US817989A - Furnace for burning pulverized fuel and other substances. - Google Patents

Description

No. 817,989. PATENTBB APR. 17, 1906.

` A. M. BBSN D. A. BETTINGTUN.

PURNAUB FOR BURNING PULVERIZBD FUEL AND OTHER SUBSTANGES. Prummel rum) Px xa. moa.

4 suma-,snm n.

No. 817,939. PATENTE!) APR. 17, 1906. A. M. ROBESON C. BBTTINGTON. FURNACE FORBURNING PULVERIZBD FUEL AND OTHER SUBSTANCES.

APPLICATION FILED APB 13. 1905.

NTHCNY M. ROBESON, OF

BETTINGT i our M. Rossburg, Transvaal,

son, resi T Q and CLA, A`orrori, residing at Bos ton, ing4 uffolk," State of Massaehuset, ted certain new and useful '1 i -s in Furnaces for Burnin P or other Substances, of whic i is a full, clear,l and exact den i such as will enable others skilled in o which it appertains to make and s e of the objects of the invention is to so A. struct a furnace that the roducts of comustion and unconsumed fiiel will double ack upon themselves before escaping from the retort of the furnace.

Another object is to construct a furnace so that the retort will extend in an upward rlirection and be provided with means for projecting the material to be burned into the retort in an upward direction.

Another object is to so construct a furnace that the slag and unconsumed products will fall directly out of the retort of the furnace and into a pit or other means for receiving the same.

Another object is to construct a furnace so that the slag and other unconsumed` roducts will fall from the retort into a pit and be conveyed therefrom.

Other objects will appear from the hereinafter description.

It is a well-known fact that when coal or other material pulverized or reduced to a fine powder is introduced into a furnace with the proper amount of air combustion is practical] perfect, rovided the fuel sup lied, the qua ity of the Ifuel, and the air-supp y remain constant within narrow limits; but when any of these features change either the fire goes out or it burns very inefliciently. We have experimented with many forms of furnaces on a working scale for burning owdered fuel and other material and find tliat while one form may answer well for one kind of material it will be found unsuitable for another. Furnaces which have been heretofore constructed for burnin coal with three or four per cent. of ash, W ich makes no elinkers, clog up and are inoperative in a short time if I on of Letters Patent.

- 4hprll18,1905. Serial No. 255,470.

OFFICE.

URG,TRANSVAAL, AND CLAUDE A.

, MASSACHUSETTS.

vvl)i FUEL AND OTHR SUBSTANCES.

Patented .April i7, 1906.

fed with coal containing as high as twenty per cent. of ash. Furnaces which have heretofore been constructed having a given crosssection will possess a certain critical capacity which if exceeded in even the slightest degrec results in the oint of combustion gradually creepinur in tlie direction of the flow of the gases and finally going out. This is a common fault of a furnace using powdered coal or other material in which the course of the gas is not directly back on itself during combustion and is due to the fact that the mixture of the powdered fuel and other material and air is really of an explosive nature, havin a definite but slow rate of transmission o the point of explosion or combustion. The point of combustion commences to cree forward the moment the speed with whic the mixture of air and fuel introduced into the furnace exceeds that of the rate of transmission of the point of explosion, the result being that the flame soon blows out. The rate of transmission of the point of explosion depends on the inainmability of the dust and the temperature of the mixture. No practical control can be had over the inaminability if any kind of coal is to be burned,

and therefore it remains that the tempereture of the mixture and its velocity only can be varied in order to make the point of explo sion stable,

By causin the mixture to turn upon itself ,and return a ongside of the incoming stream or separate and return along two sides of it or spread out in a circular or mushroom form and return on all sides, as would be the case if the retort were vertical and circular and the incoming stream central, not only is a regenerative action secured, which in itself would insure the point of explosion being close to the point of entrance to the furnace of the explosive mixture, but the very act of chang ing the direction of the flow of the gases changes the velocity of portions of the stream and at the turning-point by producing eddies, Vlespecially if the form of the furnace is unsymmetrical as regards ideal flow-lines, and thereby brings about the condition of decreasing velocity coincident with increasing temperature, thus creating a very stable condition.

After many experiments we have discovered that the vertical form of furnace is very efficient for carrying out our invention and is IOO the one we prefer if fuel or other materiad i which produces slag while being burned i A material return or double back upon them' selves for the purpi se of controlling the point of combustirn can be ap lied to a horizontal or inclined. furnace, per iaps to greater advantage for certain services than to a vertical furnace. Therefore we do not confine ourselves to any particular form of furnace.

