US1363361A - Pulverizer and process of fine pulverizing - Google Patents

Description

' F. SEYMOUR.

PULVERIZER AND PROCESS OF FINE PULVERIZING.

APPLICATION FILED 1AN.7,1919.

1,363,361. Patented Dec. 28,1920.

3SHEETSSHEET 1.

IL M ilr' I INVENTOR W,&

ATTORNEYS F. SEYMOUR.

PULVERIZER AND PROCESS OF FINE PULVERIZING.

APPLICATION FILED JAN. 7, 1919.

Patented Dec. 28, 1920.

3 SHEETS-SH ET 2.

IIHWIIHI MIHHHHMWHHI I INXgNTOR ATTORNEYS F. SEYMOUR.

PULVERIZER AND PROCESS OF FINE PULVERIZING.

APPLICATION FILED JAN-7,1919.

1,363,361, Patented Dec. 28,1920.

3 SHEETS-SHEET 3- INVENTOR ATTORNEYS UNITED STATES PATENT OFFICE.

FREDEREK SEYMOUR, OF EAST ORANGE, NEW' JERSEY, ASSIGNOR T0 AERO' PULVERI ZER COMPANY, A CORPORATION OF DELAWARE.

PULVERIZER AND PROCESS OF FINE PUIiVERIZING.

Specification of Letters Patent.

Application filed January 7, 1919. Serial No. 269,995..

T 0 all whom it may concern Be it known that I, FREDERICK SEYMOUR, a citizen of the United States, residing at East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Pulverizers and Processes of Fine Pulverizing, of which the following is a specification.

My invention relates to pulverizers adapted to reduce coal and coke to an impalpable powder by beating andfriction and to mix the pulverized product with a desired porportion of air for perfect or efiective combustion, and to force the mixture direct to the furnace preferably, or else to the place of deposit or classification and to a process of fine pulverizing. Other friable materials .may be pulverized.

The class of pulverizers to which the-invention relates to that employing a series of concentric chambers from the feed end to the discharge end thereof, a horizontal shaft mounted centrally within these chambers and carrying a series of rotating spiders or disks to which paddles are secured so as to work in the concentric chambers. Separating the concentric chambers are peripheral diaphragms with axial openings for the passage of air and the material being pulverized, I

At the discharge end of the pulverizer is a fan, on the same shaft, which induces acurrent of air through the pulverizer upon which the material in course of treatment will be borne successively from one chamber to the next and when pulverized will be discharged mixed with air through the fan.

Between the last pulverizing chamber and the fan preferably is an auxiliary air inlet forsupplying such additional air as may be desired over and above the air. needed for pulverizing, but the auxiliary air may be admitted elsewhere;

Pulverizers of this class are principally used to pulverize coal, to mix the powder with the air required for perfect combustion and to deliver the mixture to a furnace where the coal is burned in suspension like a gas. It has become a standard requirement in recent years that th coal should be reduced to such a fineness that 85% of it will pass a sieve or screen having 40,000 interstices to the square inch'and more than 95% of it should pass a screen having 10,000 interstices to the square-inch, and very slight excess of coarse particles over these standard commercial requirements are considered objectionable, and pulverizersheretofore in use, of the type above mentioned, have failed to produce a product of the required fineness, particularly after the pulverizing parts have become partially worn.

The standard requirements of the prod not above mentioned have become so thoroughly accepted thata pulverizer which cannot meet and maintain those requirements under ordinary conditions of wear, is not marketable.

The requirement has been adopted as a compromise between the power cost of finer pulverizing and the combustion advantages to be derived therefrom.

I'have found after prolonged experiments that the required fineness maybe secured by an adjustment of the relations between the diameters of the pulverizing chambers, the diameters of the axial openings in the diaphragms separating the chambers, and the diameters of the disks carrying the paddles, and that the herein described adjustment 1 positively facilitates the process of air separation within the plllverizer, whereby the too coarse particles are thrown into the pulverizing zones,-wh-ile the sufliciently fine particles are borne by the axial air current through to the discharge.

