US1163650A - Furnace-burner. - Google Patents

Description

a. L. roam. FURNACE BURNER. APPLICATION FILED IIMY 20, I914.

Patented Dec. 14, 1915.

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R O T N F- V m a. L. roeusn. rumce BURNER. APPUCATlON FILED HAY 2, 191$. 1,163,650. Patented Dec. 14, 1915.

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FURNACE BURNER.

To all whom it 'raay concern: I

Be. it known that I, GEORGE L. FOGIiER, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in F urnace-Burners, of which the following is a specification.

This invention relates to furnace burners, and particularly to burners for burning finely divided or pulverized solid fuel, and also to apparatus for feeding the fuel to the burner.

The object of the invention is to provide apparatus for feeding and burning solid fuel which thoroughly mixes the fuel and air and produces practically complete combustion and also feeds the fuel into the burnerat a uniform rate so as to produce a steady flame and even temperature.

A further object of the invention is to provide apparatus of the character described embodying means for introducing into the moving stream of fuel successive streams of air under uniform pressure in order to gradually separate the particles of fuel and thoroughly mix the fuel and air and progressively consume the same, the pressure of which air streams are propor-'- tioned or controlled so as to prevent the liability of the flame flaring back in the burner, and thereby insuringthe injection into the furnace and the consumption therein of all of the fuel.

The invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the drawings Figure 1 is a longitudinal sectional elevation of apparatus em: bodying the invention; Fig. 2 is a side ele-,

vation of the fuel. feeding devices; Fig. 3'

1s a sectional elevation on the line 3-3, Fig. 2, looking in the directlon of the arrows; Fig. 4 1s a similar sectlon onthe line 4-4, Fig. 2; Fig. 5 is a cross section on the line 5-5, Fig. l, looking'in the direction 6 isa similar section.

of the arrows; F i on the line 6-6, ig. 1; Fig. 7 is a similar section on the line 7-7, Fig. 1; Figs. 8 and 9 are detail cross sections, taken respec tively on the lines 8-8, Fig. 5, and 9-9, Fig. 6, looking in the direction of the arrows; and Fig. 10 is a cross section on the line 10-10, Fig. 1.

The burner shown in the drawings comprises a main casing, preferably formed of an outer portion 1 and an inner portion 2,

Specification of Letters Patent.

Application filed May 20,

Patented Dec. 14, 1915. 1914. Serial No. 839,806.

I the latter being tapered or gradually reduced'in cross section inwardly toward the furnace. Said member 2 is hollow and forms an intermediate mixing and initial combustion chamber 3. It is threaded into the lnner end portion of. casing member 1 against the periphery of an annular wall or plate 4 which surrounds the inner end portion of an inner hollow member 5, which 1s tapered or reduced in cross section in wardly toward the furnace. Said member 5, in the form shown, is a part of the main casing member 1 and is hollow to provide a mixing chamber 6 into the outer end of which projects a nozzle 7, the body portion 8 of whichis threaded into the outer end of the main casing member 1. Intermediate its ends the nozzle 7 is provided with an annular plate or wall 9, which may be a separate part, but is shown as integral with the nozzle.

The plates or walls 4 and 9 are shown in detail in Figs. 5, 6, 8 and 9. Plate 4 is provided with a plurality of openings 10, shown as radial slots, which are inclined longitudinally of the burner, as shown in Fig. 8. Plate 9 is provided with a similar set of circumferentially spaced openings 11, shown as radially disposed slots, which are also inclined longitudinally of the burner. The slots 10 and 11, however, are inclined longitudinally of the burner in opposite directions, as will more fully hereinafter appear.

he hollow member 5 at its outer end is round in cross section, ually changes inwardly to form a wide, flat mouth 5 opening into the intermediate mixing and initial combustion chamber 3, which extends back into the main casing member 1 around the hollow member 5 and is provided, outwardly beyond-the plate 4, with a side air inlet 12, through which air is supplied to theburner through a conduit 13 having a suitable regulating valve 13, =-'shown as a slidable plate valve. Part of the air supplied through the inlet 12 moves'inwardly through the chamber 3, and part through a-side opening 14 in the outer end of the hollow beyond the plate 9, and into the mixing chamber 6.

