JULY. ON MECHANICAL PUDDLING. BY MR. T. RUSSELL CRAMPTON, OF LONDON. In introducing this paper to the meeting, the author trusts his observations may lead to instructive discussion, both with regard to solving the problem of Mechanical Puddling, and to the effect which the substitution of machinery for hand labour may have on the future of the iron trade; and he feels that it is a subject eminently fitted for the consideration of the members of this Institution, since success depends to so great an extent on the application of the proper mechanical appliances. Puddling, as the members are aware, is the process of eliminating certain impurities from cast iron, whereby its character is sought to be changed from a hard, unyielding, brittle material, to one of a comparatively soft and ductile nature. The operation requires considerable intelligence and excessive labour, and it is the successful combination of these two elements which constitutes the great difficulty, as evidenced by the high wages that good puddlers can command. The difference in individuals of this class is very marked, it being far from uncommon for a bad puddler to cause a loss in weight of say 10 per cent. of material, leaving a large amount of phosphorus in the iron, which in consequence is inferior in quality; whilst a good puddler will, with the same pig, lose only 5 per cent. or less in weight, and succeed in reducing the phosphorus to a greater extent, producing better iron. This is readily accounted for: the former neglects his firing and omits to attend to his firebars, thus creating an intermittent action, more particularly as regards the supply of oxygen by which the iron becomes oxidised or cut to waste. He also neglects to rabble or puddle regularly, so as to bring every particle of the iron into immediate contact with the fettling. The good puddler on the Downloaded from pme.sagepub.com at UNIV OF VIRGINIA on June 4, 2016 JULY. MECHAh’ICAL PUDDLING. 245 other hand, by his skill and attention, not only produces good iron from ordinary pig, but in some cases from bad pig also. Experience has shown tbt the latter class are few and diminishing in number my. Although the requirements for good puddling are apparently so simple, manual labour is not to be depended on for this purpose; consequently mechanical puddling has been called into requisition. Su5cient has been established by various workers in this field of enquiry to enforce the conviction that puddling by a revolving chamber is superior as compared with hand puddling or other rabbling, as not only are the yields increased, but the quality of the product is most strikingly improved. The most careful efforts have been made to obtain equal results by hand from like material, but in every case the rotary puddled product was the best ; with such facts before them, it is presumed, the Mechanical Engineers will overcome every mechanical difficulty, if it has not already been accomplished. The several drawings shown in Plates 40 to 43 are for the purpose of giving a general idea of the various arrangements that have been proposed, without entering minutely into their details. Fig. l.-wa~kfsr and Warren’s, dated 1853.-The barrel chamber is here placed obliquely, revolving on a horizontal axis, and is heated by an ordinary fire at one end, the flame passing out’at the other through a fixed flue. Fig. 3.--11Zaudssbayy’s, dated 1858.-The puddling or melting furnace is a cylinder caused to revolve on an oblique axis, the flame being deflected into the revolving portion in a line with its axis, and escaping from the same face or end. This appears to be the first occasion on which the heat has been so directed in revolving furnaces. Fig. 5.-Tooth’s, dated 1861.-This comprises a drum revolving on a horizontal axis, with a fireplace at one end and a movable fluepiece at the other, which is described as capable of being moved away in any direction for the purpose of enabling the ball to be extracted, and through which the gases escape to the chimney. This appears to be the first time a movable fluepiece N2 Downloaded from pme.sagepub.com at UNIV OF VIRGINIA on June 4, 2016 246 MECHANICAL PUDDLING.’ JULY. had been proposed to serve as a door and flue ; the fireplace was also movable. Fig. 6.-Also Tooth’s (Yates being associated with him), dated 1863.-This has the puddling furnace revolving on a vertical axis, the flame passing from a fixed fireplace, and deflected, as in Maudslay’s, into the revolving portion in a line with its axis, and escaping out of the same face or end of the furnace. Fig. 8.