In the 'class of pulverizers in which the diameters ofthe pulverizing chambers increase from the feed end toward the dis- 1 charge end, this adjustment maybe made by maintaining the same or nearly the same diameter for the axial openings in the diaphragms throughout the pulverizing part of the machine, and increasing the diameters of the paddle carrying disks from the feed end of the machine toward the discharge end, commencing in the, first chamber with a disk which is of less diameter than the axial opening of the diaphragm, through which that chamber discharges, and successively Patented Dec. 28, 1920.

increasing the diameters of the paddle carrying disks until the last one-is as large or larger than the axial opening in the diaphragms on either-side of it.

Inpulverizers of the class where the pulv verizing chambers are all of the same diameter, I make the relative adjustments .by varying the diameters of the axial openings in the diaphragms on either side of the pul-;

verizing chambers from the feedvend ofthe machine toward the discharge end making the axial opening in the first diaphragm of a diameter larger than that of the revolving disk in the first chamber, and gradually decreasing the diameters of the axial openings in the other .diaphragms until the diameters of the axial openings on either side of'the last chamber become less than the diameter of the disk revolving in that chamber. In this class of ulverizer the diameters of the paddle carrylng disks are preferably all of substantially the same diameter.

I I have described. the preferable adjustment of parts but this may be varied without departing from the spirit, of my invention, so long as the adjustment of disks in ing and diaphragms on either side of pulverizchambers progresses in such way that the disk in the first chamber is smaller in diameter than the axial opening in the diaphragm through which it discliarges and the disk 1n the last chaniber is indiameter as on either side.

By the described adjustment, I relate the carrylng power of the ciirrent of air passlarge as or larger than the axial openings ing axially through the machine to the sizeof the particles which are to be carried throughthe several chambers;

By the described adjustment, I further decrease the thickness of the tubular-sheet of air as it passes axially through the pul-1 verizing chambers from the feed end of the machine toward the discharge end, and I increase the bends or waves 'in this axial current as it passes from the feed toward the discharged the machine, and in the classof pulverizers above mentioned in which the diameters of the pulverizing chambers increase from the feed end toward the discharge end and in which the diam= eters of the disksmay correspondingly increase, it is obvious that the particles being pulverized when passing-the disksare compelledto travel on. curves of increasing radli. Like successive results may be real-uized in the'class of pulverizers in which the pulverizing chambersare of uniform diameter by successively increasing the diameters of the disks and decreasing the length of the arms or lugs carrying the paddles. If it be desired that the paddles and arms or lugs carrying them shall be uniform throughout the pulverlzing chambers, the radii of'the disks and consequently of the curves in r are very fi-ne.

'tlon is made by the described'adjustment;

Prior to my discoveriesthe paddles were which the particles travel will nevertheless increase appreciably, inasmuch asthe preferablef construction in such case is one in which the paddles rotating in the first chamher are the farthest from the. peripheral lining of the chamber, those in the last chamber are nearest to the lining. and those in the intermediate chambers are at intermediate distances from the lining, .thus permitting an appreciable increase in the diameters of the disks from the feed end toward the discharge.

Machines of this character revolve at high speed, the peripheral speed of the outer edge the power of the axial current v in the successive chambers, being-the greatest in the first chamber, where the particles are relatively large, and the least in the last pulverizing' chamber where the particles For this variation compensa usually carried by spiders of which the hubs were smaller than the axial openings through the diaphragms on either side, the axial air current measuring on a'radial line was relatively thick, offering substantial. resistance so that particles of material passed in a spiral line from the first pulverizing chamber to the fan without other substantial deflection, being carried through on the axial current of air so near to the axis of the pulverizer that the operation of centrifugal motion upon the small but too coarse particles was often insulficient to force them out of the axial current to-the' periphery, with the resultthat coarse particles in substantial quantities were earned through the machine without being reduced to the desired fineness.

T An exception to the foregoing construction is a pulve'rizer which has not come into commercial use 1n than that of the paddle carrying disk in the which the axial openingin the'first diaphragm is of smaller diameter first chamber, the axial opening in the second diaphragm is of larger diameter than the paddle carrying disks in the: second chamber, and the axial opening from the final pulverizing chamber into the fan is of .less diameter than that of the paddle carrying disks, the pulverizing chambers are of increasing width from the feed end toward the discharge endand the paddles carried by the revolving disks are of successively decreasing widths and increasing -lengths a construction which tends to over-load and clog the first chamber and to defeat the purpose of fine pulverizing.

