X^ Air-Furnac£i employed in Iron Foundries 



by the flue or throat, narrowetl on pnrpofe to throw back part 



of tlio flame, and keep the furnace equally hot throughout, aa 

 mav be more particubri'y viewed in the vertical fc<ilion, fig. 2. 



EE, the furnace brirs on which the coals reft, and where 

 the combuftion is maintained. 



FF, openings called teafing-holes, by which the coals are 

 introduced to rep;ur the lire. 



GG, fire-brick buildings called bridges. Thefe are meant 

 to concentrate the flame, that it may ad as violently on the 

 metal as poflible. Upon the height of the bridge much de- 

 pends in fufing the metal fpecdilv, and with little lofs. The 

 height of this may be feen in the vertical fcftion, fig. 3. G. 



til H, the charging doors, bv which the metal is introduced 

 in the fliape and ftate of pig-iron, lumps, fcraps, Sec. &,c. 

 The iron generally occupies the iurtiace acrofs to I, cahed the 

 back wall, and is never meant to approach the bridge nearer 

 than the dotted line, left the metal in melting fliould run 

 back into the grates, in place of delcendiiig into the general 

 reft-rvoir or cavity below. The corners of notches, h, h.,h, by 

 receive a flout catt-iron frame lined with fire-bricks. This 

 is hung by i^ieans of a chain and puiley,. and can be:raifed 

 and dcpreiil'd at pleafure. This frame is, properly 1 peeking, 

 the charging door, and is always carefully made air-tight by 

 means ot moiftencd fnnd. 



KK, the flues hr openings by which the flame enters the 

 chimney. Thefc are 15 inches by lo. On maiiitai'ni.iig 

 tbefe openings of a proportionate fize to the other parts de- 

 pend in a great meafirre the ]x)wers and cecoiX)nYy of llie 

 furnace. . 



' LL, 'lading doors, by which ladles are introduced, in the 

 c'afe of' fmali fin-races, to lift out the metal and diftribule it 

 to tb'e various moulds. 



MM MM, binding' bolts to limit within proper bounds 

 the expanflon w'hich takes pl'ace in the buikliiigiwhien the 

 furnace is highly hea<ed. 



FJo;. 2. vertical fedion of one of the furnaces, and its ap- 

 propnate fiait or'eWnfmey. ' 



K, the cra.tcs. 

 ■■ F,'The'te'a(itig-hbre. 

 "'G; the bridge.' -'■ ' ' 

 '"H, the C'l^a'r^i'ng;^ door. 

 ■•'R; ihv' ftneer opening into the chimney, 



'Xa tile lad'ing^d'if)r. 



M M,' the binder or binding bolt. 



N, the ir*rerior>jl' the fialk or chimney, 30 inches fqware. 



00, the fire brick- work, 9 inches thick. 



PP, fpace 



