USRE16984E - Btjbneb asx mexhqjb of burning jpoel - Google Patents

Description

June 5, 1928. v. G. LIEACH 1ND MLI'THGD OF BURNING FUEL BURNER 5 Sheets-Sheet Original Filed March 21, 1924 Den zz June 5, 1928. -v. G. LEACH Re; 16,984

BURNER AND METHOD OF BURNING FUEL- Original Filed March 21, 1924 3 sh sf hee 2 Hiiii.

Derzzozz Qardieach 1 June 5, 1928. LEACH Re. 16,984

BURNER AND METHOD OF BURNING FUEL Original Filed March 2 1924 3 Sheets-Sheet "5 lfll II N

V E. i. Garcia each.

Rt-issued June s, 1923.

vlmuou n, tumors, or cnrcnoo, rumors.

BURNER METHOD or Bonanza FUEL.

orlglnalqio. 1,552,438, dated September 8, 1925, Serial No. 700,736, filed March 21, 8 24. Afiiillcatlon tor mum filed Alert! is, 1ecs.- Serial no. 289,781.

This invention relates .to o. burner and method of burning fuel more particularly designed for pulverized fuel.

In the large majority of burners designed for the use of fincly dividcd fuel, the fuel is introduced into the furnace suspended in :1 current of air, both air and fuel having csscntially the same velocity. -Upon being introduced into the furnace, the fuel gives roll its volatile content almost instantl'K and this volatile content readily burns. he small particles of dcvolutilized fuel, however, soon surround themselves with an atmosphere of carbon monoxide or carbon dioxide which has to be scrubbedofi before furtherw'colnibustion can proceed. This scrubbing action is best brought'about by the creation of a relative vclocity between the fuel particle and the surrounding atmosphere of gases. Either the fuel particles should travel faster than the gases, or the gases should travel faster than the fuel particles.- .If there is such relative inovcmcnt of the particles and gas, the film of partially-consumed gases which surrounds each fuel particle will be constantly scrubbed oil and combustion will be completed in a short length of flame travel.

Finely divided fuel, being highly cxplosive when thoroughly mixed and suspended in the proper amount of airgshould be introduced. into the furnace at u muzzle velocity that creates an ample margin of safety between the velocity of the entering fuel and the velocity of rate of flame propa gation, in order that the lire shall not creep back into the feeder line and create an explosion.- It is exceedingly diflicult to give this desired'muzzlc velocity without driving the fuel a great distance through the "furuuce and creating it very long flame which, of course, will necessitate very large furnaces.

The principal object of the present invcntion is to provide means and method for obtaining short 'fianic coi'nbustion and this is attained first by ahigh muzzle velocity and second by instantly spreading the entering uir and fuel out over a wide area so that their forward velocity is i very greatly rcduccd, thus securing all the benefits of a. low velocity burner with the safety margin of the high velocity burner" Now I have found that these udventagcous results can be obtained by the use of a burner heving two passages therein "adapted to project strcamsof fuel and air obliquol inwards a einst each other to pro. duce a an-shaped ems in a plane perpenilicular to the plane in which such passages 1e The scrubbing notion, above referred-to, is

particles have stored in them a certain amount of kinetic energy which causes them to shoot forward at a higher velocity than the air or gas'es in which they have been supported. I V

Other and further important objects of this invention will be apparent from the disclosures in the specification and drawings.

The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings v Figure 1 is a side elevation of a burner constructed in accordance with the present invention. x I

Figure 2 is a plan view of the same.

Figure 3 is-nu end view of the same.

Figure 4 is .a section on the line IVIV of Figure 1. I

Figure 5 is a section on the line V-V of Figure 2. P

Figure 6 is a vertical section through a water tube type boiler fitted with one of the improved burners.

Figure 7 is a sectionon. theline VII -VII of Figure 6.

Figure 8 is a vertical section through an other form of water tube boiler showing three alternative positions of the burner. a Figure 9 is 2 vertical section through a Stirling boiler fitted with the improved burners. y

' Figure 10 is a section on the line X-X of Figure 9.

Figure 11 is :1 section through a reverhatory furnace fired by a burner constructed in accordance with the present invention.

As shown on the drawings:

The burner is constructed with two passages therein adapted to project stream-is et air curr x 'ing powdered fuel against each other to produce u fan-shaped flame in a plane perpendicular to the plane in which said passages lie. Various forms of conp of air and struction may be employed. In the particular form illustrated by way of example the burner is formed from a metal tube flattened at the end and depressed inwardly at its center portions as atll, and provided with an exit orifice 12. By flattening the tube and curving the ends inwardly two passages are formed on either side of the .flattened portions 11 adapted to project streams powderedfuel obliquely against each other. These impinging streams create a fan-shaped flame perpendicular to the planein which such passages lie.

The impinging streams are projec ed to- 16 wards each other at such an angle that the velocity components of the two streams in opposition to each other is greater than the velocity components in the direction of the resulting flame. In the preferred form of construction shown in the drawings this angle is about 140.

Further, as shown, the distance the streams are projected before they mutually impinge is only a small fraction of the length of the resulting flame.

W'ith impingement occurring close to the burner and at a wide angle there is atendency for a part of the resulting flame to strike back towards the burner. As shown the flattened portions 11 of the burner do not contact ahd the stream of air and fuel passing between such portions carries forward such part of the wise strike back.

Various installations of burners are shown in Figures 6 m 11 inclusive. In Figures 6 and 7 a burner 14 is shown inv connection with a horizontally-batfled water-tube boiler comprising steam drum 15, header 16, downcomer 17, tubes 18; brickwork setting 19 and battles 20.,and 21.