Some pulverizing is done in the first chamber and-the remaining action-is a treatment of fine particles.

- tion of them are fine. enough, and if all these from a steel plate and are fastened to the could now leave the machine, leaving the coarser particles behind; for further verizing, the action would be perfect. All prior pulverizers are partial failures here; but my improvements reach the coarser particles, mingled with some of the fine, it is true, but reaches them, and my object is, by the described adjustment, in the successive chambers positively to direct the coarser particles and the current of air in which they are suspended farther and farther from the axis of rotation as pulverizing progresses and by the same adjustment positively to decrease the radial dimension of a cross section of the axial current from the feed end to the discharge end of the 25- pulverizer and augment the waves or bends in said axial current, and concurrently to regulate and 'evenly distribute the work among the several chambers.

It is preferable that the described adjustment should be made progressively and about uniformly from one chamber to th next commencing at the feed end, but m invention is not limited to such relative dimensions but extends to any relative dimen- 3 sions which commence with a paddle carry ing disk of less diameter than that of the axial opening in the adjacent diaphragm and ends with adisk having a diameter equal to or larger than that of the axial openings in the diaphragms on either side.

By the described adjustment the solid particles which are still too coarse to meet the aforesaid commercial requirements as.

they become finer and finer in .their progress through the pulverizer exposing pro portionately larger and larger surfaces to atmospheric resistance are nevertheless thrown out of the axial current to the periphery which is the pulverizing zone because concurrently with the reduction. in I size of the solid particles there successively occurs at coincident intervals an increase in, centrifugal force, a decrease 1n the radlal distance to he traveled by the particles to escape the axial current and an increase in the angle of deflection.

The disks are preferably .of one piece cut hub by shearing bolts with a cross section sufiicient to keep the disk and the paddles revolving with'the shaft unless an unusual obstruction, such as a railroad spike or bolt or other substantial piece .of tramp iron or other metal should enter the pulverizer with A moderate proporpulthe coal as sometimes happens. The shearmg of these bolts saves a bad wreck in the pulverizer. The paddles are carried on arms extending from the disk or they may be produced of a fineness which will more than pass the commercial requirements above referred to.

I find that the passage of the coarse particles across and out of the axial current and to the periphery is facilitated and made more certain by directing them into narrow concentrated streams by means of radial or nearly radial grooves on the faces of found it advantageous to make them of manganese steel and to obtain them from foundries operated by men skilled in the composition, casting and heat treatment of manganese steel, and while the cost of cast the paddles, andfiner pulverization results no increase of power and manganese steel paddles, heat treated for ductility and to resist abrasion is high, the excess cost is more than offset by increased wearing qualities and freedom from breakage.

I have found corrugations an inch wide and one-eighth of an inch deep across or partly across the face of the paddle, as

herelnbefore described, to work satisfactorily, but my invention is not limited to I any dimensions, butextends to all sizes and shapes of ridges and depressions of the character described. It is desirable, but not necessary, to case the paddles from twopat terns, putting the ridges in one pattern where the depressions are in the other, and

to place paddles froin each pattern on alternate arms of .each disk, otherwise the paddles have a tendency so to throw the material being pulverized, asto wear the lin ings of the pulverizers unevenly and in strips.

Other objects will appear fromthehere inafter description. In order'that my invention may be-better understood, attention is directed to the acing a form of the revolving parts companying drawings, forming. part of this specification, in Which- Figure 1 is a vertical sectional view through a pulverizer of the type referred to which has pulverizing chambers of successi vely increasing toward the discharge end.

Fig. 2 is a vertical section through a pulverizer of the .type referred to in which the pulverizing chambers are ofuniform diameter.

Fig. through the last pulverizingchamber, showand the relative diametersof the ,disk thereof and of Fig. 4; is a view through the first chamber showing a form which it may of the revolving parts and of the relative diameters of the first disk and of the first dia hragm.

ig. 5 is a view in perspective of a corrugated paddle with lugs on the inner edge for attaching it to a disk withoutarms.