-Damks’, dated 1869.-This is similar to Tooth’s of 1861 ; it revolves on a horizontal axis having a fixed fieplace at one end, and at the other a movable fluepiece serving as a door and flue for giving admission to the furnace and for the exit of the gases to the chimney. Fig. 9.--Bellers’, of Philadelphia, dated October 31-41871.-This puddling furnace revolves on a horizontal axis, the flame passing from a &xed fireplace into and out of the same face or end of the furnace, similar to that shown in Maudslay’s and Tooth’s of 1863, except that the drum is horizontal, Maudslay’s being oblique and Tooth’s vertical. When the puddled ball has to be discharged, the puddling chamber itself is removed from the fireplace or fixed portion of the furnace. Fig. 10.-Siemens’, dated November 5th, 1871.-The furnace revolves on a horizontal axis; the flame passes into it from a regenerative gas apparatus and out at the same face or end, similar to Maudslay’s, Tooth’s, and Sellers’, a door being arranged at the opposite end for withdrawing the ball. Fig. 12.-Craqton’s Dust-Fuel Fu~nace,dated 1872 and 1873.- A is a revolving chamber which is made to rotate on a horizontal axis; the speed can be adjusted to any velocity up to say 10 rev. per min. ; B B is the refractory lining; and C C the wheels on which the furnace revolves. D is the movable flue- piece lined with suitable refractory material, capable of being removed when access to the furnace is required ; in the case shown in the drawing the fluepiece rests upon three wheels E, which run on iron rails and have screws F on the axles of the wheels for keeping the fluepiece against the furnace. G is an opening in the movable fluepiece, through which the air and fuel are injected. H is the pipe Downloaded from pme.sagepub.com at UNIV OF VIRGINIA on June 4, 2016 JULY. MECHANICAL PUDDLING. 247 through which regulated streams of air flow, and which conveys the fuel from the coal reservoir to the furnace through the nozzle I. A plan of this is shown enlarged in Fig. 15, Plate 44; and at K are several partitions in the bend of the injection pipe for the purpose. of preventing the fuel and air separating on passing the bend. L is a double-way cock for the admission and exit of the water to the double casing of the furnace ; the flow of water is shown by arrows. The water enters at L, passes into the pipe M, and is delivered at the end N into the casing, circulating through the whole casing and making its exit at the end of the pipe 0, passing thence to the cock L, and leaving it by the pipe P. The water is then conducted by the pipe P to the fluepiece, entering through a flexible pipe at the lowest point and leaving at the highest point at R. SS are the wearing joints of the furnace and fluepiece directly in contact with the water casing. T is the opening in the fluepiece for the exit of the products of combustion into the chimney, where they may be utilised in producing steam or heating the air, or both. The cod, which is ground and sifted previously, is brought into a, tank U, shown in Fig. 14, by a screw or creeper. In order that the powdered coal may not clog, stirrers V are used, which serve also to bring the coal from the tank to the feed rollers W W. The opening from the tank can be made larger or smaller as required by a sliding door X. The distance between the rollers can be adjusted and the feed regulated with the greatest accuracy by a lever and screw Y; two scrapers clear the rollers. The coal falls through a shoot Z to the air pipe H, into which it is induced by the current of air traversing it from a blast reservoir. It will be seen that the horizontal drum system of furnace in all the above cases, provided with separate fireplace, operates on the metal in a similar manner. Fig. ll.--llleoha&aZ Rabble.-The mechanical rabble process waa suggested at an early date : it consists essentially in substituting machinery for working the ordinary rabble instead of manual labour, thereby reducing the hard work. The drawing shows the rabble operated upon by one of several different mechanical Downloaded from pme.sagepub.com at UNIV OF VIRGINIA on June 4, 2016 248 MECHANICAL PUDDLING. JULY. means. This system, however perfect it may be, leaves the hand work of balling up untouched, and therefore can hardly be expected to be as useful as the revolving drum system, which displaces all severe manual labour.