US1974373A - Apparatus for the production of combustible gas from solid fuel - Google Patents

Description

Same 1, 393%.. c. WHITFIELD 1,974,373

APPARATUS FOR THE PRODUCTION OF COMBUSTIBLE GAS FROM SOLID FUEL Filed July 7, 1950' 2 Sheets-Sheet l Sepia 18, 1934. c. WHITFIELD 1$974,373

APPARATUS FOR THE PRODUCTION OF COMBUSTIBLE GAS FROM SOLID FUEL Filed July 7, 19 50 2 Sheets-Sheet 2 Patented Sept. 18, 1934 t. rim-iii,

APPAR Tus FOR THE Hatcheries" 4 or M S KBLF AS FR M. 9!? FU L oiiiirl sfwhiifiidljmoii,"'tifiifiiifuiigiafic Application Juli-7, masterin and' In Great Britain @ugust 3,1929 8 (515615151 (olyizc-ic'j -.i hi' ..1 re at o rel tw q s pr ers where;vv in cgrnbustible material is burnt as fuel for the p du i n of as- 1 i- 1 s g .tW the P e met cd anda p us h v 5 lqssi ofleijiciency isprincipally due to the absence of; adequate contrcl, .f or the air supply and to the cpnditiens under which the air. is brought intov contact with the fuel. The function of the gratex isto support. the ,fuel,bed so that'the air may 16 have access to the underside of the ..same., ,The air apertures in the grate are therefore more or, less suhject to beelosedpneovered,iby the fuel itselfso that they arein the aggregate of suflj cient area to admit the air freely upto the maxidemand forthe grate through the uncov-t cred, portions. The Volume of air passing-through, the grate as a whole, is therefore determined. byQ- the total resistance of. the fuel; bed to.,the; fdrawff, whether ornot such fdrawl is assisted, 26 by'forced or induced air supply to the grate. ,The

volume of air passing through' any one part of the fuel bed is therefore dep endent upon the total resistanceof such, part of the fuel bed ,;-(i.,e. b oth the; resistanceinthebody'of the fuel bed gg'and the resistance at the grate due topartia-l stqppag of theigrate apertures by the fuel) ,the. local resistance of thegrate itself being substam many negligible as above explained, and as in 1; practice considerable variation of fuel bed re- 30 "sistance is bound to exist, unequal;distribution-ofthe air talics place from the very start, resulting nt-u e ua {combu n e -u a b r tion thus-produced tends to, accentuate the origi-, v .-nahdifference: ofresistanceuin the fuel bed-so a. "wartime f ectis ul t ai :U l fl o use tionis at present only controlled by the use of v wea er des f i h av b o Wh h= e-= rherrqp rt Qna ee ct Q un q al h i ht .i wh ru ti n t f ll e an a owst io 40' the combustion to spread from the hi her points of I-eornb tion whichis assisted: by the levelling and se tling action- 0f $1. v ,bed of fuel due to the, weight thereof. 1 Unequal-combustion means un- -equal temperatures and while a; certain minimum "'temp'erature is required the difficultyat, present ei iprienced is to maintain such temperature and. atlthe, saiilfe .t ineprev h ri m ii nt ghte awayffrpm the grate resulting from the s a a c m usti wh c Q cu sa an attem t to obtai un f r mb i ri iarau t aoi th a a ugrl a a th gra es. surface, results in blow-pipej action pf theair un -the fuel and the formation of clinker away m. "I.::','U'-.-,TI' v: r. i :r-a 3-5512. "Iheformation of clinker in the fuel mass of vf F -18 I itself rendersit necessari to have depth of v fuel in :the producer than would be rear quired if thez combustion,could-be, effectedatlthei grate-and equally over-the entire :surface foninl A argas producer itis essential that the .CO-z whichg C0 is i produced when andflwhere the clinker-is being formed, must pass througha mass ofpincandescent carbon inorderto beaconvertedinto 00;: Air; passing through clinkerfiinthebody ofza. as producer, that; is. to,-say,; awayi-fromithe grate results yin practice in an increase of the CO2 contentof-thegas. .5 1, s o

