US1737854A - Centrifugal pulverizer - Google Patents

Description

Dec. 3, 1929. o. A. KREUTZ}BERG 1,737,854

CEN'IRIFUGAL PULVERIZER Filed June 7, 1923 Pafentek] Dec. 3, 1929 PATENT OFFICE OTTO A. KREU'TZBERG, OB LAKE BI'U'IEF, ILLIN'OIS CEN'IBIFU'GAL PULVERIZER Applieation am Inne r,

The purpose of this invention is to provide a type of' pulverize'r mdapted tobe built in comparatively small sizes so as to secure to the users 01 smaller quantities of its product E the same economies which are now available (0 large manufacturers ano1 producers who can afi"ord to employ the larger types of pulverizing machines. lt consists in various fea tures and elements of construction and their m combination as herein shown anl escribed;

and asindicated by che claim.

In the clmwings: Figure 1 is 21 sie e1evation panrfly in seotion showing a pulverizing machine embodying this invenon.

Figute 2 is an ex11 e1evation of the machine with its connoction 't0 the air separator broken away and with a carrier pla'te remove to reveal certain features of construction.

Figure 3 is a large detailed section showing a special form 015 packing ring.

Briefly, this machine c01'1sists of an annular grinding member whose inner 'circumference forms the grinding surface co-operating with a. series of' rollers which are driven around this track.at such a vel0city that their pressure against itd11e to centrifgal force is several times greater than their own weight. The annular member itself is also revolved about its axis at a sufficient speed to retain the materialon the grinding surface untilit is so finely pulverized as to be readily picked up by the air blast used in conjunction with an air separater preferably of a type already shown and described in my pending applicmtion Seria1 #47 2,500. By virtue 01T the revolution of the rollers their effeotiveness as crushing niembers is multiplied several times and the necessary weight of the machine is thus reduced g reatly as compared with a mechanism in which on1y the weightof the rollers is utilized. And by virtue of the rotation of the annular grinder and certain related &eatures hereinafter described, used in conjunction with the air separ'ator it is p0s- 1923. Serial 11'0. 648,849.

sible to seoure much finer pulverizing than whom gravity alone is relied upon for feed- 1ng the material.

In the drawings the annular grinding track 1s showr x at 1, s'ecured in a cast rotor, 2, whose hulo, 3, 1s fixed to the end of 2 hollow shaft, 4, gournaled in bearings 5, in a, supporting frame 6, within the hollow shaft, 4, there is journalgd a similar shaft 7, carrying a drive pulley, 8, at one end shown conncted by a belt, 9, to any convenient souroe of power, not shown. At its opposite end thereis secured to said shaft, 7 a spider, 12, an a removable sp1der or plate, 13, which are connected by bo1ts, 15, so as to constitute a cairrier for &sho gmnd1ng rollers, 16, which are shown as four 1n number.

Adjacent the pulley, 8, the shaft, 7, is fitted'with a drive pinion, 17, meshing with s gear, 18, which is fast 011 the hub of a pin- 1on, 19. Said pinion, 19, meshgs with a gear, 20, fixed to the hollow shaft,"' i, for driving tl 1e rotor, 2, at a slower speed than the eat- 11e1 which supports the rollers, 16, within 1t and in the same direction of rotation as sa1d carrier.

For convenience of the ge'ar, 20, may also be arranged to mesh with a gear, 21, on a shaft, 22, carrying a sprocket wheel, 23, counected. by a chain, 24, with the sprocket, 25, of a feeding device, 26, of familiar construm tion in Which a, swinging gate member, 27, is oscillated by a pitman, 28, driven from a, crank, 29, on the s'haft of sprocket, 25. F01 throwing the feeder out of service when desired, a clutch, 30, may be arranged for disengaging the gear, 25, from its Shaft at Will.

Preferably, although not necessarily, the grinding track or surface of the ring, 1, is ooncave in cross section While the peripheral surfaces of the rollers, 16, are corresponding1y convex. Cennecting with the concave surface of the track, 1, the rotor, 2, provides an annular Wall, 31, sloping toward the axis and an ap'plied guardmember, 32, at the olpposite side of the rollers forms a similarly s oping retaining wall, 33, so that an annular trough is thus provided in which the materia] to be pulverized is retained by centrifngal force as rotor, 2, revolves.

The material is fed from the mechanical feeder, 26, into a chute, 34, Which discharges preferablyjust above the edge 0f a central opening in the plate, 32, to which the intake conduit, 35, of the air separator is connected. The lower Wall of said conduit is inclined at, 36, so that materia l falling from the mouth of the chute, 34, tends to discharge against this inclined surface und to flow or roll into the side 0f the annular trough formed by the Wall, 33, thence by centrifugal force it tends to shift to the center of the trough which is formed by the grinding ring, 1, entering between the point-s of contact of the rollers, 16, and thus cominq directly in their path as they revolve upon this track.

