US1828712A - Outfeeding means for fuel pulverizing machines - Google Patents

Description

Oct. 20, 1931. P. A. HIRSCH 1,828,712

OUTFEEDING MEANS FOR FUEL PULVERIZING MACHINES Filed June 1; 1926 2 Sheets-Sheet 1 INVENTQR 1 mm. 9 wank T s K K Whdl A'i'TORNEYS,

Oct. 20, 1931. P, A. HIRSCH OUTFEEDING MEANS FOR FUEL PULVERIZING MACHINES Filed June 1, 1926 2 Sheets-Sheet 2 INVEN TOR @my y 81 MMKATTORNEYS Patented 20, i j I i I p j OUTEEE I NG MEANS tonrwr eerwmzimMACHIN S I A p ication elea iirim jr, nae/ser l No: 1 12356. v

This invention is a novel outfeedin'g means Fig. "4;is a partial perspective view of'a for pulverizing machines, having reference peripheral portion- Of -the r tary fan or particularly tothe pulverizing of coal, or flower.-

-' q a i other fuels. The invention-is herein: shown Referring in; detail to the illustrated struc- 5 embodied in" a type of'pulverizing machine ture 1F i'gxl shows a pulverizingmachine of having a chambered casing, with an .operat' the horizontal type, the same as my aforesaid nig shaft therein, and impact 'beatersfior Patent 1,479,540, although in some cases it paddles revolved by the shaft, while axial air could as well be arranged vertically as'in my flow causes progressive advance of t-he m'aother Patent 1,479,541 of the same date.

" 1o terial. being reducedyalthough features of Mounted ona-base11is shown a cylindrical M the present invention may be otherwise emdrum or casing 12' preferably lfixed againstbodiedr A prior pulverizer of the type and rotation. The drum may be-constructed'in for the purpose referred to, isillustrated in two orthree radially divided sections for the my Patent No. l',479,540=of. January'1, 1924. purpose of assembly, disassembly and trans- One of the main objects ofthe present inportation; The lower right'hand part of the vention is to improve the delivery-of the pul casing is shown as having a' dropped extenverized material from'the machine, namely sion;14 in: which foreign material may be colinto a delivery or fan chamber, and the dis-i lectedaswill be described,ra removable'cover charge thereof from the fan chamber,-and in orfrece'ptacle15 being attached to the open '35. the'case of fuel theadmixturethere'ofwith side of the "extensionby which the foreign I 35 described.

5 or blower.

additional quantities of air- 0f combustion;- I material "may be removed from timeto time. thisinvolving a novel-structure of delivery The {drum'or casing encloses successive chammeans or fan and the novel'method'or mode bers' or spaces and is shownv as lined :with a of operation secured thereby. v steel lining'or'ring '17 in each of-the pulver Other and further objects andadvantages i zing spaces or chambers, the right hand-one of the'present invention will be explained-in 'of these linings being perforated at 18 above the hereinafter followingdescription of an the extension 14 to permit heavy and foreign illustrative embodiment thereof, or wi1lbe material .to be discharged from the chamber v apparent to those skilled in-the art. :To the into the extension. V a v 7 30 attainment of the objects and advantages The-drum at'its right end is closed by a cirreferred to the present invention consists in cular end-wall or casting or head 19 having a the novel method and machine, and the; novel central or axial opening 20- by which the-mafeatures of operation, combination, arrange: terial to, be-pul-verized'can enter the drum. I ment and constructionfherein illustrated or The head l 9 is shown formed with an eXten' I v a x 5 I; fi vsion2'1,' the lower part of whichis inclined In the accompanying drawings. Fig-ul' is so as to facilitate the infeed'of materialto' the substantially "a central vertical cross section 'pulverizer and the d scen of heavy-for ign v of a pulverizing machine illustrating; the materials'toward the extension-14; The eX" present invention, the fuel and air infeed tension-21 m further shown as giving support g 40 shown at the right end and thedelivery means to one of the be'arin gs 24 of I the 1 operating at the left end'of-thelfigurefl I 1 shaft the'other end of the shaft hav- Fig. 2 is a detail perspectiveview showing 'ing. a similar bearing 26 supported upon one of the pulverizingmembers, beaters or a fixed? frame extension {or bracket 33. paddles OfthiS inventiomand its relation to The driving shaft 25' may be rotated at high the fast rotatingwheel or-fdisk whichcarries speed through its exterior'extension 28 in any it. 3 desired mannerQfor example through belt Fig. 3 is a right elevation takenpa'rtlyin and :pu'lley'or direct. coupled motor, turbine section onithe line 3-43 of-Fig.'-1:and showing or the like. I u I 1 the preferredconstruction of the delivery "fan The left or discharge end of the drum is r +5 shown asclosed by an'end wall or head 29 side the drum, while the air draft for the final discharge and dilution of the pulverized materials is provided by a suction fan or blower located beyond the pulverizing chambers, and exterior to the pulverized discharge wall or head 29. For this purpose a fan cas-. ing 31 is shown, which may conveniently be integral with the head 29. The bracket support 33 for the bearing 26 may also be in? tegral with the fan casing. The fan casing has alsoa peripheral extension 34 providing a tangential exit passage or discharge 35, analogous to that shown in said prior Patent 1,47 9,540, but herein shown directed upwardly, as is frequently necessary for blowing out or delivering-the mixed fuel and air toa furnace.