{the object ofthe inventiongis toiovercomeworif. mitigate the disadvantagesas above set out, of the presentmethodsandpl-ant;1 a:

Accordingto the-invention; the-impr edmeth-a 0d cf; obtaining ;unifQ1'-m combustion of fuel ;;ona. grate for -the production 10f gas. consists in; pro -i viding a restrictive sectionalqcontrolz of the airupp y was o d p e ed n a s faee, ;sueh -control; giving l a ;predeter.mined; re-e sistance tq thejpassage-of air; so that each sece-z tion admits only: the; volume ofaair required toe produce its proportion of vcarbon monoxide tome obtained 1 fromiphe: carbon content :of a the; fuel. 2- 0 According tqxfurthen-features; of 'theiinventicnthe-air; apertures of theyg ratearesuchas to pIOw'; video as; -l,a rge an;are a as possible consistent withsupporting-the fuels; Otherfeatures ofthe linven-s y; tion are embodiedinthe description which follows 5 and inthe'appended claims.

Upon the accompanying drawings z-e #:I': :1: Fig.=- 1 is a x'plan;- showing the side; andcentralg firebars asused-inconstructing a. grate according to one exampleiofthe invention. -;Eig; 2 is .-afront end elevation of some of the firebars ofithegratem i- Fig;,3 is arearend elevation of-,Fig.-2. t ;;Fig.- 4 isa side elevation of the front vend-of one of the firebarsshowingthe controlrshutter.

-Fig., 5 is a side-elevation .-.of the rearsend of one of theputside;bars showing the end shutter. 1 Fig- 6 shows cross sectional views of the firebars t ai Fig}.

3: $1" imiwu. :13: gig .Fig -H is a cress sectional.,elevationoflone half fil h wlowerapart -of a .gas;.-producer showing :a modifiedconstruction of grate according to the enti n--, i

fig t-8; is an en arged elevation showing ithe de s.

sqiv e b rpt hebar ai Ei sILn-J 1:;105

,Fig, 9is a plan of Fig. 8 with parts shown in.

Section. ,t r I g LE s 10; iS

'31: 1 5. vi ,4: fi' i. a cross-sectional'view on line. 10--10 Figfii is;'gatartiintsiiataami iie and tively close intervals, the notches extending in" depth to the web. There are therefore longitudinal air slots between each bar as wellas the radiating slots therefrom provided by the notches, the width of the slots being proportioned according to requirements of the grates, in particular as to the fuel to be used. The bars are provided with an intermediate wider part I on each side between the notches, so as to provide spacing members for the bars intermediate of their length. The grate may be suitably arranged in a general horizontal plane although it may be inclined. For completing and controlling the supply of air to the iongitudinal chambers provided between adjacent grate bars or girders and also to enable clearing the" chambers, shutte'r fiaps are pivoted between the girders, both at the front and at the back of the grate. Both shutters being mounted for swinging in the same direction, a clearing rake may be used to push out whatever may have collected, if and when necessary. The front flaps g are between the bars and short so as to leave an opening below them, while the back flaps h are bars. The front flaps g are pivoted on lugs a" cast on the inside of the bars, while the rear flaps h are'pivoted on a rod supported by brackets h 40 secured to the end bars.