As before stated, for certain kinds of fuel or other material-namel r, those containing over four per cent. of a siag-forming ash-a form of furnace, if powdered material is to be burned, which will rid itself of the accumulations of slag, is imperative. We have experimented with many devices and forms of furnaces to attain this object and find the furnace which we will hereinafter describe to be very eflicient fer this purpose. The slag whlch it is desired to remove from the furnace is liquid at the normal working tem` perature of the combustion-chamber or retort, but becomes viscous whenever it reaches a place where, for any reason, there is a lower tem erature. Also, the slag which causes troub e is that which impinges on the walls of the retort and runs down them and not that which remains in suspension in and is carried along with the products of combustion. These sus ended particles soon cool off enough after leaving the retort to render them incapable of sticking to surfaces, and therefore finally settle down with the dustash and give no further trouble.

The yertical form cf furnace lends itself best to the disposal of slag for two reasons: (a.) The area of a horizontal secticn of the vertical retort being always much smaller than that of a horizontal furnace of the same output, the radiation of heat into the slagpit, which must be directly under the peripheral walls cf the retort, will be much less in the vertical form, thereby allowing the deposited slag to become colder and render the operation of removing it less trying to workmen. (b) The articles of slag which are carried along W1th the products of combustion are moving in a downward direction toward the slagit just before leaving the combustion-cham er, and being relatively heavy and of a globular form instead of making a turn of ninety degrees into a horizontal direction along with the gases and dust they continue thelr rectilinear direction and roject themselves into the slag-pit. It is t ese considerations that make the vertical form of furnace preferable to the horizontal for coals containing large quantities of slag; but all of the principles on which we base our invention can be applied to horizontal or inclined furnaces.

The preferred type of our invention is illustrated 1n the accompanying drawings, which s part of this application, in which the ference characters refer to similar e different views.

a horizontal section of the fur- `he line 1 of Fig. 2. Fig. 2 is a on the line 2 2 of Fig. 1. tss-section on the line 3 y vertical cross-section Fig. 5 is a cross-sec- 6 is cross-section of the line 6 6 of Fig.

B is the cornbustioq C is a slag-pit immetl tort.

D represents a pi e for -f the retort pulverize coal or i if to be burned and mixed with ai of this ipe D is turned upward an upwardly into the retort. This i. pipe which rojects into the retort` covered witlli) some refractory mate' may be water-jacketed.

The retort has its walls E formed o fractcry material, owing to the intense produced within it, and it should be mad as to permit free expansion, especially in a. verwhich are preferably kept at a short distance from the walls of the retort in order to form an air-space G to lessen heat radiation.

In the furnace here shown the horizontal section of the retort is rectangular; but it may be made in any other form which the circumstances of the case demand. The to of the retort is arched with fire-brick; but 1t may be formed of fiat refractory material and could be closed by means of a waterjacketed metallic cover, if desired.

At the bottom of the retort on one side is an opening H for the escape of the products of combustion. This o ening is in the form of a single arch in one of) the long sides of the retort; but it may be formed of more than of the short ends of the retort, the essential thing bein that the outlets shall be as lowI down in tlie retort as possible, so that the, time of combustion ma be as long as possiucts of combustion be caused to double back u on themselves. The height of the retort bustion of all the combustible particles of the material fed into the retort before they are permitted to esca e.

On the side of t e retort opposite the o ening H are the cleaning-openinvs J an an o ening K, which is made use of for igniting t e fuel and as an inspectiondoor, The covers L of these doors are made, preferably,

of slabs of refractory material suspended by tical direction. Itis also surrounded on three 9 sides by the walls F of the boiler-setting,

ble for a given height o retort and the prod- IIO one arch, or it could be formed in one or both s ould be such as to insure a sufficient comproducing an air-blast wi th a pulverizingmachine, thereby blowing the powdered material directly into the retort as fast as produced, or it may be of a form which delivers the pulverized material without an air-blast, in which case the pulverized material is blown into the furnace through the medium of any air blast producing apparatus into which is fed the ulverized material by means of an suitab e feeder, suitable means being provi ed to vary the proportions of the air and pulverized material delivered to the furnace. In su plying the air instead of forcing it througli the pipe D with pulverized material the air may be mixed with the material as it is projected from the upper end D of the pipe, suitable means being provided for introducing the air separate from the fue] at this point.