The infeed of the fuel may be by a hopper 37, suitably supplied with coal or other material after preliminary grinding to a suitable size. The hopper 37 loads to a regulatable feed comprising a rota-ted star wheel 38 bringing successive fuel portions into the following passage 39, the materials passing downwardly by gravity into the separating chamber 41, the walls 42 of which may be integral extensions of the casting 21 containing the central inlet aperture 20. One of the walls 42 may contain an opening 43 forthe admission of air, and it will be understood that any of the air admission opening or ports may be regulatable by a damper. \Vithin the chamber 41 may be any suitable separating means such as a magnetic shell 44 turned continuously by a shaft 45, these parts indicated in dotted lines. Electromagnets within the shell may maintain a condition of strong magnetism so that all iron particles will be caused to adhere strongly to the shell and thus carried around to the outer portion of the chamber, where they are progressively detachedfrom the shell by the scraper or flange 46, thus depositing the iron particles in the receptacle 47 from which they may be removed through the aperture 43. The shafts of the star feed wheel 38 and of the magnetic shell 44 may be suitably driven in ,synchronism during the operation of the pulverizer, and the speeds may beadjustable in any usual manner to regulate the rate of fuel feed, a slower rate of feedbeing accompanied by a greater degree of pulverization.

The fuel passing through the separating chamber 41 descends into the passage 48 in the extension-21, a plate 49 acting as ashield to insure the materials entering with adescending motion or preventing their entering into the first pulverizing chamber above the operating shaft.

There maybe a single pulverizer chamber within the drum, or a series of them, and Fig. 1 shows a first reduction chamber 51 and a second reduction chamber 52, within which the fuel will be progressively pulverized by the fast rotating heating means mounted within each chamber upon the shaft 25. Thus the shaft is shown as having pinned or keyed to it in each chamber a hub 54 on which is mounted a disk 55, around the circumference of which are mounted a series of-peripheral beaters or paddles 56. Such a beater structure has been already explained'in said prior patent, although the structure of the beater hereof is considerably improved with resulting increase of efliciency and length of life, as will be explained.

Located between the first and second pulverizing chambers 51 .and 52 is shown a means for effecting a sudden obstructing of the whirling.motionproduced by the fast rotating paddles in chamber 51. This whirl obstru'ctor may be in the form of a series of blade-like vanes 60 set edgewise to the axial advance of the material and extending from or near the periphery of the chambers to or toward the shaft. Preferably the vanes 60 are relatively stationary, and they may stand radially or otherwise. The action of such vanes has been described in said prior patcut. The several vanes may be mounted and interconnected by means of a peripheral ring 61 attached to the lining 17, and an inner ring 62 loosely surrounding the shaft 25.

