US2806597A - Concentrate classifiers - Google Patents

Description

' P 1957 P. L. GRIEGERSEN I 2,806,597

'CONCENTRYATE CLASSIFIERS Filed March 18, 1954 3 Sheets-Sheet 1 IN V EN TOR. -Peler 4 'rqerse/z Sept. 17, 1957 Filed March 18. 1954 P. L. GREGERSEN 2,806,597

CONCENTRATE CLASSIFIERS 3 Sheets-Sheet 2 INVENTOR. Pelt)" Greyersen I Atty.

P 17, 19.57 P. L. GREGERSEN 2,806,597

CONCENTRATE CLASSIFIERS 3 Sheets-Sheet 3 Filed March 18. 1954 v INVENTOR.

' P652)" 4. Greyerse'n United This invention relates to concentrate classifiers adapted for use in classifying ore concentrates and particularly in the recovery of precious metals such as gold. It is the principal purpose of my invention to provide a device of this character with means whereby the classification of the material according to size is carried on efliciently and those over size particles of the extremely heavy precious materials may also be collected as nuggets without having to go back to the regrinding with other over size particles.

The nature and advantages of my invention will appear more fully from the following description and the accompanying drawings wherein a preferred form of the invention is shown. It should be understood, however, that the drawings and description are illustrative only and are not intended to limit the invention except insofar as it is limited by the claims.

In the drawings:

Figure 1 is a somewhat diagrammatic view in side elevation of the classifier showing the hopper from which the material is fed to the classifier and the general construction of the classifier unit itself;

Figure 2 is a longitudinal sectional View taken substantially on the line 2-2 of Figure 1;

Figure 3 is a sectional view taken on the line 3--3 of Figure 2;

Figure 4 is a fragmentary sectional view taken on the line 4-4; of Figure 3;

Figure 5 is a fragmentary sectional view taken substantially on the line 55 of Figure 3; and

Figure 6 is an enlarged fragmentary sectional view taken on the line 6-6 of Figure 2.

Referring now in detail to the drawings, my invention is shown as embodied in a classifier wherein the concentrates to be classified are fed from the hopper 10. A water supply conduit 9 is used to supply water to the concentrate as needed. The hopper 10 has a discharge spout 11 which extends into a classifier screen unit 12. The unit 12 is supported on a suitable framework 13 in a tank 14. The over size material passing through the unit 12 is collected in a portion 15 of the tank 14, while the smaller size material is collected in the portion 16 of the tank. Suitable conveyors indicated at 17 and 18 are utilized to draw off the collected material from the tank portions 15 and 16. My invention is particularly concerned with the construction of the unit 12 and will be described in detail hereinafter.

The classifier unit 12 utilizes a plurality of screens 19, 20, and 21, all of which are conical in shape. The inner screen 21 is the coarse screen. The intermediate screen is of finer mesh and the outer screen 12 is of still finer mesh. For example, the inner screen 21 may be inch mesh, the screen 211 may be inch mesh and the screen 19 /8 inch mesh. Material of more than /a inch size will ride through the screen 21 and be discharged at its larger end. The material between inch and inch passes through the screen 21 along with the finer material of less than /4 inch size. The screen 2-41 retains the par- Patent "ice ticles between A and inch size and carries them to discharge at its larger end. The remainder of the material passes through the screen 2% to the screen 19 which carries over the material of more than inch size while the finer material passes through the screen and falls into the section 16 of the tank 14. All of the over size particles retained on the screen 21 pass through a collecting ring 22 and are kept out of the collecting ring by an extended portion on the screen 21.

