US1520236A - Steam-boiler furnace - Google Patents

Description

Dec, 23, 1924.

w. A. GILCHRIST STEAM BOILER FURNACE Original Filed Feb. 8. 1919 Patented Dec. 23, 1924.

WILLIAM A. GILGI-IRIST, OF NEW YORK, N. Y.

STEAM-BOILER FURNACE.

Application filed February 8, 1919, Serial No. 275,838. Renewed. March 19, 1923.

' To all whom it may concern:

Be it known that I, WILLIAM A. GIL- oi-rnis'r, a citizen of the United States, and a resident of New York, county and State of New York, have invented certain new and useful Improvements in Steam-Boiler Furnaces, of which the following is a specification, and which are illustrated in the accomanying drawings, forming a part thereof.

\Vhile it has long been recognized that loss of economy and the production of smoke may result when the combustion of furnace gases is checked by contact with the relatively cool surfaces of a. steam boiler, adequate provision for insuring complete combustion of the gases evolved from solid fuels has not heretofore been made without unduly restricting the furnace outlet or retardin destructive distillation in the fuel bed. When the fuel contains a relatively large proportion of volatile constituents the effect of chilling the furnace gases by contact with the boiler shell or tubes before coml'iustionhas been completed is readily noticeable from the production of smoke. There is, however, an equally important loss of economy if the burning gases rising from solid fuel containing only small quantities of volatile constituents are allowed to come in contact with the boiler surfaces. While smoke may not result in the last mentioned case, the chilling of the gases before their combustion has been completed nevertheless result in the escape of unconsumed combustible gas with a corresponding loss of economy. It follows that whether the flames principally comprise. burning hydrocarbonaceous gases rising from a bed of fuel containing large proportions of volatile constituents or burning carbon monoxide rising from a bed of fuel containing only small amounts of volatile constituents, greater economy will be secured if the construction of the furnace is such as to provide ample time for the combustion of the gases to be completed before they come in contact with the relatively cool surfaces of the boiler.

The present invention accordingly relates to steam boiler furnaces and contemplates a construction wherein the burning gases rising from the fuel travel over masonry walls entirely for such a distance be yond the fuel bed as to avoid any cooling of the gases by contact with the boiler until sufli-cient time has elapsed for complete combustion of all inflammable ingredients. The object of the invention is to provide an improved steam boiler furnace wherein solid fuels may be burned with great economy and without the production of smoke, even though the fuel may contain a large proportion of volatile constituents and moisture. The improved construction also provides that the fuel will be burned with such rapidity as to secure increased capacity from a plant of a given size.

In the accompanying drawings Fig. 1 is a longitudinal sectional View showing a furnace embodying the features of improvement provided by the invention, one of the boilers associated therewith being1 conventionally represented in elevation, anc

Fig. 2 is a transverse sectional view taken partly upon a plane extending centrally through the fire box of the furnace and partly upon a plane extending through a combustion chaniber and upright flue located immediately in rear of the said fire box.

For simplicity of illustration Figs. 1 and 2 of the drawings show an application of the improved furnace to the familiar type of return tubular boiler, two of which, as 10, 11, are provided. Inasmuch, however, as the exposed surfaces of all boilers are normally much cooler than the ignition temperatures of combustiblegases, it will be undcrstood that boilers of any type present the same requirement that combustion of the furnace gases should be completed before they come in contact with the boiler, and that the invention is not limited in respect to the type of boiler with which the improved furnace is to be used.

If desired, the two boilers 10, 11, may be arranged in a pair served from a single fire box, as 12. In carrying out the invention, the fire box 12 is preferably extended in front of the boilers and is provided with a masonry arch or roof 13. The grate 14 may be of the form commonly employed for supporting the particular kind of fuel intended to be used and for admitting air for combustion through the same from the ash pit, as 15. As shown, the arch 13 and grade 1 1 extend continuously between the side walls 16, 17, these being located to embrace the two boilers 10, 11, with suitable flue spaces, as 18, 19, 20, between and at the sides of the boilers. The furnace front 21 is formed with the usual clean-out and firing doors, 22, 23, while, if saw-dust or the like is to be used as fuel, the arch 13 will also be provided with feed openings, as 24, 25.

To permit a free escape of gases from the fire box chamber, the fire box 12 is preferably wide open at its rear end throughout its entire width and height. There is thus an unrestricted communication between the chamber of the fire box 12 and a combustion chamber 26 located in rear of the same. The floor 27 of the combustion chamber 26 is preferably on the same level with the grate 14 but the boilers as 10, 11, on the other hand, are desirably so located as to be not only a substantial distance above the floor 2'7 but also a substantial distance above the level of the arch 13. The furnace gases accordingly have a relatively long upward travel after entering the combustion chamber 26 and before coming in contact with the boiler shell.

