US1195174A

US1195174A - Fire-box

Info

Publication number: US1195174A
Authority: US
Publication date: 1916-08-22
Anticipated expiration: 1933-08-22

Description

P. BEER.

FIRE BOX.

APPLICATION FILED SEPT. 14. I914.

L1 95,1 '74. V Patented A 22, 1916.

3 SHEETSSHEET I.

P. BEER.

FIRE BOX.

APPLICATION FILED SEPT- 14, 1914. l ,1 95, 174:. Patented Aug. 22,1916.

I l 3 SHEETS-SHEET 2.

P. BEER.

FIRE BOX.

APPLICATION FILED SEPT-14,1914.

1 ,1 95, 1 74. Patented Aug. 22, 1916.

3 SHEETSSHEET 3.

PAUL BEER, OF DES MOINES, IOVT A.

FIRE-BOX.

Specification of Letters Patent.

Patented An 22, 1916.

Application filed September 14, 1914. Serial No. 861,602

1 0 all whom it may concern:

Be it known that I, PAUL Benn, a citizen of the United States, residing at Des Moines, in the county of Polk and State of Iowa, have invented new and useful Improvements in Fire-Boxes, of which the following is specification.

The present invention relates to new and useful improvements in fireboxes for kilns, boiler installations, heating plants, bake ovens, asphalt stills, etc, and more specifically to a. grateless gravity feed firebox wherein the combustion of the fuel may be precisely controlled and completely effected without the production of smoke or the escape of unconsumed combustible gases.

In most localities bituminous coal is the cheapest fuel which can be used for burning clays and shales in clay products kilns, boiler furnaces, heating furnaces, etc., and on account of its cheapness, practical experience shows that bituminous coal is the only fuel which is commercially feasible for use in the majority of the arts. As burned by the methods and in the appliances heretofore known, however, the use of bituminous coal in this class of work is open to serious objection. In the first place bituminous coal is a very smoky fuel. The production of smoke is extremely wasteful, for smoke consists of finely divided particles of unburned carbon and. its appearance always indicates the presence of invisible combustible gases which have escaped from the furnace unignited during the process of combustion. Inasmuch as kilns and furnaces of the kind I have referred to consume vast quantities of fuel, the degree of perfection to which the elimination of smoke and the combustion of the fuel can be carried assumes, from a com mcrcial standpoint, vital importance. Again the l: rge quantity of smoke produced from bituminous coal, as it is now burned, makes it impracticable to use this coal as a heatproducing agent in fine pottery kilns because of the effect of smoke upon the ware in the kiln. In consequence of the effect of smoke, it is quite often found necessary this, and in other arts, to substitute a comparatively expensive fuel for bituminous coal. In the second place, it is sometimes neces sary, in burning certain wares, to change from a reducing to an oxidizing heat action, or vice versa, at will.

M 7 invention has, for one of its objects,

an appliance for elimination of the smoke nuisance and for the development of the full thermal value of the fuel by igniting and burning all the combustible elements thereof, a portion of which if left unburned would take the form of smoke and the invisible combustible gases always associated with smoke, and thereby prevent the formation of smoke and derive and utilize the total heat content of the fuel.

Another object of my invention is to employ the heated ash and a portion of the live dcvolatilized coals for the purpose of preheating a portion of the air used to accomplish or promote combustion of the fuel.

Another object of my invention is to render practically automatic in operation that portion of the firebox known as the fuel table upon which devolatiliza-tion of the fuel is caused to take place.

Another object of my invention is to provide in a grateless firebox an underdraft and a top draft for combustion which, according to my invention, may be employed for temperature control, heat distribution, and heat characterization, as well as to assist in fuel combustion.

Another object of my invention is to provide an air supply for furnaces which will be ample and under perfect control, whereby the intermingling of the air and fuel will so complete that every particle of the fuel comes in direct contact with some particle of oxygen, whereby no excess air beyond that required for complete combustion in practice will be admitted to the furnace. EX- cess air absorbs a. large part of the heat which might be otherwise utilized in heating the products of the kiln.

My invention contemplates the combustion of the fuel in two distinct processes. First, the devolatilization of the fuel on the fuel table. Second, the oxidation of the carbon in the devolatilized coal below the fuel'tal'ile. The devolatilization of the fuel is not a coking process for that would imply distillation of the fuel. The fuel on the fuel table is ignited and burns freely. These two processes of combustion proceed according to my invention together and in the same chamber.

