US539827A - Wilhelm schmidt - Google Patents

Description

W. SCHMIDT.

Patented VMay 28, 1895.

(No Model.)

COMBINED TUBULAR BOILER AND SUPERHEATER.

No. 5:,s9,827.A

" UNITED STATES PATENT EE'ICE.

VILHELM SCHMIDT, QF WILHLMSHHE, GERMANY.

COMBINED TUBULAR BOILER AND SUPERHEATER.

SPECIFICATION forming part of Letters Patent No. 539,827, dated May 28, 1895. Application filed December 22, 1893l Serial No.494,485 (No model.)

To a/ZZ whom, it may concern:

Be it known that I, WILHELM SCHMIDT, a subject of the King of-Prussia, German Emperor, and a resident of Wilhelmshhe, near Cassel, in the Province of Hesse-Nassau, Kingdorn of Prussia, German Empire, have invented a new and useful Combination Consisting i of a Tubular Boiler and a Superheater, of

which the following is an exact specification.

This invention refers to combinations of steam-boilers and superheaters, and my improvements in such combinations relate, rst, to the arrangement of a tubular boilerwith coiled pipes, and, second, to the arrangement of a reservoir connected with both ends of the boilercoil,but with only one end of the superheater-coil, as willbe more fully described Khereinafter.

Before entering into thedetails of the mode of construction of my improved combination shown inthe drawing, I think it necessary7 to give some preliminary statements and explanations, in order to render the idea of the invention perfectly clear and intelligible.

If steam is to be superheated to a temperature of about 300, the heating-gases should have, as is well known, a temperature of at least from 500o to 600. The said former temperature will be reached best by arranging the superheater above the steam-generator, and exposing it tothe furnace-gases of the same,`or, in other words, by arranging the,

superheater behind the steam-generator with regard to the direction of the furnace-gases of the latter, and exposing it to a zone of said gases, in which the temperature amounts to about 600. The regases need, thus, be cooled down by the boiler proper but to about 600, while generally,in a steamgenerator without superheater an exhaust of the heat down to 250 is required. As is well known, however, the greatest part of steam is generated in the fore-part of a boiler, the remaining part, that is generated by exhausting the heat from 600 down to 250, being of but small quantity, and necessitating comparatively large heating-surfaces. Extended trials made with locom0tive-engines have proved, that about fifty per cent. of the whole of the steam is generated in the small part surrounding the re-box. It results from this,

that, when arranging a superheater for temperatures of about 300 above or behind a steam-generator, the latter not only may have a comparatively small heating-surface, but should have such a one; and it will be seen, further, that such boiler with superheater will yield at least the same effect, as a larger boiler, that v.consumes a like quantity of fuel, since thefurnace gases of both boilers are exhausted in like degree, t'. e., are escaping into the smoke-stack with -the like low'vv temperature. Owing to these facts, now, the boiler or generator employed in 'my improved combination is composed of coils oreoiled pipes. These latter offer, in themselves,certain advantages for every boiler-plant. They could, however, not be, employed in a more extensive degree, especially for large plants, as there arise in the practical use of them serious drawbacks difficult to be overcome, as'will be shown in the following.V

The main point to be considered in the use of coiled pipes as steam-generators consists in the rapid circulation of the water or of the mixture of water and steam within the coils. Such circulation is indispensably requisite. The same is considerably hindered or delayed, however, by the great friction arising between the Water and the inner walls of the pipes, especiallyT if the latter are of a somewhat great length and of but small inner section. This disadvantage could be overcome, seemingly, by using pipes with larger section. This section, however, necessitates dimensions of such size, that it is nearly impossible to bend such pipes. A perfect change, however, in all these circumstances occurs, if the tubular boiler withcoiled pipes is combined with a superheater. There is no necessity any more for providing s0 large a heating surface for properly exhausting the heat of the tireor furnacegases, but a boilerof but'vthe fifth or sixth size with coils of but smallsection will be sufficient for delivering the desired effect, even if a larger number of horse-powers is required.

The heat of the tire need not be cooled by the heating-surfaces of the boiler proper downto 250, as this is performed by the superheater; and the generation of steam will be a regular one, and free of shocks, as the circulation of the Water, or of the mixture of water and steam.

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respectively, within the short coil with its small section is a very active one. The best elfect, however, of the combination of a tubular boiler (with coiled pipes) with a superheater is attained by arranging a reservoir between the boiler-coil and the superheating coil, for the purpose of separating water and steam. I have represented this arrangement in the accompanying drawings, in which is shown a vertical section through the tubulous boiler, the superheater and the said reservoir.

The coil d of the tubulous boiler, which is heated from the furnace b, is connected by its two ends a a2 with the reservoir c, coil-end a terminating into the lower compartment of the reservoir by the mediation ofva bent tube a5 extending upward within said compartment; coil-end a2 terminating into the upper compartment of the reservoir by the mediation of a bent tube a3 likewise extending upward within that respective compartment. The further details ot' the reservoir will be more fully described hereinafter.

