US1711044A - Pulverizing apparatus - Google Patents

Description

A ril 30, 1929. F. H. DANIELS 1,711,044

PULVERI ZING APPARATUS Filed, April 12, 1927 INVENTOR RED H DANIELS Patented Apr. 30, 1929.

UNITED STATES PATENT OFFICE.

FRED H. IJANIE-L, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO RILEY STOKER CORPORATION, OF WORCESTER, MASSACHUSETTS, A CORPORATION 01 MASSACHU- sum-rs.

PULVERIZING APPARATUS.

Application filed April 12, 1927. Serial No. 183,182.

My invention relates to pulverizing apparatus and more particularly to a two-zone machine in which the material is broken preliminarily in one zone and then reduced to y 5 the desired degree of fineness in the second zone.

One form of two-zone pulverizing appara tus comprises a rotor disk separating the space within the casing into two pulverizing zones on opposite sides thereof. Material is introduced into one zone through the casing wall and an outlet is provided centrally of the second zone, the parts being so arranged that the material must pass peripherally 1a around the rotor disk from the first to the second zone, and then pass inwardly from the periphery towards a centrally located outlet. The material in the second zone is subjected repeatedly to the blows of heaters 320 which, because of centrifugal force, tend to hurl the material back into the peripheral portion ofthe casing, and only such material may escape as can be borne like a cloud on a current of air from the periphery towards the outlet.

The present invention-has to do with improving. a machine of this type, and the primary object of this invention is .to provide a simply constructed apparatus which is highly efficient in its operation and which will crush coarse material, eliminate hard .foreign bodies therefrom, and deliver it in a finely pulverized condition as desired.

In the machines of this type as heretofore constructed, it has been considered advisable to provide swinging hammers to effect the preliminary crushing operation and to surround these hammers with a perforated grid which cooperates with the hammers to.

49 crush the material. This grid has given trouble due to the liability of tramp iron being introduced with the material to be pulverized, and such tramp iron may either break the hammers or grid or cause excessive wear thereof, and if it escapes into the second pulverizing zone, the pegs which are ordinarily used for the beater members may become broken and the utility of the machine will be impaired. This grid may moreover 50 become plugged and obstructed, particularly if wet material is being treated, thereby re ducing the capacity and efficiency of the apparatus.

It is therefore a further object of the inprovide an apparatus of this type in which the preliminary crushing members are so located relative to the other parts that they material, and the parts are so arranged that the material may pass freely and without obstruction from the first to the second pul-' verizing zones. Since different types of material tobe pulverized require different treatments, it is advantageous in a machine of this type to regulate the speed of rotation of the various pulverizing members, and it is accordingly a further object of this invention to so con struct and arrange the parts of such an aparatus that the preliminary crushing memrs may be revolved at a different speed from that of the final pulverizing members, and each may be regulated as desired inde pendently of the other.

The operation of a pulverizing apparatus of the type under discussion is affected to a marked degree by the moisture content of the material being treated. An increase in the moisture content usually results in an increase in the power required to drive the machine, and a decrease in the maximum capacity at which it can be operated. Moreover there is a decided tendency for wet material to stick to the interior surfaces of the apparatus and thereby obstruct the flow of. material into the second zone. .Various attempts have been made in the pasttobvercome these difficulties by introducing hot air into the machine with the coarse material, but these prior arrangements have not proved to be a satisfactory solution of the problem, chiefly because the air was not admitted at the proper points.

It is accordingly a further object of my invention to provide air inlet ports to one of the pulverizing zones, and to so arrange the parts that hot or cold air may be introduced into the pulverizing zone in regulatable amounts and the streams of air may be so controlled and directed that they will effectively aid in preventing accumulation cooperate directly with the casing Wall in effecting such preliminary breaking of the partition separating the zones preferablycomprises a rotor disk arranged to carry certain of the pulverizlng elements. The

parts are so arranged that material must pass peripherally around the rotor and; then against the centrifugal force set up in the second pulverizing zone towards a centrally located outlet. The final .pulverization is .greferably effected by means of revolving eaters mounted on the rotor, and cooperating with these there may be stationary pegs arranged closely adjacent to their path. The preliminary crushing is preferably accomplished by means of revolving hammers and these may be so arranged that they cooperate with the surrounding peripheral casing wall to strike the material repeated blows and break it by impact. .Inorder to aid in transporting the material from the first to the second zone, air isintroduced at suitable localities and this is preferably admitted through a series of openings adjacent to the periphery of the first zone near the hammers, and it is desirable to so direct the jets of air that they sweep across the peripheral casing wall in such a manner as to aid transporting the crushed material through the annular passage surrounding the rotor disk and thence into the second pulvcrizing chamber.

