632,338. Glass-annealing levers. HARTFORD-EMPIRE CO. July 15, 1947, No. 18862. Convention date, Nov. 23, 1945. [Class 51 (ii)] [Also in Group XIII] In a muffle-heated glass-annealing leer in which products of combustion from the muffle are passed through a heat exchanger to preheat air prior to its discharge into the tunnel, the heat exchanger is located in part below and part at a side of the ware conveyer. In the leer shown, heating gases from a transverse combustion chamber 14 pass rearwardly through a chamber 19 into longitudinal heating ducts 26 of rectangular crosssection arranged at the lower corners of the tunnel beneath the conveyer band 6, these ducts being connected to left and right hand bottom heat exchange chambers 29 which in turn are connected to vertical chambers 35 in the side walls of the tunnel. The chambers are formed with staggered partitions 31 - 33 and 36, 37 respectively so that the gases are caused to follow a tortuous path and finally escape to exhaust stacks provided with draught inducers. Air from a blower 43 is supplied to a header 47 in the top of each chamber 35 which is connected by pipes 48 to a bottom header 49 connected to a second bottom header 51 from which the air is led by pipes 52 to a second top header 53. This header is connected by pipes 54 to a third bottom header 55 connected to a fourth bottom header 57 from which the air is led by horizontal pipes 58 to a rear inner header 59 in the associated chamber 29. The air then passes successively through outer and inner headers 60a, 62, 64 and 66, interconnected by horizontal pipes 60, 61, 63 and 65, and is finally admitted to longitudinal pipes 67 formed with nozzles through which downwardly-inclined jets 68 of preheated air are discharged beneath the heating ducts 26, see Fig. 3 (not shown). Air from these jets passes upwardly between the sides of the ducts and the tunnel walls so as to create a transverse circulation of the atmosphere. The pipes 67 terminate in transverse pipes 69 formed with nozzles through which forwardly-directed jets of air 71 are discharged over the top 11 of the main heating chamber. Specification 491,954 is referred to.
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