US2672296A - Fluid impact pulverizer - Google Patents

Description

March 16, 1954 w VENABLE 2,672,296

FLUID IMPACT PULVERIZER Filed Jan. 4, 1949 5 Sheets-Sheet l 5 Fig.1. 60 55 INVENTOR William/Mayo Venab/e March 16, 1954 w. M. VENABLE 2,672,296

FLUID IMPACT PULVERIZER Filed Jan. 4, 1949 5 Sheets-Sheet 2 3% x. INVENTOR MW/amflayo flenab/e 7 gww aw. 0; W

March 16, 1954 w. M. VENABLE FLUID IMPACT PULVERIZER 5 Sheets-Sheet 5 Filed Jan. 4, 1949 INVENTOR Mayo V /Iab/e X ofiu, 750x019 541% Wi/Uam March 16, 1954 w VENABLE 2,672,296

FLUID IMPACT PULVERIZER Filed Jan. 4. 1949 5 Sheets-Sheet 4 INVENTOR W/W/am Mayo Vena/e March 16, 1954 w. M. VENABLE FLUID IMPACT PULVERIZER 5 Sheets-Sheet 5 Filed Jan. 4, 1949 INVENTOR WIN/am Mayo Venab /e f, 0x441 K o. .well;-asi.a-;maximum;ssize desirable;

Patented Mar. 16, I954 NI TE .iijisS Tl"1il? 1- PAT E 70 F F ,1 C 2, f7 -2 ,296 FLUID-IMPACT PULVERIZER William 1 Mayo V enable, Pittsburgh, Pa.,1 a s signor, Why mesne assignments, toBla'w-Kno'x Company,

mean ime a we c of De aw :Appliqation-January 4, 1949, Serial No. 69,127

- s glaims; Cla- 241-39) 3 i, This invention relates. 'toxmills of .thetimpact" -cu1tiesare overcome inthe mill of this invention. pulverizer type for-grinding various kindsrof solid In this invention the partsv of the apparatus material. Moreparticularly, itirelates .to, ;a mill gare so arran ed and 'pr'opor'ti ne a e of iin which streams ofza;gaseousnatmosphere in cientyariety to circulate, the materiallwith a which such material is suspended are directedminimum-expenditure of power to separate toward acommon-pointtocause thecomminution coarser material for recirculat on f om fi of such material to desired particle size. ,terial as adequately as practicable and to' avoid Impact pulverizers.oreatomizers as they are the grindingsof material,excessively beyond a sometimes'called, encompassia numberof types minimum size eonsidered mo'st desirable Furancl aroused toogrind-a variety of materials. In 5 in't e mil Of; this invention a id e -general, such pulverizersiproduce fine grinding of of materials otdiflerent, charactercanibe ground such solid material.by turbulencein the. gaseous to predetermined.particle size,,flsuch materials atmosphere-carrying theiragments of such mawould include solid fuelsvsuchasjcoaland coke terial or by thel'collidingl'actionof thestreams ,i "of-varying degrees of, hardness.- This invention within the --apparatus .icarryingizsuch material. 5 is also, applieableto thepulverization oimaterials Thus particlesmaycollide with oneianother when having special; chemical or physical j properties moving in opposite oreconverging directions or ,such-asgrinding abrasives, insecticidepowders,

I may collide:withsomemortionmfatheiapparatusi; paperpulprpowd cata yst f r-hyd c rbon nand thus be: subjectrto fraotureuili'urther, such version and many others, ,Other Objects an particles may impingeupon-oneganotherv or upon zo vantages of thisinvention will 'be apparent from a portion :of the apparatus wit ig-lancing blows the following description and fromth'e'dra wings,

. and be reducedin size-Joy. attrition. in which,

Inmillsof the type withowhichthisinvention Figure 1. is awerticalview in crosssectiQn f a is --c0ncerned,-th'ese particles. are: entrained in g I mill made in accordance with thi invention, with the gaseousatmosphere byojetsii'onqejectors di 5 its returnpassages removed, and of a separator rected was to haveaiccmmon intersection. In associated therewith;