Referring more particularly to the drawings illustrating one embodiment of this invention, and in which like reference numerals indicate like parts Fig. 1 is a vertical section, somewhat diagrammatically shown, of a pulverizer embodying this invention;

. 21is a vertical section on the line 2-2 of Fig. 1; h

Fig. 3 is a sectional detail on the line 3-3 of Fig. 1, illustrating the manner of mounting the rotor shaft;

Fig. 1 is a section partly broken 'away on' the line H of Fig. 1, showing the arrange ment of the pulverizing pegs in the second zone.

Fig. 5 is a perspective View showing one of the rejcctor blades in the second zone; and

Fig. 6 is a section partly broken away on the line 6-6 of Fig. 1, showing the construction of the manifold.

The embodiment illustrated comprises a casing 10, which may be substantially cylindrical in shape and within which the pulverization is'eifected. This casing communicates through a centrally located-outlet passage 11 with a fan casing'12, these parts being suitably constructed to permit assemblage and removal of the various elements of the machine. The two pulverizing zones may be formed by a partition within the casing and this partition in the present comprises a rotor disk 15 mounted centrally of the casing on a horizontal shaft 16. The disk is spaced from the-inner walls of the 'casing 10 sons to provide an annular passage 17 therearound, this passage being the only communlcation between the two zones" but as illustrated they are mounted ,on a second shaft 23.- The shaft 25 which is mounted in suitable bearings 24 and 25, projects through the casing wall 26 as illustrated, and may be driven by any suitable 'means, such as a pulley 27 secured thereto.

Fastened to the inner end of this shaft 23 is a collar 29 which is provided with flanges 30 spaced apart and arranged to hold the swinging hammers. 'Mounted between these flanges on a bolt 31 passing therethrough are the arms 33 projecting inwardly from the hammer head 22. .These arms 33 are mounted in pairs for the sake" of rigidity of construction and may be suitably fastened in any way to the hammers 22 such byc'asting. The inner ends of these arms 33 are perforated to fit the bolt 31. As shown in Fig. 2 a number of sets of these arms and hammer heads are provided around the periphery of the collar 29 and these are all arranged to swingfreely about their pivotal mountings. It will be observed that the inlet 20 is located between the hammer heads and thcirsupports, so that the material will fall into contact with the hammer heads and be struck a blow as it enters the casing. This material is'hurled against the inner casing wall, which mav comprise a liner plate 35, and is struck repeated blows by thehammers and thoroughly crushed by such impact. 1 i

Air is admitted to this preliminary crushing zone preferably through ports 36 spaced peripherally around the casing wall p 26. This construction provides streams or 'jets of air which flow close to the peripheral wall of the casing and prevent the sticking of til) . in hammers.

than is desirablevfor delivery to the second zone. As is well known, when a large lump of material is broken by impact, a certain amount of extremely fine material results,- and in my apparatus this fine material is i removed by the air jets as fast as it forms.- Any suitable'means may be provided for controlling the air flow through the openings 36, and in the embodiment illustrated I have shown these openings covered exters nally by a hollow annular manifold 37 which i provided with an inlet 38. The effective size of the inlet is controlled by means of an adjustable butterfly damper .39 pivotally' mounted therein. It is frequently desirable to heat the air flowing through the orifices 36, this being particularly important when the material undergoing treatment has a high moisture content, and for this purpose the inlet opening 38 may be connected by a duct to any suitable. air preheating arrange ment, many different types of which are well lmown to those skilled in the art. If the pulverizin apparatus is being used to pre pare coal for combustion in a furnace, it is common practice to heat air by circulating it through passages in the furnace walls.