Beyond the second pulverizing chamber 52 and between it and the fan casing is shown another set of obstructing vanes 65, with an outer ring 66 interconnecting them. These have a special function herein, in addition to the function possessed by the vanes 60; this to be explained more fully hereinafter. An inner ring 67 unites the inner ends of 65. It will be noticed that within and between the pulverizing chambers there are no annular or other division walls or so -called diaphragms, nor any substantial obstruction to the axial progressof the materials, between the axial entrance aperture 20 in the head 19 and the axial exit aperture 30 in the head 29. This aperture 30 is of considerably less diameter than the pulverizing chambers, and of less diameter even than that of the pulverizing elements, that is, the diameter from tip to tip of the paddles. In these and other respects to be explained the present invention is materially difi'erent from said prior patent and other prior structures of which I am familiar; The aperture 30, indeed, is shown of su'ch'small diameter that materials progressing through it pass into the interior of the rotary fan structure, an important consideration. I

The 'fan chamber 32 may be almost of the full diameter of the main casing, as shown, but the fan 7 0 is preferably of considerably ma ma: p

' smalleridiameterf Itis' shown'm'oiintedson a hub 71 keyed to the'jshaft-2'5.. A znovelsand efficient fan construction isshown wherein the hub 71 carries a disklor circularrplate 7 2, p posite to whichiis ail-ing or annularplate73, the disk and the ring. supporting, and being interconnected by, a series of fan blades 74; With this invention the blades 74 are" ar-i ranged to'handle the supplemental air of com: bustion-which may be introduced'intothefan ,chamber 32 by way of the-axial inlet '36,

I whichmaybe damper governed,=the air being on the disk nearits periphery by means ofv an outer bolt or pivot 78, the plateformed with a concentric slot 79 engaged by an inner bolt 80 engaged in a, threadedperforation 81 in the disk... By this. arrangement the .fuel

whirling fan blades 76 may be adjusted in their angle and operation .Figs. 3 and' i'show two different angular adjustmentsof these. members,while Fig. 3'in dot-and-dashdines shows the two extremes of adj ustment'as pref erably used.' It will be observedthat the fuel j whirling blades 76 are slanted from the ra dius, whereasthe supplementalair whirling blades 74 are preferablyradial; The slant-of theblades 76, and themeans ofadjustment thereof, aflord anadvantageousaction as will I bedescribed. a i. The paddles, hammers or beaters,56' are. herein constructed and mounted in a novel manner giving substantial advantages. In the hammer-mounting of'said prior patents the continuity of the surfaces of thesupport ing disks is substantiallyinterrupted near the periphery by protruding portions of thepad clles and the bolts by which they areinounted. 'By comparative tests it has been found that these protruding elements are not merely' the source of wear and expense, but owing to their being in thepath of the centrifugally flowingpowdered materials they cause a dis-'- turbance of the flow and impair the efiiciency of the reducing'action; These objections are Wholly overcome by thepresent construction in which the sides of'the disk are uninterrupted by protrusions and the whirl I ing materials are able to pass'smoothly outwardly intothep aths of the beaters or pad dles, rendering the beating action more 'thor ough and-actually resulting in a greaterfineness of pulyerization and increased capacity of the machine, with reduced power.

-- :l-Tlie paddlesioribeaters are, llowances relative:v arrangementin Fig. I 1, and .the -preferrdt details of; structureiin Fi'g.;f2". Each Q paddle comprises'aLT-shape body '85,--1nounted preferably swingably atlthe periphery of the disk 55 The enlarged-portion"o nhead of the paddle body 85 is formedwith an outer flange I 86, and a remoyable'paddle face plateor block 87"Iis-..provided with a shoulder 88: engaging the'fiange 86, giving an -interlo'ckingaction,

andienabling the centrifugal thrust :ofgthef l blocks87 to be received'b-y Itheflange'SG with-J out anyv shearingstrain upon the bolts 89 by which the blockis secured fiOE-thG body... The

forward side orjface' 90i-ofthefblock 87*is shown'incline'd forwardlygiving an-efi'ective beating action andallowingfor wearby'abra' sion'at a greater rate near lthe periphery of thelblock without substantially impairing theeffectiveness of theaction'lf'The thin-web portion 91 ofthe paddle body 85 is perforated andin use is arranged' inla irece'ss'in the}pe-; riphery of the disk 55, so-"as not to protrude beyondthe flush surfaceof. the "disk This recess ispreferably in the form of, a kerf 92, and there may be a separaterecessor kerf for 1 each ofthe paddles or-there maybe. a continuous kerf or grooveextendinghentirely around the peripheral edge of the disk 55.