My invention contemplates the combustion of the fuel in the firebox by means of an under-draft which passes through heated ashes and devolatilized coal, whereby the air is raised in temperature above the ignition point of the combustible gases in the fuel. The air so preheated is utilized in the decarbonization of the devolatilized coal and such as is not thus utilized comes in contact with the fresh fuel on the fuel table and because of its high temperature combines with and unites with the volatile gases in the fuel immediately upon their liberation, thus promoting a thorough combustion and preventing the escape from the ignition chamber of any combustible matter whether in the form of smoke or in the form of invis ible combustible gases.

My invention further contemplates a top air admission through a baflie arch whereby the air is raised to a temperature in excess of the ignition point of the combustible gases in the fuel by means of reflected heat from the crown of the ignition arch, and the in candescent inner surface of the ba'lile arch. The air through this opening may be used for temperature control and heat distribution as well as for combustion of the fuel on the fuel table.

My invention also contemplates the admission of air between the fuel on the feeding plate and the lower part of the ballie arch, which may be used to assist in fuel combustion and in heat characterization.

My invention further contemplates the use of doors in conjunction with an air passage through pipes 011 either side of the firebox to which no resistance to the free passage of air is offered, said air passages being provided with cover plates so that the supply of air may be regulated and an oxidizing or reducing heat obtained at will.

My invention also contemplates a hooded mouth which holds the supply of fresh fuel, before its descent into the furnace.

lVith the above and other objects in View, the invention consists of the novel features of construction, combination and arrangement of parts, all of which will be hereinafter more fully described and particularly pointed out in the appended claims.

This application in its main features, except for one or two minor improvements, present the same matter as would a division of my co-pending application, Ser. No. 811,284, filed January 10, 1914.

In the accompanying drawings: Figure 1 is a vertical section through a fire-box constructed according to my invention, on the line 1--1 of Fig. 3, and shows an application to a clay products kiln. Fig. 2 is a horizontal sectional view on the line 2-2 of Fig. 1. Fig. 3 is a front elevation of the fire-box. Fig. 4 is a sectional view on the line l1 of Fig. 1. Fig. 5 is a sectional view corresponding to that shown in Fig. 1, of a slightly modified firebox as applied to a down draft pottery kiln. Fig. 6 is a view of the modfied form of fire-box applicable to a boiler installation. Fig. 7 is an elevation of a shield to be used in combination with the ash pit opening.

The fire-box herein disclosed comprises side walls 1, a front wall 2 and in Figs. 1 to 5 inclusive is in open communication with a flue 3 through which the gaseous products of combustion pass to the object to be heated.

Referring to Figs. 1 to 4:, a crown arch A is provided over the mouth of the firebox and continues into a conical combustion arch 5 leading to the flue 3. Set rearwardly from the front wall 2 is fuel table arch 6 mounted at either end in the side walls 1 of the firebox, and protected by the curved angle plate 6 against injury from the firemans tools. The space underneath the fuel table arch 6 provides an ash pit opening 7 through which the ashes may be removed from the fire, and through which an underdraft of air for promoting combustion passes. A water pit 8, such as is common in these structures, having a grating 9, is provided at the bottom of the fire-box. Mounted above the table arch 6 and supported thereby, as well as by the front wall 2 of the firebox, is an inclined fuel table 10 preferably made of slabs of fire-clay as shown. Above the fuel table 10 is a horizontal feeding table 11, preferably made of metal, its outer edge having a vertical lip and its ends being flattened and set into the side walls 1 of the structure. Overlying the inclined fuel table and set rearwardly from the feeding table 11, is .a baffle arch 12 mounted in the side walls 1 of the fire-box, and superposed upon the arch 12 is a second arch 13 having one or more bricks removed at the top thereof, as shown in Figs. 1, 5 and 6, to leave a space or opening 14. A pair of doors 15 closes the mouth 16 of the fire-box above the feeding table 11, these doors being provided with dampers 17 whereby the volume of air flowing through the mouth 16 may be precisely regulated. The mouth 16 being bounded by the

battle arches

12 and 13, by the top of the fuel table 10 and covered by the doors 15 with damper 17; completely surrounded and controlled. I term it a hooded mouth to distinguish from a mere aperture for the reception of fuel. If high heats are required, the side walls 1 of the fire-box are preferably constricted at their rear portions as shown in Fig. 2. Approximately opposite the bottom of the fuel table 10 and set rearwardly therefrom, are the outlets 18 of a pair of pipes 19 passing through the front wall 2 of the firebox, and provided at their outer ends with sliding cover plates 20 whereby the volume of air flowing through pipes 19 may be precisely regulated. Projecting from the side walls 1, behind the openings 18 of the pipes tion of the fuel.

pipes 19, and immediately upon its issue therefrom further serves to prevent its rushing back to the flue 3 and mingling or stratifying with the products of combustion.