The uppermost portion of the reservoir forms a steam-dome, and the saturated steam is led from that dome by the mediation of pipe d into the superheating-coil cl, from which the superheated steam is led away by pipe d'2. The feed-water for the boiler, or for coil a respectively, enters the latter through the pipes a5 a', and leaves the coil, after being heated and partly turned into steam within the same, bythe pipes a2 a3. The mixture of water and steam separates within the upper compartment of the reservoir c, the steam collectingr within the dome,.the boiling water mixing with the feed-water, and heating the same.

The superheater consists of a number of superposed flat horizontal coils, which are connected with each other to a continuous passage. This connection of the coils, however, is made in such a way, that two divisions are formed out of them; the first division, next to the boiler-coil, being passed by the steam in a direction like that of the furnace-gases; the other division being passed 4by the steam in the opposite direction; that is to say, opposite to the direction of the furnace-gases. Both divisions are connected by the bent tube d3. The said superheating-coils are arranged in the annular space between the outer wall e and the inner wall e. The furnacegases coming from the re-place b are led through the said space, and leave the whole apparatus at f. It will be seen now, that the circulation of the water,`or of the mixture of water and steam respectively, within the boiler-coil will be a very intense one, as, first the said coil is but short, and has but a small section; and as, second, the contents of coil a are constantly under the pressure of the water-column within the lower compartment of reservoir c. The generation of steam is, therefore, a very intense and rapid one, as well as free of shocks, and the steam then enters the superheatin g coils without the least addition of water, as the latter is perfectly kept back by the reservoir. The water now circulates again and again through the boilercoil, so that the whole of the water within reservoir c is heated to a high degree of temperature. This circulation will, as a matter of course, be the more active the greater the difference in pressure between the water-column within the lower compartment of the reservoir, and the waterand steamcolumn within the boiler-coil; and further, the less the resistance offered by the friction between the said waterand lsteam-column and the inner walls of the boiler-coil. It results herefrom, that the whole of the water contained within, or entering, the said boilercoil cannot be turned into steam at so rapid a circulation, and it becomes thus, necessary to provide the reservoir c for separating both parts of the water-and-steam mixture leaving the boiler-coil, as but the `steam can be permitted to enter the superheating-coil, while the hot water must remain.

Concerning now the special construction of the reservoir, the latter is divided into two superposed compartments by a horizontal plate c having secured to it aver-tical tube g extending downward to the neighborhood ot the bottom c2. The vertical tube a5 communieating with end a of the boiler-coil is arranged in the same compartment of the reservoir, and extends upward to the neighborhood of plate c aforementioned. The purpose of this arrangement is to separate and precipitate sediments and the like contained in the feed-water, for preventing the boiler-coil from becoming incrustated. The feed-water enters the upper part of the reservoir through the funnel h, and the sediments separated by the heating of the water ow, together with the latter, down into the under compartment of the reservoir through tube g. The water, then, in order to enter the opening of tube a5, flows upward again, while the sediments remain back, and precipitate on the bottom c2.

The uppermost part of the vertical boilercoil a, or that part situated between the coil a proper. and the pipe 0,2, is formed to a horizontal coil a4, the purpose of which is to break the intense heat discharged by the fire, so that the superheater is prevented thereby from becoming pervious.

Having thus fully described the nature of this invention, what I desire to secure byLetters Patent of the United States is 1. The combination with a superheater, consisting of a column of horizontal coils forming two superposed divisions, of a tubular boiler also consisting of coiled pipes, the ends of the boiler coil being connected with a reservoir divided in two compartments, one of the latter being adapted to cause the vseparation of the sediments, the other the precipitation of the same, said former compartment being connected with the lower end of the lower superheating coil-column, the

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upper end of the latter being connected with the upper end of the upper superheating coilcolumn,rfor the purpose as described.

. 2. The combination with a superheater, consisting of a column of horizontal coils forming two superposed divisions, of a tubular boiler also consisting of coiled pipes, the ends of the boiler coil being connected with `a reservoir divided in two compartments by a plate allowing communication between the said compartments. one of the latter be-` ifng adapted to .cause the separation of the sediments, the other the precipitation of the same, said former compartment being connected with the lower end of the lower super- 'heating coil-column, the upper end of the latter being connected with the upper end of the upper superheating coil column, for the purpose as described.

3. The combination with a superheater consisting of a column of horizontal coils forming two superposed divisions, of a tubular boiler also consisting of coiled pipes, the ends of the boiler coil being connected with a reservoir divided in two superposed compartments by a plate carrying'a tube, the

l to cause the separation of the sediments, the` upper of said compartments being adapted lower the precipitation of the same, said tube being adapted to convey the sediments from the upper to the lower compartment, said upper compartment being connected with the lower end of the lower superheating coil-column, the upper end of the latter being connected with the upper end of the upper superheating coil-column, for the purpose as described.

4. The combination with a Snperheater consisting of acolumn of horizontal coils forming two superposed divisions, of a tubular boiler also consisting of coiled pipes, the ends'of the boiler-coil being connected with a reservoir divided in two superposed compartments by a plate carrying a tube, the upper of saidcompartments being connected with the upper end of the boiler-coil, and with the feedpipe, and being adapted to cause the separation of the sediments, the lower compartment being connected with the lower end of the boiler-coil, this end terminating shortly below the bottom-plate of the upper WILHELM SCHMIDT.

Witnesses:

R. HERPICH, E. Soiunrzn.

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