by means of a trans verselstud 93,-whichmay be a simple pin without head at-either' end, and this stud in turn maybe held againstdis- 1 placementby a cotter pin"94,'screw or other means securing it to the web' 91; of the. paddle. Instead of a single integral disk 55 provided with' an edgegrooye or kerf 92, this disk may be builtiup, for example by two circular plates spaced'slightly apartto accommodate faceiplates or blocks 87 which are readily" renewable, so that the lifeof thecapparatu andthe ease of renewal'a-re greatly enhanced.

Not only is efiiciency increased,- as explained,

but the first cost" of the machine is reduced,

since the renewable face block 87 maybeicoin' .7 1

posed-*of' hard steel While the paddle body 85 mfayjbe o-f'cheaper material as a lower gradei 0 steel; i v

1 In operation themachinecombinesa regus lated air and coal "feed at one end and at'the other end a suction fan oflow 'pressureand 1 5 power receiving thepulverized materials and discharging themcentrifugally. In the'first pulverizing chamber 51 anymetal and other heavymaterialnotremoyed in the separat-ing' chamber will be thrown down centrifugally 1 .into the extension-'14. The entering-fuelfis v The web 91 is heldin placein the kerf 9 2 faces take the brunt of the reduc'ingEaction,

and these two elements arereadily and cheaply replaceable. Succeeding the first reducing chamber are the fixedv vanes which totally obstructthe whirling motion while permitting substantially uninterrupted. axial progress. Pulverizing occurs at this point, not merely by the impact of the fast whirling particles against the fixed vanes but by;rub

bing and attrition along the surfaceof the vanes and moreoverby an action of throwing back of the heavier particlesinto-the reducing chamber, permitting only the finer particles to progress, as explained-in said patent.

Passing from the vanes 60 the materials under treatment are again thrown suddenly intowhirling motion and are furtherreduced by impact and attrition. The peripheral surface of-the interiorof the apparatus is substantially free from. obstruction to axial progress. There are. no rings or diaphragms and the high centrifugal pressure ismaintained throughout the length of the mill upto the point where the'reducing action is completed. At this point'the vanes-6f)- 0p: erate to overcome the .centrifugal pressure and permit the whirling mattersto be drawn inwardly to the contracted-outlet 80. The dynamic energy of the whirling matters striking against the stationary vanes causes them to spread so as: to reach the outletaperture. In effect the-centrifugal action is converted to a centripetal motion. 7 The end wall 29'acts as-a dam so as to confine the fan. or one of the full diameter of the paddles might result in excessive pressure or suc-. tion and tend to extract the whirlingmatters from the main-casing faster than is consist ent with efliciency and fineness of reduction,

fourths. of the diameter of the reducing devicesgives satisfactory results. It keeps the air and materials, in progress but avoidsex: cessive suction. Maximum internal centrifugal'pressureis thus maintainable, the divertingvanes65 operating to bring the mater-ialstothe outlet, andthe fanoperating upon them for final centrifugal discharge. This refers to the blades 76 and one feature thereof is their relativelyfsmall size and their adjustability ofangle. I

