US2654541A - Dispersion mill - Google Patents

Description

F A. SULLIVAN DISPERSION MILL Oct. 6, 1953 Filed Jude 25,, 1949 Q@ b QN 9% Patented Oct. 6, 1953 Frank A. Sullivan; Salem,

Tri-Homo Corporation, ration of Massachusetts Application June 2-5, 1949, Serial No. 101,369

4 Claims.

1 This invention relates to improvementsin dispersion mills of the general type suitable for performing grinding, milling and homogenizing operations in the processing of various" materials and substances in liquid and paste forms, such as gums, fatty acids, More particularly it provides im-' paints, pigments, dye stuffs, and the' like. provements in such mills whereby materials and substances to be acted up'on are more-effectively induced into the mill and more effectively and efiiciently treated before discharge, as compared with anyprior comparablemill of which-I am aware. v V

Dispersion mills of 'the'general' type to which the invention relates ordinarily accomplish their grinding, milling. and homogenizing functions-as the' result of the'action of closely related surfaces of two members at least one of which has rotary motion relative to the other, the material or sub stance being treated passing. between the closely related relatively moving surfaces and being ground, mixed, and its constituents generally comminuted, priorto discharge from the mill. Various proposals have been advanced hereto fore directed toward accomplishing a thorough and satisfactory reductionof all solid particles that may be present in any particulanmatrial or substance undergoing. treatmentin a mill. It has been proposed, for example, to provide two and even more stages ,of grinding and pulverizing action Within the mill, withthe'material r sub-e stance passing successively through the different pulverizing action before stages of grinding and However, notwithstand= delivery from the mill.

ing the prior efforts 'to satisfactorily reduce and pulverize all solid particlesv in'materials or sub'=' stances being. treated, none of the prior comparable mills, so far as I am aware, accomplishes complete and satisfactory elimination'of objec=' tionable solid particles. One characteristic of such mills which aggravates the problem of failure'to eliminate objectionable'solid particles may betraced to the desirability of having the working surfaces of at least one of the-grinding membersof the mill of a nature to itself loosen par ticles of its surface material in the course of op-"- eration of the mill, and these dislodged solid particles get into the stream of the material or substance undergoing treatment. The number of such dislodged solid particles may be considerable in any particular batch of treatedmaterial, and they ordinarily are hard enough to resist pulverization in the mill. Rather, their nature is such thatthey cause other particles to be dislodged from a grinding surface. This is especial- Mass., assignorf to The Salem, Mass., a corpo 1y true when abrasive stones are employed-as the-grinding members, abrasive particles breaking away from the surfaces and being present in objectionable sizes and materials and substances delivered from the prior mills which have employed abrasive stones.

Also, feed of materials and substances into the prior comparable mills has been slow and sluggish, especially when the materials have been of thickpaste consistency, requiring screw conveyors and the like in the inlet passage-to move the material into the action of the grinding members of the mill. 7 I I It is among the objects of'mypresent' inve'n tion' to provide a dispersion mill wherein the main grinding; milling and homogenizing action is accomplished between relatively closely related rotor and stator surfaces between which the ma terial or substance being treated is caused to move outwardly by centrifugal force, and'wliere in means is provided at a working face of therotor for creating suction tending to draw the inaterial or substance-into the space betweenthe closely related'rotor and stator surfaces.

Another object is to provide a dispersion mill wherein the main grinding," milling and homogenizing action is acomplished by abrasive rotor and stator surfaces tor :and stator surfaces effect a final pulverizing'" action on any solid particles which may have escaped adequate reduction in the main action of the mill.

v A further object is to providea dispersion mill having coacting abrasive surfaces between which the main grinding, mil-ling and homogenizing action occurs, and wherein a final pulverizing action occurs between abrasive-resisting surfaces, subsequent .to the main action, with means for simultaneously adjustingthespacing of the abra sive surfaces-and of the abrasive-resisting surfaces. I

It is moreover, my purpose and object generally to improve'thej structure, efficiency and effectiveness of dispersion mills and the like; and more especially such mills Whereinit is desirable to pulverize abrasive particles which maybecome dislodged from an abrasive surface and become mingled with the material being processed.