The intermediate mixing and initial combustion chamber 3 communicates with a final primary mixing and combustion chamber 15, located casing member 5, outwardly but its section gradouter Walls 17 and 18. The tapered inner casing member 2 is sealed into the outer and inner walls 17 and 18, and said inner wall is provided with a number of openings 19 which establishcommunication between chamber-15 and the hollew chamber 21 between the inner and outer walls of casing 16. Air is supplied to chamber 21 from a conduit 23 through an air inlet 22, said conduit being provided with a suitable regulating valve 23 v The inner end of casing 16 is also doublewalled to form a water jacket, having a hollow water space 24 therein provided with a water inlet 26 and a water outlet 27. This water jacket keeps the inner end of the burner cool and prevents it from being burned out. Preferably, a suitable wall or shoulder 28 is formed on the inner end of the casing 16, which abuts the outer surface of the furnace wall 29, as shown in Fig. '1.

The burner described is adapted for burning liquid, gaseous or solid fuel, but preferably is supplied with finely divided or pulverizedsolid fuel. If gaseous fuel is used the gas supply pipe is coupled directly to the outer end of-the nozzle 7 When solid fuel, such as pulverized coal, coke, lignite, sawdust or the like is used it is fed to the burner by any suitable mechanism arranged to deliver the fuel in a steady stream. The fuel feeding mechanism illustrated comprises a fuel supply bin 30, having inclined bottom Walls leading through an opening 32, which is controlled by a slide valve 33, into the chamber 34 in a hollow cylindrical casing member 35, in which is located a fuel feeding member, such as a jig, shaker or the like. The feeding member shown comprises a spiral conveyer 36, the shaft 37 of which is provided on its outer end with any suitable means for driving the same, such as the rotatable friction plate 38, driven by an adjustable friction pulley 38, or any other suitable speed changing mechanism whereby the fuel may be supplied at any desired rate. Shaft 37 at its outer end is j ournaled in the casing 35 and at its inner end in a journal member 39 secured to the wall of a conduit 40 into which the inner open end of the casing 35 projects. Said conduit at one end is open to the atmosphere through a suitable regulating valve 41 and its other end is reduced to form a nozzle 42 leading into a prelimi nary mixing chamber 43within a casing 44 screwed into the other end of the nozzle 7. A pipe 45 communicating with a suitable source of compressed air leads into thereduced nozzle 42 and produces-an injector effect therewith which forces the fuel forwardly into the burner. Preferably the outer end of the casing 44 is provided with slots or openings 44, which are inclined in the same manner as the slots 10 and 11 in order to initially mix the fuel with a small amount ofair, and to assist in separating the particles of fuel from each other, and also produce a whirling stream, as will be readily understood. 7 1

In operation the driving mechanism for. the fuel feed is started, and the gate valve 33 is opened to allow the fuel to feed downward by gravity into the hollow casing 35, through which the fuel is carried by the spiral conveyer to the conduit 40. The valve 41 is opened to admit air into the conduit 40 and the supply of compressed. air through pipe 45 is opened to thereby force the fuel into the burner. An injector or siphon effect is produced at the open end of the conduit 40, thereby inducing a. constant and uniform feed of the fuel by suction, and the slight vacuum efi'ect produced carries back through the conve yer chamber 34 and into the hopper 30, and there promotes the downward flow or settling of the fine or pulverized fuel. The fuel is first mixed with air in preliminary mixing chamber 43 and the stream is discharged from nozzle 7 into the mixing chamber 6, )referably at a pressure slightly higher than the pressure of the air supply through conduit 13, to prevent back flare of the flame. In chamber 6 the stream is met by a stream of air flowing from the conduit 13 into the outer end of the primary mixing chamber 6, and which has a spiral or swirling movement, due to the inclination of slots 9, so that when it meets the stream of mixed air and fuel emerging from nozzle 7 an intimate mixture of the two streams is produced. The converging walls of the hollow member 5 compact the streams of mixed fuel and air in their course through the furnace and thereby assist in the intimate mixture thereof. The combined streams emerge from the mouth 5 of the preliminary mixing chamber 6 in a. compact stream which is discharged into the intermediate mixing chamber 3, where the initial combustion takes place and the flame usually begins. Conduit 13 also admits a stream of air under pressure into the outer end of the intermediate mixing and initial combustion chamber 3, which stream has a whirling movement, due to the slots 10 in plate 4, so that the sec ond additional stream of air is also thor oughly mixed with the stream of burning fuel.