Bach of the rollers, 16, is formed with a neutral bore, 37, which provides considerable clearance around the retaining holt, 15, and each of said bolts, 15, is specially hardened t0 resist wear und is' further protected by a. 1oose sleeve, 38, which may be of iron pipe or the like and may be readily replaced when it is worn out by friction between the liore, 37, cf the roller a'nd the holt, 15. In their normal running position, the rollers, 16, beil1g held against the grindinsz ring, 1, by centrifugal force, their bores, 37, d0 not engage either the outer o1 the inner sides of the sleeves, 38, but contact with them only intesponse to the driving efl'ort of the carrier which serves to revolve the rollers, 16, within the 'ring, 1. While in a pulverizing mill, it is hardly practicable to lubricate the holt-s, 15, andt-heir sleeves, 38, said sleeves will reduce the friction on the rollers, 16 to the minimum. When either the sleeves, 38, 01' the rollers, 16, become unduly worn, their replacement is rendere very simple by the removal 0f the plate, 32, and the spider member. 13, which gives imrnediate access to ehe rollers on the belts or studs, 15. Similarly. the grinding ring, 1, may be taken out 0f the rotor, 2, if necessary and refinished orreplaced.

F01 withdrawing the pulverized material from the grinding ring a pulley, 8, on the shaft, 7, is connected by a be1t, 10, with a pulley, 11, on the shaft 0f a suction blower, 40, which is coupled through an exhaust pipe,

y 41, with the air separater, 42, whose interior construction may be substantially simil'ar to that shown in my pe1iding application, Serial 472,500. The air is drawn by the blower, 40, through the air separator and through the grinding mechanism, entering the latter from a return pipe, 43, leading from the so-called cyclone of the system to which the blowe'r, 40, discharges through its outlet, 44. The air entering at, 43, asses through openifigs, 45, in the central portion of the' rotor, 2, and the carrier, consisting of the parts 12 and 13, being of spider formation pen'nits said a.ir t0 be drawn between the grinding ro1lers 16 am]. thus in proximity to the material which is being treated on the grinding ring, 1. That portion 0f this material which is sufliciently fine is thus picked up by the air current and carried up through the conduit, 35, into the air separator, 42, where the coarser particles are dropped out and returned through the pipe, 46, While the finer material is -retained in the air dur rent und discharged through the blower 40.

' As shown, the return pipe, 46, from the air separater, 42, dischargias close to the inclined lower wall, 36, of the air conduit so that the material falling on this inclined surface, 36, will feed down it by gravity under and ast the upwardly moving air current induce by the suction of the blower, 40. This material to be reground meets the material falling from the ahnte, 34, for initial treatment, the passage of the latter material .through the upwardly moving air vcurrent serving 1:0 remove therefrom the particles which are a1- ready of required fineness. The grinding mechanism is enclosed in a dust-tight casing,

-47 to which the outlet conduit, 35, is closely 'erate without clouding the air in its vicinity wi th dust. T0 secure efliciency in the air separation system, I prefer to form the edge of the annular guard member 32, with a groove, 48, interlocking with a groove'd fing, 49, which defines the edge of the outlet openingr in the casing 47, so that a substantially airtight connection is thus afloided between the grinding member and the casing at this outlet.

F01 excluding dust from the bearings, the hub, 3, of the roter, 2, i s made with an annular re0ess, 2", Which pockets a hardened ring 50, positioned 150 bear against the inner end of the hub, 51, of the carrier and. provided with pressure springs, 52, t0 maintain such engagement. As" shown in Figre 3, the oil duct s 53, leading from the annular channel, 54, at the end of the bushing, 55, furnish lubricant from the shaft bearing to the recess, 49, which in combination with t he pressure cf the ring, 50, will prevent any d1ist from machingz the bearing itself. A similar ring, 56, is lodged in the end 0f the bearing, 5, to cooperate with the outer shoulder 01 face of the hubs, 3.

I claim:

In a 'pulverizer having rotary crushing elements, a fixed casing therefor provided with an air inlet opening and a centrally disposed outlet gpening at one side 0f the plane 01 revolut1on of sa1d elements, means f01 creat ing suction at said outlet opening to carry oif the pulverized material, and an air separater connected by an upwardly directed passage fr0m said outlet, including an inclined Wall extending upwardly from the lower side of the outlet to serve as a ahnte for feeding back coarse material dropping out o:f the air current or returned by the separaton said separater having a return conduit extending downwardly through said Passage for discharging tovvard the inclined wall.

In testimony whereof, I have hereunto set my band at Chicago, Illinois, this 26th day of February, 1923.

OTTO A. KREUTZBERG.

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