US3044622A - Classifier system - Google Patents

Description

July 17, 1962 CROFT 3,044,622

CLASSIFIER SYSTEM Filed June 17, 1959 4 Sheets-Sheet 1 INVENTOR. George M. Croft yyy Ew vzg July 17, 1.962 G. M. CROFT 3,044,622

CLASSIFIER SYSTEM Filed June 17, 1959 4 Sheets-Sheet 2 INVENTOR.

George M. Croft BY v 2.??

July 17, 1962 G. M. CROFT 3,044,622

CLASSIFIER SYSTEM Filed June 17, 1959 4 Sheets-Sheet 5 Fig.3.

m I nml INVENTOR George M. Croft BY M ATTORNEY)" July 17, 1962 G. M. CROFT CLASSIFIER SYSTEM 4 Sheets-Sheet 4 Filed June 17, 1959 INVENTOR George M. Croft A ATTORNEY! Patented July 17, 19 82 3,044,622 CLASSIFIER SYSTEM George M. Croft, Fox Chapel Borough, Pa, assignor to Maine, Ina, Sharpsbnrg, Pa, a corporation of Pennsylvania Fi led Suzie 17, 1959, Ser. No. 821,059 Claims. (El. 2&9-144) This invention relates to a classifier system in which solid state particles to be sorted are accompanied by a gas, generally air, to assist in the classifying action. More particularly, this invention pertains to apparatus and method for such a classifier system utilizing cooperating rotating and fixed means for separation and rejection of oversized particles, on the one hand, and segregation and removal of particles of predetermined fineness, on the other hand.

In constructions made in accordance with this invention, it is possible to classify a wide variety of materials with relative economy in terms of cost of equipment and expense of operation. In addition to such flexibility, this invention provides means for segregating relatively wide size ranges of a given material for selection of an end product of desired size, or size range, with improved division between wanted material, even when very fine, and unwanted oversize material. Moreover, such advantages are obtainable with quieter acting, less vibration and more readily controllable classifying action. The classifier systern of this invention may be used separately by itself on ground or unground material supplied thereto from storage or elsewhere for classification; or it may be used in a circuit with any of a variety of impact pulverizers where the operation is to include both classifying and grinding in a continuous cycle.

Other objects, features and advantages of this invention will be apparent from the following description and the drawings, which are illustrative only, in which FIGURE 1 is a view in elevation of one embodiment of a classifier system of this invention;

FIGURE 2 is a plan view of the embodiment shown in FIGURE 1 taken along line IIII thereof;

FIGURE 3 is a view in section taken along line III- III of FIGURE 1;

FIGURE 4 is a view taken along line IVIV of FIG- URE 3;

FIGURE 5 is a view taken along line V--V of FIG- URE 4;

FIGURE 6 is a view in elevation of a portion, partly broken away, of a rotating selector shown in the foregoing embodiment;

FIGURE 7 is a view in elevation of a modified rotating selector taken along line VIIVII of FIGURE 8;

FIGURE 8 is a plan view of the modified rotating selector shown in FIGURE 7; and

FIGURE 9 is a schematic view of a grinding and classifying operation utilizing a classifier system embodi ment of this invention.

Referring to FIGURES 1 to 6, the embodiment illustrated therein comprises a vertical circular vessel 10 which may have a door opening on one side thereof closed by a cylindrical door 11. Vessel 10 is supported on a frame 12 and receives fresh or raw material through a feed subassembly 13 optionally positioned on the right or left hand side as illustrated in FIGURE 2. subassembly 13 comprises a hopper 14 communicating with the interior of a feed conduit 15 in which a feed screw 16 is positioned for rotation in a feeding direction at a selected speed by a variable speed electric motor drive 17 connected to feed screw 16 by a rotating'belt or cable 18. A support 19 maintains subassembly 13 at a desired height which in this illustration enables flange 20 of conduit 15 to be connected to a mating flange 21 on a branch pipe 22. leading into an extension pipe 23 communicah ing tangentially with the interior of vessel 10. A cap 2 on pipe 23 supports an air blow pipe 25 which receives air from an air blower (see FIGURE 9) to propel feed tangentially into vessel It). Pipe 23 is connected to an inlet pipe 26 carried by vessel 10 and communicating as aforesaid with the interior thereof through an opening 27.