Combustion of the gases within the chamber 26 will be stimulated if the combustion chamber 26 is bounded at the rear by an upright masonry wall, as 28. Furthermore, if the fuel contains a large proportion of volatile constituents, destructive distillation will also be stimulated if the wall 28 faces directly into the chamber of the fire box through its open rear end. This arrangement is also particularly effective in promoting the rapid drying of a fuel which contains moisture. In any case, the wall 28 becomes highly heated, thereby promoting combustion of the gases in the chamber 26 and, by radiation and reflection of heat, assisting in maintaining a high temperature in the chamber of the fire box 12. This is desirable with solid fuel of any kind for it promotes rapidity of combustion and secures increased capacity for the plant.

In carrying out the present invention the Wall 28 (Fig. 1) is extended a substantial distance above the level of the arch 13 to adjacent the underside of the boiler, as 10, 11. The upper portion of this wall accordingly forms, with the front wall 29 of the boiler setting and the adjacent portions of the side walls, 16, 17, a relatively long upright flue 30 leading out of the combustion chamber 26. As the walls of the flue 30 are of masonry, a high temperature will be maintained within the flue and combustion of the gases during their upward travel will be continued until all inflammable products have been consumed. It will, of course, be understood that the top of the Wall 28 will preferably be separated a sufficient distance from the underside of the boilers to provide for the merging of the fines 18, 19, 20, under the boilers.

While the wall 28 will in all cases be located sufiiciently close to the rear end of the fire box 12 for effective radiation of heat into the fire box chamber, its exact location may be varied in accordance with certain properties of the fuel intended to be used. In event the fuel contains moisture, as in the case of wet saw-dust, bagasse, peat or lignite, whereby the products of destructive distillation will be largely diluted with water vapor, the wall 28 will be so located as to provide a larger combustion chamber 26 and flue 30 than will be required for a fuel like bituminous coal from which only combustible gas is evolved. With dry fuel containing only a small proportion of volatile constituents whereby the burning gases are not diluted with water vapor and con tain but little hydrocarbon, the wall 28 may be so located as to still further reduce the size of the combustion chamber 26.v The extension of the wall 28 above the level of the arch 13 not only provides the upright flue St) leading out of the combustion chamber 26 but it also substantially increases the amount of surface from which heat will be radiated onto the fuel bed within the lire box. Furthermore, it will be observed that the increase in the amount of surface which is effective in radiating heat back into the fire box is proportioned to the distance at which the wall 28 is located from the fire box. It follows that when the wall 27 is so located as to provide a large combustion chamber 26, as when the burning gases are diluted with water vapor which has been evaporated from a wet fuel, the amount of radiating surface which is effective for drying the fuel is also increased.

The upright surface of the wall 28 is not only important for insuring reflection and radiation of heat upon the fuel bed but the construction of the wall in this form also serves to prevent its being rendered ineffective by accumulations of solid matter which may be carried over by the flames.

WVhilethe Walls 16, 17, 27, 28, and 29 and the arch 13 will usually be composed of refractory clay products, commonly termed masonry, the use of the word masonry in the accompanying claim is not intended to impose any limitation with respect to the particular composition of the refractory material employed, nor to the form in which it is used. Vertical enlargement of the combustion chamber 26, by its connection with the flue 30, which forms an extension of the said combustion chamber, permits of a relatively close location of the heat reflecting wall 28 to the fuel bed without corresponding reduction in the volume of the said combustion chamber. Likewise the substantial elevation of the boilers as 10, 11 above the fuel bed and the provision of the extended flue 30 between the combustion chamber 26 and the boiler she-ll, substantially prevent loss of heat from the fuel bed by direct radiation upon the boiler. This is of special importance in the use of low grade fuel since it is otherwise difficult to maintain sufiiciently high furnace temperatures for rapid drying and destructive distillation of these fuels.

I claim as my invention:

1. In a steam boiler furnace, in combination, a grate for supporting the fuel bed, a masonry arch and masonry side walls extending over and about the grate and form ing therewith a fire box which is closed except at its rear end where it is open for substantially its entire width and height, a forwardly facing upright masonry wall beyond the rear end of the arch but adjacent the open end of the fire box and extending substantially from the grate level to and a substantial distance above the level of the said arch, a horizontal upwardly facing imperforate masonry floor extending substantially at the grate level from the rear end of the grate to the said upright masonry wall and constituting the floor of a combustion chamber having a direct commumcation with the chamber of the fire-box through the open rear end of the same, a boiler set ting comprising masonry side walls and an upright masonry front wall extending upwardly from the rear end of the said arch and forming with the first mentioned up right masonry wall and the adjacent portions of the side walls of the setting an upward extension of the said combustion chamber within which the furnace gases are completely protected from contact with the boiler shell.

