Pulverizing mill

Abstract

Claims

Dec. 16, 1 4. 1,519,990. 9 v 9 C. H. BREERWOOD PULVERIZING MILL Filed March 7, 1924' Patented Dec. 16, 1924. f UNITED STATES 1,519,990 PATENT OFFICE. ' cmnnns It. imnnnwoon, OEALLENTOWN, PENNSYLVANIA, ASSIGNOR T FULLER- LEHIGH COMPANY, A CORPORATION or PENNSYLVANIA. PULTERIZING MILL. Application filed March 7, 1924. Serial No. 697,548. To all whom it may concern: Be it known that I, CHARLES H. BREER- wooo, a citizen of the United States, residing at Allentown, in the county of Lehigh, State of Pennsylvania, have invented certain new and useful Improvements in Pulverizing Mills; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. - This invention relates to pulverizing mills of the type set forth in the U. S. Letters Patent Nos. 849,779; 922,468; 1,039,721 and 1,358,837, issued to James W. Fuller, and known as the Fuller mill. lhis type of mill embodies in its construction a grinding or puiverlzlng ring in whichthe material is reduced to a finely divided state by means of appropriate grinding'devices, usually a plurality of balls. The grinding ring forms a raceway for the grinding balls and the latter are propelled about the raceway by pushers v mounted on a yoke, in turn connected to a power driven shaft. lhis general construction is illustrated, for example, in S. LettersPatent No. 1,358,837. In this particular type of mill, two grinding balls are employed with corresponding pushers to ac propel them, mounted on a pair of yoke arms. Two other yoke arms carry a pair of plows which are adjusted to operate in the grinding ring and which are arranged symmetrically with the rinding balls about the yoke. Each of these p ows is provided with a forwardly projecting, downwardly extending inclined surface which serves to elevate the material picked up by the plow to the region above the grinding ring where there are an lifting devices, such as a set of lifting blades, supplemented by a superimposed, fan, for carrying the pulverized material to the upper part of the mill, where it is floated against a screen for separation of the fine from the 4 coarser particles, or, as in another type of mill, carried into air currents for ultimate separation by an air separator. e he present invention relates particularly to an 1m rovement in the plow which op- 59 erates in t e grinding ring to elevate the pulverized material above the ring and into the zone of action of the lifting devices and fan. ere constructed as shown, for example, in U. S. Letters Patent, No. 1,358,837, the plows have been found in practice to be ina certain amountv of the material which banks or packs around the grinding ring out of range of action of the grinding balls for reduction to pulverized form, and also out of the path of the plows for elevation to the upper regions of the mill where the coarse, unground partieles would again find their way back to the grinding ring for pulverization. This condition introduces a power loss, in that additional power is required to drive the grinding balls and plows against the resistance of the packed material in the ring, and furthermore, reduces theoutput of the mill. An object of this invention, therefore, is to provide means associated with the grinding elements to prevent this accumulation of unground, partially ground, or fine packed material in the grinding ring of the mill. Such means is in the form of a plow positioned between a pair of grinding elements and constructed and arranged to elevate the pulverized material from the grinding ring to superjacent lifting devices, and at the same time, to pick up and deposit in the path of the succeeding grinding elements, the coarse or unground material left by the preceding grindingelement, which coarse particles are then subjected to pulverization and eventual elevation from the grindin ring to the lifting devices above. In this way, the gathering'of dead, packed material in the ring is prevented and the mill can be operated with the expenditure of less power 90 and with an appreciable increase in output. The means with which the plow is provided to efi'ect the distribution and disposition of material as described, consist of a pair of inclined surfaces, one of which is adapted to elevate the material above the grinding rlng and into the zone of action of the lifting devices, and the other of which has an extension which runs to the rear of the .plow providing a passageway for the material past the plow, from which it is deposited in the path of the next succeeding grinding device. Additional features of the vinvention with reference to constructional details will be brought out in connection 1 with the description of the accompanying drawing, in which- Fig. 1 is a sectional view in elevationof shown in Fig. 2 a Fuller mill of the type illustrated in U. S. Letters Patent No. 1,358,837, Fig. 2 1s an enlarged view in elevation of the yoke, showing the pushers