US1811438A - Pulverizing apparatus - Google Patents

Description

June 23, 1931. R. s. RILEY ET AL 1 3 PULVERIZING APPARATUS Original Filed Nov. 7, 1925 2 Sheets-Sheet l WITNESSES Ozuaon 012/110 27 F :H: -67 J6- LJLJ J INVENTORS 1i. GQNFORD RILEY June 23, 1931. R. s. RILEY ETAL PULVERIZING APPARATUS Original Filed Nov. '7, 1925 2 Sheets-Sheet 2- INVENTORS R. SQNFORD RILEY ozusozv ORA/6' ATT RNEY Patented June 23, 193,1

UNITED STA ES PATENT OFFICE ROBERT SANFORD RILEY AND OLLISON CRAIG, OI WORCESTER, MASSACHUSETTS, AS- I SIGNOBS TO RILEY STOKEB CORPORATION, WORCESTER, MASSACHUSETTS, A COR- PORATION OE MASSACHUSETTS PULVEBIZING APPARATUS Original application filed November 7, 1925, Serial 1T0. 87,889. Divided and this application 1928. Serial No. 106,082.

Our invention relates to pulverizing inachines and more particularly to a machine of the beater type arranged to comminute solid material and mix it with air for transportation as desired.

that grinding zone.

This application is a division of our prior application, Ser. No. 67,639, filed Nov. 7, 1925, now Patent No. 1,759,134, dated May 20, 1930. a

A -machine of the type shown in th United States patent to Blyth, No. 1,446,151, of Feb. 20, 1923, comprises a rotatable disk which has pegs on opposite sides thereof interfitting with stationary pegs on the casing walls and between which the material is pulverized by impact and attrition. The machine has two grinding zones on opposite sides of and connected by an annular passage around the disk. In the first zone, the material is crushed as it is thrown outwardly by the centrifugal action of the revolving pegs and is caused to pass around the edge of the disk into thesecond grinding zone. Here it is forced to travel inwardly against the centrifugal action of the revolving pegs toward a centrally disposed outlet.

The Bl th ty e of machine is particularly adapted or pui verizing coal and feeding it to a furnace burner in condition for combustion, but there are certain defects inherent in the construction which render it inefiicient for such purposes. The pegs are relatively fragile and the are so arranged that if a large and hard orei n body, such as a chunk of iron, should be ed to the machine,'a number of the pegs might be broken from their fastenings and these in turn aid in the destruction of the remaining pegs in There moreover has been excessive wear on the pegs due to the necessity for the pegs to crush the coarse material preliminary, whereasit is found that such an arrangement serves more efliciently for the final stages of pulverization.

It is accordingly the primary object of our invention to overcome these'difliculties and provide a unitary, simply constructed and efficient machine which will pulverize coarse material to-a desired degree of fineness, and

filed Kay 1,

in which the danger of breakage of the pulverizing members is lessened and their useful life is increased. Other objects will be hammers, adjacent the inlet which are arranged to crush the material preliminarily and feed it to revoluble heaters surrounding them. If hard foreign bodies are likely to be found in the material, a perforated grid may be located around the hammers. The grid serves both to retain the material in contact with the hammers until it is crushed to a small size and to distribute the material uniformly to the heaters all around the hammers. As afurther feature of our invention, the material, after it passes the preliminary breakers and beaters, may be fed to the peripheral portion of a second pulverizing zone which has a centrally located outlet and be therefurther pulverized as it passes inwardly towards the outlet.

One embodiment of this apparatus takes the form of a substantially cylindrical casing having an inlet and an outlet located centrally on opposite sides and between which is mounted a rotatable disk spaced laterally and peripherally from the casing wall to form two connected zones. In the first zone, swing hammers are mounted adjacent the inlet to break the material as its enters the casing, and surrounding these are sets of pegs mounted on the disk and the casing wall respectively. Similarly, in the outlet zone pegs are mounted on the disk and preferably lntermeshed with stationary pegs on the op- Eosite casing wall, and these are arranged etween the annular passage around the disk and a central outlet so that the material must pass inwardly towards the outlet. In the first zone, the hammers are pivotally mountedto revolve with the disk and a perforated grid is arranged around the hammers to cooperate in crushing the material preliminarly and feeding it directly and radially to the surrounding pegs while preventing the escape thereto of large sized bodies. A rejector, preferably comprising a set of revolving blades, may be provided to prevent the escape of coarse material from the second zone and to return it for further treatment by the revolving pegs.

