending across the front of the grate and with hollow bodies 3, 4 with which the helical outer tubes 2 also communicate. Peripheral openings 18 are provided in the tubes 1 to allow communication with the hollow bodies 3. Stuffing-boxes are provided at 5, 6, 7, and 8. Worms 15, 16 are provided adapted to engage with teeth 9 and worm-wheels 10 to effect the rotation of the bars. The bars communicate at their rear ends with a collecting- tube 20, from which the cooling-water is conducted away by a pipe 23. The velocity of flow of the water may be regulated by a valve. In a modification, the helical tubes and inner tubes may be welded together at their rear ends so that the water may first circulate through the helical tubes and return through the inner tubes, or conversely, or where more than one helical outer tube is provided, the water may flow through them in opposite directions. The inner tubes are in this case provided with separate return pipes 23, the tube 20 being dispensed with. The tubes 1, 2 at their rear ends pass through dished plates 21 rotatably mounted in the wall of a compartment enclosing the rear end of the grate. The tubes 2 may be circular or semicircular in cross-section. In the modification shown in Fig. 5, a helical tube 27 surrounds the inner tube 1 and communicates with it at the rear as shown, and the circulation of the cooling-water takes place as indicated by the arrows.