and plows, liftingdevices and fan in superimposed relation, all mounted on the yoke, Fig. 3 is a plan view of the arrangement 3 Fig. 4' is an enlarged plan view of the improved plow constituting the subject matter of this application, Fig. 5 is a. side view of the plow shown in Fig. 4, and Fig. 6 is an'end view of the plow. The details of construction of the mill illustrated in Fig. 1, and its operation, will be found to be fully described in U. S. Letters Patent, No. 1,358,837, and, since, the present invention concerns merely the plow, but brief reference will be made to the mill construction. The mill as shown in Fig. 1 has an outer sectional casing 7 in which material to be pulverized is introduced through a feeder 8. Mounted in appropriate bear ings and extending through the mill is a shaft 9 which supports a yoke 10 and is driven by a pulley 11 connected as by means of a belt, not shown, to .a source of power. At approximately the midpoint of the mill, is a grinding ring 12 which forms a raceway for the grinding balls 13. The grinding balls are projected through the grinding ring by means of pushers 14 and, in the arrangement shown, there are two grinding-balls with a pusher for each, the pushers being mounted on opposite yoke arms 15. In symmetri-' I cal arrangement with the balls and pushers are two plows 16 mounted on opposite yoke arms 17. The number of grinding balls and plows and their arrangement is, of course, unessential so far as the present invention is concerned, and may be varied in accordance with the dictates of proper design for any given set of conditions, or requirements of the mill. For example, instead of having two grinding balls-with two pushers, four such balls might be employed with one or more plows situated between apair of balls, or the plows might themselves be used as pushers to propel the balls while functioning as plows, whic changes in the mill assembly will be understood without. further illustration. ' .Mounted on the yoke 10 above the grinding ring are lifting devices consisting of a plurality of lifting blades 18 and above these also mounted on the yoke 10 is a fan made up of a plurality of fan blades 19. which lifting devices and fan progressively raise the material from aposition above the grinding ring to the screen 20 through which it is floated, and the coarse particles separated from the fine. Thefine material after screening, enters the outer space 21 and gravitates to the lower receiving chamber 22' where it is discharged through the spout 23. The details of construction of the plow constituting the particular subject matter of this invention, are illustrated in Figs. 4, 5 and 6, to which reference will now be made. The low has a body portion 24 and a forwar 1y projecting or extending portion 25. The body portion 24 is hollowed out to reduce-weight as shown at 26, and is provided with a hole 27 for receiving a vertical pin 28, projecting upwardly from the yoke arms 17 and by which the plow is supported secured on the yoke arms. In lace of forming the extension 25 with a sing e inclined surface for picking up the pulverized material in the grinding ring and elevating it to the zone of action of the lifting devices, the present invention providesa plow, the extension 25 of which has a air 0 inclined surfaces 29 and 30 separated by a substantially vertical partition wall 31. The .inclined'surface 29, which is the inner surface, considering the plow in its operative osition in the grinding rin acts to pic up the pulverized material rom the ring an to elevate it into the zone'of action of the lifting devices 18, which in turn, still further elevate the material into the region of o eration of the fan. At the outer side 32 o the plow the wall is cut away so as to provide a shelf-like surface. 30 which'is a continuation of the surface 30 and extends to the rear end of the plow. The inclined surface 30 serves to pick up the material and lead it to the other surface 30, over which the material moves past the plow, until it is deposited in the path of the followmg grinding ball for pu'lverizatio'n. Instead of cutting away the entire wall so as to provide 7 the surface 30 the wall may beformed with a channel 33 of which the surface 30 forms the lower side wall, this channel extending i from the front to the rear and providing a passageway for the material past the plow- The inclined surface leads to this channel so as to introduce the material into it and the material then passes to the rear of the plow as before. Inthe drawings the plow is shown as having a channel 33 in its outer wall, but the construction of the other form in which the wall is entirely cut away will bereadily understood. After the material has been deposited in the path of the following grinding ball and has been acted upon by the. ball, it is picked up by the next low and elevated by means of the inner sur ace 29 to the lifting device