Referrin to the drawings w ich illustrate certain em odiments of our invention, and in which like reference numerals indicate like parts Fig. 1 is a vertical sectional view of the machine; 4

Fig. 2 is a section on the line 22 of Fig. 1

Fig. 3 is a sectional view showing the preliminary breaker;

Fig. 4 is a detail of the preliminary breaker showing the paths of the swing hammers;

Fig. 5 is an isometric view of a grid section; 0

Fig. 6 is a detail view showlng the manner of mounting the pegs;

Fig. 7 is a sectional view on the line 77 of Fig. 1; and

Fig. 8 is a jector blades.

The embodiment of our invention illustrated in the drawings comprises a substantially cylindrical two-part casing 10, the first part of which forms the pulverizing casing and the second a fan casing. -Mounted in suitable bearings 12 at each end thereof is a shaft 13, rotated rapidly by suitable means, which passes centrally through the casin 10 and is arranged to carry the pulverizlng rotor and the fan. A rotor, which in the present instance is shown as a disk 15 formed of two plates, is mounted within the casing on the shaft 13 to rotate about its center, and this disk is spaced laterally from the interior walls of the easing to form two grinding zones 16 and 17. The periphery of the disk is also spaced from the inner periphery of the substantially cylindrical casing 10 so as to form an annular passage 18 around the disk which connects the two grinding zones. This disk 15 may detail view of one of the rebe suitably fastened to the shaft 13, as by means of a sleeve 19 keyed to the shaft which has a flange 20 thereon arranged to be bolted 'to the disk and to removably support it.

The preliminary. crushing operation may be accomplished by means of hammers, which in the present instance comprise bars of iron 25 pivotally mounted on pins 26 which pass through the flange 20 and a collar 27 slidably mounted on the sleeve '19. An enlarged head 28 on the pin separates the hammers 25 from the flange 27 and the hammer is prevented from sliding ofi the bearing surface of the pin on which it swings by means of a collar 29 suitably fastened to' the shaft. The hammers, as shown dia rammatically in Fig. 4, are narrow bars 0 iron arranged in groups of three, the first of which is straight, the middle one bent to one side and the last bent to the other side, so that they will successively sweep scross substantially the entire width of the pulverizing zone adjacent the grid. The material to be crushed is introduced from a suitable feeding apparatus through the spout 30 communicating with an opening 31 in the side wall of the casing 10, which may be suitably located but is shown as being above the shaft 13 and extending to one side thereof.

As an effective aid in the vreliminary crushing operation, a grid 32 is arranged adjacent the periphery of the revolving swing hammers and serves to hold the material within the crushing zone for a certain length of time. As shown particularly in Fig. 5, this grid may be made in quarter sections to permit easy removal from the casing, and it is provided with a flange 35 which is adapted to be bolted to the adjacent portion of the side wall 36 of the casing. This grid 32 is provided with openings 40 which are of such size and shape as is best suited for the particular material being ground. These openings, which are not shown to scale, may be about in diameter and they serve to permit material crushed b the hammers to escape radially through tli e peripher of the grid. Since the grid is of considerable thickness and the openings are relatively small, it will be seen that the rapidly moving material, to escape through these openings, must be crushed fairly finely.

Arranged outside of the stationary grid are a number of sets of alternately revoluble and stationary pegs. The stationary pegs 42 are mounted in concentric rows on the casing wall 36 and the revolvin pegs 43 are mounted on the face of the dis terfit with and illustrated.

