US2701536A

US2701536A - Grate structure for refuse burning furnaces

Info

Publication number: US2701536A
Application number: US122168A
Authority: US
Inventors: Henry C L Miller
Original assignee: HOFFT Co Inc
Current assignee: HOFFT Co Inc; HOFFT COMPANY Inc
Priority date: 1948-12-29
Filing date: 1949-10-19
Publication date: 1955-02-08
Anticipated expiration: 1972-02-08

Description

Feb. 8, 1955 H. c. 1.. MILLER 2,701,536

CRATE STRUCTURE FOR REFUSE BURNING FURNACES Original Filed Dec. 29, 1948 2 Sheets-Sheet l 44 .FII1. 1

Feb. 8, 1955 H. c. L. MILLER 2,701,536

GRATE STRUCTURE FOR REFUSE BURNING FURNACES Original Filed Dec. 29, 1948 2 Sheets-Sheet 2 INVENTOR. flay/w d1. MILLER.

Unied. St tes.

Pfurnace; :The grate section of the furnace includes: at?

, 2,701,536 seriesiof gratebarsf 17" carried by (tlhe Iibeamsl'lg-intbe'rw me iate a series 'para e space water cooe tu es GRATE STRUCTURE FOR REFUSE BURNING 19.= :The fuel supporting' surface of the grate,.- there- FURNACES n Y fore, comprises the water-cooled tubes withrtherinter-rl:

. niposedgrate bars 17. Said grate-bars have isubstantialljci' horizontally extending fuel supporting: surfaces mounted-r: in spaced relation to provide air passages of the usual stepladder type.

- Below-the? grate bars-.there is provideda tuyere sec'- ltion having a/series of pivotally mounted pusher fingersrl? 20 interposed between the tubes. 19,-which-continuev downwardly terminating in a transverse header tubei2l-ri Said header tube is provided'ateach end with a: returnrrl 7 Company, Inc., a corporation of Indiana. f Original application December 29, 1948, Serial No. 67,802. Divided and this application October 19,1949, SerialNo. 122,168 T e 1 Claim. c1. 110-8) Hai C. L. jMiller, Richinond, Va., assignoitqr jin 'rtj 1 This' application is a division of application Serial No. 67,802, filed December. 29, 1948, for Refuse Burnflow pipe 22, being supportedby a transverse' bearing":

ing;,Eurnace (now abandoned), and relates toimprovements .-1n furnaces ofpthe. type adapted for burning such lfuels as bark, cottonseed, .cocoanut hulls; sewer sludge, garbage, and like material having a high mois-' ture content, and wherein such material often cmbodies-such. non-combustible foreign matternas dirt,

vrz'icradle 23 mounted on the cross .beam -2 side walls 25 of the furnacer v 4 carried "by the" .Mounted transversely of the-furnace adjacent headertube =21 there-is provided a pivotallytmounteddump consisting of a series of dump bars 26,--which-.ri r3pantheashpit -27.- Each dump-bar is: formedu'atoneif sarid,iand,the like. .Such furnaces are'util'ized both'foru consuming saidmaterial-and utilizing the heat-produced withtan.arcuate-bearing-port on 28 and --a :slotted recess i-"29. --Thezbearing portion .28 of each dump barhaswitsri";

for 'bo ileryor .other power producing purposes refer-rv ence. .being had as illustrative of theart to Letters Patent. .-to. Hoift et. .al. -No.- 2,257,957, issued October -7, 19.41, for. Furnace Grate and to Puckett No. 381,182,";

improvements in the grate structure of furnaces of this-'- characterz which will'. overcome various problems of sanddaden materials. I

ZThe-If ature of this airlfc'ontrol ofmthegrates. ;--In1 furnaces of this type the upper section upon which the fuel is -first received v is generally irnperforate, merely providing a forehearth for receivsing..;the fuel and-directing .1it.on,-tofith'e grate bars. For thejpurposeof.facilitatingthe drying action and burning of' wet fuel; the forehearth is'pr'ovided with =-*'P it 9f@- a 1...ap rtu es. f rmi p g and is in communication with a damper'contrOlledair duet: communicating with the air chamber below. the e ""HQWWF FLJP. respec to... th p area v r which intense rcombustion takes place; a separate air zonehis provided which is damper acontrolled' for'in; dividually' regulating the corn bust ion in the dump a'rea ill-{comparison W t theme rate a a-. Thus-,1- zoned air :bdntrdl. v is provided, the primary zone being. incom h c t o k t Mi rate. su ace et een he. .f.orehearth and the a c qntrolled zone of air supply beifigvP Y S1 f2I.lh'ii? arthz nd a ontrolled Q l5of- 1,- S PP Y Be ge. Provided e mp. a a In-this manner'th'efuel is more efficiently conditioned in passing'over tlfef forehearth on to.the grates and the combustion thereof is better controlled as between the grate .anddurnp areas. W

combfustionarid controlinthe burning of moisture and r v i V Y 1 .35 into.-.th e pivot..tube at one end :andpassesitherethroughii mandout the same'end: :-.The.'counterweight -26a-. has -it rearsurface arcuatelyformed with its center of'curva Fig. 1 is a central vertical section through the furnace.