As shown in Fig. 6, a is the left hand side fire bar, I) is one of the central or intermediate fire bars and c is the right hand side fire bar. Likewise, inthe form of grate construction illustrated in Figs. '7, 8," 9 and 10, there are employed fire barssuitably'shaped and arranged so as to provide a left hand side fire bar, central or intermediate fire bars and a right hand side fire bar. In the form of gas producer grate shown in Figs. '7, 8, 9 and 10 there is a subdivision of the longil'tudinal chamberswhich longitudinal chambers are provided between the'barsand separate admission of air to each sub-chamber is provided. This subdividing of the longitudinal chambers into sub-chambers so as to form the sub-chamlbers is effected by providing a central bar it in and for each longitudinal chamber on which bar are secured angle pieces 'm arranged in pairs at uniform intervals along the bar and together forming dividing members extending across the :longitudinal chamber. The firebars are provided with vertical ribs 12 on their sides, spaced at similar intervals, with which the dividing members m will normally register. The central bar is mounted to be slidable longitudinally Withi-n' the chamber so that the dividing members m may act as clearers to remove any ash which may have fallen through into the chambers. The underside or bottom of the chambers is'forme'd or defined by longitudinal plates 21., se- Tcured by-screws n to the grate bars and having longitudinal slots or notches 0, arranged centrally of the chambers and spaced at the same 1 respectively which are notched at 3.

formed with vertical ribs 12 similar to the ribs b arranged over the ends of the bars so as entirely to' 3 close the end of the air chambers between the' supply for the subdivision of the longitudinal chamber in which it lies. The slots or notches 0, though wider than the grate apertures, are short and of a less area than the grate apertures for the subdivision, so that while providing eifective control or restricted air supply according to the invention, they ar large enough to release any ash or bits f fuel which may fall into the chamber.

In the further example as shown in Fig. 11,

there is employed the left hand side fire bar, central or intermediate fire bars, and the right hand side fire bar, respectively designated p, q and r. Said fire bars are formed with flanges 10 q and The notched flanges take the place of the plates n in the preceding example. Longitudinal bars 15 carrying angle pieces u are provided, similar to the bars 7:: and angle pieces m, and the firebars are The slots and spaces at the grate surface are such as to provide as large an air supplyarea as possible consistent with practical requirements as to strength and durability. Those in the grate illustrated herewith are suitable in size for most IQ of the usual fuels but the same area may be obtained with a greater number of narrower slots and spaces to provide a surface for use withfine or crushed fuel. V

Experimetally, a suitable inlet area was found 1105; to be about one sixth or less of the total area of i the apertures of the grate section associated therewith, or about one eighteenthof the'ar'ea of the said grate section surface. Useful control may, however, be obtained evenwith an inlet area for each chamber which is as much as oneeighth of the area of the said grate section surface. For efiicient working a grate section of not larger than half a square foot is preferred and not less than four sections are desirable inthe 1 grate.

In use, the restriction or control of the'air supply is obtained at the entry to the air charnhere instead of at the grate surfaca so 'thata low velocity, steady and uniformly limited and" distributed supply of air passes up through the air spaces of the grate and renders it possible to produce gas containing a smaller percentage of C02 on a thin bed of fuel than is possible ona deep bed to which this method ofcontrol has not-= been applied. It therefore follows, also, thatai producer having this grate will be more efficient since the resistance to the fiow of gas will be more uniform, a lower temperature in the gas will reduce the loss of sensible heat and also the wear and tear incidental to higher temperatures, com bustion being effected under conditions of lower air velocity results in temperatures sufficiently hi h to effect the complete gasificaticnof thefixed carbon, yet low enough to prevent the dis sociation of the methane and other fixed hydro-' carbons. The improved grate, as a gas producer, is capable of burning small fuel,or refuse, and of providing a high quality of gas therefrom.

It will be obvious that variations in constructional details may be made, without departing from the invention, the essential feature of which" is the provision of a grate wherein the air supply is controlled in such manner as to allow of uniform distribution, that is, all parts of the grate its area are under control, individually and (or) collectively, and capable of uniformity of action.

1. A grate for the combustion of figelfonthe production of a combustible gas comprising bars arranged side by side and having upper and lower flanges extending laterally from the sides of the bars so as to form separate closed air spaces between them, means providing vertical partitions between the fire bars subdividing said spaces into chambers along the length of the bars notches in the edges of said upper flanges forming air outlet apertures leading from said chambers, and notches in said lower flanges which collectively provide an air admission aperture for each chamber, the total area of the apertures in the lower flanges being not more than one-third of the total area of the apertures in the upper flanges.

