GB1040339A - Improvements in or relating to baking ovens - Google Patents

Abstract

1,040,339. Baking ovens. T. & T. VICARS Ltd. Aug. 30, 1963 [Sept. 5, 1962], No. 33985/62. Heading A2A. A tunnel oven, Figs. 1 and 2, for baking products such as bread, biscuits or confectionery carried, in the direction indicated by the arrow 3, through the oven on the upper flight of an open-linked, substantially horizontal, travelling conveyer belt 2, whose lower flight moves in the opposite direction, indicated by the arms 4, comprises an outer shell 1 enclosing a series of baking chambers, of which only the first and second are shown, since any other baking chambers are similar to the second. In each baking chamber, upper and lower banks of heat-transfer tubes 5, each D- shaped in cross-section are arranged above, below, parallel to and equi-distant from the conveyer, with their flat surfaces facing it, so that they radiate heat on to the products. The tubes are connected by manifolds 6. A fan 10 circulates hot gases from a gas or oil burner 7 through trunking 8, the upper and lower banks of tubes 5 and trunkings 9 and 11. The latter returns the gases to the burner 7 for re-heating and re-circulation. Any excess gas is discharged through a vent pipe 12. The tubes 5, in each bank, are separated by long narrow slots 13. In each baking chamber, the upper and lower banks of tubes are spaced, respectively, from the head and bed of the oven by spaces 15 and 16. A fan 14, Fig. 3, circulates air through trunking 17, then through the space 15, where the air is heated by the upper ducts 5, then through the slots 13 between these ducts, then through the open links of the conveyer belt 2 and the slots 13 between the lower ducts 5, and then through the space 16, where the air is heated by the lower ducts. Near the entrance to the first baking chamber of the oven, Figs. 1 and 2, the upper tubes 5 are made shorter than the lower ones to accommodate a downwardly flanged canopy 18 containing a manifold, connected to a source of steam and having branches 19 provided with nozzle openings, through which steam is fed into the oven In an alternative construction, the tubes 5 are triangular in cross-section.