In operation, the fire is started in the ash pit of the fire-box and the fuel is slowly fed thereupon until the mass of hot coals reaches the fuel table arch 6. Fresh coal is thereafter fed down the fuel table 10 over the feeding table 11 until the fire reaches part way up the fuel table. Thereafter, fresh coal is fed into the mouth of the fire-box 16 upon the feeding plate 11 in front of the baffle arch 12, and allowed to feed down the fuel table 10 by gravity. At this stage, the activity of combustion may be increased or diminished or held constant at will. The coal upon the inclined fuel table, owing first to the angle of the fuel table, and second to the pressure of the green fuel in the mouth 16 of the firebox, feeds slowly and regularly down the fuel table which, at this stage, is incandescent. It is an important feature of the invention that the fuel table is inclined so that the supply of the fuel to the fire will be con tinuous rather than intermittent. .Vith the fire advanced to the stage above indicated, the fuel table 10, the inner surface of the baffle arch 12, and the ignition arch 5, will have reached a stage of incandescence, and as the coal slides down the incandescent fuel table, it is at all times in a heat Zone whose temperature is higher than the ignition point of the combustible elements, or combinations thereof, of the fuel; as a result the volatile gases are ignited immediately upon their liberation from the fuel, during the travel of the same down the fuel table toward the bottom of the fire-box. Thus, no green coal is ever directly fed upon the devolatilized or glowing fuel, and fuel feeding down the fuel table is ignited and is completely devolatilized before it reaches the bottom of the fuel table. This provision, with sufficient air supply, prevents the formation of smoke and obviates the temporary chilling of the fire, which is sure to occur when green coal is thrown directly on glowing coal.

The air supply for ignition and combus tion of the volatile gases ordinarily flows through the opening 1+1: of the baffle arch, or through an opening provided by means of a bar, between the fuel feeding into the mouth of the furnace 16, and the bottom of the baffle arch 12. Insomuch as this air must first pass in close proximity to the inner incandescent surface of the baffle arch 12, or the ignition arch 5, its temperature is raised above the ignition point of the volatile gases in the coal, and these are ignited as fast as they are liberated from the coal, thus preventing smoke formation. The air supply which passes through opening 7 is largely utilized for the combustion of the carbonaceous por- There are times however and especially after cleaning the fire, when more air than can be utilized for combination with the carbonaceous portion of the fuel will pass through opening 7, and this excess of air, highly heated after its passage through the glowing coal, is utilized in promoting combustion of the volatile gases in the fuel on the fuel table 10. At these tunes the supply of air through mouth 16 and opening 1a must be cut down, provision for which is made.

The overdraft opening 14 and mouth 16 have important functions. If the fuel used runs high in impurities, thin clinkers will start forming in front of the glowing coals, under the fuel table arch, shortly after the fires are cleaned. As this clinker becomes more and more impervious to the passage of air, the deficiency must be supplied by opening wider the passages through li and 16, provision for the precise regulation of which is made. In addition to this function of supplying deficiencies of air, the opening through the baffle arch 12, alone or in conjunction with the opening at the bottom of baffle arch 12, the air supply through which is'under perfect control, may be used to characterize the heat; that is to say, these openings may be manipulated to produce an oxidizing or a reducing heat according to the effects which may be necessary in burning certain special products. By entirely closing the mouth 16 and depending upon the underdraft 7 alone, or when a heavy clinker is formed in front of the glowing coals, as viewed from 7, by admission of the requisite amount of air through the pipes 19 regulated by sliding cover plate 20, a reducing heat may be obtained; whereas, if the top draft through opening 11 or between the fuel and the bottom of the baflie arch, or both in conjunction, be opened and air admitted thereto, an oxidizing heat can be produced. The overdraft opening l lmay also be used for heat distribution, as for forcing the heated products of combustion through a low duct 22 of Fig. 5 as is necessary in certain types of pottery kilns. The truncated conical ignition arch 5, of substantially a slit funnel form, has an important function in that it serves to heat directly the air flowing through the opening 1% which impinges against the ignition arch, or may heat by reflection the air which passes under the battle arch 12 and above the fuel in the mouth 16 of the fire-box. It also serves to thoroughly mix the products of combustion and prevent their stratification prior to the entry of said products of combustion into the flue 3, and thus aids in the generation of a uniformly heated and thoroughly mixed flow of gas.

