US1870409A - Classifier - Google Patents

Description

Aug. 9, 1932. J. H. v. FlNNEY ET AL 1,870,409

CLASSIFIER Filed June 19, 1929 3 Sheets-Sheet l o OR 111+ KJ JOHN H.V. F\NNEY AND AL NDER D-MA RIOT BY 1932- J H. v. FINNEY ET AL 1,870,409

GLASSIFIER Filed June 19, 1929 3 Sheets-Sheet 2 INVENTOR JOHN H4V FINNEY and ALEXANDER D Patented Aug. 9, 1932 UNITED STATES PATENT? OFFICE JOHN H. V. FINNEY D ALEXANDER D. MARRIOTT, OF DENVER, COLORADO, ASSIGNORS,

BY MESNE ASSIGNMENTS, TO THE DORR COMPANY, INC., OF NEW CORPORATION OF DELAWARE YORK, N. Y., A.

GLASSIFIEB Application filed J'une 19,

This invention relates to multiple deck or multideck forms of apparatus for effecting wet classification of material.

A well-known form of single deck classifier for pulps formed of finely divided solids in suspension in liquid, includes a pulp receiving tank supplied with pulp through a suitable trough or launder and having a sloping bottom or deck extending from the deep end of the trough, which is provided with an overflow outlet, and upwardly, above the fluid level determined by said overflow outlect on the bottom of the tank and are conveyed by the rake units upwardly along the drainage deck and discharged therefrom. Liquid may also be supplied at the drainage deck, preferably just a ove the liquid level in the tank, to wash out-any of the fines which may have been carried up with the larger particles.

Heretofore multideck classifiers have in general been made up of a plurality of single deck classifiers or units arranged end to end with the first classifier (to which the material to be classified is supplied and from which the solids pass to and successively through the other units) placed at a low level and the others progressively higher. The material which settled in the first classifier unit is conveyed over a drainage deck in a dewatering or drainage zone and discharged or transferred into the fluid containing portion of the trough of the second unit and this action is repeated until the settled material is discharged from the last or highest unit.

During such transfer of the settled solids upwardly from unit tounit, washing liquid introduced into the upper unit in the drain- 1929. Serial No. 372,202.

age zone overflows from each unit to the drainage zone of the next lower unit until the lowest unit is reached whereupon the liquid is discharged from the apparatus. It,

will be evident that a high efficiency in washing is possible by reason of the counter-current features of these multideck classifiers.

Also, in such multideck classifiers, corresponding rake units in the various classifier units are connected together in series and operated together both as to the usual reciprocatory movement and as to movement of the rake units toward and from the sloping bottoms of the troughs and the drainage decks.

Multideck classifiers of this type are of considerable length and therefore require considerable ground area for their installation. Furthermore, there is a very considerable distance between the overflow outlet of the first unit and both the discharge outlet for the rake sands and the inlet for wash liquid.

The broad object of the present invention is to provide a form of multideck classifier having various features of compactness and simplicity not found in multideck classifiers heretofore in use. Other objects of the invention are to provide for reduction in overall length of multideck classifiers by suitable arrangement of the individual classifiers, as by placing them in overlapping relation, and to provide simple and compact means for driving the rake units of the classifier units.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings in which Fig. 1 is a top plan view of an illustrative embodiment of the invention;

Fig. 2 is a view in side elevation of the structure at the inside of the first unit, certain of the parts being shown in section;

Fig; 3 is a view similar to Fig. 2 of the mechanism at the interior of the second unit;

Fig. 4 is a view in elevation of the end of the classifier at the right in Fig. 1, part of the casing being broken away to show the.

underlying structure and other parts in the interior being indicated in dashed lines; and

Fig. 5 is a side elevation in-which parts of the internal structure are indicated in dashed lines.

