Recuperative counter-flow furnace

摘要

355,839. Heat treatment furnaces. HEVI DUTY ELECTRIC CO., 4100, Highland Boulevard, Milwaukee, Wisconsin, U.S.A. June 4, 1930, No. 17236. Convention date, June 5, 1929. [Class 51 (ii)] Charging and discharging charges, conveying.- Relates to heat treatment furnaces of the kind having preheating heating and cooling sections, and comprises constructions for promoting heat interchange between the goods in the preheating and cooling sections. The furnace shown in Figs. 1, 1a and 2 comprises a chamber having two superposed tracks 17 for charge-carrying trays 19, an elevator shaft 12 at one end, and two feed rams 22, 23 by which the trays can be fed through preheating and heating sections 3, 1 on the upper track, and heating and cooling sections 2, 4 on the lower. The chamber is closed by end doors 10, 11, the lower of which opens by a downward movement and carries short rail sections 17a, which align with the lower rails 17 when the door is open. The rails 17 are perforated to reduce their weight and to provide air circulating openings. The preheating and cooling section 3, 4 are in open communication, and heat interchange between them is promoted by the provision of side flues 37 which serve to direct the flow of convection currents. The openings 42 in the floor plates preferably increase in size from both sides to the middle, and the goods trays may have similarly formed openings. The elevator 13 is locked in receiving position at the upper level by a plunger 60 operated through toggle links 63 from an electromagnet 69a in circuit with the motor operating the feed pusher at the opposite end of the track. Another form of furnace comprises two side-byside tunnels 49, 50, Fig. 9, through which the trays are passed in opposite directions, so that the preheating section of each tunnel is adjacent the cooling section of the other. The floors and roofs of the two tunnels are perforated, and circulation of convection currents takes place through the tunnels and the' connecting flues 54, 57. The ports 53, 55 preferably increase in size from the partition wall between the tunnels.