As shown, vessel 10 is provided with a duplicate set of pipes 22, 23 and 26 at from each other for tangential feeding either in the direction of rotation of a shaft 28 or counter thereto, the duplicate feed subassembly shown on the left hand side of FIGURE 2, being adapted for coarser feed relative to a given desired end product size when shaft 28 is rotating in a counterclockwise direction when viewed from the top. Normally, but one feed subassembly and inlet extension would be used on a selected side at one time and the flange of the unused inlet 26 would be blanked off by a flange cover. Less coarse feed material would preferably be fed into vessel 10 at a lower point such as that illustrated by the level of pipes 29 or 30, progressively finer raw material being fed in at progressively lower points but above a vertically adjustable funnel 311. In some cases with relatively fine feed material, or ones of relatively light weight, such as mica, the feed preferably is supplied directly to an impact grinder before the ground material is introduced into vessel 1%. When classifier w is to segregate relatively fine end product, the shaft 28 preferably is rotated in a clockwise direction when viewed from the top and the fine overhead end product is discharged through a riser 32 at the top of vessel 10. On the other hand, counterclocliw'ise rotation of shaft 28 provides a less fine overhead end product for comparable feed to the classifier. Whenever vessel 10 is not connected in the circuit of an impact grinder or pulverizer, feed material containing a range of particles of varying sizes may be fed directly to the classifier shown for classification and oversized particles separated in vessel It) sink to the bottom 48 and pass out through an opening 33 and outlet pipe 34. Bottom 48 preferably has the portion thereof away from opening 33 tilted in the direction of that opening to facilitate movement of oversize particles out of vessel 10 through outlet 34. Hence, such classifier embodiment is very flexible and useful, especially where a number of different substances may have to be classified therein at respectively different times.

Shaft 23 is journaled in. thrust bearings 35 and 36 respeotively at the bottom and top of vessel It) and extends downwardly through the bottom bearing, with suitable packing therein, for fixed engagement by driven pulleys 37 driven by bolts 38 at a selected speed in a selected direction by an electric motor speed reducer set 39 mounted in a cabinet support 40 with suitable provision therein for proper tensioning of the belts 38. The lowest end of shaft 28 may be supported in a cup bearing 41 sup ported on a stand 42. Such mounting of shaft 28 ininimizes the power required for driving the shaft and the members carried thereby and any tendency to vibrate.

A distributor disc 43 is fixed to shaft'28 and vertically adjustable thereon. The outer edge 44 of the distributor disc is variably spaced from the inside of funnel 31, to define an annular opening between disc and funnel which normally is set larger when coarser material is to be ground and smaller for finer material. The disc spins particles which land thereon and provides an opportunity for classification by strip air entering the opening through a pipe '45 to remove finer and lighter portions in the course of the upward path of such air. Further, some strip air may find its Way up through outlet 34 depending upon the circuit in which vessel Iii may be connected. When grinding somewhat gummy or sticky materials the 3 upper surface of disc 43 may be provided with upstanding radial vanes to assist in such distribution. Strip air ontering through pipe preferably is conducted through a stationary ver "cal sleeve 46 in spaced relation to the lower end of shaft 28 within vessel 10. A cap (-7 is affixed to shaft 28 in spaced relation to the upper edge of sleeve so that the strip air from pipe 45 makes a rcentrant turn and is discharged downwardly toward the bottom it? of vessel 16' before moving upwardly through funnel 31 and the annular opening between the inside of the funnel and edge 44. Such strip air helps also to sweep any oversize particles on bottom into the opening 33.

A rotating selector is fixed to shaft 23 and, as shown, comprises four tiers, each of which has a plurality of radial arms welded to a hub fixed to the shaft. Each of the arms is in the form of an angle in cross section and the outer tips of the arms in each tier support a circular band 52 connected to certain spaced arms in that tier by bracl: ts 53. The bands 52 expose the ends of the radial arms 5'3 and close the space between each tier as shown in 6. The underside of the segmental spaces between the arms in th lowermost ticr are closed by a round closure plate fastened thereto as by welding. Preferably, the outer ends of the radial arms above the lowest tier are vided with a vane 55 sloping downwardly and in a direction away from the horizontal flange of the respective arms. The arms 55% in all of the tiers have the horizontal flange-s thereof pointing in the same direction and the arms in each tier are angularly spaced relative to the arms in the next lower tier, in general echelon hion. For coarser grinding operations requiring l." ger end product, the selector 49 may be rotated in the direction of arrow with the vertical flanges of the arms Ell, leading. Conversely, for finer predetermined end product specification on the same feed material, selector 4-9 may be rotated in the opposite direction by shaftZfi.