The objects of the invention may be car ried out by placing the tanks of the individual classifier units in overlapping relation, for example, side by side with the conveying devices or rake units of two adjacent classifier units working in opposite directions. Preferably the tanks of the.classifier units are formed as compartments in a main tank being separated by suitable partitions arranged to extend above the liquid level in the tanks of the classifier units, and the sloping bottoms of the adjacent classifier I, Referring to the drawings, 69

tanks are inclined in opposite directions. The actuation of the rake units of the various classifiers may be effected by means of a single shaft extending across the various classifier units and operatively connected with the separate rake units by suitable mechanism which is different for successive units in that the direction of rotation with respect to the inclination of the sloping bottom is different for two adjacent classifier units. In both cases use may be made of eccentrics actuating oppositely extending levers having their fulcrums supported on rocker arms adapted to compensate for the harmonic vertical movement imparted to one point on each lever and impart to an- .other point on each lever a substantial rectilinear movement during the major portion of the forward stroke of the rake unit, the levers for one of two adjacent classifier units being of the first kind and the levers for the other classifier unit being of the second kind. By using an even number of classifier units, it is possible to arrange at one end of the apparatus, the influent launder, the over- 110W outlet of the first unit, the sands-dis charge outlet of the last unit, and the'inlet for the washing liquid.

In successive compartments the oppositely inclined sloping bottoms or decks start at greater heights in succession. Also there are suitable means of intercommunication between the various units so that the rake sands discharged from one unit are transferred to the next higher classifienunit and liquid, containing fines in suspension, overflows from each classifier unit to the next lower classifier unit so that, for example, wash fluid introduced into the highest unit will pass counter current through the various units.

10 designates a multideck classif' er embodying the present invention and comprising four units'A, B, C and D, arranged in order in corresponding compartments of a rectangular casing or main tank 11 having a front wall 12 (at the right in 1), a left sidewall 13 forming one side of the tank of unit A, a right side wall 14 forming one side of the tank of unit D, and a rear wall 15. The classifier units have many corresponding parts which will, for convenience, be designated by the same reference numerals in connection with the letters a, I), c, and d to indicate the classifier unit to which such parts belong.

The unit A is separated from the unit B by a vertical partition 16 and includes a subordinate tank or trough having a sloping bottom or deck 17a extending upwardly and rearwardly from the lower part of the front wall 12 of the casing 11 (Fig. 5) and above the fluid level 18a determined by the lip at an overflow outlet 19a in the front wall 12,

to provide a drainage deck 20a which terminates above the upper end of a downwardly inclined channel or chute 21a emptying into the lower end of unit B. The fluid material or pulp to be classified is introduced into this unit by means of a launder 22, and the solids or sands which settle in the deep portion of the trough, between the partition 16 and the left wall 13 of the casing (Fig. 4), are conveyed upwardly along the sloping bottom or deck 17a and discharged into the chute 210 by means of a rake unit 230: which is made up of the usual cross members secured to suitable longitudinal members, is reciprocated a lip 24 at the outside of the casing.

The unit B is separated from the unit 0 by means of a wall or partition 25 and has an inclined bottom or deck which extends from a line at the rear wall of the casing at a leyel above that of the lower edge of the deck 17 a,

upwardly and forwardly to a line adjacent to the front wall 12 where' it discharges the accumulated solid material, conveyed upwardly therealong by a rake unit 236, into a chute 21?) which leads to the lower end of the unit (3.. In this unit B the normal fluid level 18b is determined by an overflow outlet 19?) through which liquid overflows to the drainage deck of the unit A and serves to wash back the fines carried up with the larger solids.

The unit G is separated from the unit D by means of a wall or partition 26 and its deck17c is at a higher level than that of unit B and extends upwardly and rearwardly from the front wall 12 to a line near the rear wall 15 where it discharges the settled solids into a chute 21c and then into the lower end of unit 1). V Unit C also has a conveying rake unit 230 and the liquid level 180 is determined by an overflow outlet 19:; throughof the unit B.

In the same manner, unit I) has a sloping deck 17 d extending upwardly and forwardly from the-rear wall 15, a conveying rake unit 23d, and overflow outlet 19d to direct overflowing liquid to the drainage deck of unit C. In this unit I), however, the sloping bottom extends to the front wall 12 and the, settled solids or rake sands are discharged through an outlet 2165 in said front wall and over a lip 27. The washing liquid is introduced into this unit D in any suitable manner, as through a pipe or launder 28.

