Straight-line continuous furnaces

Horizontal straight-line continuous furnaces are more common than rotary hearth furnaces, rotary dram furnaces, vertical shaft furnaces, or fluidized bed furnaces. 

Other forms of straight-line continuous furnaces are woven alloy wire belt conveyor furnaces used for heat treating metals or glass lehrs (fig. 1.5), plus alloy or ceramic roller hearth furnaces (fig. 1.6) and tunnel furnace s/tunnel kilns (fig. 1.7). 

Alternatives to straight-line horizontal continuous furnaces are rotary hearth (disc or donut) furnaces (fig. 1.8 and secs. 4.6 and 6.4), inclined rotary drum furnaces (fig. 1.10), tower furnaces, shaft furnaces (fig. 1.11), and fluidized bed furnaces (fig. 1.12), and liquid heaters and boilers (sec. 4.7.1 and 4.7.2). 

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