Fig. 6 is a view in perspective of a corrugated paddle with lugs on the back of it by be attached to arms extending from the periphery of'the disk.

In all the above views corresponding parts are represented by the same numerals' of reference. I v

1 is a base 'upon which is securely bolted the shell 2 of the pulverizing apparatus. Within the shell 20f the pulverizing apparatus in the present instance are four concentric pulverizing chambers 3, 4, 5 and 6, an auxiliary air chamber 7 and a fan chamber 8. The pulverizing chambers are arranged concentrically. The chambers referredto areseparated by the ' diaphragms 9, 10, 11, 12 and 13h Mounted centrally in the apparatus 1s,a shaft 14, driven by any electric motor'not shown, .45

, mounted in bearings 15 and 16. .The fan such. as a direct connected or by a. pulley on the end ofthe shaft turned by a belt connect-, ing'with a source of power. The shaft is suitable means,

chamber 8 .has a discharge openmg'17 ar I rangedtangentially with respect to the same plgddles 22.

from which any suitable pipe, one madex of alvanized sheet iron, not

shown, will con' uct thepulverized material intimately mixed with air to the place of use, deposit or separation; Mounted on the shaft 14 within the pulverizing chambers are the disks 18, 19, 20 and 21 carrying the The disks are preferably but l t necessarilycarried on cast .iron hubs 23, and are held to the hub byshearing bolts 24:. Retaining rings 25 held in lace by ta screws 26,serve to hold the dis on the hu after the bolts 24 shall have-sheared. The arms 27 may be either rigid or ofthe swing type. Angle iron palms 28 are riveted to the ends of the arms of the disks,t o which palms diameter from the feed end L lined with plate linings 30 rolled to a 3 is a view looking longitudinally .relative diameters of disks carrying thefor instance,

in s in the dia revolve paddles 6" may be'bolted the paddles22. The paddles may be secured to the disks by any other suitable means, as for instance the means shown at 22'.

Keyed to the shaft within the last chains ber is [a fan 29 of any of the well-known desi ns.

lh'e pulverizing and fan chambers are circle in the pulverizing chambers and to the usual spiral in the fan chamber and held in place by bolts or rivets through the lining 30 and shell 2, and held away from the shell where desired by the filler 31, or by any other suit able means.

One or more air inlets 32 areprovided through the shell 2 into the auxiliary a1r' chamber 7 and-the inlets are provided with dampers 33 to regulate the amount of air which shall-be admitted. Material is fed tothe pulverizer through a chute 3 1 by any convenient form of feeding device and a slide' or .damper is provided in the feeding of which air inregulable device by means admitted with the material known to me, but my invention is not limitedby any specific construction, but has reference to. the described adjustment of the disks and axial openingsin diaphragms, and to the described means of directing the particles toward the periphery in narrow concentrated streams.

I have found that very satisfactory results are obtained in a machine in which the pulverizing chambers are four in numwide between the diaphragm in which revolve paddles'6 long axially and 3% wide radially, and in which the diameters of-the pulverizing ing from the feed end to the discharge end of the pulverizer were respectively 32- 3 1 chambers proceedas" and as and in which the radii of the paddles proceeding from the feed end to'the verizer' were 11",12t, 13%" spectively, and in whichtheradii of the axial openings in the diaphragms were 13% These dimensions may be varied'within the aforesaidlimitations keeping in mind the purpose for which the adjustment of relative diameters of disks and axial openfind' also t tained in a pulverlzer in which the pulver izing chambers were four (4) in number, were of a uniform" diameter of 3 6", 7%"

hragrhs is made. F at improved results are ob-7'l20 discharge end of the pul-' and 14-2" re- Wide between the diaphragms and in which long axially and 3%" wide radially and in which the radii of the disks carrying the paddles. proceeding from the feed end to-the discharge end of. the pulverizer were 13", 13%", 13% and/13%" respectively, and in which the radii of the axial openings in the diaphragms were15", 14 13 and 12% respectively.-

The class of pulverizers in which the chambers are of progressively increasing diameters is the preferable class for the application of my invention, requires less power and produces a finer powder.

