360 



THE CIVIL EXGINEER AND ARCHITECT'S JOURNAL. 



[^ Decembeb, 



HIGH-PRESSURE STEAM GENERATOR. 

 Invented by J. A. Leon, C.E. 



In the beifinninfr of this century the tubular boilers of Wonlf 

 and Riimfiird were used for generating steam. Soon after Trevi- 

 tliick's flued-hoilers were introduced, it was found that metallic 

 flues surrounded witli water were more effectual than tubes tilled 

 with water, and surrounded by the products of combustion. Since, 

 the number of flues in a boiler increased successively until they 

 formed SJ^e multiflux locomotive boiler. 



Flued boilers ouirht to be used only where they cannot be 

 avoided, as on railways or for navigation. The space occupied by 

 the flues reduces the size of the steam-chamber. The water at its 

 maximum height covering these flues only a few inches, does not 

 permit the use of the float-stone, the best water indicator on sta- 

 tionary boilers. The metallic flues are sometimes left dry, and 

 burst. Boilers of that description are not easily cleaned, free 

 access to the inside being almost impossible; the result of such 

 neglect, if it causes no explosion, it increases greatly the tear and 

 wear, and the expense of extra fuel is very considerable. 



The common cylindrical horizontal boiler, being the simplest, the 

 safest, and the most easily cleaned, ought to be preferred as a sta- 

 tionary generator. The only objection against its use was its small 

 area of heating surface ; but the greatest part of the wasted Iiot 

 air leaving the boiler can be absorbed before reaching the chimney 

 by an appendix vessel, containing water for feeding the boiler. 



To obviate the defective method of cooling the cylinder by in- 

 jecting cold water in it. Watt condensed the steam in a separate 

 vessel. Here, in place of injecting cold water, mud and all, into 

 the boiler, this compound is primitively received into the heater, 

 where the water, before reaching the boiler, deposits its insoluble 

 matter, and acquires an elevated temperature. The generator 

 receiving by this process a constant supply of hot water, keeping 

 the steam steady, no perturbation is felt, as when injecting cold 

 water. 



This heater requires no extra room: its place is below the boiler, 

 and behind the fire-grate bridge, a space commonly fiUed with rub- 

 bish. A great advantage of this heater is, to keep the supply of 

 water in almost a quiescent state, which give^ the efl"ectual means 

 of obviating the evil of bad water. The sediment accumulates, in 

 one or more heaps, in the front of the heater, where the water 

 happens to be the least agitated. Those deposits are received in 

 some recipients placed near the man-hole. The generator, fed with 

 water almost clean, is no more liable to burn. 



Fig. 1. 



iY)...-\i,.5 "i-^ 



a 



■Eh- 



Fig. 2. 



The heater is comparatively of a small size. In the engraving 

 the generator's axis has 26 feet, its diameter 4 feet, while the 

 length of its heater is only 14, feet, its diameter 4 ft. 6 in., and, 

 notwithstanding this, its heating surface is twice as much as the 

 heating surface of the boiler itself, which is here 150 square feet. 

 In reducing the 300 square feet of the inner and outer surface of 

 the heater to 120 square feet of effective heating surface, the whole 

 apparatus has 150 and 120, or 270 square feet of heating surface. 

 This divided by one square yard, or 9 square feet, per horse power, 

 will prove a 30-horse power for the capability of the steam gene- 



rator. Tlie grate, 5 by 6 feet, or 30 s'piare feet, harmonises per- 

 fectly witli a 30-li(u-se high-pressure boiler. 



The u])|)er and lower brick flues are very large, and answer for 

 burning all kinds of combustible — vegetable, as well as mineral 

 fuel. 



The boiler and its heater are screwed and cemented together, 

 when set on the furnace. If rivetted together, their tran.sport by 

 land and sea would not be so easy. 



Reference to Engravings* 

 Fig. 1, Longitudinal section. — Fig. 2, Top view of Furnace and Boiler. — 



Fig. 3, Vertical section through line 1 — 2, fig. 1. Fig. 4, Vertical section 



through line 3 — 4, fig. 1. 



A A', Cylindrical boiler, with hemispherical ends, containing only the steam- 

 chamber, and the water to generate steam. 



B B' Horizontal reservoir, composed of two concentrical cylinders, leaving 

 an annular space filled with water, supplying the generator A A', by 

 means of the short vertical pipes b b', set into the sockets a a' 



c c, Joint bolts fastening A to B with curved cramp-irons. Th(r annular 

 space between b b' and a a' is filled on the spot with iron cement. 



d. Damper, with pulley d' and weight d". 



e, Stop-valve betwixt the feed-pipe e' and the plunger-pipe e". 



ff. Two erect cast-iron segments, resting upon cast-iron plates Y, on the 

 top of the furnace. On those curved girders the boiler A A' is sus- 

 pended liy its brackets g. with holts, pegs, and nuts, g' , g", g"' . 



h h\ Main steam-pipe and stop. valve. 



i, Whistle regulated by the float i', to give the alarm when the water falls 

 below its minimum level. 



i i', Man-holes to boiler A and to heater B. 



t, Safety-valve. 



m m', Gauge-cock and pipe-indicator of maximum of steam. 



n n', Ditto, ditto, of minimum of water. 



o', Discharge-cock and pipe for emptying the water from both vessels, A 

 and B, and for filling them by means of a perpendicular pipe connect- 

 ing o' with an elevated water-tank. 



p. Passage from the furnace-door to the fire-grate g. 



p', Moveable fire-mouth, in the shape of an arched-top bayed window, 

 placed in the fire doorway, its narrow part inside the furnace, for burn- 

 ing bundles of bagass, or dried squeezed sugar-cane ; each bundle is 

 pressed into the fire-mouth, and acts I7 turns as a furnace-door. This 

 sort of hopper is removed when wood or coal is used. 



Qf Fire-grate. 



r, Moveable plate, shifted when necessary to clean the flues. 



s, Fire-hriiks surrounding the sockets a a', not shown in tiie engraving. 



t, Two fire-brick lumps, on which rests the heater B. 



M, Two return brick flues, joining before reaching the damper d. 



V, Interverted arched bridge. 



M>, Partition between upper leading flue x, and lower return flues a. 



y, Cast-iron plates, ou which are placed the girders//'. 



z, Ash-pit. 



* We are indebted for tlie drawings to a worlf timt flir. Leon Is about publishing, oa 

 '* Colonial Macllioery for Alaoiifacturing and Retiniug bugar." 