Fig. 2 is a view of the grate cleaning blowers taken substantially on the line 22 of Fig. 1.

Fig. 3 is an elevational view of the dump area of the furnace taken substantially on the line 3-3 of Fig. 1.

Fig. 4 is a section through the dump and adjacent grate elements.

Fig. 5 is an elevational view of the pivotal mounting of the dump with portions broken away.

In the drawings there is shown a furnace for the burning of wet fuels which are fed therein through the intake duct 10, generally from a superimposed hopper. The fuel indicated at 11 passes on to a solid forehearth section 12. The forehearth includes an air zone section for predrying of the fuel which comprises a perforated or pinhole grate 13. The forehearth sections are supported at the rear by a frame including vertical legs 14 and the cross beam 15. The forward end of the forehearth is carried by the wall 16 of the vention resides; in the zoned- '2 end 'thereof'with a counterweight 26a extending-radjaw The under surface of the grade. bars 1 adjacent the counterweight 26a, 'is formed? cent the header tube .-21-.

is-.formed. along one side thereof: with a-lug 31nengag'eable within. the slotted keyway29-. Said .tube, WhiClIT 30 provides atwater cooled' pivot for the dump carriesaui :water inletpipe 32' extending: therethrough', :Lbut: ter

minating short of one end-thereof. q

.At .theopposite end there is.-a water outlet 33,-.the

arrangement being such that cooling water is discharged adjacent the header tube -21 and a through such fan are 40 as to, at;-all,times extend in; :substantialr sealing-irelationii3 a with the-header. tube when: the? dump is 1 lowered;- with the dumpbarsE-extending vertically downward; as .-sho,wn-

in dotted. lines. Thus, the. counterweight; serves toi-hol d the .fuel. bedewhenwthewdump, is lowered and. thereby ii preventsunburned fuel from. sliding down into the a pit'during thedumping operation.-

The upper-edge of the counterweight is formed with a lr'earwardly extending and curved .knob. 34 having reverse. curvature substantially conforming-to the ee vature...of..the 1 tube" 21-providing -a bridge for: theefue passing-from ,the. grates oi1 t o: :the -dump.-.; This kno and the. counterweight further serve. as a'clinker. breake to break away any clinkerlformation bridging t h andtdump- .TheJug 31. carried. by the-pivot; tube -30 v away; at 35.:to provide a spacerfor receiving'the respec tive (grate :bars as they are mountedon the'pivOI-Htub for replacement. In. event.of breakage of anye-of bars. in. the vdumping. operation, .they.- may be read pivot tube has an arm 36 suitably located thereon from which an actuating dump rod extends exteriorly of the furnace walls for rocking the dump from its horizontal supporting position to its downwardly extending dumping position.

As distinguished from the usual furnace construction, and to provide a reverse flow of hot gases for drying the fuel bed and depositing partially or unburned material thereon, the usual bridge wall 37 is extended upwardly and curved rearwardly at 38 to extend over the fuel bed and thereby direct the hot gases thereover, permitting them to pass upwardly from over the fuel bed and out- 5 wardly through the passage 39 in a direction substantially flow of gases, but any partially burned or unburned material will drop back on to the fuel bed for consumption,

instead'of being carried "into the secondary furnace. This has-the-dual advantage of more rapid drying'and' preheat all: material thereby eliminating tlie"usual -practice of periodically :rernovin g :Esuc'li material by hand or' mechan' ical mea'nss For additionally serving to'eflect rapidity of "drying of the-oncoming wet fuel and increase the =C0i'i1bliStiOi1 efficiency, a"series of air jets -are provided for' developing' rapidaair flow'over the surface ofthftiel bed foreffect ingu'emoval of the moisture. As shown herein a series of jet tubes 40 are mounted in parallel spaced relatio'n tojeie tendhrough the lower portion of the"'bridgewall' '37 through which ;a =stream of steam driven-air is directed over-the '-lower' half *ofthe' fuel bedpropelled"by' the steam nozzle 41. An opposedf companion "series of air" jets' '42 are mounted in *parallel'spaced relation in the top wall 43 of the 'furnace' which are fed by' 'the'steam nozzles 44 to projectthe air stream downwardly over and parallel with the upper portion of the fuel bed.