In chamber 3 the fuel is only partially consumed, the total air supplyv up to this 'point being inadequate for, complete combustion. The carbon changes into carbon monoxid (CO), and by connecting a conduit to the open end of the chamber 3, and conducting the stream issuing therefrom to a superheater then to scrubbers and to a reservoir the burner can be made to serve all the purposes of a gas producer, or, the gas can be conducted directly to a furnace or internal combustion engine and burned.

The air stream admitted to chamber 3 from the conduit 13 is annular and forms a curtain just inside the Wall of said chamber, thereby shielding and protecting the casing wall from burning and preventing radiation and loss of heat. The air gradually mixes more and more with the stream issuing from the chamber 6, and supplies additional air to the flame as the fuel is consumed, so the combustion is progressive or gradual through the chamber 3.

The air supply to the final chamber 15 from conduit 23 is regulated so as to be just sufficient to produce complete combustion of all of the fuel, that is, to oxidize all of the C or CO to CO While passing through the chamber 21 it cools and prevents the Walls from burning and also conserves heat. The fresh supply of air is also discharged into chamber 15 near the walls thereofso that it acts in the same manner as in chamber 3, gradually mixing with the burning fuel and progressively consuming the same, and also acts as a curtain to protect the inner Wall 17.

It is essential that the air supplied through the conduits 13 and 23 shall be at the same pressure and at a pressure slightly less than the pressure of the air supply through the pipe 45 so that the flame will not flare back into the fuel supply and ignite the same, possibly with an explosion. For this reason the conduits 13 and '23 are preferably connected to a common air supply pipe 50, as shown in Fig. 1. The valves 23 and 13 regulate the quantities of air introduced through said conduits, which should preferably be greater than that supplied through pipe 45 in order that the latter pressure .will be quickly dissipated in chamber 6. It of course is to be understood that it is not necessary that both of the air supplies should come from the same main conduit. Each may come from a different source, so long as the pressures of the air supplies are maintained the same.

The burner described is simple and very economical, as it produces practically complete combustion of any fine or pulverized solid fuel.' Advantage can therefore be taken of all of the heat units in the fuel and the waste, as ashes, in the ordinary furnace is largely reduced. Also, the mixture of the air and fine fuel is so intimate and gradual that practically none of the fuel is carried out unconsumed through the stack. What I claim is 1. A fuel burner; comprising a mixing chamber, an initial combustion chamber, and a final combustion chamber, said chambers opening into each other in the order named, a preliminary mixing chamber opening into said first named mixing chamber, a connection from a source of fluid pressure opening into said preliminary mixing chamber, a fuel supply conduit opening into said preliminary mixing chamber and surrounding said fluid pressure connection, and means for introducing streams of air from an additional source of pressure into the first named mixing chamber and each of the combustion chambers.

2. A fuel burner, comprising a plurality of combustion chambers connected in series, a mixing chamber opening into the first combustion chamber of the series, means for introducing a supply of mixed fuel and air into said mixing chamber under a fluid pressure directed longitudinally of said mixing and said combustion chambers, and means for introducing streams of air from an additional and common source of pressure into said mixing chamber and each of said combustion chambers.

3. Apparatus for feeding and burning finely divided solid fuel, comprising a hollow casing, means for feeding fuel progressively through said casing, a hollow conduit communicating with a source of compressed air and arranged to receive the fuel from said casing, a burner having mixing and combustion chambers therein communicating with said conduit, and means for introducing a supply of air under the same pressure into said mixing and combustion chambers.

4. Apparatus for feeding and burning finely divided solid fuel, comprising a hollow cylindrical casing, a hopper arranged to discharge fuel into said casing, a spiral conveyer for feeding fuel progressively through said casing, a burner having mixing and combination chambers therein, a conduit communicating with a source of compressed air and arranged to receive fuel from said casing and conduct it to said mixing chamber, and means for introducing air under the same pressure into said mixing and combustion chambers.

In testimony whereof, I have hereunto set my hand.

GEORGE L. FOGLER.

Witnesses ELBERT L. HYDE, WILLIAM B. WHARTON.

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