Usually in single deck classifiers of the same general type as the classifier units here illustrated, the rake units are actuated by shafts extending across the higher portions of the decks; and, if the usual forms of drivmg means were to be used in connection with the present arrangement of units, it would be necessary to provide two oppositely arranged shafts. According to the present illustrative embodiment of the invention such use of two shafts is avoided by use of mechanism which includes a single shaft 29 extending across the tank substantially midway between the front and back walls thereof and having fixed thereon eccentrics or pairs of similarly arranged eccentrics 29a, 29?), 290 and 29d connected, respectively with the rake units 23a, 23b, 23c and 23d in the compartments corresponding to the units A, B, C, and D. The shaft 29 is preferably mounted in bearings on the side walls 13 and 14 and on the partitions and is driven by means of a gear 30 fixed thereon and meshing with a pinion 31 on a parallel shaft 32 projecting outwardly beyond the side wall 13 and having fixed thereon at the outside of p the tank a belt pulley 33.

In Fig. 2, there is illustrated the mechanism by which the eccentrics 29a control the movement of the rake unit 23a. This mechanism includes levers 34a and 35a connected with the eccentrics by means of straps 36a and 37a, respectively, and extending forwardly and rearwardly, respectively, from said eccentrics 29a. The lever 34a which is a lever of the first kind, is pivotally connected at its outer end with a hanger 38a attached to the rake unit 23a near its lower end, and at an intermediate point is connected by means of a pivot 39a with the upper end of a rocker arm 40a mounted at its lower end on a pivot 41a supported by connections with the side wall 13 and the partition 16. It will be evident that through the lever 34a 1 the eccentrics 29a serve to produce reciprocation of the rake 23a and raising and lowering of the lower end thereof.

In the same manner the lever 35a is a lever of the first kind and is connected by means of a pivot 42a at an intermediate point thereof, to the upper end of a rocker arm 43a mounted at its lower end on a, pivot 44a supported by connections withthe side wall 13 and the wall 16. At its outer end the lever 35a is also connected with a hanger 45a but in this place the connection is made by an interposed link 46a which allows for the toggle action of the two levers 34a and 35a.-

It is evident that, due to the provision of suitable slots in the upper ends of the hangers 38a and 45a, breakage will be avoided in the event that downward movement of the rake toward the deck is prevented by material on the deck.

It should be understood that the arrangement is such that the rocker arms 40a and 43a serve to compensate for the'harmonic vertical movement imparted to the levers and produce a substantially rectilinear movement of the rake unit 23a during the major portion of its forward movement.

In Fig. 2, the rake unit 23a is shown in raised position at the middle of its downward stroke and, when the shaft 29 is rotated further in the counter-clockwise direction as indicated by thearrow, the lever 34a will be thrust toward the right to shift the rake unit to its lowest position, and at the same time the inner end of the lever 3411 will be swung upwardly and the upper end of the rocker arm 40a outwardly and downwardly to lower the lower end of the rake unit to effective position for the return stroke. Through the lever 35a the upper end of the rake unit will be lowered in correspondence with the lowering of the lower end of the rake unit. This action takes place during the rotation of the eccentrics through an angle of substantially 90 from the position shown in Fig. 2.

During the rotation of the eccentrics through another angle of 90, the rake unit will move upwardly along the inclined bottom 17a to a position at the -middle ofits path and as the eccentrics raise the inner ends of the associated levers with a tendency to lower the outer ends of the levers the rocker arms 40a and 43a will be swinging upwardly to combine with the other motion and produce a substantially straight line movement of the rake unit parallel to the sloping bottom 17a. In the movement through the next 90 angle, the eccentrics will act to raise the rake unit and the links will act to lower 1t with the result of continuing the movement of the rake unit in a substantially straight line to the upper end of its path. In its movement through the next 90 angle, the rake unit will be raised and returned to its Fig. 2

29, they must turn in opposite directions with relation to the downward inclination of the corresponding sloping bottoms. For example, the lower surface of .the eccentrics 29a.

