Our readers may remember the excitement created in 1856 by Mr. H. Bessemer, of London, who secured an English patent for making malleable iron and steel direct from the ore, by a continued simple process, which was illustrated on page 32, Vol. XII. (old series) of the SCIENTIFIC AMERICAN. The principle of the invention consisted in forcing a stream or streams of air or gases through m o 11 e n crude iron in a suitable vessel or ap p a ratiis, by which process the oxygen of the air was made to combine with the excess of carbon in the metal, forming carbonic acid gas, which passed off under a gl-cat heat, leaving the pig iron purified and converted either into malleable iron or steel, according to the amount of oxygen that had combined with the carbon. It was afterwards proved that other persons had been making experiments in the same direction, in this country, before Mr. B esse m e r, but he was t h e first who directed public attention in a general way to the inter-esting and important subject. The theory of obtaining good m al leable iron and steel d i re c t trom the ores, by one continued process, in the manner described, is not unreasonable, and whenever this is successfuIly attaina great revolution w i 11 c e rtainl y take pl a ce in all the ar ts, b e cau se m alle able i ron and steel will th en be reduced to about one half thei r present prices. It has been asserted, several times, that this process was a fail u re, but we understand it is success-fully carried out in one of the greatest S we d ish i ron works, and Mr. Bessemer himself seems to be con. vinced of its practicability and value. The accompanying en-grav i ng is a side elevation of improved machinery recently patented by Mr. BessemCl', for conducting his process, which has been i I lu stra-ted in the London Engineer. The illustration represents three " converting" chambers, which are so situated in a strong i ro n fra min g, and so c o nss t ructed and operated, that one is tipped in such a manner (as shown by t h e dotted lines) as to receive the molten crude iron. It is then raised to a vertical position and a stream of compressed air forced upward s th rough it, when a violent ebullition of the metal takes place, and the excess of carbon is removed. It is then turned l'Ound and tipped on the opposite side of the frame, and the refined metal flows out into a proper vessel set for its reception, to be used for running into bars, &c. A A A are the conical converting vessels i nto which the molten pig iron is rece i ved, and i n t o which the air is forced", fo r refi n i n g p ur poses. T h ey ire se c ured in a very strong iron framing, an d e ach i s s u ppor te d on trun-n ion s at the sides. The whole frame is s e c u re d to a strong vertical shaft, C, in the center, on which they are made to rev oh' e, as r e qu ire d, like a t u rn-s t i le. In this manner, each is alternately brought forward to re-ceive molten pig iron from the smelting furnace by a spout, and then made to deliver the refined iron, as is sh ow n by the dotted lines. The mechanism is secured to a s olid foundation plate, D, a n d B B arc t he arms of the iron frame. G G rep re sen t the tweers at the bottoms of the converting vessels ; they are lined with fire brick, and each has a number of circular air passages in it. EE E are t h e pipes d ow n which the air is forced, first through the hollow trunnions, H H H (onp. on each vessel), which keeps them cool, then into the tweers, G G, and up through the molten metal in the c on ve rtin g vessels, A A. The re is a t o othe d segment on one trunnion of e.ach ch amber, which takes into I ruck, F. When this rack is moved back and forth, it gi yes a semi-ro tat i ve motion to the chambers, as sh own by the dotted lines. Mr. B es semer employs a hydraulic pump to operate the rack bars, F, and in this manner he secures a very simple and effective method of tipping the converting vessels. A ri ng of cogs is b olte d to th e frame of the c e n t ral axis, and into th is there gears a pinion which is rotated by the crank, R. In this manner the entire framework and mechanism are rotated on the central axis, and each converting vessel has a motion on an axis of its own. By k n o w i n g the exact weight of molten p i g metal in each converting vessel and the amount of carbon (generaIly about 3 per cen t) in i t, the exact qu an ti ty of air can be forced through the metal, to reduce it either to ste el or malleable iron, In th i s manner the blast regulates the quality of the product. Great exactness in the operatio n s is re q u i red to pro d u c e the qual i ty of metal required. The number of cubic feet of air that passes into the vessels is registered by a counter, and the blast cy l i nders a n d hy d ra u l ic pumps are operated by two high pressu re engines which are not s h o w n. The fumaces in w hich the pig i ro n is smelted are so situated above the fram e, that the molten metail will flow in to the vessels, as represented at the o n e side. This apparatus or mechanism is an improvement in the details for carrying out the principle set forth i u ;Mr. Bessemer's first patent. No new scientific discovery is set forth in the one which he has lately taken out, .and none is required, The principle is well understood and in our opinion, progress is being made for the perfect manufacture of iron and Iteel diNct from the ore. The common practice of running off and cooling crude iron, whe n it is mad e in the s mel t i ng furnace, then re-melting it in a reverberatory furnace, for refining purposes, de-serves to be condemned. The great labor and trouble involved in running it i n to pigs, an d the expense entailed t o re-melt it, will yet be all saved. T he heat of the molten pig m e tal, us it com es from the furnace, can and should be utilized by such a process and arrane;ements as those we have illustrated and described.
This article was originally published with the title "Iron and Steel Improvements"