and fan for ultimate proj ection through the screen 20 and separatlon, any coarse particles which are retained by the screen being deposited again in the grinding ring by gravity. As before noted, the pair of inclined surfaces 29 and 30, to gether with the extension 30, serve to keep the grinding ring clear of accumulatin material by keeping it 1n active c1rcu ation after deposit in the inding ring for pulverization, and this e ects a saving in power and increases the output of the m111. I claim: r 1. In a pulverizing mill, having a grinding ring, grinding devices operating in said 'ring and superjacent lifting devices, a plow of the character described positioned between a pair of grinding devices, and embodying means for elevating the pulverized material to the zone of action of the lifting devices and means'for picking up coarse or unground. material lying in the grinding rin and depositin it in the path of the succee g grinding civics. 2. In a pulverizing mill having a grinding ring grinding devices operating in said ring and superjacent lifting devices, a plow of the character described positioned between the grinding devices, said plow having inclined surfaces, one of which is 1 ing ring, grinding devices operating in said adapted to elevate pulverized material from the ring directly to the zone of action of the lifting devices, and another of'which is adapted to pick up coarse or packed ma 'terial left by the preceding grinding device for deposition in the path of the next succeeding grinding device, substantially as described. 3. In a pulverizing mill having a grinddevices, a plow ring and superjacent lifting d b positions eof the character describe tween the grinding devices, said plow-hav- I mill having a grinding ring, grinding de-- mg a pair of inclined surfaces, one for ele-- vating pulverized material from the ring, directly to the lifting devices, and the other for conducting the residual material ast the plow and depositing it in the path 0 the .succeeding grinding devices for ulveriza tion and eventual elevation to e lifting devices, substantially as described. 4. The combination with. pulverizing vices operating in and lifting devices situated above said ring, of a plow having a pair of inclined surfaces and being rovided with a channel,-one of said su aces being adapted to lift pulverized material from the ring into the region of operation of said lifting devices, and the other of said surfaces communicating with said channel, substantially as, and for the purposes, set forth. 5. The combination with a pulverizing mill of a plow, having a pair 0 forwardly and downwardly extending inclined surfaces and being provided with a channel, one of said surfaces leading into said channel, substantially as descrlbed. 6. The combination with a pulverizin mill of a plow of the character describe having a pair of forwardly and downwardly extending inclined surfaces, separated by a substantially vertical partition, said plow bein provided with a passageway for materia along its side, which terminates in one mill, having a grinding ring, grinding de-, vices operating in said ring and superjacent lifting devices of a plow of the character described, having a pair of forwardly projecting and downwardly inclined surfaces separated by a partition wall, one of said surfaces being inwardly inclined and adapted to elevate material into the zone of action ofthe lifting devices, the outer surface of the plow being provided with a channel and the other of said inclined surfaces curving outwardly into the channel, substantially as described. 9. The combination with a pulverizin mill of a, plow, having a forwardly an downwardly extending inclined surface at its front end and having its outer side wall cut away so as to provide a shelf-like surface over which the material is moved past the low as the latter moves, this shelf-like su are communicating with the surface first-named. 10. A plow for use in a pulverizin mill, having a'grinding ring, grinding evices operating therein, and lifting devices situated above said ring, which comprises a body portion, a forwardly and downwardl inclined surface located near its front on and a. shelf-like surface formed-on the out-' er wall of the bod portion and extending to the rear end 0 the plow, this surface communicating at its forward end with the inclined surface. of said inclined surfaces, substantially as 11. A plow for use in a pulverizing mill, In testimony whereof I afiix my-signature. CHARLES H. BREERWOOD.

Description

Topics

Download Full PDF Version (Non-Commercial Use)

Patent Citations (0)

    Publication numberPublication dateAssigneeTitle

NO-Patent Citations (0)

    Title

Cited By (2)

    Publication numberPublication dateAssigneeTitle
    US-2009121060-A1May 14, 2009Alstom Technology LtdFine grinding roller mill
    US-7963471-B2June 21, 2011Alstom Technology LtdFine grinding roller mill