In Fig. 5 I have disclosed a slightly modified form of ignition arch 5 which has more or less a stream line formation. In this modification I disclose the fire-box as applied to an updraft pottery kiln, provided with a horizontal flue 22 in addition to the vertical flue 3. In such a structure the gaseous proclucts of combustion as they pass from the fire-box, impinge against the conical ignition arch 5 and are directed downwardly through the flue 22, or upwardly through the flue 3, according as the opening 14 through baflle arch 12 is opened or closed. The proper proportion of distribution of heat through

flues

22 and 3, is determined by observation of the condition of the kiln at the time. It is to be understood of course that the inclined ignition arches 5 and 5 are interchangeable, and that either they or a straight ignition arch, as shown in Fig. 6, may be used in connection with either a down draft or an up draft kiln; the main functions of the inclined ignition arch are to heat by reflection the air admitted through the

mouth

16 or 14, to divert the course of the air to the fuel table, and to assist in mixing the gaseous products of combustion. The tubes 19 afford a supplementary air supply, whereby regulable and controlled quantities of air may be supplied to the fire whenever necessary or desirable, and comprise an ad ditional control for characterizing the quality of the heat produced by the furnace. The baffie bricks 21, which are incandescent during the course of burning, immediately heat the air supply flowing through tubes 19 and prevent the injection of a stream of cold air into the fire or into the hot products of combustion.

In Fig. 6 I have shown my furnace as applied to a power or heating boiler. In this instance I have dispensed with the reflecting ignition arch 5 and have substituted therefor a straight ignition arch 5 and have provided a rear wall 25 in which there is an opening 26 through which the highly heated products of combustion may pass on their way to the surface 27, in this instance a boiler to be heated. It will be noted that the ignition arch of the fire-box is continued under the boiler beyond the rear wall 25 as a combustion arch, in order that the combustion of the gases may be completed before they reach the surface of the boiler. The opening 26 is placed below the top of the fire-box as will be noted, whereby an eddying motion of the products of combustion is promoted which serves to thoroughly mix them and prevent their stratification.

In Fig. 7 is disclosed a shield 28, having thereon a cover plate 29 which may be placed in front of the bottom opening 7 in the event of high winds. Such a provision operates to prevent an excessive draft and to retain the heat within the kiln.

While I prefer a constricted fire-box as shown in Fig. 2, I do not consider this feature absolutely essential. Such a form, however, gives, as I believe, better results a top draft opening through the said baffle arch and means to control the flow of air through said top draft opening.

2. A grateless fire box comprising a combustion chamber for the fuel, a passage therefrom for the flow of the products of combustion, an automatic fuel feeding device comprising an inclined fuel table, ports for permitting the flow of air to the fuel from underneath the inclined fuel table from the top and from the sides respectively, and means to control the flow of air through said ports, whereby the combustion of the fuel may be accurately controlled.

8. In a grateless fire-box, a combustion chamber, an inclined fuel table for fuel, an air inlet port below said fuel table, a passage for air communicating with said combustion chamber above said inlet port but below the top of the fuel on the fuel table, and means to control said inlet port.

4%. A coal consumer comprising a grateless fire box having an ash pit opening at its bottom, hooded mouth for the fuel above the ash pit opening, an inclined fuel'table leading from said hooded mouth to the interior of the fire box, the upper portion of said fire box comprising a combustion chamber, and said fire box having an over-draft opening leading directly from its mouth into said combustion chamber whereby ignition will be completely effected in the firebox and before the heated gases or combustion products pass up the flue.

5. The combination with a fire box having an ash pit opening and amouth for the reception of fuel, of an inclined fuel table leading from the hooded mouth and extending downward substantially on a 45 degree angle, a baffle arch positioned within the firebox over the fuel table and adapted to ra diate heat thereto to devolatilize the fuel thereon, said baffle arch having an overdraft opening formed therein communicating to the combustion chamber.

6. The combination in a fire-box of an ash pit opening, a mouth positioned above the ash pit opening and a combustion chamber, of an arch within the fire-box extending over the ash pit opening, an inclined fuel table resting upon the said arch and extending from the mouth to the combustion chamber, a baffie arch positioned above the fuel table said baffle arch having an overdraft opening formed therein connecting the mouth with the combustion chamber for the purpose specified.

7. The combination with a fire box including an ash pit opening, a hooded mouth and a combustion chamber of an arch positioned rearwardly from the ash pit open- '1 ing, an inclined fuel table, above said pit opening leading from the hooded mouth to the combustion chamber, a baffle arch positioned above said fuel table and adapted to reflect and radiate heat thereto to devolatilize the fuel thereon, and an overdraft opening formed Within said baffle arch, for the purpose specified.

S. In apparatus of the class described, a grateless fire box having a combustion chamher, an underdraft opening leading into said combustion chamber, an inclined fuel table PAUL BEER.

Witnesses:

FLORENCE M. TODD, RALPH L. READ.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.