Untitled record

Application filed September 1,1880. (No model.)

To all whom it may concern :

Be it known that I, Benjamin Brazelle, of St. Louis, in the county of St. Louis and State of Missouri, have invented certain new 5 and useful Improvements in Steam-Generators, of which improvements the following is a specification.

The object of my invention is to provide a steam-generator of strong and simple conio struction, in the operation of which a constant, rapid, and thorough circulation of water shall be effected, the volume of contained water relatively to a given amount of heatingsurface be reduced, the tendency to foaming 15 be diminished, and the production of drier steam correspondingly insured, and the economization of fuel be promoted by the utilization, as far as may be, of the heat of the escaping products of combustion.

To this end my improvements consist in the combination of a cylindrical shell closed at both ends and adapted to be located above a furnace, a fire tube or tubes traversing said shell, and a steam-receptacle located within 25 the shell below the water-level; also, in the combination, with a cylindrical shell having closed ends, of a series of fire-tubes traversing said shell, a steam-chamber located within said shell below the water-level, and a series of wa30, ter-tubes; also, in the combination, with afurnace having an upwardly-projecting throat or outlet for the products of combustion, of a vertical shell inclosing steam and water receptacles, a fire tube or tubes traversing said shell, 35 and a return flue or flues opening into the furnace below the level of its throat or outlet. The improvements claimed are hereinafter more fully set forth.

In the accompanying drawings, Figure 1 is 40 a vertical central section through a steamgenerator embodying my improvements; Fig. 2, a horizontal section, on an enlarged scale, through the same at the line a; a; of Fig. 1; Fig. 3, a vertical central section through the 45 furnace, taken at right angles to Fig. 1; Fig.

4, a view in elevation of the same; Fig. 5, a plan view of the same with the ash-pit door in section; Fig. 6, a horizontal section through the furnace-casing at the center of the fire50 door; Figs. 7 and 8, vertical central sections, showing modified forms of my improvements;

and Figs. 9 and 10, horizontal sections through the same at the lines y y of Fig. 8 and z z of Fig. 9, respectively.

To carry out my invention I provide a cy- 55 lindrical shell, A, of iron or steel plate, which is closed at top and bottom by flanged heads a a', the lower of which, a', is preferably placed a short distance above the lower end of the shell, as in Figs. 1 and 8, to form a com- 60 bustion-chamber, and in such case is usually connected to an inner ring, a², which is united at bottom to the shell by a bar or a plate of Πsection in the ordinary manner. The shell A is located above and supported upon a cylin- 65 drical furnace, B, provided with a grate, b, fire-door ash pit b², and ash-pit door b³, and having a suitable lining of fire-brick or other non-conducting.material. The heads a and a¹are connected by a series of fire-tubes, a³, 70 through which the products of combustion pass to the uptake a¹¹, to which is connected an exit-flue, a⁴, provided with a damper, a⁵. Flanged circular heads a⁶ a⁷ are riveted to and made steam-tight with the shell A between 75 the heads a a', thereby dividing the shell into an upper and a lower water-chamber, the upper portion of the former constituting a steamspace, as in the ordinary vertical tubular boiler, and the space between the heads a⁶ a¹, 80 less that portion thereof which is occupied by the tubes, forming a separate steam-chamber, A', below the normal water-line of the generator, said chamber communicating with the steam-space A² in the upper water-chamber, 85 above the water-line, by a central steam-pipe, a³, which is open at both ends and passes steam-tight through the upper head, a⁶, of the steam-chamber A', from a point near the top of the steam-space A² to the lower portion of 90 the chamber A'. The heads a³ a⁷ of the steamchamber A' are connected by a series of water-tubes, a⁹, each surrounding and concentric with one of the fire-tubes a³, so that an annular water-space is formed between each fire- 95 tube and its encircling water-tube, and a series of return water-tubes, a¹⁰, connects the heads a^e a¹, the return-tubes being arranged in a circle about the series of fire-tubes, and between the same and the shell A. A pipe, 100 A³, connected to the shell at the upper portion of the. steam-space A² and below the lower

240,299 head, it⁷, serves for the attachment of a glass water-gage, A⁴, steam-gage A⁵, and gagecocks. Steam is supplied to the engine from a pipe, A^e, communicating by connections A⁷5 A⁸ with the steam-space A² and steam-chamber A', and furnished with a valve or cock, A⁹, by means of which steam may be taken from either receptacle, as desired. A suitable safetyvalve, A¹⁰, is connected to the pipe A⁶, and io pipes A¹¹ A¹² are connected to the lower portion of the shell for the attachment, respectively, ofcheck and blow-off valves for the supply and discharge of water to and from the generator.