In the accompanying drawing:

Fig. l is a side elevation of'a dispersion mill thereof being shown in medial cross=section;

number in the treated Fig. 2 is a cross-sectional view on line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary cross-sectional view on a larger scale, showing the coacting pulverizing surfaces which form the annular discharge passage around the periphery of the rotor.

Referring to the drawing, any suitable base lfl may support the spaced, vertically disposed risers I2, [4 which, in turn, support the tubular sleeve l6, one end of the sleeve seating rotatably in an annular recess 18 in riser l4, and the other end portion of the sleeve being exteriorly threaded at 20 and screwed into the interiorly threaded shank 22 of a housing indicated generally at 24, the' shank 22 extending into an opening 26 in riser l2 and being secured against movement therein by the set screw 28.

A shaft 30 extends through sleeve l6, being journalled at 32 in riser l4, and having ballbearing support at 34 in the opposite end portion of sleeve 5, the shaft extending out of this endf of the sleeve into the interior of housing member 24' where it is equipped with the wheel-carryingplate 36. Shaft 30 may be driven from any suitable source of power as through the medium of a belt (not shown) trained over a pulley 38 which may be fixed on shaft 30 adjacent to the riser I4.

The housing 24 preferably will be at least in part of double wall construction to provide space between walls for circulation of water for cooling purposes, one wall 42 of the housing beingremovable and having an opening 34 therethrough axially aligned with shaft 30. The delivery end of a conduit 46 is removably secured in opening 44, the conduit leading from a hopper 48 or the like from which material to be processed fiows through the conduit into the interior of housing 24.

A feature of the invention resides in means interiorly of housing 24 whereby a more effective y grinding and homogenizing action on the material takes place, with a final and ultimate treatment of the material which pulverizes any solid particles which may have escaped the main treatment without being pulverized.

According to the invention, a substantial annular ring 50 of abrasive material is secured, as by bolts or screws 52, to the interior of wall 42 of the housing, the ring being concentrically arranged relative to the axis of shaft 30, and constituting the stator grinding member. An abrasive wheel 54, constituting the rotor grinding.

member, is secured to the wheel-supporting plate 36 as by screws and a larger central screw 58, the wheel 54 being concentric with shaft 30.

Also mounted on the housing wall 42 is the,

inwardly projecting annular member which encircles the abrasive ring 50 and the abrasive wheel 54 at their peripheral regions, being spaced a little outward from their peripheries opposite their adjacent faces and extending with slight" inclination of its interior surface opposite the main peripheral surface of wheel 54, so that material delivering from between the adjacent opposed surfaces of the ring and wheel is caught and re-directed by the member 60 whereby the material is directed and guided generally toward the periphery of the wheel-carrying plate 36,, escaping between the member 60 and the plate 36 into the outlet passage 62 at the bottom of housing 24 and discharging thence into the chute 64.

The face of wheel 54 which is toward'ring 50 preferably is provided with a series of equally spaced radial grooves 66. These have relatively opposite a face short radial extent with part of their extent of ring 50 and part opposite the central space within the ring, whereby material delivered into the central ring space and entering between the opposed ring and wheel faces is caught in substantial amounts in the radial grooves 66 and forcibly carried around on the wheel, with centrifugal force urging it forcibly outward toward the periphery of the wheel. In this action, the walls of the grooves 66 create a substantial suction as the wheel rotates, and the suction effect tends to draw material into grinding co-action between the ring and wheel, a result which is of particular importance when the material being processed is viscous and sluggish.

The spacing of the coacting surfaces of ring 412 and wheel 54 may be readily adjusted by manual rotation of sleeve l6 which, because of its threaded engagement at 20 with shank 22 of housing 24, will cause the housing and abrasive ring 50 to move in direction to bring the ring and wheel closer together or further apart, depending upon the direction of rotation of sleeve [6, assuming that set screw 28 first will be loosened to release shank 22. As herein represented, the rotation of sleeve I6 may be effected by manual rotation of a shaft 68 journalled in a support 10 rising from base [0 between the risers shaft 68 having a worm 12 fixed thereon and in mesh with a worm gear 1-4 fixed on sleeve IS.