One 'of the difficulties met in pulverizing coal is that tramp iron and other large and hard foreign bodies may be present in the coal, and if they get into the casing they must either be pulverized or they themselves will in turn break the pulverizing elements of the machine. One important feature of this invention therefore involves provision for eliminating such tramp iron and preventing injury to the pulverizing hammers. To this end, I provide a pocket or receptacle preferably at the lower portion of the casing in the first zone, into which the tramp iron may be deposited out of the path of the revolving hammers, and even if this pocket fills with the material to be pulverized, nevertheless the hard foreign bodies will become embedded therein and may be removed from time to time. This pocket 40 as shown in the drawing may have a slide door 41 in the bottom thereof through which the material may be removed.

The secondary and final pulveriza-tion of the material is effected in the second zone on the opposite side of the disk from the revolv- This pulverization is preferably accomplished by means of heaters and the preferred form of beater comprises, as illustrated, pegs mounted on the rotor and arranged to revolve at high speed. These pegs 42 may be of suitable construction and maybe fastened in place in any suitable manner as shown in the patent to Riley N 0. 1,576,472, the pegs being provided in that case with ferrules having resilient flanges which are clamped inplace between the clamping ring 4 and the main plate of the rotor 15, whereby the pegsare given a slight degree of freedom of motion and are resiliently mounted, so that shocks incident to the .pulverizing operation will be more fully and easily, absorbed. .Since the revolving pegs 42 may give toofinea degree ofpulverization depending upon the rate of passage of the air through the casing, it is preferred to provide a set of stationary pegs closely adjacent tothe revolving; egs, and the pegs are ordinarily so arrange as to cause eddy currents to be formed in the air within the second pulverizing zone or otherwise to aid in getting the material through the casing at an eflicient rat-eand yet cause it to be properly pulverized.

The pegs 42 are preferably short and they H are spaced by a considerable distance from the liner plate 46 on the side wall of the casing so that material which is already-in a very fine condition may pass freely by the ends'of the pegs without being subjected to further treatment and may thus get to the.

outlet opening without delay. The stationary pegs l5 which are mounted'preferably in the same way as the revolving pegs, with their flanges between the liner plate 46 and the casing wall 47, project preferably to a. position fairly close to the rotor disk 15.

hese pegs may be suitably spaced and of such size as is found most desirable for the type of material to be treated, and if necessary other rows of stationary and revolving pegs may be placed between those shown.

and the outlet orifice for subjecting material to still greater pulverizing fiction.

The rotor disk 15 is preferably mounted on a sleeve 50 and is suitably bolted'to a flange 51 projecting therefrom. The shaft 16 may be mounted in bearings 52 outside the fan casing and 53 located within the exitpassage 11. The latter. bearing is of suitable construction, and as illustrated may have supporting legs 54: cast on the lower portion of the exit pipe 11, or otherwise secured thereto, these legs being arranged to supportthe inner end of the shaft 16. An oil passage 55 may be provided to keep the bearing" lubricated, and by forcing oil into this pipe 55 one may insure keeping dust out of the bearing.

Since some coarse material might escape from the pulverizing pegs in the second zone and so. get to the centrally located outlet, I prefer to provide rejector blades which revolve across the outlet and are so constructed and arranged as to hurl back into cloud on a current of air.

the pulverizing zone such coarse particles as are not fine enoughto be carried like a These rejector blades as illustrated comprise U-shaped ,members 58 which cooperate with a beveled ring 59 surrounding the exit opening to the pipe 11, and'the U-shaped open side of the rejector blade faces in the direction of travel thereof so that it will scoop the coarse particles from the outgoing air and cause them to be hurled inwardly, glancing off from the ring 59 into the path of the revolving pegs 12. These rejector blades may be suitably casing at a desired rate, and deliver it to an outlet orifice 61 which coinn'iunicates with a desired locality, such as a furnace burner, if fuel is being pulverized, or a storage bin. The construction of the fan is immaterial to the presentcase and may be as desired. The shaft 16 is rotated in the present instance by a separate pulley 63 so that the speed of the fan 60 and the revolving pegs may be as highas desired, irrespective of the speed of the hammers carried by the shaft 23.

