280 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Septejibeb, 



of contracting considerably the flue area, and increasing proportionately the 

 amount of power requisite to draw the air through the tulies, and conse- 

 quently tlie rods in the tubes would cause a loss of power to the engine 

 from the increased resistance to the blast. lie thought therefore the rods 

 must have caused an equal amount of gain to neutralise this loss, by bring- 

 ing the air into more effective contact with the sides of the tubes, as the 

 result showed no loss on the whole. 



Mr. McCoNNELL thought it was certain at least that the use of the rods 

 did no harm; and it must either be considered that tliere was no advantage 

 in a large flue area, or that there was considerable advantage in mixing the 

 air in passing through the tubes. 



Mr. Slate was of opinion that even on the ground of economy a large 

 number of tubes was advisable, because with the violent and frequent action 

 of the pieces of coke the tubes were soon worn out; whereas by increasing 

 the number of tubes the velocity of the draught would be diminished, and 

 the tubes would be less worn and would last longer. 



The Chairman remarked that the larger the area of the flue, the better 

 it was for the engine, as it must offer less resistance to the blast-pipe ; but 

 he was not certain what this resistance actually amounted to. 



Mr. CowPER said that Mr. Daniel Gooch had found from his indicator 

 cards, that the resistance of the blast-pipe amounted to 11 or 12 lb. per 

 square inch, at a moderate velocity of about 30 miles an hour. 



Mr. McCoNNELL observed that as a certain quantity of heated air had to 

 be conveyed from the fire-box to tlie chimney, and a certain area of heating 

 surface was also required, there would be an important reduction effected in 

 the resistance of the blast-pipe by increasing the number of tubes, so as to 

 increase the area of passage and reduce the length of the tubes, diminishing 

 proportionately the resistance of the air passing through the tubes. 



The Chairman said he was present when the experiments were tried that 

 were mentioned by Mr. Ramsbottom, to ascertain the difference between the 

 degree of exhaustion in the smoke-box and in the fire-box ; the experiments 

 were tried with a long-boiler engine, and a glass water-gauge was fitted into 

 the smoke-box and another into the fire-box. The degree of exhaustion in 

 the smoke-box averaged three times as great as that in the fire-box, and this 

 proportion was found to be nearly the same at all velocities ; the greatest 

 amount of exhaustion observed in the smoke-box supported a column of 

 water 13 inches high. He thought that the whole resistance of the blast- 

 pipe and the back pressure in the cylinder, did not amount to more than 15 

 per cent, of the power of the engine. 



Mr. Slate remarked that assuming it to be 15 per cent., it followed that 

 10 per cent, of the whole power of the engine was absorbed by the friction 

 of the air in passing through the tubes, as the exhaustion in the smoke-box 

 was three times as great as in the fire-box ; or one-third only of the pressure 

 of the blast was efl'ectively acting in the fire-box. 



Mr. McCoNNELL thought it was an important subject for investigation, to 

 ascertain the actual power lost by the resistance of blast-pipes of different 

 sizes, and under the different circumstances of size and number of tubes. 

 In his own practice he had found that small tubes and many of them pro- 

 duced the best efl"ect ; the limit in reducing the size of the tubes was their 

 stopping up with pieces of coke whilst working. 



The Chairman said he thought there was some advantage in the form of 

 boiler proposed by Mr. Ramsbottom, and that amongst the various modifica- 

 tions that had been proposed of the locomotive boiler there was not one 

 that was so likely to be useful. 



REGISTER OF NE'W PATENTS. 



CASTING PIPES. 



David Yoolow Stewart, of Montrose, Scotland, ironmaster, for 



^^improvements in the manufacture of moulds and cores for casting 

 iron and other substances." — Granted January 1; Enrolled July 4., 

 IS 19. [Reported in the Patent Journal.'] 



This invention has reference: First — To the formation of the 

 moulds for casting pipes, or other similar articles, of a uniform, or 

 nearly uniform, shape throuj^hout. 



Secondly — To the construction of moulds, and parts connected 

 therewith, so that they may be readily moved into and out of the 

 drying stoves. 