2. A grate for the combustion of fuel for the production of combustible gas comprising bars arranged side by side and having upper and lower flanges extending laterally from the sides of the bars so as to form separate closed air spaces between them, means providing vertical partitions between the fire bars subdividing said spaces into chambers along the length of the bars, notches in the edges of said upper flanges providing outlet apertures leading from said chambers, notches in said lower flanges which collectively provide an air admission aperture for each chamber, the total area of the apertures in the lower flanges being not more than onethird of the total area of the apertures in the upper flanges, and the ratio of air inlet area to the area of the grate surface apertures being uniform for the whole of the grate area.

3. A grate for the combustion of fuel for the production of a combustible gas comprising bars arranged side by side and having upper and lower flanges extending laterally from the sides of the bars so as to form separate closed air spaces between them, slidable bars between the fire bars, vertical partitions on said slidable bars for subdividing the chambers along the length of the bar notches in the edges of said upper flanges forming air outlet apertures from said chambers, notches in said lower flanges which collectively provide an air admission aperture for each chamber, the total area of the apertures in the lower flanges being not more than one-third of the total area of the apertures in the upper flanges.

4. A grate for a gas producer comprising longitudinally extending grate bars each having a vertically extending web section and upper and lower flanges that extend laterally from the web section, the adjacent grate bars being constructed so that there is provided between them and between the upper and lower flanges thereof air spaces that provide separate air supply chambers, the upper flanges of the grate bars being notched to form the grate surface apertures through which air passes from the air supply chamber to the fuel, and means for subdividing the space between adjacent bars into several relatively small air supply chambers, means in the lower wall portion of each chamber for the admission of air to said chambers but only in a restricted manner, the construction of said last named means being such that the air inlet area for any one chamber is not larger than one-third of the grate surface apertures leading from said chamber.

5. A grate for a gas producer comprising grate bars constructed according to claim 4, being further characterized in that the upper flanges of the bars at the edges of the notched portions are of such a width that at least some of those portions of the adjacent flanges are spaced apart and that the space between those portions of these adjacent flanges form part of said grate surface apertures.

6. A grate for the combustion of fuels for the production of a combustible gas, said grate comprising bars arranged side by side and having upper and lower flanges extending laterally from the sides of the bars so as to form with the associated parts of the grate separate closed air chambers between the bars, the upper flanges of said bars being constructed and arranged so that they collectively form an apertured grate fuel supporting surface through the apertures of which air from the air chambers can flow to the fuel in the grate, the grate construction also being such that in a wall portion of each chamber other than that part provided by an upper flange there is provided an inlet aperture lead-- ing to an air chamber to which the particular aperture corresponds, the inlet aperture for each chamber being not more than one-third of the grate surface apertures leading from the corresponding chamber, and vertical partitions between the fire bars, which vertical partitions carry members whereby each chamber in which the partition is located is'subdivided.

7. A grate for a gas producer comprising a fuel-supporting member formed interiorly with a plurality of separate chambers, said member having air outlet apertures in its upper face extending from each of said chambers and having air inlet apertures in its lower face extending from each of said chambers, the total area of the said air inlet apertures for each chamber being not more than one-third of the total area of the said outlet apertures for the same chamber.

8. A grate for the combustion of fuel for the product of a combustible gas comprising bars arranged side by side and having upper and lower flanges extending laterally from the sides of the bars so as to form separate closed air spaces between them, slidable bars between the fire bars, vertical partitions on said slidable bars for subdividing the air spaces along the length of the bars into chambers, notches in the edges of the upper flanges forming air outlet apertures from said chambers, notches in said lower flanges which collectively provide an air admission aperture for each closed air space, the total'area of the apertures in the lower flanges being not more than one-third of the total area of the apertures in the upper flanges, and said grate being divided 7 in not less than four sections and none of the sections into which the grate is divided being larger than a half square foot.

CHARLES WHITFIELD.

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