APARATO DE CALEFACCION.

摘要

1298966 Heating bakers' ovens BAKER PERKINS Ltd 24 Aug 1971 [14 Oct 1970] 48927/70 Heading A2A Heating apparatus such as a bakers' oven has a continuous gas circulation system comprising means for withdrawing gas from the oven chamber, means for heating the withdrawn gas, first duct means to receive the heated gas and Serve as radiant heating means for the chamber, and second duct means receiving gas from the first duct means and discharging it into the chamber; the first duct means being positioned in the path of the gas discharged from the second duct means. In a bakers' two-zone tunnel oven having a conveyer 2, each zone A, B has a separate circulation system comprising a header 5 through which gas is withdrawn from the zone by a fan (not shown), a gas burner (not shown) for heating the withdrawn gas by mixing products of combustion with it, headers 8, &a in the base and roof of the oven chamber receiving the heated gas, a series of radiant heating ducts 10 extending in either direction from each header 8, 8a to branch connections 12, and a series of discharge tubes 11 extending from the connections 12 and having inwardly directed openings. Each series of ducts 10 and tubes 11 comprises a row of parallel tubes disposed across the width of the chamber, and the tubes 11 are staggered with respect to the ducts 10 so that the discharged gas is directed between the ducts 10. The gas passing between the ducts 10 induces a circulation in the chamber, except in the first part of the feed zone A where, to provide for more gentle heating, the spaces between the ducts 10 are bridged by baffles so that the gas does not pass directly into the chamber 1 but is deflected around the sides thereof. A quantity of gas is exhausted from each zone to compensate for the inflow of products of combustion from the burner. The invention may also be applied to an oven in which goods are carried along upper and lower runs of a swing-tray conveyer, heating tubes being arranged above the upper run, below the lower run, and between the two runs.