The disclosed fan-as a discharge means for a pulverizingmill can be advantageously used with other types of mill than the impact millherein disclosed, for example with ball mills, roller mills. One duty of such fan isjto 'niaintain-the progress of'the whirling matters, coal dust or other material in suspension in air, through the pulverizer and its outlet, and a second duty is to deliver these materials-to the furnace or other place of use, and frequently to provide and mix therewith supplemental air of combustion. These two functions are in some respects quite dif- 'ferent and the best results are found to be attainable by aseparation of functions as herein disclosed, enabling the materials being treated to behandled and discharged separately from the supplemental air. A low suction and pressure isldesirable for the coal dust :or other material, especially when the interior ofthe main casing is progressively cleared for example as alreadydescribed in connectionwiththe vanes 65.. On the other handthedelivery of the coal dust and air intoca furnace demands enough pressure to overcomethev resistance of the burners and piping, with some sparepressureto regulate distribution. The present invention gives satisfactory .results .for both purposes and this is effected moreover by the novel fan hereof operating in the usual type of fan housing annexed to the pulverizer outlet. The fan chamber, except near the periphery and discharge, is effectually divided into separate chambers by the unperforated disk 72. At the pulverizer side of this disk is what may be termed: the dust chamber and at the other or outer side the air chamber. Operating in the air chamber are the whirling blades 74- which operate to draw air inthrough the axial inlet 36 "and throw it centrifugally out through the discharge 35, with relatively high pressure andzrate of flow. The solid materials or'dust never reachesthe air chamber or contacts the air blades, but is, handled entirely separately in the dust chamber. The removable dust blades 76 thereby take all the'brunt ofthe wear from the progressing solid materials; enablingthe fan to be renewed by merely replacing these parts, thus greatly minimizing upkeep expense. 2

The swivelled attachment of the dust blades 76 permits the suction and pressure lhave. found that afan of not over threeto be'adjusted to the. conditions. Expert.

' ments have indicated that the nearer the put.

' chamber into two subchambers and the separation of the functions of the fan as deblades 76 are set to a tangential position the finer will be-the pulverization. 1 Thus the adjustment shown; in Fig. 4: gives slower discharge and finer pulverization than that shown in Fig. 3, which will result in coarser pulverization but increased capacity of out- The arrangement thereby permits the machine to be adjusted in accordance with the material being ground and the desired fineness of product, the angle of the dust blades to be set to themost advantageous angle.

It will be observed that the adjustment of the dustblades and the resulting discharge of dust does not affect the dischargeof air by the air blades 74. dependent up to the pointv where the discharged matters meet and mix in the general discharge outlet 35. The division of the fan scribed may be brought about in various ways. The dust tegral extensions of the air blades, and the disk 7 2 adjusted axially. to relatively increase blades the feedingaction of 5. A fan as in claim (l. and wherein the disk, air blades,and dustblades constitutearotor The two actions are 1n-v blades could be made as .in-

project laterally, with means for ad usting consist of angle pieces arranged to their-angular relationship to the air blades.

LA fan for feeding V comprisinga casing, a shaft rotatable therepulverized material,

in, a disk on the shaft separating the interior of the casing into a dust chamber and a" wider air chamber,

"radially disposed air blades secured to theairside of the disk, and I if nonradial dust blades secured to the opposite side of the disk, said dust blades being adjustable to different angles whereby to vary= the fan.

of considerably smaller diameter than the-' interior of the casing.

In testimony whereof, I have aflixed if signature hereto.

PAUL- ARTHUR iinason;

V I the sizeland actionof the dust blades and dea,

' plemental air, or

. crease those of the air blades,

; pulverizing action.

ment of air flow or discharge by the, fan would cause a change in the fuel outflow and thereby alter the actions within thepulverizer wherea pulverizing machine principles and attaining the objects of theand vice versa. 'It is to be understood that dampers may be employed to regulate the admission of sup-- tions can be made without affecting the Ordinarily ,an a

as with the present invention even very hlgh the flow of the combined materials to the furnace, and such reguladjustair pressures can be supplied for distribution to combustion points without substantially altering the constancy of the action" and progress through the pulverizer. 1

. Itwill thus be seen that I have; if

embodying. the

of the disk and air blades at the opposite side I of the disk, the dust blades being angularly I disposed with reference to the air blades.

2. A fan asinclaim 1 and wherein the'dust v blades are detachable and removable independently of the air blades.

' v 3. A fan as in claim l and'wher'ein the dust

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