To providea zoned air control forequ'alizing combustion as "betweenfthe dump and grate barsfon the' one hand; and'provide an air supply to the fuel' 'pass'ing' over the*forehearth,-=the ashp'it 27 communicating with the dump -bars is*-"sea1ed-off by a division wall I 45. said divi sion 'wall has an opening 46 into the -ashpit providing an aircon'duit which is controlled by 'a pivotally 'mounted damper 47 connected to the control 'rod' 48 extending throughthe clean-'out trough '49 and having 'acl'ean-out' opening-50 for the removable closure plate 51.

The pinhole' forchearthgrate 13 extends' ov'er anair chamber 52 into which'-air-'-is directed by the conduit 53 controlled by thedamper 54. The'=air supply "entering the fur'nace below'the grate bars 17 and tuyeres' isre stricted to such zone, but"thougli ma'nipulation of "the dampers; 47 and '54 the air may be admitted to 'fthe restrictedzone of the dump and the forehearth respectively. Such co'ntr'ol has the effect ofcont'rollingthe combustion over the dump area wherethefuel is driest and the corn- Through bustion would otherwise "be undu'ly intense. su'eh air' control combustion may be better'equalized over the-entire grate surface, including the dump. The air zone' directing-air to the Ifo'reh'e'artli,' and the control thereof,"

assists n the distillation of moisture from thewet fuel and pe'r init more rap'id'burnin'g-thereof 'o v"er the gra'te.

T more *co'nviently and efiectivelyprevent clogging of are supported by the brackets-56 underneathsaidgrate bars and-extend in par'allel space relation to the grate and in transverse rela't'ion to the grate bars.

handle "portion63 projecting beyond-tlie'wall16 of the furnace. Through movement of the handle the respectiveheaders' may-be-oscillate'd in a plane parallel to'said I g Y I I! Eachof the f headers" is provided with'a seriesof nozzles 57 arranged" bars so that the fluid stream projected from the nozzles may "be-caused" to sweep over the fuel supporting surfaces of the grate bars through such area that the several headers will jointly cover the entire grate surface.

The pusher fingers 20 are manipulated in the usual manner through their several actuating rods 64 which ar6e connected through the arm 65 t0 the actuating-lever 6 An advantage of thefurri'acestructure herein shown, and wherein the secondary furnace, is above'theprimaryfurnace instead 'of being-to the front thereof, the furnace is'thereby' 'made accessible from all four sides. Thus, a clea'n-outopeningwvith'a cl'osur'cap is provided at 67 in'addition to; the'end'wall clean-out openingsas indicated at 68 and at 50. This is a material advantage not only in rendering the interior ,of the furnace more accessible for cleariing,--but*alsofor repairing the grate bars, and particularly replacing burned out and broken dum'p' bar's. I I

From the foregoing,-it will be observed that-the abovedescribedfur'nac'e has many-advantages both in res'pect to operation rnaintenance, and cleaning and*iri'"-res'pect 1to' the'-'efiiciency, drying and preheating in"the"bu'rhing etthe wet fuelfed thereto.

I claim:

In a furnace for burning wet fuel"hav'ing a downwardlyl sloping' grate including 'gra'te' bars 'having' substantially horizontally extending fuel supporting surfaces mount ed in 'sp'aced relation to provide 'a se'ries -of horizontal air' emitting slo'ts therein, thecombinatior'i therewithof a series'of fiuid"discharge no'zzles'rn'ounted on"the'pn'der sidel'ofsaid gratebars' directed towards-said'slots, said serieslying 'ina plane substantially parallel to and spaced I below said fuel supporting surfaces and slots through \which'a fluid streamis discharged for blowing'accumulated matter" therefrom, an' adjustable header' rnountd below said grate bars carrying said nozz'les'in""spaced relation, 1 and "means" to oscillate said headerin a plane" parallel to said bars so that the fluid stream projected from-said nozzles'may becaused to'sweep over the fuel supporting "surfaces 'of' said bars in a dire'ction fron'i'one end to the other thereof.

References Citedinthe file of this pat'ent- UNITED STATES PATENTS 205,431 f Snider- June 28,-"1878 981,254 I 12111310; 1911 1,025,788 i: "-1912 1,315,158 a 1919'- 1,437,182 Jackson" Nov.28, 1922 1,543,801 Smith 4 June 30} 1925 1,620,672 Miller Mar. 15,1927 1,789,223 Drake Ian.'l3,-'-1932.1 1,865,753 1932 ,9 ,'1 '4 1,984,344" 1934" 2,269,273 1942 2,381,182 1945 2,386,336" 1945 FOREIGN PATENTS I