The operation of my improved pulverizer is as follows, when used for pulverizing and feeding coal to a furnace to be burned in sus ension in air:

. ower is applied to the shaft 14 to rotate it at the proper speed, say 1400 revolutions a minute. The material to be pulverized is introduced through the chute 34, and with the material is admitted air in quantity sufficient to prevent the pulverizer from clog-' ging,say seven pounds of air to one of. coal. The fan 29 induces a draft through the pulverizer from the feed end to the discharge end thereof. The material entering the pulverizing chamber 3 will be shattered by the rapidly revolving paddles 22, the corrugations upon the faces of which will prevent the shattered particles from being propelled by the impact axially toward the discharge end of the pulverizer and will guide them toward the periphery where they are further pulverized, by friction among the particles, and on the paddles, and by driven contact with the lining 30. As the particles of material are reduced in size the fine par ticles arecarried by the axial air current through the opening in the diaphragm 9 into the pulverizing chamber '4, the coarser particles being again thrown by centrifugal force toward the periphery are held in the pulverizing chamber 4 for such further reduction in size as will permit the axial current to overcome centrifugal force and carry the particles through the axial opening in the diaphragm. Nearly all of the material as it leaves the chamber 3, although much reduced, is still vtoo coarse to meet commercial requirements. At the periphery of this as of all chambers the coarser particles predominate and away from the periphery the finer particles predominate,-but as the axial opening in the diaphragm 9 is larger than the disk 18 the axial air current while on its way from chamber 3 to chamber 4 is comparatively thick measured on a radial lineand is not much deflected by the diaphragm 9 toward the axis of rotation, and the particles of coal or other material, while in chamber 3 and relatively large, are subjected to less'centrifugal force than in the succeedin chambers all of which combines to make t e carrying power of the axial air current greater between the chambers 3 and 4 than between any other pair of chambers, preventing overeload and clogging in cham ber 3 where the particles are the least sus: ceptible to flotation in air.-

When the solid particles enter chamber 4 their course is moderately deflected toward the periphery by the disk 19 whose diameter preferably more nearly approaches the diameter of the opening in the diaphragm 9, the axial air current measured on a radial line becomes thinner and as it passes the disk 19 theradius of the curve of rotation is longer, centrifugal force is higher and the axial current laden with solid particlesis deflected toward the axis of rotation by the diaphragm 10 by a larger angle than that of the corresponding deflection occasioned by diaphragm The average size of the particles in chamber 4 is smaller than in chamber '3, they are more readily home on with an axial air current and are less easily thrown out by centrifugal motion, but the described adjustment of parts compensates the changed condition of the material.

The solid particles and the air move through the succeeding chambers 5 and 6 in the same way, the tubular axial air current growing thinner, the waves and deflections thereof more pronounced and the radius of rotation increasing until in chamber 6 the radius of the disk 21 is longer'than the radius of the axial opening in either'of the diaphragms 11 or 12.

The corrugations on the paddles 22 revolving in the chambers 3, 4, 5 and 6 serve to line up in concentrated streams the solid particles of material-and thus lined up the solid particles more readily overcome atmospheric resistance, escape the axial current and reach the periphery.

From the chamber 6 the axial current of air and material is drawn through the auxiliary air chamber 7, where is drawn in and added to the current such additional air as is needed for combustion, say seven pounds more of air to one of coal. The auxiliary air meets the axial current at right angles or nearly so and the two intermix to some extent in the chamber 7, and the mixture is completed in passing through the fan.

The whole mixture is then expelled through the discharge opening 17 and is conducted by the discharge pipe to the place of use, deposit or separation.

Thus, vmy adjustment goes to -the treatment of the larger particles of coal, although some portion of the particles, already sulficiently fine, go along with them.