In the modifications shown in Figs. 7 to 10, inclusive, the internal steam-chamber, A', is an annular vessel located within the waterspace and surrounding a single fire-tube, Figs. 7 and 9, or a series of fire-tubes, Figs. 8 and 20 10, and having a free circulation of water around, above, and below it, the water passing downward on its outer and upward on its inner side, as indicated by the arrows. The vessel A' is closed at top and open at bottom, 25 and its outer wall projects downwardly below the inner, forming a deflecting-ring, which is interposed between the opening of the chamber and the downwardly-moving currents of water, between the exterior thereof and the 30 shell. The steam from the chamber A' passes out continuously under the edge of the shorter inner wall to the steam-space A², whence it is supplied to the engine, and its place is supplied by accretions of steam generated from 35 the water passing around and under the outer wall.

My improvements, so far as hereinbefore set forth, are capable of use with a furnace of the ordinary description and a direct draft, but 40 are especially designed and adapted for the greater economization of fuel by their combination with means for utilizing heat which would otherwise pass directly from the upper ends of the fire-tubes to the chimney. To this 45 end I provide a circular throat or outlet, B', for the products of combustion, said throat extending up to or slightly above the bottom of the shell A, and communicating through the combustion-chamber at the lower end of the 50 shell with an annular passage, B², surrounding the throat, said passage being connected by a return flue or flues, B³, with the uptake a¹¹. The connection of the return-flue B³ with the passage B² must be below the top or open55 ing of the throat B', which requirement will be answered either by extendingthe throat upwardly, as in Figs. 7 and 8, or by forming a downward extension of the shell or its bottom water-space ring, as in Fig. 1. A series of 60 arms or projections in the passage B², radiating from the central throat, B', supports the generator in proper relation to the throat B' without interrupting communication between the throat, the annular passage, and the re65 turn-flues. The return-flues B³ may be either within or external to the shell A, as preferred, and in Figs. 1 and 2 a single annular return flue is shown, the same being formed between the shell and a concentric cylindrical casing, B⁴, connected at top to the uptake a¹,¹, and at 70 bottom to the periphery of the annular passage B².

In Figs. 7 to 10, inclusive, a series of tubular return-flues is arranged within the shell A, extending from one head thereof to the 75 other, similarly to the direct-draft fire-tubes.

In operation a constant and rapid circulation is induced by the action of the heat upon the water in the annular spaces surrounding the fire-tubes a³, the currents ascending through 80 said spaces and descending through the return water-tubes a⁹. The steam generated passes into the upper steam-space, A², aud thence through the pipe a⁹ into the steamchamber A', in which, it will be seen, it is en- 85 tirely out of contact with the water, and is further subjected to the superheating actiou of the return flue or flues B³. In addition to the provision of superior facilities for circulation, a capacious reservoir of dry steam is substi- 90 tuted for the unduly large water-space existing in vertical tubular boilers of the ordinary construction, materially reducing the volume of contained water as compared therewith and correspondingly facilitating the free and 95 rapid generation of steam. The thorough circulation also prevents accumulation of scale or deposit in the tubes, and the provision of a separate steam-chamber effectually obviates foaming, even with an exceptionally high wa- ico ter-level. The effect of the upwardly-projecting throat of the furnace, in connection with the surrounding annular passage, is to create an upward draft through said passage, inducing a downward draft through the return-flues 105 which open thereinto, and correspondingly rendering available the heat of products of combustion, which would otherwise escape unutilized into the chimney.