An annular shroud 57 extends from an annular cover etwec-n riser 32 and the side walls of vessel 10 and the uppermost tier in selector The shroud is provided with a c ntral opening communicating with riser 32 and 9. depending cylindrical flange 59 so that any material entering, for example, through opening 27 must pass through at least one tier of the rotating arms 54). In the case of coarser feeds, the tendency of oversize particles tl erein is to move readily toward the bottom of vessel 30 during v-Jhi h time any sufiiciently light particles therein are stripped therefrom by strip air from pipe or strip air which may introduced above funnel 31 as through the pipe or Stl if such pipe is not being used a feed inlet. Generally, the wider the range between the size of the feed particles and the size of the esnred rd product, the greater the number of tiers of arms 3 preferred in selector 49, while with relatively fine for/ s, a single tier maybe suitable.

In place of selector particularly where selection is not particularly difficult, a fan type selector 69 such as that illustrated in FIGURES 7 and 8 may be utilized. In selector the upper and lower hubs 61 are provided with radially extending arms 62 forming upper and lower spid rs to the outer ends of which arms 62 vertically extending paddle or fan blades 63 are afiixed to reject ovcrsizcd particles while permitting sulficiently small or light ones to enter the center of selector 6% and pass upwardly between the upper arms 62 to the center of th shroud and the riser thereabove.

End product material flowing upwardly through riser 32 exits through a product outlet 64 from whence it passes by pipe 65 to a collector which may be in the nature of an air filter bag collector from which the end product material is taken for storage or sacking or other treatment. A pipe 66 may also be provided and connected to an air blower to additionally control the pressure relation between the top and bottom of vessel 10, suitable valves being provided in all of the air connections for the purpose of sh ttting them otf or regulating them as desired for a selected operation. Generally, the pressure in vessel it) will decrease as one moves toward the top thereof. Further, in addition to, or in lieu of, fresh or original feed, recycle material from a pulverizer be fed to vessel 10 through a pipe Such as pipe 29 connected to the off-take from a grinder or pulverizing mechanism.

An operative hook-up of the classifier device of FIG- URES l to 6 is schematically illustrated in FIGURE 9. Therein, a blower 6'7 driven at a selected speed by a motor 63 supplies air to a manifold 69 which in turn through suitable valves 70 supplies air to the respective air receiving members described above at respectively selected pressures which may be indicated by manometers 71. In the case of fine material to be ground, which may be relatively light so that oversize particles therein, for example, take too long to move down through vessel 16, such material may be fed through a feeder subassembly 13 directly into a feed chamber 72 in which there is a high pressure aspirating nozzle 73 comprising a portion of a jetting gun 74 directed against an interstitial target mass 75 in an impact pulverizer 76 such as that disclosed in my copending- United States patent application Serial No. 8l9,04l filed June 9, 1959, for Impact Pulverizer, now Patent No. 2,991,946. Oversize material from vessel 10 passing out through outlet 34 may enter feed chamber 72 along with any feed from feeder 13' and strip air may enter feed chamber 72 through a pipe 77, which may be connected to manifold 69. Grinding air at much higher pressure is supplied through pipe 78 to nozzle 73. Material from pulverizer 76 may be Withdrawn through an off-take pipe 79 and returned to the interior of vessel 10 through pipe 29. In this way, a continuous combined grinding and classifying cycle is obtainable with the economy and flexibility provided by the classifier system of this invention. Such classifier system may also be used separately as a classifier on fresh feed carried into the interior thereof by feeder subassembly 13, or at some other height preferably above funnel 31 for respective segregation and removal of sutficiently fine material at the top and of oversize particles at the bottom. Or, fresh feed may be introduced by pneumatic pressure into the interior of vessel 10 at such selected height for classification in accordance with this invention.

Various details and changes may be made in the illustrated apparatus and steps, and other embodiments pro vided, without departing from the spirit of this invention or the scope of the appended claims.