The described adjustment of relative diameters positively directs the solid particles toward the periphery, successively lengthens the radii of the curves of rotation with no reduction in the number of revolutions, increases the centrifugal force to which the solid particles are subjected in -each successive chamber, thins the tubular axial current of air on which the solid particles are home from any chamber to the next succeeding one, and impresses upon that current, however tumultuousit may be,

adapted to permit waves toward and from the axis each succeeding wave being more pronounced than its predecessor, each of which elements 1s related to the diminishing size of the solid particles as they pass from one chamber to the next and to the increasing difliculty of separation, and with all of'them concentrated streams of particles prod ced by the grooved faces of the paddles coo erate. In the use of the word diaphra or diaphragms, heads at either end of the cylindrical shell in which the pulverizing is done and by the term first diaphragm I means that diaphragm through which the contents of the first chamber are discharged.

What I claimis 1. A pulverizer comprising a chamber, the passage of air and solids longitudinally therethrough, and rotary pulverizers mounted to operate transversely to the passage of said substances, said pulverizers provided with .iimpact means shaped to guide material radially outwardly against the inner wall of sa d chamber and between the outer edges of said impact means and said wall.

2. A pulverizer comprising a chamber adapted to permit the passage of air and solidslon 'tudinally therethrough, and rotary pulverizing members therein formed with radial ribs and grooves to form impact members and guides to direct solids out- 7 wardly against the inner wall of said chama through whichair and solids may be longi:

ber andbetween the outer edges of said pulverizers. and. said wall.

3. A pulverizer comprising a chamber provided I with annular pockets extending from its inner wall, and pulverizers mounted to rotate 1n said chamber and projecting into said pockets, said pulverizers provided I with radial ribsand grooves adapted to form impact members and operating to guide material within said pockets*out wardly against said inner wall. 4. The apparatus substantially as defined in claim 3, together with suction means to draw material longitudinally through said chamber. 4

5. A pulverizer comprising a chamber tudinally drawn, a set of annular diaphragms arranged in spaced relation and projecting from the inner wall of said ch'amberf to form annular pockets therebetween, disks mounted to rotate in said chamber, pulverizers mounted upon said disks an l projecting into said pockets, the

adjacent disks and diaphragms at the inlet ofsaid chamber providing a comparatively wide and tubularspace for air and solid material moved therethrough, the adjacent disks and diaphragms toward the exit of sad chamber providing a thin and radially it is not intended to inc ude the v the opening in 1 about the same in in the next preceding diaphragm thereto. 7

The method of selecting and pulveriz-. ing material in a longitudinally disposed pulverizers pro j acent diaphragms toward the exit opening beingclosely related radially to form a ra-' dially undulating thinner tubular space for they passage of air and pulverized solids. 7. A pulverizing mill comprising a chamber, through which air and solids are adapted to be drawn, annular diaphragms projecting inwardly therein, disks provided with pulverizers, rotative in said chamber in cooperative relation to said diaphragms, the axial opening in thediaphragm toward the inlet to said chamber being larger than the adjacent disks and the axial opening of the diaphragm toward the exit of said chamber being substantially the same size as the adj acent disk.

8. A mill ing a pulverizing chamber through which air and solids may be longitudinally drawn, spaced annular diaphragms forming bafiies and pulverizing 'charq'bers projecting in wardly from the wall of said chamber, disks carrying pulverizers mounted to rotate in said chamber in cooperative relation with said diaphragms, the diameter of the disk at the inlet end of the chamber being less than. the diameter of the opening of the next sue hra ms' therein formin baflies and annular P b o pockets, and a Series of disks carrying pul- Verizers rotative therein, in cooperative relation with said diaphragms, the diameter of the disk nearest the inlet of said chamber being substantially less than the diameter of the adjacent diaph comprising a chamragm, and i the diameter of another-of said 'disksrbeing length as that of the opening chamber, which consists in producing a flow A of air and solid material longitudinally therethrough, and subjecting material to successive transverse pulverizing actions inan elongated annular space thereina vhlch is relatively thick and substantially undb; I In witness whereof I have hereunto set 10 structed toward the beginning of the pulmy hand at the boron h of Manhattan, city verizing action, and WhlCh is thin and radiand State of New ork, this 4th day of ally undulating toward the end of the pul- January, 1919.

Verizing action.

11. A method substantially as set frth in I FREDK SEYMOUR claim 10 inwhich material is also guided In presence ofradially outwardly against the inner walls C. CURTIS of the chamber. 7 JOHN J. EANAGAN.

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