The collecting ring 22 serves the dual purpose of mounting the large ends of the screens 19, 20 and 21 and of providing a pocket 23 for segregating extremely heavy particles of the material being classified and retaining these particles while permitting the lighter particles discharged over the screens 19 and 20 to pass through the ring 22 to the compartment 15 of the tank 14. The ring 22 as shown, comprises an outer conical wall 24, a flange 25 and an inner conical portion 26. The portion 24 is joined to a rim portion 27 which extends inwardly to a mounting flange 28 for the outer screen 19. The portion 26 has a radial flange 26a at its smaller end which extends outwardly. The rim portion 27 has a conical flange 29 which tapers inwardly and is spaced from the flange 28 at its inner end. This construction provides the channel 23 with a tortuous entrance passage to restrict the flow of material into the chamber 23. The rim portion 27 terminates at the mounting flange 28. Four spokes 30 arranged ninety degrees apart, support a hub 31 at the center of the ring 22 for mounting a supporting shaft 32.

The ring 22 has a plurality of clean out apertures 33 in the rim portion 27. These apertures are normally closed by cover screens 34 held in place by plates 35 that are fastened to the portion 27 by screws 36. The chamber 23 will gradually fill up with the heaviest precious metal particles, such as gold nuggets, and these are removed periodically by detaching screens 34.

The screen 20 is notched at its large end to fit on the tapered portions 30a of the spokes 30 against a shoulder 37 on each spoke. This construction serves to locate the screen 20 at the proper space from the outer screen 19 which is fitted over the flange 28.

The mounting of the inner screen 21 which is subjected to the load of all the material entering the classifier, is accomplished by notching the screen 21 as indicated at 38 to receive each spoke 30 of the ring 22. The screen 21 extends beyond the spokes far enough to overlap the conical portion 26 of the ring so that material on the screen 21 does not fall upon the passage 39 between the rim portion 27 and the smaller end of the cone shaped portion 26. A solid metal ring 40 is fitted on the free end of the screen 21 that extends beyond the spokes 30. This ring is notched at 41 to receive the bevelled portions 42 on the spokes 30. It is secured to the screen 21 by screws shown at 43. The beveled portions 42 of the spokes 30 are terminated just inside the ring 40 so as to provide a guide to position the ring 46 and the screen 21. A shoulder 44 is also provided on each spoke just inside the screen 21 to position the screen.

At the other end of the classifier unit 12, means are provided for mounting the screens and centering them about the shaft'32. 1 The means comprise a casting 45 which has an outer flange portion 46 to receive the screen 12. This casting also has a raised rib 47 spaced inwardly from the flange 46 to fit over the small end of the screen 20 and support it in position. Spaced inwardly from the rib 47 are four L-shaped spokes 48 formed on the casting 45. These spokes have their inner ends joined by a hub 49 for the shaft 32. The small end of the screen 21 fits around the spokes 48. The shaft 32 extends through the casting ring 45 and through the bottom of the spout 11 where it is supported by a bearing 50. The spout 11 is formed to fit over the shaft 32 so that the material entering the classifier unit 12 flows on both sides of the shaft. The casting 45 and the collector ring 22 are held against the screens 19, 20, and 21, by four bolts 51. The bolts 51 extend through apertures in the casting 45 and through apertures in the four spokes 30 of the collector ring 22. Nuts 52 are threaded on each end of each bolt 51 to hold the casting 45 and the collector ring 22 together.

When the shaft 32 is rotated, the material fed into the unit 12 is moved along the screens to their lower ends and thus classified according to size. Generally the liquid level within the tank 14 is high enough to submerge the lower portions of the screens and facilitate the washing and separation of the concentrates. The ring 22 receives the material from the screens 19 and 20 so that any particles of the heavier precious metals such as gold nuggets, have an opportunity to supplant the lighter rock particles in passing over the inner edge of the cone shaped portion 26. These particles work their way into the chamber 23 and are collected there for removal at intervals.

It is believed that the nature and advantages of my invention will be clear from the foregoing description.