The method of operating the furnace is as follows: In starting the furnace a brazier filled with wood and greasy waste is introduced through the hole H and lighted. The brazier is formed so as to allow of a moderatelyfree passage of the powdered fuel through it when placed over the end D of the fuelsupply pipe. The blast is then started at a very low rate, and the material is fed into the retort at such a rate as not to smother the fire in the brazier. The powdered material immediately partially ignites and gradually heats up the retort. In a sh time the retort is sufficiently hot to allow of the removal of the brazier, after which the rate of combustion will be increased until working conditions are reached. While we have here stated that the brazier is passed throu h the opening H to start the fire, yet it is understood that 1t may be started in any other manner, as the startin material may be passed into the retort trough the openin at the bottom thereof. After the retort as been thorou hly heated the material to be burned may le varied at will without there being the slightest tendency on the part of the fire to go out, or the air and material sup ly can be completely cut off for a considera e time, provided the doors and drafts be closed, and the furnace then be started up in a short time by simply renewing the material and air-supply. It is preferable to so regulate the drafts of the furnace as to make the pressure within the retort about the same as that of the atmosphere to avoid loss of heat through infiltration of air; but if for any reason it is desired to have the pressure within the furnace greater or less than that of the atmos here the furnace will work equally well. Afltber the fire is started in the retortthe products of combustion and the burning material are projected upwardly in the retort until they reach a certain point, which varies accordin to the force With Which the material is injected into the retort,

and other conditions, whereupon the products of combustion and the ignited material will fall downward or double back upon themselves. The products of combustion will )ass out through the opening H into the boiler-chamber and circulate around the boiler-tubes and ass out through the opening P. The solid particles of unconsumed material, such as slag and other substances, will fall throu h the bottom of the retort and into the s ag-pit. If any of the liquid slag falls up against the inner walls of the retort, it will trickle downthe sides thereof and, owing to the construction of the bottom of the retort, as shown at S, and the sides, as shown at S', will also drop down into the slagpit. If the slag-pit is provided with a waterreceptacle, such as shown, the slag will fall into the water in the said receptacle. The endless conveyer W being operated will remove the slag from the receptacle or the pit and throw it onto the carrier X. Any of the ash or solid materials carried from the retort into the boiler-chamber will fall on the oor of the boiler-chamber and can be thrown out throu h the openings M*l in the bottom of said c amber and into the carrier, the carrier operating to remove or convey both the slag from the slag-pit and the ash from the boilerchamber in the construction shown.

Of course it is to be understood that if the endless carrier is not used for removing the slag the said slag may be removed through the extended portion U of the slag-pit in a manner Well known.

As many changes could be made in the above construction and many apparently` widely-different embodiments of our invention could be made without departing from the scope thereof, we intend that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limitin sense. We desire it also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which as a matter of language mi ht be said to fall therebetween.

aving now describedlour invention, what we claim as new, and desire to secure by Letters Patent, is*

1, In a furnace, a combustion-chamber closed, exce t at or nearthe bottom thereof and means or injectin a finely-divided solid fuel and a su 4porter o combustion substantially vertically into the chamber, the open part of the chamber permitting `the escape of products of combustion.

' 2, In a furnace, a combustion-chamber closed except at or near the bottom and means for injecting amixtme of fuel and a supporter of combustion substantially verti- IIO cally intdthe chamber, the open part of the chamber permitting the esca e of products of combustion and unconsume material.

3. In a furnace, a combustion-chamber, means for injecting finely-divided solid fuel .substantially vertically into the chamber in one direction, said chamber having an exit adjacent to the point where the fuel is injected, whereby the products of combustion and unconsumed fuel are caused to double back in the combustion-chamber before passing from the chamber.

4. In a furnace, a combustion-chamber, a pipe through which pulverulent fuel is injected substantially vertically in one direction into the chamber, said chamber having an exit therein adjacent to the end of the pipe whereby the products of combustion are caused to double back in the combustionchamber before passing therefrom.

5. In a furnace, a combustion-chamber closed except at or near the bottom thereof, a pjipe or nozzle at the bottom of the chamber a jacent to the opening from thev chamber, through which finely-divided solid fuel is projected substantially vertically into the chamber, the opening om the chamber permitting the escape of products of combustion.

6. In a furnace, a vertical rcombustionchamber closed except at or near the bottom, means for supplying to the combustionchamber fuel and a supporter of combustion, said means being so arranged with respect to the combustion-chamber as to cause at least some of the burning fuel to be supported or held in suspense by the incoming material.

7. In a furnace, a combustion-chamber, and a single means for supplying to the combustionfehamber a mixture of fuel and a supporter of combustion, said means being so arranged with respect to the combustionchamber as to cause the fuel burning in the chamber to be supported and held in suspense by the incoming material.

8. In a furnace, a combustion-chamber having an opening near its lower end for the passage of products of combustion and anv other opening adjacent thereto for the passage of unconsurned products, and means for injecting material to be burned into the comd bustion-chamber so arranged as to keep the material in suspense While burning.

9. In a furnace, a combustion-chamber having an opening near the lower end thereof for the passage of products of combustion and another opening for the passage of unconsumed material and means for injecting material to be burned upwardly into the combustion-chamber.