- order to grindto asufii'cient;degreet-vofirfineness, -Figure 2 isayiew inicross section taken, along the particles are-recirculated tosisuch jets until line II-IIofFigure 1; reduced'to the desired degreeiaThetgaseous ata Figure 3 is a view in crosstsection taken. along mosphere is produced and maintainedas the conline H'- i urel and Show n thef eturn sequence of the operation of the jets nwitnsuper-w passages; r heated steam or -compressed airii; .When the Figure 4 is a yertical viewinrcross section of nature of the material tO b QZ-gIOUIId; requires it,: I the separator and of a feeding means'for the mill other compressedgasesimaysbeiusedh:fiIhese gaso1 this inventiontaken at right angles toithe view eous fluids, inclusive:ofasuchryaporsras;may be; shownin Figure 1;

present, inspirate the particlesi of solidimat erial FigureiA i g ew n ro ot eni eken along whichare to be ground andtcausetthem tonbe susline IVA -IYA of Figure 4; pended in the streams ofigaseousfluid and par- Figure 5 is a. view, taken, along line-W4; of Fig- -tic1es so created. z t r ure 3;

In the pulverizing ofcoal-sornther particles, it ;;wFigure, 6, is, .a vertical; view. in cross section of frequently happenssthat particles. whichzhave alanother embodiment ofthis invention;

r ready been ground to the:predetermineddesired 1 -Figure .7 is; a-viewhincross section taken along degree of finenesstremain in theastreams; being line VIL-rYILQf i ure 6; I I

recirculated andz-thusareisubjectgto-unnecessary Figure 8 isaplan viewof one-half.of the emregrinding. with the --coarsers-particlesgwhich are 3745' bodimentshown inlifigure 6; and also borne :in the streams, rsince for/.eachstype 01" 4 Figure 9 is a vertical view incross section taken material it is desirable that thetparticlessbe re along-line IX IX of Figure 8. duced. only toathat" degree ,of.:-fineneS.S..-Which will ,G Referring to-thegpreierred embodiment shown :exclude =particlesocoarser -thannaw certain size, in Figures; 1; to alaeylindriealcasingfl l1 is 00mparticlesi finerethan :thatzcertaincmaximllm $126,150 P d s t t l b 11 ine k c q fi ,L e

become, in certainicases,eundesirablesbecause itz -n-zlsqb ply' welded together inlea'ko o is wasteful 10f .ipowen andreduces .zthetcapacity of;

Qasing lll together with bottom ll, and l'a top a .the mill or because :the ;use= ofi;whic;h she ground plate,;de1ine;a:grinding,chamber}l3 "in 'which particles are to her-putirenderssaiminimumsize as openings I through each of which a nozzle l6 projects. Each nozzle I5 is held in a block l1 threadably connected to a plate is which is bolted in sealed engagement with an annular rim l9 welded to casing it around each opening [5. superheated steam or compressed air is supplied to nozzles [6 through the respective pipes 20. For grinding coal superheated steam is usually supplied to nozzles l5. Nozzles 16 are horizontally directed toward a common intersection, the point center of which lies on the vertical axis of chamber l3.

Each nozzle [5 is provided with a coaxially positioned barrel 2| pointing toward said common intersection and spaced inadvance of the respective nozzle 16 an amount which provides an annular inlet 22 which constitutes the inspiration zone for each jet or ejector comprising a nozzle [6 and its attendant barrel 2|. Each barrel 2| is aiiixed and held in place in the bore of a bracket 23 fastened to bottom l4. Connecting all of the inspiration zones 22 there is a common annular enclosure 24 formed in chamber l3 by an annular top plate 25 and an inner cylindrical wall 25 through which the foreparts of barrels 2! project. In plate 25 there are a series of restricted openings 21 corresponding in number to the number of inspiration zones 22 and located directly above such zones respectively. Each opening 21 has a scoop 28 associated therewith and adapted to direct particles touching the inside of said scoop into and through said opening.