The pulverizing bodies in the second zone may comprise a set of pegs 50 mounted on the rotor which intermesh with a set of stationary pegs 51 mounted on the casing. Any suitable number of rows of these pegs may be provided in each zone, as desired, and the pegs may be variously arranged and of different lengths and sizes within the scope of our invention. As shown, the pegs 51 extend substantially the whole distance from the casing wall 52 to the side of the rotor 15, whereas the pegs 50 mounted on the rotor are preferably short and are spaced by a considerable distance from the inner casing wall. This provides a comparatively quiet zone adjacent the casing wall through which the very fine material coming from the first grinding zone may escape directly to the outlet, and aids in the rec1rculation of the material.

The pegs which may be suitably formed preferably comprise iron bodies 53 cast in a flangid ferrule 54 of drawn metal (see Fig.

e'peg is mounted loosely within a pass between pegs 42, as

so as to in v hole in its support and the flange 55 of the plates 56 and 57 which form the rotor disk and are suitabl bolted together. Separations of these p ates is permitted by the removable collar 27 slidably mounted on a constricted portion of sleeve 19 as shown in Fig. 1. The pegs 42 and '51 on the casing wall are likewise clamped between the removable linin plates 58 and 59 and the adjacent outer wal s. In order to permit removability and replacement of these-various parts, the fan casin 60 and the wall 52 between the fan and t e pulverizing chamber are removable laterally, as will' be understood. The peripheral portions of the parts making up the casing 10 are provided with liner sections 62 to receive the wear,-which are adapted to be slid into place and there bolted to the outer casing walls. 7

In order to prevent the escape of coarse particles from the second pulverizing zone, we provide a suitable rejector device which in the present instance comprises a series of blades 72 removably threaded into a collar 7 4 clamped to the sleeve 19 (Fig. 7). The rejector blade which may be of various shapes is illustrated in Fig. 8 as of a substantially U shape arranged with the open ortion of the U facing in the direction 0 the revolution of the blade. The blades, Wl'llCh revolve rapidly, are so shaped that they will scoop the coarse particles from the air as they attempt to pass through the outlet opening 75 and hurl them back into the grinding zone. In order to aid this action, a ring 76 is provided with a beveled face 77 located close to the outer ends of the revolving blades 72 and so arranged that as the material is thrown outwardly from the U- shaped blades it strikes against this beveled face and is hurled back towards the rotor disk 15 and thence carried centrifugally into the path of the revolving pegs.

While the material may be moved through the casing by suitable means, we preferably introduce a supply of air into the preliminary crushing zone'along with the material to be pulverized, and provide a suctionfan arranged to draw the material agalnst the centrifugal force set up by the revolving pegs and force it from the casing. For this purpose, an inlet 80 (see Fig. 1) is provided for the introduction of air from a suitable source of supply, and this air may be heated if desired to aid in drying the material being pulverized, as is often the case where a wet coal is being ground. The amount of air introduced through the opening 80 may be regulated by means of a suitable damper 86.

In the fan casing 60, a suitable type of suction fan 84 is mounted on the shaft 13 to rotate therewith. This fan serves both to The operation of this apparatus insofar as it can be'understood, is somewhat as follows. While we may rotate the rotor at any suitable speed, we prefer to give the pegs a velocity of at least 10,000 feet per minute if coal is to be pulverized. The fan which is so constructed as to create a powerful current of air through the machine, draws air into the machine and forces it from the discharge pipe 85 which leads from the fan chamber. The material to be pulverized,

such as coal which is to be burned in a furnace, is introduced into the chute 30 in a suitable size, preferably lumps of not over an inch in diameter, and this material falling against the swing hammers 25 is struck a severe blow and there broken by impact. The rapidly revolving swing hammers force the broken material through the grid openings radially in every direction and into the paths of the revolving pegs 43. Here the material is pulverized further by the successive impacts of the revolving pegs and by striking the stationary pegs. The pegs 43 serve also as fan blades tending to move the material rapidly away from the swing hammer zone and to force it through the annular passage around the rotor 15 into the final pulverizing zone. The fan effect of these pegs is however balanced to a desired degree by the revolving pegs in the second zone, depending upon the size, number and location of the pegs. In using a machine of this form, reliance may be had on a magnetic separator to insure removal of iron from the coal to be ground, although if such a hard foreign bod would not reak the swing hammers nor could a large piece escape through the relatively small openings in the grid. This insures a certain degree of protection for the relatively fragile pegs from severe shocks which might cause their breakage.