10. In a furnace, a combustion-chamber open at or near the bottom thereof for the passage of products of combustion and unconsumed material, a pit under the combustion-chamber the inner surface of the Walls of the combustion chamber overhanging the walls of the pit and means for injecting the material upwardly into the combustiolb chamber.

il. In a furnace, a combustion-chamber, open at the bottom thereof to permit the passage of unconsumed material, the said combustion-chamber having an opening near the bottom thereof for the passage of products of combustion, a pit under the combustionchamber, the inner surface of the Walls of the combustion-chamber overhanging the inner surface of the walls of the pit, and means for injectin pulverulent material upwardly into the com ustion-chamber.

12. In a furnace, a combustion-chamber havin an opening for the passage of products o combustion, a pipe near said cpenin and through which a pulverulent materia may be injected into the combustionechamber substantially vertically in one direction, and the products of combustion are caused to double back upon themselves in the opposite direction before passing through the openin from the combustion-chamber.

13. n a furnace, a combustion-chamber, a pipe through which a pulverulent fuel may be projected upwardly into the combustionchainber, the combustion-chamber being open only at or near the bottom thereof near t ie end of said pipe whereby the products of combustion and unconsumed material Will be caused to double back and move downwardly before passing from the combustion chamber.

14. In a furnace, a combustion-chamber loo open only at or near the bottom thereof for the assage of products of combustion, said com ustion-chamber surrounded by an airspace and having a channel in its wall communicating with said space through which aA 105 gas may be supplied to the combustionchamber, means for controlling the su ply of gas, and means for injecting upwardly into thel combustion-chamber pulverulent materia 15. In a furnace, a combustion-chamber having an opening near the bottom thereof for the passage of products of combustion, said combustion-chamber also being open at its lower end through which slag or other uni 15 consumed material may fall, a device for catching said material, means for conveyin away said material and an upWardlyFeXten ing pipe through which material to be burned Emy be injected into the combustion-cham- 12o 16. In a furnace, a combustion-chamber, having an c ening for the passage of products of com ustion and another opening in the bottom thereof for the escape of slag or 125 other unccnsumed material, a second chamber adjacent to the combustion-chamber into which the products of combustion pass having an o ening in the bottom thereof through whic ash or other material carried 13o IIO by the products of combustion may escape, and means extendin from the opemng in the bottom. of the com ustion-chalnbcr to the opening in the second chamber adapted to remove both the slag and ash.

17. In a furnace, a combustion-chamber and a boiler-chamber, separated by a wall having an opening through which roducts of combustion )ass to the boiler-c amber, the bottom of t e combustion-chamber provided with an opening for the escape of slag and the bottom of the boiler-chamber provided with an o ening for the escape of ash or other materia and an endless carrier extending from the opening under the combustion chamber to the opening under the boiler-chamber for the purpose of removing both the sla and ash.

18. In a 'urnace, a vertical combustionchamber closed except at or near the bottom, means for supplying to the combustionchamber pulverulent fuel and a supporter of combustion, said means being so arran ed with respect to the combustion cham er that the incoming fuel will support or hold in suspense some of the particles of the burning fuel.

19. In a furnace, a vertical combustionchamber closed except at or near the bottom and a sin le means for supplying to the combustion-c amber a mixture of fuel and a supporter of combustion, said means bein so arran ed with respect to the combustlonchamer as to cause some of the articles of the burning fuel to be supporte or held in suspense by the incoming mixture.

20. In a furnace, a combustiomchamber open at or near its lower end for the passage of products of combustion and unconsum'ed material and means for injecting material to be burned into the combustion-chamber, the said means being so arranged as to keep some of said material in suspense while the material is burning.

21. In a furnace, a combustion-chamber, means for su plying to the combustionchamber a fuel) and a supporter of combustion, said means being so arranged as to cause the burning fuel and products of combustion to double back and to envelop the incomin fuel.

22. n a furnace, a combustion-chamber, closed except at or near the bottom thereof, means for supplying pulverulent fuel into the chamber near where it is o en, the parts being so arranged as to cause tEe products of combustion and unconsumed particles to double back and envelop the incomin fuel before passing from the combustion-c amber.

In witness whereof I have hereunto set my hand7 at Johannesburg, South Africa, this 11th day of March, 1905.

ANTHNY M. ROBESON.

In presence of- THos. GREY, W. J. CLARKsoN.

In witness whereof I have hereunto set my hand, at the city of New York, in the county of New York and State of New York, this 31st day of January, 1905.

CLAUDE A. BETTINGTON.

In presence of- LoUIs N. WHEALTON, T. R. RIcHARDs.

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