1008 IRON 



The furnace has a firo-grate, in outward appearance like the ordinary puddling 

 furnace, but it differs from this considerably in several particulars. It has a fan blast 

 under the grate to urge the fire and produce gas. It has also jets of fan blast over the 

 fire, injected for the purpose of ensuring the more perfect combustion of the fuel. 

 This blast is regulated by a valve, by whieh the workman has a perfect control of the 

 quantity of gas produced and consumed, and ho is thus enabled to make the tempera- 

 ture suit the requirements of the charge in the different stages of the puddling process. 

 The ashpit and fire-hole are closed by doors to prevent the escape of the blast through 

 the fire, and the fire-hole has a coil of wrought-iron water-pipe cast into it, for the 

 purpose of allowing a stream of water to circulate around it to keep it cool. The 

 bridge-plate between the fire and the charge of metal has also a coil of water-pipe cast 

 into it for the same purpose. It has a lining of fire-brick on the side next to the fire, 

 and a covering of fettling on the side next to the charge. It also has a course of 

 fire-brick on the top, and is thus perfectly protected on all sides. Fastened on to the 

 bridge-plate is a ring with a flat surface on one side, which ring has a pipe or pipes 

 cast into it, and is made in one piece or in sections. The pipes are for the purpose of 

 admitting \\ater to keep the ring cool, and the flat face is the part that the end of the 

 revolving furnace rubs against, and forms a butt joint. This face should be cast on a 

 metal chill to harden the part exposed to abrasion from the end of the revolving 

 chamber rubbing against it. 



The revolving chamber is made of two end-pieces, so formed as to be banded with 

 wrought-iron bands, and to have detachable rings on the part most exposed to the 

 fire. It rests on carrying rollers, to allow its free rotation. It has also suitable ribs 

 for strengthening it, and holes for rivetting the rings and staveplates upon it. These 

 two ends are connected together by a series of staveplates to form a cylinder, and are 

 of suitable length according to the desired size of the chamber. They have hollow 

 ribs, running longitudinally, which serve the double purposes of holding the fettling 

 and keeping it cool, and when rivetted together, form an open-ended cylinder, one end 

 of which butts against the ring that is fastened to the bridge-plate, where the gases 

 are admitted over the bridge from the grate, and the other open end serves the purpose 

 of a doorway for the reception of the charges of metal, and for their removal ; also 

 for the escape of the products of combustion through a moveable head-piece which 

 connects the revolving chamber and the chimney. This moveable piece answers the 

 purpose both of door and flue. It can be moved at pleasure by means of a suitable 

 apparatus overhead, and when in its place for puddling, the escaping gases pass through 

 it into the stationary flue, and from thence to the chimney or boiler. When it is 

 removed for the introduction or removal of the charge, the end of the revolving chamber 

 is open, and balls of great weight can be very readily removed. When the moveable 

 piece is adjusted for puddling, it is held in position by suitable props. It has also an 

 arrangement of water-pipes for keeping it cool, and a stopper-hole in front, so that the 

 operations going on inside can be seen at all times. 



The vessel is made to revolve by means of a toothed wheel, fixed longitudinally 

 upon it. A suitable engine is attached to each machine, so that the chamber can be 

 made to revolve at any speed that may be required according to the different stages of 

 the operation. 



The chamber is lined in the following manner : The ' initial ' lining is composed of 

 a mixture of pulverised iron ore and pure lime, worked with water into the consistency 

 of a thick paste. About one-third of the inner surface of the chamber is covered with 

 this mortar in a layer projecting about one inch over the hollow ribs. After about 

 four hours, the first part of the lining, as described, will be found hard, and in the same 

 way the remaining parts are filled in and are allowed to set. The furnace is then 

 ready to receive the fettling. About one-fifth of the whole quantity required in the 

 shape of pulverised irpn ore is thrown in upon the above-mentioned lining. The 

 furnace is heated up, and is made to revolve slowly until the iron ore is found to be 

 completely melted. The apparatus is then stopped, and that part of the molten iron 

 ore, which has not been consumed by glazing the ' initial ' lining surface, runs to the 

 lowest level of the furnace, and there forms a pool, into which there are put a number 

 of small and large lumps of iron ore, of such dimensions as will bo required to allow 

 the said lumps to project over the surface of the liquid ore by from two to six indies. 

 This first part of the fettling is allowed to set when a fresh quantity of pulverised ore 

 is thrown in. The furnace is again made to rotate slightly until the newly-added ore 

 is liquefied, when the apparatus is again stopped, and the pool is filled with lumps as 

 before. In this manner the whole of the inner surface is gradually fettled, and euro 

 is taken to regulate the position of each pool so that the vessel or apparatus shall at 

 all times find itself properly balanced. From 2 to 2 tons of iron ore are required to 

 fettle a 700-lb. rotary furnace. Rather more than the ordinary quantity of hammer 

 or rolled cinder is used, and upon that the iron is charged either in a solid or molten 