The operation of the device will be apparent from the above disclosure. The material to be pulverized, such ascoal in lump form, is introduced by means of a suitabze feeding mechanism, through the pipe 19 to the inlet opening.20. Here the material is struck repeated blows by the hammers 22, which revolve within the. first pulverizing zone, and broken preliminarily. Jets of hot or cold air which enter through the openings 36 sweep across the inner peripheral walls of the casing and tend to transport the finer material through the annular passage 17 to the second "pulverizing zone. Any tramp iron or other foreign body which enters with the material will be deposited in the receptacle 4:0 and become embedded in such coarse material as gathers there, it being removed whenever convenient. There are no obstructions between the revolving hami'ners 22 and the second zone and there is therefore no o1: portunity-for material to accumulate in this preliminary pulverizing, zone. As soon as it has been broken sufficiently fine, it'remains in the first zone" only so long as is necessary to enable the air current to pick it up and carry it into the second zone. The coarse material in the first zone is hurled against the inner liner 35 of the casing which may be of ..suitable construction and shape, and isbroken by repeated impactsas distinguished from attrition which is involved if a body of coarse material lies in the casing and the hammers must drag over it. The air openings 36 all the way around the casing insure kee ing the preliminary grinding zone clear 0 the fine material and provide uniform operation throughout, since the material may escape to the second zone anywhere around the periphery of the rotor 15.

\Vhenxthe material reaches the second zone, the finer" clouds'may' pass adjacent to the outer wall 46 past the stationary pegs 45' and between the rejector blades 58 through the out-let and fan *asing, but 'the coarse material will be struck by the rapidly revolving pegs {l2 and broken by impact and the repeated action of these pegs on the material will very quickly reducev the particles to a fine size. The stationary pegs 45 serveto set up eddy currents in the revolving air mass and prevent the material from being held too long in the outer peripheral portion of the second grinding zone. The number of these stationary pegs and tlieirsize determines to a certain extent the fineness of pulverization, and if it is desired to produce very fine material the stationary pegs may be removed in part or wholly and the beater pegs 42 given such size as is found most desirable. Any coarse particles which may by chance reach the outlet opening are scooped from the issuing stream by the rejectors 58 and thrown back into the second zone for further pulverization. The swing hammers 22 are preferably rotated'at a slower speed than the rapidly revolving pegs, as it is not necessary that they have a veryhigh velocity. It, however, is feasible in certain instances to have the hammers 22 revolve with the shaft 16 at the same speed as the pegs 42.

By means of this apparatus I provide a very simpleconstruction which will pulverize coarse material to a uniform degree of linenessand in which the degree may be regulated" depending upon the conditions within the pulverizer. By, regulating the rate of air flow through the casing as d c termined by the adjustment of damper 39, one may insure holding the dust cloud within the casing for a long or short time as desired, and thereby'subjecting it to a greater or less pulverization action. If the material has considerable moisture in it, the air entering through openings 36 maybe heated to a desired temperature in any suitable manner, and the hot air jets will prevent accumulation of masses of wet material within the casing wall, thus aiding in drying out the moisture and in conditioning the final pulverized material.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

' 1 A pulyerizing apparatus comprising a casing havlng aninlet for coarse material and an outlet for the pulverized material, means forming two pulverizing zones adjacent the inlet and outlet respectively which are peripherally connected, heaters in the outlet zone to pulverize the material finely and hammers mounted to revolve in the inlet zone, which cooperatewith the surround ing casing wall to crush the material preliminarily, the space outside of the hammer path communicating directly with the pe Iipheral passage connecting the tWofpulverizing zones whereby the material, crushed preliminarily may pass freely .to the second zone.

at one point to "provide a pocket within which tramp material-may gather, the space outside the hammer path communicating directly with the peripheral passage to the second zone, thereby' permitting crushed material to pass freely from the hammers to the second zone,-and heaters in the second zone to pulverize the material ted thereto.

