US1678827A - Boiler furnace - Google Patents

Description

July 31, 1928. 678,827

C. SCHILLINGER BOILER FURNACE Filed July 14, 1926 V Mg, 1;. QKIIIIIIIIIIIIIIIII INVENTOR. yaw W ATTORN Ill Patented July 31, 1928.

UNITED. STATES" PATENT OF ICE.

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Application filed m 14,

old' boilers that were set very low. In mostcases, however, the cost of raising the boiler or the possible lowering of the floor in order to provide room to install the stoker beneath the boiler is so high as to make the 1nstallation prohibitive, and in many instances 1t impossible to do either because of structural dificulties. Tnsome instances this type of stoker has been installed under low set boilers with standard furnace arrangement. but invariably the installation has proved ineficient, particularly when burning the finer grades of anthracite, and t was not possible to obtain very hlgh ratmgs One of the objects of the present invention is to provide a furnace structure embodying a traveling or chain grate stoker which is adapted to be 1nstalled n-front of the boiler setting so as to make 1t unnecessary to either raise the holler or lower the floor, and which is simple 1n construct on, and of high eficiency and great ilexiblhty, and in which complete combustion is insured ,together with very low ash pit loss.

Another object of the invention is to provide a novel and improved method of promoting combustion which is part cularly adapted for use with traveling or chain grate stokers.

The several features of the invention, whereby the above mentioned and other objectsmay be attained, will be clearly understood from the following description and accompanying drawing in which the figure is a longitudinal sectional view, partly diagrammatical, of my improved furnace structime My improved furnace structure, as illustrated in the drawing, is particularly adapted for use with an old boiler Where it is desired to substitute a traveling or chain grate stoker for the stoker previously used. The combustion chamber of the stoker is indicated 2 and the chamber of the boiler is indicated at 4;. The Stoker may be of the usual construction having a chain grate 6, and a plurality of air supply compartments 8 arranged between the runs of the chain for supplying air under pressure to the up 1926. Serial in.- 122,293.

per run, the air supplies to the several compartments being separately controlled.

As shown, the traveling rate is arranged in front of the boiler .cham er with'its rear end spaced a distance from the front wall of said chamberto provide a space throu h which the ashes may be discharged from t e grate. The combustion chamber is provided with a front wall 10 and a horizontally arranged to wall or roof 12 extending to the front wal of the boiler chamber. The front wall 10 of the combustion chamber is verticall arranged and its lowerportion is inelined downwardly and forwardly to provide an ignition arch 14 extending to the upper edge of the fuel receivin opening 16,

a fuel hopper 18 being provide which leads I into said opening. v The combustion'chamber is further provided with a rear arch 20 which extends from the front wall of the boiler chamber over a little more than one-half the length of the grate. The underside of the rear arch is inclined upwardly and forwardly with its rear end portion arranged in proximity to the grate. The forward .end of the under side of the arch is curved in an arc to the front end of the arch which extends upwardly a distance parallel with the front wall of the combustion chamber.

The top side of the rear arch and the opposed under side of the top wall or roof of the combustion chamber define a passage leading from the space-above the front end portion of the grate to the combustion chamber, a gas inlet opening being provided in the front wall of the boiler chamber which extends between the rear end of the top wall or roof of the combustion chamber and the rear end of the arch. The rear portion of the roof of the combustion chamber isarranged horizontally except for its extreme rear end which is curved in an arc to the inner side of the front wall of the boiler chamber. The correspondingrear portion of the top side of the rear arch is' inclined rearwardly and downwardly at a considerable angle so as to provide a rearwardly flaring expansion space between said corresponding rear portions of the roof and arch. The remaining portions of saidwalls of the pasage are arranged parallel and are in-.

clined slightly downwardly and rearwardly except for the forward end portions thereof which are arranged horizontally. The height of the space between the bridgev wall A half the length. of the space between the and the chamber roof, except between the rear portions thereof,-,is substantially onefront wall of the combustion chamber and the front end of the rear arch.

With this arrangement, by admitting an -excessive amount of air to the rear end portion of the grate, the low volatile ases gen'-. eratedbeneath the rear arch are b own for- 7 cause them to thoroughly wardly' with sufficient velocity through the restricted space beneath a air through the fuel bed are carried forwardinto the ash pit.

rear arc 15; by the high velocity under the rear arch to the front end of the stoker where the gas velocity is reduced very materially as-above described, which permits the particles to drop back upon the fuel bed at this oint, thus materially aiding ignition and, 0 course, in creasing the efiiciency. With the standard furnace these fine particles would be blown The s ace between, the to and the roof of t e combustion chamber is designed and shaped, and the gas velocity is high enough over the front portion of the rear arch to keep the top service of the rear arch swept clear of all fine ash and dust. This space or passage has a so-called Venturi effect, that is, the gases slow up as they reach the enlarged rear endof the passage and come nearer to the boiler, sothat they will not im inge at too high a velocity against the boi er tubes, and also so as to give the fine ash carried in the gases time to precipitate or drop down upon the rear end portion of the top surface of the rear arch, at which point means may be provided for easily removing this fine ash.

' Also, with this arrangement practically any percentage of CO within practical limits can be maintained at the point Where the gases enter the boiler by varying the amount of air admitted through the last or rearmost compartment of the stoker. It has been found that 17 per centum of CD, can be maintained continuously but the temperature at so high a percentage of CO is excessive, causing the refractories to melt, but by admitting more air through the rearmost compartment, the CO can be brought downto any desired point, and it has been found that from 14 to 15 per centum of CO is as high as it is desirable to maintain. With. this construction of furnace it has side of the tense? been found to be possibleto burn very fine sizes of anthracite, coal and at the same time obtain higher ratings and higher efliciencies than it has been possible to'do heretofore, and in most cases it is possible to install stokers where it would be im racticable to able, and the cost'in many instances is less In the illustrated construction the rear do so if a standard furnace on y were availarch. is made up of two walls 22 and 24 arranged one over the other and spaced a distance apart with their front and rear ends closed. Air under ressure is admitted in the s ace thus provi ed between the two walls 0 the arch through a damper controlled opening 26 which may be in communication with any suitable source of compressed air suppliy. The air thus admitted to this space 1s ischarged through a duct 28 leading to one of the air supply compartments 8 of the stoker, preferably the forward one. This air in passing through the space between the two walls of the rear arch cools the steel work and castings supporting the arch, and thus becomes preeated before it passes-to the'stoker compartment where it is utilized to support combustion. Such ventilating or cooling of the rear arch is necessary because of the intense heat to which the arch is subjected on both sides thereof,

As will be evident to those skilled in the art, my invention permits various modifications' without departin from the spirit thereof or the scope oft e appended claim.

What I claim is: A furnace of the class described having, in combination, a traveling grate, a boiler chamber at the rear of said grate, a front wall, a top wall arranged substantially horizontally and extending substantially over the length of the grate, and a rear arch extending over substantially one-half of the length of the grate and arranged in proximity thereto, the forward end of said arch being spaced a distance from .said front wall to provide an expansion space, and the top side of said rear arch together with the opposed portion of said top wall providing a restricted passage leading from said expansion space to the boiler chamber, said arch being made up of two walls arranged one above the other and spaced a distance apart with the spaces between their ends closed, means for admitting air under pressure to said space between said walls of the arch, and means for discharging the air. after passing through said space beneath the ppper run of the grate to support combusion.

In testimony whereof, I have signed my name to this specification this 12th day of July, 1926. A

CHRISTIAN SOHILLINGER.

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