.The burner 14 is inserted through an aperture in the front Wall of the boiler setting .so as to direct a laterally extended sheet of flame beneath the boiler.

' In Figure 8 is shown three alternative applications of a burner 22 in connection with a vertically baffled water-tube boiler.

An arrangement in which one,' two or three burners may be. employed simultaneously isshown in Figures 9 and 10 where burners 25, 26'and 27 are employed for heating a Stirling or vertical watcr-tube type boiler. One of these burners 25 is arranged in the bottom of the combustion chamber while the other two, 26 and 27, are located at opposite points in the side walls of the combustion chamber.

In Fi ure 11 a metal furnace 30 is shown fitted with a burner 31 of the construction above described.v Air is fed to the burner by means ofa fan 32 and simultaneously powdered fuel is supplied to the burner from a bin 33 by the feeder 34.-

" While a portion or all of the 'air required flame as would other-.

for combustion is introduced with the fuel from a suitable blower, additional air may, if desired, be introduced into the combo tion chamber as for example through apeia turcs 28 as shown in Figures (3 to 10.

This desirable that the fuel shall. be intimately and uniformly mixed and distributed throughout the current of air issuing from the burner. ,In the conveying and distributionof finely divided fuel suspended inair, the tendency is for the particles of fuel to separate out and travel along in strata o r streaks, creating an uneven or spottcdcombustion condition in the furnace. The construction of this burner is such that the finely divided fuel is very intimately rcmixed or blended with the air in which it is suspended at the very point of introduction into the furnace. This mixing or blending action, coupled with the slow flame velocity and accompanied by the maximum dilference in velocities between the fuel particles and their surrounding atmosphere causes the flame to be unusually short and the combustion efliciency to be very high. To. these advantages may be added the margin of safety created by a high muzzle velocity which is ordina r rate of flame propagation.

1 am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art.

I claim as my invention:

1. An apparatus for burning powdered fuel comprising a source of powderedfuel, a source of air under sufficient pressure to pro ject the powdered fuel mixed therewith through a burnerat a specd greater than the speed of flame propagation through the mixture. said burner having two passages therein adapted to project streams of air carrying powdered fuel obliquely inwards against each other to produce a fan-shaped flame in a plane perpcndicuhtr to the plane in which said passages lie.

2. A method of burning powdered fuel comprising projecting two streams of air carrying powdered fuel against each other at a speed greater than the speed offlame propagation whereb ignition does not occur until the velocity 0' the streams is reduced by the mutual impingement. v 1

3. A method of burning powdered fuel comprising projecting two streams of air car iau swicomprising projecting two streams of air carrying carrying powdered fuel against each other at a speed greater than the speed of flame propagation whereby ignition does not occur until the velocity of the streams is reduced by the mutual impingement and projecting stream of air carrying powdered fuel in the same direction as the flame produced by the union of the first mentioned streams and between the latter. I

6. A method of burning powdered fuel comprising projecting two streams of air carrying (powdered fuel against each other at a spec greater than the speed of flame propagation whereby-ignitiomdoes not occur until the velocityof the streams is reduced by the mutual 1mpingement, the angle between the two streams being such that the velocity components of the two streams in opposition to each other is greater than the velocity components in the direction of the reshltinglgiames.

7 A e comprising projecting two streams of air carrying powdered fuel against each other at a speed greater than the speed of flame propagation whereby ignition does not occur until the velocity ofthe streams is reduced by mutual impingement, the distance the streams are projected before they mutually impinge being a small fraction of the length of the resulting flame.

-8. An apparatus for burning powdered fuel comprising a source of powdered fuel,

'a source of air under suflicient pressure to project the powdered fuel mixed therewith through the burner at a speed greater than the speed'of flame propagation through the mixture, said burner having two passages therein adapted to projectstreams of air carrying powdered fuel obliquely inwards 1 ing thod 'of burning powdered fuel perpendicular to the plane in which said passages lie.

9. An apparatus for burning powdered fuel. com rising a source of powdered fuel, a

source 0 air under suflicient pressure to project the powdered fuel mixed therewith through a burner at a speed greater than the speed of flame propagation through the mixture, said burner having two passages therein adapted to project streamsof air carrying powdered fuel obliquely inwards against each other to produce a fan-shaped flame in a plane perpendicular to the plane in which said passages lie and a third passage for projecting a stream of air carrying powdered fuel bet-ween the discharge ends of the first two passages and in the same direction as the flame produced by union of the first mentioned streams.

10. An apparatus for burnin powdered fuel comprising a' source of pow ered fuel, a source of air under suflicient pressure to project the powdered fuel mixed therewith through a burner at a speed greater than the speed of flamepropagation through the mixture, said burner having two passages therein adapted to project streams'of air carrypowdered fuel obliquely inwards against each other at an angle such that the velocity compone ts of the two streams in opposition to each other is greater than the velocity compo e hts 'nz'flie direction of the resulting fan-shaped ame.

11. An apparatus for burnin powdered fuel comprising a source of powdered fuel, a source of air under sufficient pressure to project the powdered fuel-mixed therewith through a burner at a speed greater than the speed of flame propagation through the mixture, said burner having two passages therein adapted to project streams 13f. air carrying powdered fuel obliquely inwards against each other to produce a fan-shaped flame in a plane perpendicular to the plane in which said passages lie, the distance between the discharge ends of the first two passages to the point of impingement of the two streams being only a small fraction-of the length of the resulting flame.

VERNONG. LEACH.

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