A baffle plate 29 is located in a horizontal plane above the respective barrels in spaced relation to said barrels and plate 25 by legs 30. Each leg 39 is welded or otherwise fastened respectively to a barrel 2! and baffle plate 29. While baflle plate 29 is a circular disc in the embodiment shown, it may be made rectangular or in any other shape for the purpose of directing the material that may come in contact with it outwardly through an annular passage 3| respectivelyjbetween plates 25 and 29. This passage 31 must be of suflicient area to permit the partially ground material to pass through with enough gaseous fluid to carry it but must not be so large that the fluid flow through passage 3| is too small to retain the larger fragments in suspension. In each case, passage 3! must be designed for the particular kind of material to be ground.

A wear plate 32 is afiixed to baffle 29 on the top side thereof in the center. This wear plate 32 is adapted to prevent undue wear of bafile 29. The material of which wear plate 32 is made may be of a yielding material to minimize abrasion or of any material suitable for use with the particular character of the material to be ground. Yet, as are all of the parts of the apparatus, it must also be designed to withstand all temperatures and other factors which will be encountered in operation. Four curvilinear vanes 33 are set in battle 29 and extend above and below the two surfaces thereof. Vanes 33 constitute upstanding and depending walls running from wear plate 32 to the outer edge of bailie 23 in the manner of curved equally spaced spokes on a wheel. Thus, the gaseous streams of gaseous fluid carrying particles of solid material of different sizes leaving an impact zone 34 generally defined by wall 26, bottom l4 and baffle 29, will be given a rotational or centrifugal motion by the depending portion of vanes 33 in addition to that already existing in the chamber as- 2l, where it is held a consequence of the portions of vanes 33 projecting above baffle 23. This rotation in one direction relative the axis of chamber is imparts to the gaseous atmosphere and suspended particles in the chamber a movement which centrifuges the larger of the entrained particles toward the lower portion of easing iii. In addition-this motion centrifugesthe finer material toward the upper portion of casing It and facilitates the removal of as much thereof as possible from the gaseous fluid which is to be recirculated through barrels 2l. Scoops 28 are inclined in a direction counter to the direction of motion imparted by vanes 33 and thus collect such larger particles for recirculation through inspiration zones 22 and regrinding.

A housing 35 is located in the center of the top of plate 12. This housing supports a nozzle block 35 in which a nozzle 31 is threaded. Housing 35 also supports a barrel 38 spaced from nozzle 3'! to provide an annular inlet 39 which is the inspiration zone for the feed jet or feed ejector which comprises nozzle 31 and barrel 38. Gaseous fluid to operate nozzle 3'! is supplied through a line 48.

Housing 35 has an opening on one side thereof adjacent inspiration zone 33, to which opening there is connected a feed conduit 4!, as shown particularly in Figure 4. A bracket 42 fastened to the edge of plate l2 supports conduit M. The outer end of conduit 4! is opened for connection to a flared hopper 43 to which fresh material is supplied. A screw conveyor 44 is rotatably supported in conduit ll and is turned by a sprocket 45 on the shaft thereof for material advancing engagement with the inside of conduit 4!. Intermediate the ends of conduit 4| in advance of hopper 43 there is a pipe connection 46 leading to a separator.

An annular hood 41 is centrally supported on the underside of plate l2. This hood includes a frusto-conical recess 43 around the outer portion thereof, the outer peripheral side 49 of which is somewhat longer than the inner peripheral side 50. Hood 41 also includes a cylindrical center portion 5| spaced equally from side 58 and forming an inner annular passage 52. Center portion 5i is also fastened to the underside of plate 12 and extends downwardly a distance substantially equal to the vertical projection of side 58. Passage 52 is connected through openings in plate l2 with four return passage conduits 53 composed of pipe sections forming a reentrant loop as shown in Figure 5, connected directly into auxiliary annular enclosure 24 through the lower section of easing In. A butterfly damper valve 5 is rotatably supported by a pin 55 in each conduit 53. The conduits 53 are of relatively large cross-sectional area, which area can be efiectively changed to obtain the desired velocity of gaseous fluid with such entrained solid material as may be therein to enclosure 24 by adjustment of the setting of damper 54. In some cases dampers 54 can be entirely closed to achieve particular velocity conditions through passage 3| and in the remaining portions of the apparatus. Two uptakes 56 are connected with chamber 13 through plate l2 adjacent the uppermost section of casing in. In this position uptakes 55 are shielded at least partially by side 49 of hood 41. In addition, the aggregate cross-sectional area of uptakes 55 is substantially less than the aggregate crosssectional area of conduits 53.