The use of abrasive surfaces for effecting grinding and homogenizing treatments of various materials and substances has definite advantages as regards efficiency and effectiveness of any'particular processing procedure. 'I-leretofore, however, there have been disadvantages accompanying the advantages. Perhaps the more serious disadvantage has been the fact that the abrasive surfaces inherently are of a nature to wear away in service with resulting deposition of abrasive particles in the material being processed, and these abrasive particles are so hard that they ordinarily pass through the processing apparatus without appreciable reduction in their sizes. Actually their inherent hardness tends to dislodge other abrasive particles from the abrasive surfaces, and their presence in the delivered material or substance is highly objectionable in many cases. For example, the presence of even a relatively few of these solid and hard abrasive particles is readily noticeable in paint as soon as the paint is brushed on a surface.

My present invention provides means for positively pulverizing such abrasive particles, and any other solid particles escaping the main grinding and homogenizing action of my apparatus. As best seen in Fig. 3, the periphery of the wheelcarrying plate 36 is shaped to provide the stepped inclined surfaces 16, 18 which may be treated or coated to provide extremely hard abrasive-resistant surfaces. Stellite is a preferred material for these surfaces T6, 18, it being highly resistant to abrasion. Similar surfaces 80, 82, of.

passage of any solid particles, and this restricted l2, lkthe.

.routlet may :besadjusted: as a'mesultxofvthe: earlier ..gdescribedzadjustment of; the spacing: of the -coactsring surfaces of3ringt42:andzwheehfid.irHencepassuming rotation of wheelecartying pl-ate'aEfi aznd man adequate supply; of material; tcrbe processed and80j 82. The material is propelled withiconsider'able pressure from behind,.and thegannular ioutlet will be adjusted to permit escape'of. material which has been adequately reduced-sand I freed of solid particles. Any solid particlesicoming into the annular discharge,passage-are,pulverized ,by being driven} between t thes-hard ,Stellite, surfaces 18," '82. "The! considerable pres- ...sure,i,built,.up from behind, positively-.forces;the

solid particles into the pulverizing action of the surfaces l8,"82, thereby avoiding clogging of the outlet as well as assuringrthat no appreciable; or

objectionable particles of'- solidzmatter can be mingled with the processed material delivering to the outlet passage 62 and chute 64, assuming a proper adjustment of the annular outlet passage at the periphery of plate 36.

It will be apparent from the foregoing description, in connection with the drawing, that I have greatly improved the efficiency and effectiveness of dispersion mills by providing rotor and stator abrasive surfaces between which the main processing of material is eifected, with means at the rotor surface for strongly inducing flow of the material into the grinding and homogenizing action of the apparatus. Also, I have provided an extremely effective pulverizing action prior to discharge of the processed material which greatly improves the delivered product and which pulverizes any solid particles which may have escaped adequate reduction by the abrasive elements, especially such particles of abrasive material as may have been dislodged from a surface of an abrasive element.

I claim as my invention:

1. In a dispersion mill, a relatively fixed housing, a relatively thick ring of abrasive materialfixed on a wall of the housing interiorly of the housing, a rotor plate within the housing, a relatively thick disk of abrasive material mounted on said rotor and disposed opposite and in slightly spaced relation to said fixed ring of abrasive material whereby adjacent generally parallel surfaces of said ring and disk define a passage for centrifugal movement of material between them, means for delivering material through a wall of the housing into the central opening in said ring whence it enters between said generally parallel surfaces of the ring and disk, an annular member fixed on a wall of the housing and relatively closely surrounding the peripheries of said ring and disk, said rotor plate having an annular peripheral portion outward of the periphery of said abrasive disk, and said fixed annular member coacting with the periphery of said abrasive disk to provide an annular passage leading to said peripheral portion of the rotor plate and having an annular edge portion coacting with said peripheral portion of the rotor plate to provide a restricted annular outlet around said peripheral portion of the rotor plate, and abrasive-resistant material on the coacting surfaces of said restricted outlet whereby they are more resistv:ant;to erosionwtharithevcoactingcsurfaces of said x: abrasiveiring and. disk.