Thirdly — To a mode of constructing cores; and also to the 

 moving or starting cores (when of a large size) out of the cast- 

 ings. 



In casting pipes, if of ordinary sizes, the patentee arranges to 

 cast them in sets of six, in one ilask or box, which is placed on 

 end, as represented in the annexed engraving. a,a, is a pit, formed 

 in the ground, with a metal lining i, b, to maintain tlie relative 

 positions of the working parts. A screw c, is sustained in a verti- 

 cal position in the centre of the pit, and fitted into a step </, at the 

 bottom, so as to admit of a rotary motion. This screw c, is fitted 

 with a nut e, wliich supports, and is fixed to, a plate /, sliding up 



and down on guides g, g, on the sides of the pit; this up-and-down 

 motion being caused by the rotation of the screw c. To the bot- 

 tom end of the screw, a spur-wheel h, is affixed, gearing with the 

 pinion ), fixed on a shaft fr, ap.d 

 worked by means of a wrench- 

 handle from the top. The plate 

 f, sustains six rods /, /, /, four 

 only being seen in the engrav- 

 ing, that representation being 

 a vertical section; these rods 

 are arranged in a circle around 

 the screw c, taking it as a cen- 

 tre, in which order they pass 

 through, and are sustained by, 

 the top plate m, through which 

 they pass. The rods /, are sur- 

 mounted by what he terms the 

 patterns n, n, fitted to the rods 

 /, so as to rest on a shoulder, 

 and rise with the rods, and at 

 the same time admit of being 

 readily removed from the ends. 



The flask or mould-box o, is 

 constructed of four separate 

 lengths, each in two halves, and 

 hinged on the bolt p; this is 

 mounted on a bed plate q. fur- 

 nished with holes, correspond- 

 ing in diameter with the pat- 

 terns H, and so disposed as to 

 come immediately over them; 

 the box is so fitted as to travel 

 on rails over, and be sustained 

 in its position, so that the pat- 

 tern, on being elevated by the 

 rods /, will enter the holes in 

 the bottom of the flask. When 

 the lieight of the pattern pieces 

 n, is such as to be nearly all 

 within the flask (the lower piece 

 being the only one on the bed 

 plate), the workman then raises 

 the sand in the flask, so as to 

 surround the patterns, which, 

 when nearly covered, are ele- 

 vated still higher, by the same 

 means, and an additional length 

 of the flask or box applied to 

 the top. When raising, the 

 sand proceeds as before, till the 

 top of the centre piece r, is 

 covered, when a gate piece *, is 

 placed on it, having six gates 

 (one to each pipe), communi- 

 cating with a centre channel, in which a gate pin t, is fitted, which 

 is drawn up as the sand is filled into the box, so as to maintain a 

 free gate up to the top of the mould, by w hich the metal is intro- 

 duced; this pin t, being drawn up as the filling progresses. The 

 patterns h, having attained the height represented by the dotted 

 lines, moulds or passages will have been formed up the sand, cor- 

 responding in diameter with the exterior of the pattern; these 

 being the moulds for the parallel part of the pipes. Faucet-pieces 

 are tlien placed on the top of the rods /, and the sand moulded 

 round them; the faucet -pieces and patterns are then removed, and 

 a socket-piece placed on the rod /, having a socket both ways, one 

 taking on to the rod, the other being presented upwards, for the 

 reception of the cores, which are then lowered down into the 

 mould by reversing the action of the screw c, when the moulds 

 will be complete. Metal is poured in at the central gate, diverg- 

 ing when half-way down into the several moulds, as explained. 



Althougli the pipes are here shown as cast in sets of six, this 

 method will of course be equally applicable for other numbers, by 

 ada])ting the several arrangements of the apparatus; or where the 

 pipes are large, the moulds may be similarly constructed for one. 



The second improvement is in the construction of boxes or flasks, 

 and moulds, whereby they may be more readily handled than the 

 ordinary mould boxes, which consists simply in fitting wheels to 

 them, on which they may be wheeled about, instead of lifting them, 

 as usual; and to facilitate the transport of such, he lays down 

 rails suitable for the purpose, in and about the foundry, in such 

 positions as required, and into the drying stoves. 