I A separator 51 is joined to the upper ends of 'nection 46.

' ticlesof the :4 land are admi'x'ed'with fresh or untreated maj terial as screw conveyor 4M continues' 'to supply specific combination be encountered and thesize of fS juch particulars constitute'the engineering and-in such'connectionallof the f hiatakestli. espirator-51 campusess ranneiiake outerannular passag ifl and a nbe'ntric'mner into each "other at'f'th'ir respective-uppei ends throngs an opencurving aboutfthe 'centra r 'axis" of separato 51 to im'part rotary motiontothe'st'ream of gaseous --fiuid and entrained-"ground material rising in passage '58. The" top-"of both" passages is closed 59 below opening- "60. A bell type spended by' brackets "65 from "the Hence; as thestream passing through opening BB-ground or pulverulent 'material; suspended in the gaseous'ffiuid of the stream and meeting specifications of predeterf'mined particle sizej-passintoriser' 63* and out of the grinding mill andseparator. The coarser Fahd heavier ground material in that stream *moves'downwardly through inner passage 59 and a downcomber V o thereof by a leakproof sleeved! with pipe con- Thus such 'co'ar'serand' heavier 'par-- 66 connected-at the lower end ground material pass into conduit the inspiration 'zone' 39" of the feed jet." The 1 portions of the baflie partsincluding the passage 3i and or" the areas ofreturn passages 53, -uptakes .56, the parts of separator 5'! and of the feedingmechanism as well as the restricted-open- "ingsZT and the dimensions ofjchamber l3 will be determined in the light 'ofthe-particular qual- 1" ities of the material to be-ground, the nature of the gaseous fluid or fluids usedin the respective jets, the pressures, temperatures and the like to the apparatus. fieldbf process drawings in this case are to be considered as merely diagrammatic. Moreover, under some conditions, certain kinds of material will not require the use of any vanes 33 or such vanes may only be necessary on one side or the other of bafile 29. All portions of the apparatus will also be suitably insulated where necessary to prevent undue loss of heat.

An alternative embodiment of this invention is shown in Figures 6 to 9 inclusive. Such an alternative embodiment is useful in existing plants in which the available space is limited especially as to head room. In this alternative embodiment, a casing I including a top plate l2 and a bottom I 4' define a chamber l3. Except as otherwise noted, the Various and respective parts of the apparatus in the alternative embodiment are numbered with the same references primed, as the references used in describing the preferred embodiment in Figures 1 to inclusive, serve the same purposes and have the same advantages.

It will be noted that the grinding jets or ejectors comprisin nozzles l6 and barrels 2| are and arrangement of uptakes fid'separator 51 and conduit ll are a partgnot of this' invention', but 'ofthe inventionset, iorth iri- United States patent application Serial'No.

69,103, filed on even date herewith, in'the' name wis'e'obstruct thentry of material propelled into 5 impfictzohe ev ct-chamber W"asfqistinsuished '1 amine-preferred embodiment in Wh h themaacme s4. Thefeed jet inthe alterriative embodiand a barrel-38' which'forc'es the materialintoa doncluitwfiopem f has a Venturi bore 72 in fthe' aite ative-embduias a bailie apartfroin 'baiiieplat fl'. Barrelf'38 "lined: with'refra'ctory blocks 13', a type of provision'whichi'may 'also'bem'ade 1 in 'barrel' '38 of'the preferrewe 'nbodimeht. An-

, other purpose isjserved by""theiupw'ard'inclination of nozzle I6" and barrels2l"in that such positioningfitends 'toinc'rease the pressure of the passage 31 therebyassisting in'the'remo'v-alfof. solidi'material, including the feed enteringthroughconduit lll,

outof impact'zone 34. a

. In the alternative embodiment bafileYI'ZQ'j.) is

made with a conicaltop '74 which-producesmovementof any stream do'wnwardlylimpingmg "thereon toward thefiinnerwalls of casing; 110'.

Rotary. motion isimparted. to the stream flowing out of impact zone 34 by curvilinear vanes 33 which also serve to support bafiie plate 29 on the upward extension ofcircular wall -26".