2., A. dispersion .millwcomprising aahcusing; a stator member. secured. interiorlyigon asvallz ofsthe housing,- said stator memberhavingla surfacecdis- 1 posed generally in a.- verticallplane, a; rotorimember rotatably mounted in the housingiandwhaving a surface disposed-in awentical plane in zspaced relation to the said surface of the statorumember,

v parallel relation :andiadapted :torcoacti inprocesssaid surfaces being ;in :relativelyirclose :generally ingmaterial passing between:themgaandazoneziof whence it .enters1the;space.betweenzsaidmoacting surfaces and passesazoutwardlyt-aby s centrifugal forcepmeansu adjustabl tl-mounted' iwithinrizthe 1 housing and extending all'around :theiperlphery of the rotor member inzspacedzrelation thereto 7 'and having extent :alsojropposite: said space'rbetween the c-oactingnsurfaces; wherebyicmaterial passing outwardly from between the coacting surfaces engages said adjustably mounted means and is re-directed and guided thereby in direction generally horizontally on a course leading between a wall of said adjustably mounted means and the periphery of said rotor member, said wall of the adjustably mounted means and said periphery of the rotor member having converging extent to a restricted annular discharge region at the periphery of the rotor member, abrasive resisting material surfacing said converging portions of the wall of the adjustably mounted means and the periphery of the rotor member, and means for simultaneously reducing the space between said vertical and parallel processing surfaces of the stator and rotor members and between said converging walls of said adjustably mounted means and the periphery of the rotor member.

3. A dispersion mill comprising a housing, an annular stator member fixed interiorly on a wall of the housing and having a generally vertically disposed abrasive surface, an annular rotor member rotatably mounted within the housing and having an abrasive surface in opposed relation to and in slightly spaced general parallelism with the abrasive surface of the stator member, said stator member having an axial passage therethrough for entrance of material to said space, an annular member extending around the stator and rotor members and providing, with the periphery of the rotor member, a flow passage for material along the periphery of the rotor member in generally horizontal direction, said flow passage having walls converging to a restricted annular outlet, and the surfaces of the annular restricted outlet being of material highly resistant to abrasion, whereby solid particles entering the annular restricted outlet become pulverized by the grinding coaction of said abrasiveresistant surfaces, and means for controlled adjustment of said stator member toward said rotor member to simultaneously reduce the space between said vertically disposed generally parallel abrasive surfaces of the rotor and stator members and between said abrasive-resistant surfaces of said annular restricted outlet.

4. A dispersion mill comprising stator and rotor members having opposed abrasive surfaces spaced slightly apart in general parallelism to provide a flow passage for material entering between them, said members being relatively adjustable to vary the width of said flow passage whereby the coacting abrasive surfaces may be set to effectively process the material entering between them and moving outwardly between them by centrifugal force, an annular member on said stator member in relatively close surrounding relation to the peripheries of the stator and rotor members, against which annular member the outwardly moving material is thrown and between which and the peripheral portion of the rotor member the material is guided, said annular member having an abrasive-resistant surface converging toward a peripheral portion of the rotor member, and the rotor member having an abrasive-resistant surface opposite said converging surface of said annular member, said abrasive-resistant surfaces of the annular member and the rotor member coacting to provide a materiabpulverizing restricted annular discharge opening at the periphery of the rotor member whereby any solid particles in the material thrown against said annular member become pulverized in passing through said restricted annular discharge opening, and means for moving the stator member 8 axially toward the rotor member to simultaneously reduce the width of said flow passage between said opposed abrasive surfaces of the rotor and stator members and of said annular discharge opening at the periphery of the rotor member.

FRANK A. SULLIVAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 274,116 Gathmann May 20, 1883 657,656 Heine Sept. 11, 1900 1,066,220 Quickel July 1, 1913 1,587,063 Austin June 1, 1926 1,690,667 China Nov. 6, 1928 1,987,724 Tolman Jan. 15, 1935 2,297,637 Sullivan Sept. 29, 1942 2,362,035 Sullivan Nov. 7, 1944 2,445,617 Hofmann July 20, 1948 FOREIGN PATENTS Number Country Date Great Britain Feb. 9, 1928

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