I claim:

1. In an air classifier system, apparatus comprising, in combination, a cylindrical vessel having a vertical axis and an opening at the top thereof, a shaft extending into said vessel along said axis, means for rotating said shaft in a selected direction at a selected speed, a selector having a plurality of horizontal tiers of radial arms connected to said shaft for rotation therewith, the arms in each of the respective tiers being angularly displaced relative to the arms in another tier, said arms being angles in cross section facing in the same direction and having a vane at the outer ends thereof in the upper tiers inclined downwardly and peripherally, a plate closing the bottom of said selector and rotatable therewith, an annular shroud extending from the top of said selector to said vessel around said opening, a covering for the space between said tiers respectively, a funnel in said vessel positioned below said selector, a disc distributor connected to said shaft for rotation therewith having an outer edge in selectively spaced relation to the inside of said funnel, means for supplying strip air to said vessel at least below said funnel, means for feeding material to be classified tangentially into said vessel, an outlet for oversize material below said funnel, and an outlet for sufiiciently fine ma terial in airborne suspension above and communicating with the interior of said selector through said opening,

whereby material may be classified and oversize particles therein rejected.

2. In a gas suspension classifier system, apparatus comprising, in combination, a cylindrical vessel having a vertical axis and a fine material outlet opening, a shaft ex tending into said vessel along said axis, means below the bottom of said vessel for rotating said shaft in a selected direction at a selected speed, a selector having a plurality of horizontal tiers of radial arms connected to said shaft for rotation therewith, a plate closing the bottom of said tiers and rotatable therewith, a fixed annular shroud covering the top of said tiers and extending to a sealing position around said opening to put it into communication with the interior of said selector, a funnel in said vessel positioned below said selector, a disc distributor connected to said shaft for rotation therewith having an outer edge in spaced relation to the inside of said funnel, means for supplying air to said vessel at least below said funnel, means for tangentially supplying material to be classi-fied into said vessel, an outlet for oversize material below said funnel, and an outlet for fine material in gasborne suspension communicating with said opening.

3. In a gas suspension classifier system, apparatus cornprising, in combination, a vessel having a vertical axis, a shaft extending into said vessel along said axis, means for rotating said shaft at a selected speed, a selector having at least one horizontal tier of radial members connected to said shaft for rotation therewith, a plate closing the bottom of said selector and rotatable therewith, an annular member positioned in said vessel, an annular shroud extending from the top of said selector to the upper end of said vessel, a discoidal distributor connected to said shaft for rotation therewith having an outer edge in spaced relation to the inside of said annular member, means for supplying air to said vessel below said selector, said annular member'and distributor together defining a selected annular gap therebetween below said selector and above the lower end of said vessel, means for feeding material to be classified into said vessel above said annular member and distributor, an outlet for oversize material, and an outlet in said vessel adjacent said selector for fine material in gasborne suspension communicating with the interior of said selector through said shroud.

4. In a rising gas suspension classifier system, apparatus comprising, in combination, a vessel having a verti- I cal axis, a shaft extending into said vessel along said axis,

pered ring funnel in said vessel positioned below said s'elector, a discoidal member connected to said shaft having its outer edge positioned adjacent said funnel, means for supplying a risingcurrent of air to said vessel below said funnel, means for feeding material peripherally into said vessel above said funnel, an outlet for oversize material in the lower portion of said vessel, and outlet means in the upper portion of said vessel for selected fine material in airborne suspension in the upper portion of said vessel, said last-named outlet communicating with the interior of said selector.

5. In an air classifier system, apparatus comprising, in combination, a cylindrical vessel having a vertical axis and an opening at the top thereof, a shaft extending into said vessel along said axis, means for rotating said shaft, a selector having at least one horizontal tier of outwardly extending arms connected to said shaft for rotation therewith, a member closing the bottom of said selector and rotatable therewith, a seal extending from the top of said selector to said vessel aroundsaid opening, a' funnel in said vessel positioned below said selector, a discoiclal distributor connected to said shaft for rotation therewith having an outer edge in selectively spaced relation to the inside of said funnel, means for supplying air to said vessel at least below said funnel, means for tangentially supplying material to be classified to said vessel, an outlet for oversize material below said funnel, and an outlet for sufliciently fine material in airborne suspension above and communicating with the interior of said selector through said opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,149,463 Pardee Aug. 10, 1915 2,069,398 Wallace Feb. 2, 1937 2,487,088 Andrews Nov. 8, 1949 2,739,708 Denovan Mar. 27, 1956 FOREIGN PATENTS 3 16,901 Germany Dec. 13, 1919 951,121 France Apr. 11, 1949

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