Patent GB-344059-A (GB)
IPC: C22B19/18
Filed: 1929-12-02
Abstract: 344,059. Condensing zinc vapour. NEW JERSEY ZINC CO., 160, Front Street, New York, U.S.A.-(Assignees of Bunce, E. H. ; Palmerton, Pennsylvania, U.S.A.) Dec. 2, 1929, No. 36934. Convention date, Oct. 16. [Class 82 (i).] A gaseous stream containing zinc vapour is passed through a condensing chamber in a tortuous side-to-side path and under such conditions of heat dissipation that the zinc vapour is rapidly cooled to below the dewpoint but insufficiently to cause solidification of the molten zinc which flows through the chamber concurrent with the gaseous stream but by a shorter path into a collecting sump. The gases from a smelting or redistillation furnace pass through a passage 17 into a condensing chamber 10 comprising a flat bottom tile 12, side tiles 13 and spaced top tiles 14, preferably made of silicon carbide, and fitted with baffles 24, which may be vertically adjustable, arranged as shown in Fig. 1 to give the gaseous stream a tortuous side-to-side path through the chamber. The rate of heat dissipation from the chamber may be controlled by surrounding the bottom and sides with a loosely laid and readily adjustable layer of heat insulating brick and the top tiles 14 and tiles 26, 27 which' close the openings left by the baffles may be covered with a shallow layer of dust coal. The gases and molten zinc from the condensing chamber pass down a passage 20 into a collecting and condensing sump 11 in which the gases are cooled more slowly than in the chamber 10. The condensing sump 11 is U-shaped in cross section and is provided with spaced baffles 29, which may be vertically adjustable, shaped as shown in Fig. 4 and positioned as shown in Fig. 1 to give a tortuous path to the gas stream. The top of the sump is formed of spaced tiles 19 and filling tiles 26<1>, 27<1> and the bottom rests on a bed of loam 30 in a casing 31, the side and end walls being surrounded by a layer of coal dust 32 in a casing 33. The floor of the sump leads to a tap hole 21 through which the molten zinc is withdrawn at intervals and the gases pass up a short vertical passage 23 and along a transverse passage into an exhaust stack 22, the exit being higher than the inlet 17 to the condensing chamber in order to maintain a down draught through the plant. The bottom of the stack 22 has a sloping floor 36 in order that any zinc condensing in the stack may flow back to the sump 11. Apertures 28, 38, 41, normally closed by loose bricks or tiles, are provided to facilitate cleaning and removal of blue powder. The gases entering the condensing chamber normally are at a temperature of 800-900‹ C. and are cooled in the chamber 10 to 550-650‹ C. and further cooled in the sump 11 to 500-600‹ C. The pressure in the condenser is maintained slightly above atmospheric by adjustment of a tile 40 on top of the stack 22. The heat dissipation from the chamber 10 and sump 11 may be adjusted by varying the quantity and disposition of the heat insulating materials surrounding the apparatus and the path of the gases may be varied by raising or lowering the baffles, altering the spacing, or increasing their widths by the addition of filets.