3. A pulverizing apparatus comprising a casing having an inlet for coarse material and an outlet for pulverized material, a

rotor disk mounted within the casing andv arranged to form two peripherally connected pulverizing zones adjacent the inlet and outlet respectively, hammersm the first zone arranged to cooperate directlywith the peripheral casing wall to preliminarily crush coarse material, means forming a receptacle in which hard foreign bodies may be deposited by the hammers, and impact memhere in the second zone for finely pulverizing material delivered thereto.

4. A pulverizing apparatus comprising a casing having an inlet and an outlet, a rotor disk therein arranged to form two periphorally connected pulverizing zones, one on each side thcreofadjacent the inlet and outlet respectively, a set of hammers mounted at. one side of the disk adjacent to the inlet and cooperating with the peripheral casing wall to crush coarse material preliminarily,'

and boaters in the second zone arranged to pulverize the material as itpasses towards the outlet, said parts being so constructed and arranged, that material crushed in the,

first zone may pass freely from the hammers and, directly to the peripheral passage around the rotor and thence to the heaters.

5. A pulverizing apparatus comprising a casing having an inlet for coarse material and an outlet for pulverized material, a rotor disk mounted therein and arranged. to form two pulverizing zones connected by a periph- 2. Apulverizing apparatus comprising a "onthe rotor within t pulverizing material, a shaft for driving eral passage around the-rotor, a set of swing hammers arrahged to revolve in the first zone and cooperate with thefperipheral casmg wall to preliminarily crush coarse ma terial delivered through said inlet, and impact members mounted onthe rotor in the second zone and adapted to produce fine pulverizatiomsaid parts being so constructed and arranged as to provide a free passage for material from the hammers to the impact members.

6 A pulverizing apparatus comprising a casing having an inlet for coarse material and an outlet for pulverized material, a rotor disk mounted therein and arranged to form two'periph'erally connected pulverizing zones adjacent the inlet and outlet respectively, revoluble impact hammers in the first zone for preliminarily crushing coarse material, revoluble im act members mounted lie second zone for finely said 'hammers, and an independent shaft for driving said rotor disk. 7, A pulverizing apparatus comprising a casing having an inlet for coarse materialand an outlet for air and pulverized material, means forming two peripherally communicating pulverizing zones adjacent to the inlet and outlet respectively, means in the first zone for preliminarily crushing material, means in the second zone for finely pulverizing the material, and means forming air openings into the preliminary crushing zone which are located adjacent to thecasing periphery and feed air directly to the peripheral passage between the two-zones.

8. A pulverizing apparatus comprisinga casing having an inlet for coarse material and an outlet for air and pulverized material, a rotor disk mounted therein and arranged to'form two pulverizing zones adjacent to the inletand outlet respectively which are connected by an annular passage outside] the periphery. of the rotor, means in the firstzone for crushing mate rial preliminarily, impact members mounted on the rotor in the second zone for finely pulverizing material, and means for introducing streams of air across the interior peripheral wall of the first zone and directly towards the annular passage.

9. A pulverizingapparatus comprising a casing having aninlet for coarse material and an outlet forair and pulverized material,'a rotor disk mounted therein and ar ranged to form adjacent to said inlet and outlet res ectively two pulverizing zones connected by an annular passage outside the periphery of the rotor, revoluble swing hammers in the first zone arranged to cooperate directly with the peripheral casing wall to crush material preliminarily, impact members mounted on the rotor in the second zone for producing fine pulverization, and means for directing jets of air across the interior members in the second zone for producing peripheral Wall of the first zo'ne towards the fine pulverization, means for driving theannular passage. impact members in the second zone, and 10. A pulverizing apparatus comprising a means for driving the revoluble members in 5 casing having an inlet for coarse material the-first zone at a, different speed from the: 15

.and an outlet for pulverized material, means of the impact members in the-second zone. forming two pulverizing zones "adjacent the Signed at Worcester, Mass, this 8th day inlet and outlet respectively, revolu-ble imof April, 1927. pact members in the first zone, arranged .to

10 preliminarily orushcoarse material, impact FRED H. DANIELS.

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