2. In a steam boiler furnace, in combination, a grate for supporting a fuel bed, a masonry arch and masonry side walls extending over and about the grate and forming therewith a fire-box closed except at its rear end where it is open for substantially its entire width and height, a forwardly facing upright masonry wall beyond the rear end of the arch but adjacent the open end of the fire-box and extending from substantially the grate level to and a substantial distance above the level of the arch, a horizontal upwardly facing imperforate masonry floor extending substantially at the grate level from the rear end of the grate to the upright masonry wall, a second upright masonry wall extending upwardly from the rear end of the arch, and masonry side walls forming with said floor and upright walls a. combustion chamber having direct communication with the fire-box through the open rear end thereof and extending substantially above the level of the rear end of the arch and in which the furnace gases will be completely protected from contact with a boiler shell.

3. In a steam boiler furnace, in combination, a grate for supporting a fuel bed, a masonry arch and masonry side walls extending over and about the grate and forming therewith a fire-box closed except at its rear end where it is open for substantially its entire width and height, a forwardly facing upright masonry wall beyond the rear end of the arch but adjacent the open end of the fire-box, a horizontal upwardly facing imperforate masonry floor extending substantially at the grate level from the rear end of the grate to the upright masonry wall, and masonry side walls forming with said floor and upright wall a combustion chamber having direct communication with the fire-box through the open rear end thereof, the combustion chamber having an extension within which the furnace gases will be completely protected from contact with a boiler shell.

4. In a steam boiler furnace, in combination, a. fire-box having a grate for support ing a fuel bed and a masonry arch over the grate, the fire-box being open at its rear end for substantially its entire width and height, a forwardly facing masonry wall beyond the rear end of the arch extending upwardly from substantially the level of the rear end of the grate, and masonry walls forming with said forwardly facing wall a combustion chamber having direct communication with the fire-box through the open rear end thereof and extending substantially above the level of the rear end of the arch and in which the furnace gases will be protected from contact with a boiler shell until combustion is substantially complete.

5. In a furnace, in combination, a grate, a masonry arch extending over the grate, the said arch constituting the roof of a fire box chamber which is open at its rear end throughout the width of the grate and arch and from substantially the level of the rear end of the grate to the arch, an upright transverse masonry heat storage and reflecting wall extending from substantially the level of the rear end of the grate to the level of the rear end of the arch but located beyond the rear ends of the grate and arch and facing directly into the fire box chamber, an upwardly facing 'masonary floor extending between the grate and the said upright masonry wall substantially at the level of the rear end of the grate and constituting with the said upright wall the floor and end respectively of a combination chamber adjoining the fire box and communicating directly therewith through the open rear end of the same, and masonry walls confining a fine forming an extension of the saidcombustion chamher and leading to a steam boiler or the like, the last mentioned masonry wall springing, respectively, from the upper end of the first mentioned upright wall and from the rear end of the arch.

6. In a furnace, in combination, a grate, a

flat masonry arch extending over the grate, the said arch constituting the roof of a fire box chamber which is open at its rear end throughout the width of the grate and arch and from substantially the level of the rear speotively of a combustion chamber adjoina ing the fire box and communicating directly therewith through the open rear end of the same, and masonry walls confining a flue forming an extension of the said combustion chamber and leading to a steam boiler or the like, the last mentioned masonry walls springing respectively from the upper end of the first mentioned upright wall and from the rear end of the arch.

7. In a furnace, in combination, a flathorizontal grate for supporting the fuel bed, a flat masonry arch extending over the grate, the said arch constituting the roof of a fire box chamber which is open at its rear end throughout the width of the grate and arch and from the grate level to the level of the rear end of the arch, an upright transverse masonry heat storage and reflecting wall extending from the grate level to and a substantial distance above the plane of the arch but located beyond the rear ends of the grate and arch and facing directly into the fire box chamber, an upwardly facing masonry floor extending at the grate level from the rear end of the grate to the said upright wall and constituting wit-h the latter the floor and end, respectively, of a combustion chamber adjoining the fire box and communicating directly therewith through the open rear end of the same, and'a masonry wall rising from the rear end of the arch and constituting with the said upward extension of the first mentioned upright wall the front and rear walls: respectively of a fine forming a continuation of the said combustion chamber and leading to a steam boiler or the like.

8. In a furnace, in combination, a grate for supporting the fuel bed, a masonry arch extending over the grate, the said arch constituting the roof of a fire box chamber which is open at its rear end throughout the width of the grate and arch and from the grate level to the level of the rear end of the arch, an upright transverse masonry heat storage and reflecting wall extending from the grate level to and a substantial distance above the plane of the arch but located beyond the rear ends of the grate and arch and facing directly into the fire box chamber, an upwardly facing masonry floor extending at the grate level from the rear end of the gate to the said upright wall and constituting with the latter the floor and end respectively of a combustion chamber adjoining the fire box and communicating directly therewith through the open rear end of the same, and a masonry wall rising from the rear end of the arch and constituting with the said upward extension of the first mentioned upright wall the front and rear walls respectively of a flue forming a continuation of the said combustion chamber and leading to a steam boiler or the like.

VILLIAM A. GILC I-IRIST.

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