.Hoodl il' in the alternative embodiment is an annular horizontal plate; having' a central passage 5Z'insteadof arr-annular passage 52as'in struction a. single damperis rigidly afiixed )1 through plate the preferredembodiment} Becauseof-this conplate -54'- -suffices and is, raised and lowered by a threaded rod 15, having a hand. wheel 16 -at the upper end'thereof,

,and threadably engaging a sleeve 17. "Sleeve 71 to a cupola-78 which extends 'bywhich a it is supported.

Cupola-18 supports hood 41-- andcyl-indricalwall Return passage gconduits 53'- are" connected Finerigroundmaterial rotatin about the inner -;periphery of casing ID passes out ofcham'ber arrangement through conduit 10. A suitable separator, not shown, is connected to outlet 56' and the rejected material from that separator may be returned to conduit 4| as is done in the preferred embodiment. Brackets 23 support, in the alternative embodiment, the entire grinding jet assembly by being welded in the corresponding openings in the lowermost section of casing I 0'. Brackets 23 are recessed at 79 to provide the necessary opening between each inspiration zone 22 and auxiliary enclosure 24'.

Although I have illustrated and described but a preferred practice and embodiments of the invention, it will be recognized that changes in the procedure and structural details may be made covering said impact zone, said baiiie being interposed between said means and said plurality of jets and defining therewith a velocity exit from said impact zone, curvilinear vanes on said bafile, said vanes curving in one direction and adapted to centrifuge streams of gaseous fluid and particles around the outer portion of said chamber,

a hood centrally located in said chamber above' said baflle, a return passage directly connecting said hood and said annular enclosure, and an outlet adjacent the periphery of said chamber at the top thereof and adapted to be partially shielded by said hood, whereby coarse particles are carried to said inspiration inlets for grinding in said impact zone, finer particles of not greater than predetermined size are carried out through said outlet and gaseous fluid with less entrained material therein is circulated through said return passage.

2. Impact apparatus for pulverizing solid fuel, comprising in combination, a chamber, a well defining an impact zone in the lower portion of said chamber, a plurality of grinding jets directed toward a common intersection in said impact zone, said grinding jets having inspiration inlets outside the outer periphery of said wall, an annular plate defining with said wall an annular enclosure for said inspiration inlets, means for feeding solid material borne in gaseous fluid into said chamber adjacent said impact zone, a baflle above said common intersection and between the same and said means, said baflie being spaced from and substantially covering said impact zone to define with said wall an annular exit therefrom, means adjacent said annular exit for imparting rotational force to streams of gaseous fluid and particles exiting from said impact zone, an outlet for particles of sufficient fineness adjacent the periphery of said chamber in the upper portion thereof, and a return outlet nearer the vertical *3 8 axis of said chamber for returning gaseous fluid to saidannular enclosure around the outside of said chamber.

3. Apparatus for pulverizing solid material, comprising in combination, a closed chamber, a generally vertical wall adjacent the bottom of said chamber and surrounding an unobstructed impact zone therein, a plurality of ejectors for grinding and recirculating material to be ground within said chamber, said ejectors being generally horizontal and directed toward a, common intersection within said impact zone, said ejectors having nozzles and barrels, said barrels extending through openings in said wall, the inlets to said barrels being outside said wall in an auxiliary annular enclosure, an annular plate covering the top of said enclosure and having restricted openings therein, a baiiie plate closely spaced relative to the upper edge of said wall to provide therewith an annular outlet passage from said impact zone into the remainder of said chamber, said annular outlet passage being adjacent said restricted openings, radially oiiset vanes adjacent said annular outlet passage to impart rotational force in one direction to streams of gaseous fluid and solid particles leaving said impact zone, scoops adjacent said restricted openings extending in a direction opposed to the direction of rotation imparted by said vanes, means for feeding a stream of gaseous fluid material to be ground into said chamber adjacent said impact zone, and an outlet pipe connected to the upper outer portion of said chamber to remove gaseous fluid suspended particles of ground material therethrough.

WILLIAM MAYO VENABLE.

References Cited in the file of this patent UNITED STATES PATENTS

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