Having thus described my invention, I claim:

1. A classifier for precious metal ore particles comprising a framework, a screen unit on said framework, said screen unit comprising a plurality of concentric conical screens of different sizes arranged on a horizontal axis, one within another in spaced relation to each other, the outer screen being of the finest mesh and each of the other screens being coarser than the one outside of it, end supports holding said screens in spaced concentric relation, shaft means on the framework mounting said end supports for rotation, a hollow collecting ring joining the large end of said outer screen and having an annular restricted inwardly facing inlet opening to the interior thereof, across which the particles retained on said outer screen must pass in leaving the screen unit.

2. A classifier for precious metal ore particles comprising a framework, a screen unit on said framework, said screen unit comprising a plurality of concentric conical screens of different sizes arranged on a horizontal axis, one within another in spaced relation to each other, the outer screen being of the finest mesh and each of the other screens being coarser than the one outside of it, end supports holding said screens in spaced concentric relation, means on the large end of the inner screen projecting outwardly beyond the adjacent end support to carry large particles retained on the inner screen outwardly beyond the particles retained on the other screens, shaft means on the framework mounting said end supports for rotation, a hollow collecting ring joining the large end of said outer screen and having an annular restricted inwardly facing inlet opening to the interior thereof, across which the particles retained on said outer screen must pass in leaving the screen unit.

3. A classifier for precious metal ore particles comprising a framework, a screen unit on said framework, said screen unit comprising a plurality of concentric conical screens of different sizes arranged on a horizontal axis, one within another in spaced relation to each other, the outer screen being of the finest mesh and each of the other screens being coarser than the one outside of it, end supports holding said screens in spaced concentric relation, shaft means on the framework mounting said end supports for rotation, a hollow collecting ring joining the large end of said outer screen and having an annular restricted inwardly facing inlet opening to the interior thereof, across which the particles retained on said outer screen must pass in leaving the screen unit, and said ring having screened outlets from the interior thereof outside the outer screen.

4. A classifier for precious metal ore particles comprising a framework, a screen unit on said framework, said screen unit comprising a plurality of concentric conical screens of different sizes arranged on a horizontal axis, one within another in spaced relation to each other, the outer screen being of the finest mesh and each of the other screens being coarser than the one outside of it, end supports holding said screens in spaced concentric relation, shaft means on the framework mounting said end supports for rotation, a hollow collecting ring joining the large end of said outer screen and having an annular restricted inwardly facing inlet opening to the interior thereof, across which the particles retained on said outer screen must pass in leaving the screen unit, said ring having a plurality of circumferentially spaced outlet openings on the exterior thereof, and removable closures for said openings.

5. A classifier for precious mineral ore particles comprising a framework, a screen unit on said framework comprising a plurality of concentric screens of different sizes arranged on a common axis one within another in spaced relation to each other, the outer screen being of the finest mesh and each of the other screens being coarser than the one outside of it, end supports holding said screens in spaced concentric relation, shaft means on the framework mounting said end supports for rotation, means at one end of said unit to deliver particles to be screened upon the inner screen, a hollow collecting ring at the other end of said unit fixed to the outer screen, said hollow ring having an annular restricted inwardly facing inlet opening to the interior thereof across which the particles retained on the outer screen must pass.

6. A classifier for precious mineral ore particles comprising a framework, a screen unit on said frame work comprising a plurality of concentric screens of different sizes arranged on a common axis one within another in spaced relation to each other, the outer screen being of the finest mesh and each of the other screens being coarser than the one outside of it, end supports holding said screens in spaced concentric relation, shaft means on the framework mounting said end supports for rotation, means at one end of said unit to deliver particles to be screened upon the inner screen, a ring at the other end of the unit, the end supports at said other end having spokes joined to the ring, the ring having a flange receiving the outer screen, the innermost screen extending past said spokes and having notches therein receiving said spokes and a solid ring joining those parts of the innermost screen between the notches that extend beyond the spokes together.

References Cited in the file of this patent UNITED STATES PATENTS 471,322 Wyman Mar. 22, 1892 666,050 Gray Ian. 15, 1901 FOREIGN PATENTS 11,455 Great Britain May 9, 1910

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