GB1209209A - Industrial heating furnaces with independently controllable heating and cooling zones - Google Patents

Abstract

1,209,209. Glass annealing lehrs. E. W. BOWMAN. 19 Aug., 1968, No. 39646/68. Heading F4B. A glassware annealing lehr comprises heat treatment zones 9-15, separated by insulating walls 29, 30 and all traversed by a gas permeable belt link conveyer 8. The ware first enters heating zone 9 wherein it is heated by vertically adjustable fire-polishing burners 16 and radiant cup burners 20 from above, and burners 23 mounted under stainless steel reflector plates 24 from below, and then passes through zones 10 to 12 wherein it is further heated by the circulation of hot air. In these zones the air is continually circulated by fans 34 along ducts 33 containing heaters (33b, not shown), through slots 5a in aprons partly defining the ducts 33, through the conveyer 8 and over the ware. It is then drawn back to the fans 34 through side flues defined between the sheet metal walls 25a and the walls 29, and the ducts 31. Damper controlled fresh air inlets and exhaust air outlets 52, 36 respectively regulate the volume of fresh air entering the circulation systems and so the gas volumes and recirculation rates and the zone temperatures. In zones 13 and 14 air is similarly recirculated but without the addition of heat, whilst in zone 15 cool air is recirculated for rapid cooling of the ware before discharge. In a modification (not shown) the zones may be arranged in a straight line. The conveyer (Figs. 5 and 8, not shown) is formed from crescent-shaped members mounted on chain links that at the ends of each zone engage with idler and driven sprocket wheels, to reverse the conveyer path for travel through the subsequent zone. Adjustable doors are provided at the ends of the zones.