' the direction of downward inchnation of the sloping bottom 17a, whereas the lower surface of the eccentrics 29?), as indicated by the arrow in Fig. 3, moves in the direction of upward inclination of the deck 17?). Upon inspection of Fig. 2 it is evident that reversal of the eccentrics 29a would result in a downward substantially straight .line movement of the rake unit 23a along the deck 17a and a return movement of the rake unit in raised position to the upper end of the deck, the rake unit acting downwardly along the deck, or the wrong direction to produce the desired result. i

Although the desired operation of the rake unit 23b cannot therefore be effected from the eccentrics 29b in the same manner as the rake unit 23a is actuated from the eccentrics 29a, such desired operation may be obtained by use of two levers of the second kind connected at their inner ends with said eccentrics 29?). One of said levers 34b is pivotally connected at an intermediate point with a hanger 386 on the lower end of the rake 23b and beyond said intermediate point is pivoted at 396 to the upper end of a rocker arm 40?) mounted at its lower end on a pivot supported from the partitions 16 and 25. The other lever 35b is pivotallyconnected at its outer end with the upper end of a supporting rocker arm 43b mounted to rock about the fixed axis of a pivot 44?) and at an intermediate point, through a link 4636 with a hanger 45b. lllipon inspection of the mechanism shown in ig. 3, it will be seen that upon turning of the eccentrics 2% through 90 in the direction of the arrow, the rake unit 23?) will be moved substantially'in a straightline from the middle of its path to the solids disposal end of the deck 17 b upon movement through another 90, the rake unit will be lifted and the return stroke begun; upon movement of the eccentrics through another 90, the return stroke'will be completed and the rake unit will be lowered and placed in close proximity to the deck at the lower end of its path; and, upon rotating the eccentrics through another 90 angle the rake unit will be moved up along the deck to the position shown in Fig. 3.

It will be evident that the rake units 23a and 23b associated with the oppositely sloping decks 17a and 17 b are actuated to have different paths with respect to their, distance from said decks for the same direction of the horizontal components of their move-' ments, that is, for example, if the horizontal components of their movements are to the right of Figs. 2 and'3, the path of the rake unit 23a will be raised or spaced from the deck 17a to return! the same idly while the rake unit 236 will be in lowered position close to the deck.

The rake operating mechanism for unit C may be the same as that for unit A. and the rake. operating means for unit D may be the same as that for unit B.

It will be apparent that the type of rake actuating means disclosed herein is especially adapted for use in connection with adjacent classifier units with their bottoms inclined in opposite directions, in that the only change required from unit to unit is to change from levers of the first kind to levers of the second kind and vice versa.

Although the classifier units are here shown as formed in a tank and separated by partitions each of which serves as a common wall of se aration between two compartments, it is obvious that multideck classifiers of this kind can be built up of complete sloping bottom classifier tanks placed side by side and connected in the same general Way as the compartments in the main tank, and that the rake operating mechanism disclosed herein may be applied to such built up structure.

It should be understood that various changes may be made in the construction and arrangement of the parts and that certain parts may be used without others without departing from the true scope and spirit of the invention.

We claim:

1. A multideck classifier including a plurality of single sloping deck classifier units arranged side by sideand with their decks inclined in opposite directions, each of said units having an overflow outlet, means for arranged side by side with part of their decks inclined in one direction and part in substantially the opposite direction, means for effecting the discharge of settled solids from one unit to another in succession and means for causing fluid. to pass counter-current through said units.

3. A multideck classifier including a plurality of single sloping deck wet classifier units arranged with their decks inclined alternately in opposite directionseach having at one end an overflow outlet for excess fluid and at the other end a discharge outlet for settled solids. means for causing the settled solids to be discharged from one unit to another in succession through said discharge outlets and means-for causing Washing fluid to be passed counter-current through each of said units and from the overflow outlet thereof into-the next preceding unit and out of the classifier through the overflow outlet of the first unit.

III

4. A multideck classifier including an even number of single slo in deck classifier units arranged with the1r s oping bottoms inclined alternately in opposite directions, each of said units having at one end an overflow outlet for liquid and at the other end a. discharge outlet for settled solids, means for causing settled solids, to be transferred from one unit to another in succession through said discharge outlets, and means for causing Wash fluid introduced into the last unit to be passed counter-current through all of said units in succession and out of the over- 1 flow outlet in the first unit, the overflow outlet of the first unit and the discharge outlet of the last unit being at the front of the apparatus due to the even number of units.

5. A multideck classifier including a substantially rectangular tank, parallel partitions dividing the tank into compartments, sloping bottoms for said compartments with their lower ends starting alternately from the front and rear of the tank and at greater heights in succession, means for conveying settled solids up said sloping bottoms and discharging them from unit to unit and means for passing liquid through said units in the counter-current direction,

in testimony whereof we afix our signatures.

JUHN H. V. FINNEY. ALEXANDER D. MRIQTT.

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