In the second zone, the material probably follows different paths depending upon its surface area and weight. It is thought that the very'fine particles escape along the outer wall of the casing between the stationary pegs 51 and out of contact with the revolving pegs 50. This material may pass directly to the outlet between the rejector blades 72, but the coarse particles are scooped out of the outgoing air current by these rejector blades and hurled back into the path of the revolving pegs 50, and it then recirculates. This rejected material, as well as the coarse particles coming around the disk periphery, are struck repeatedly by should enter the casing, it

the revolving pegs 50 and hurled against the stationary pegs 51 a large number of times with the result that ultimately the material is very finely pulverized. when it is 5 sufliciently small in size so that it may be borne like a cloud on the air current 1t W111 pass between the'rejector blades and so get into the fan casing. Here the fan blades serve to keep the cloud of dust and air thoroughly mixed and to force it outwardly through the discharge opening 85 into a suitable conveyor pipe to carry the material to the furnace burner or elsewhere as desired. p

The rate of' pulverization and the degree of fineness are easil regulatable by varying the amount and ve ocity of the air passing through the machine as well as the amount of material introduced to be pulverized. If the flow of air is decreased, then internal circulation will be set up to such an extent that the material is forced to recirculate Within the casin and be thoroughly pulverized, whereas i the air is drawn rapidly through the casing, the degree of pulverization is lessened thereby. Also the rejector blades may be replaced by other forms which will be'more or less efiicient in scooping out the coarse particles from the dust cloud. It 80 will be seen that the centrifugal force set up in the first zone by the hammers and pe s causes a radial flow of the material and ai s largely in distributing the crushed material throughout the annular passage around the disk, whereas the centrifugal force in the second zone serves to aid in pulverizing the material, since the material cannot escape from the second-zone until its surface area is so large that the frictional drag of the air will carry it along in spite of the centrifugal force of the revolving parts tending to retard its passage. I

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is 1. A pulverizing apparatus comprising a casing havin an inlet and an outlet centrally. locate on opposite sides of the casing; means dividing the casing into two zones connected by an annular passage; hammers revolubly mounted adjacent the inlet in one zone to crush the material preliininarily; revolving beaters surrounding and concentric with the hammers which receive the material from the hammers and ing a second pulverizing zone which. causes the material to be fed mwardl from said beaters towards the outlet; an beaters in the second zone arran ed to pulverize'the material passing theretirough.

3. A pulverizing apparatus comprisin a casing having an inlet and an outlet; aisk revolubly mounted therein and forming two zones connected around the. disk; revoluble. pegs on both sides of the disk; and revoluble hammers concentric with and surrounded by the pegs on the inlet side of the disk.

4. A pulverizing apparatus comprising a casing having a centrally located inlet and an outlet on opposite sides thereof a disk rotatably mounted with its axis adjacent the inlet which forms two pulverizin zones connected by a passage around the dis revoluble hammers ad'acent the inlet; a perforated grid aroun the hammers; revoluble pegs on the disk and stationary (pegs intertting therewith which surroun the grid; and sets of stationary and revolvin on the opposite side-of the disk Whi verize the material passing to the outlet.

5. A pulverizing apparatus comprising a casing having an inlet and an outlet centrally located on opposite sides of the casing, a disk revolubly mounted within the casing and forming two zones adjacent the inlet and the outlet which are connected by an annular passage around the disk, a series of crushing hammers revolubly mounted in the first zone ad'acent the inlet to crush the material preliminarily, beaters mounted on the disk in' the first zone and surrounding the hammers which receive the crushed material from the hammers and deliver it to the annular passage, and beaters mounted on the disk in the second zone to pulverize the material as it travels inwardly towards the outlet.

ROBERT SANFORD RILEY. OLLISON CRAIG.

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