'Sept. 17, 1957 A. w. FAHRENWALD 2,806,681

* FLOATATION MACHINE Filed Jan. 3, 1955 I 5 Sheets-Sheet 1 k) HI I! i v IN V EN TOR.

Sept. 17, 19 A. w. FAHRENWALD' FLOATATION MACHINE 5 Sheets-Sheet 2 Filed Jan. 3, 1955 Sept. 17, 1957 A; w. FAHRENWALD 2,806,631

' FLQATATION MACHINE Filed Jan. s, 1955 V 5 Sheets-Sheet s INVENTOR. Ari/Mr W 5 /11? 14/0/0 P 1957 A. w. FAHRENWALD 2,806,681

FLQATATION MACHINE Filed Jan. 5, 1955 i 5 Sheets-Sheet 4 United States Patent FLOTATION MACHINE Arthur W. Fahrenwald, Moscow, Idaho Application January 3, 1955, Serial No. 479,395

' 1 Claim. 01. 261-93) The present invention relates to improvements in a flotation machine. There are generally speaking, three types of flotation means currently in use. One type is the closed cell type which may or may not be supplied with air under pressure. It is usually preferred when a compact circuit is desired in which roughing and cleaning of the ores may be eifected in a single bank of cells without the use of pumps. This type of machine is capable of handling relatively coarse feeds without trouble from sanding. The second type of machine is a typical open cell type in which air is usually supplied. It has no satisfactory means of roughing and cleaning in the same bank of cells. The third type of machine is an open cell type where the impeller is so designed so that at low submergence it draws in enough air to make addition of air under pressure unnecessary. It is the purpose of the present invention to provide a flotation machine that may be operated as any one of the above three types so that the operator may have in a single bank of cells, any combination of closed and open cell types that he desires for his particular operation.

More specifically it is the purpose of the present invention to provide .a flotation machine wherein the impeller is combined with a follower plate directly above it, open at the center to accommodate the impeller shaft and to direct pulp into the impeller, together with four stand pipes equally spaced from each other and located about 70% of the distance from the center of the impeller outwardly to the impeller rim. The four stand pipes extend upwardly to the bearing for the impeller shaft and provide a support for the follower plate. The lower ends of the stand pipes are open to the impeller through openings in the follower plate and the upper ends thereof open into a manifold that may or may not be connected to a source of air under pressure. The stand pipes are provided with mountings for enclosure plates which form a closed space between the stand pipes and these plates have tthe necessary inlet connections for supplying the pulp when the unit is used as a closed cell.

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 claim.

In the drawings:

Figure 1 is a view in side elevation of a bank of four cells in a flotation machine embodying my invention;

Figure 2 is an end view of the machine looking at Figure 1 from the right hand end;

Figure 3 is an enlarged plan sectional view taken on the line 3-3 of Figure 1;

Figure 4 is an enlarged sectional view taken on the line 4-4 of Figure 1;

Figure 5 is a sectional view taken on the line 5-5 of Figure 4; and

2,806,681 Patented Sept. 17, 1957 Figure 6 is an enlarged sectional view taken on the line 6-6 of Figure 5. I

Referring now in detail to the drawings, my invention is shown as embodied in a flotation machine having cells 7, 8, 9 and 10 connected in series within a single casing which has one side wall 11 provided with a froth lip at 12. The side wall 11 also has openings 13 for return flow connections. A feed inlet is indicated at 14 and a tailings discharge outlet at 15. The impeller mechanism is supported by a tube 16 which extends the length of the machine and is supported on the ends of the machine by brackets 17. This tube has an opening 18 at one end which may be connected to a blower or other source of air. The tube 16 supports impeller shafts 19, 20, 21 and 22 and the necessary driving mechanism for the impeller 'shafts as will be described more fully hereinafter.

Referring now in particular to Figures 4, 5 and 6, the impeller shaft 19 in the cell 7 is illustrated as supporting an impeller 23. The shaft 19 is supported by a bearing quill 24. The impeller 23 comprises a flat disk having radial blades 25 on the top thereof and having a central stem 26 which is bolted to the shaft 19 by means of a flange 27 on the shaft, a flange 28 on the stem and bolts 29 through the flanges. A circular follower plate 30 directly overlies the impeller 23 and is spaced slightly above the blades 25 to provide clearance. central aperture 31 to admit pulp to the blades 25 of the impeller 23. The plate 30 supports a splash cake which comprises a ring 32 on which a multiplicity of rods 33 are fixed. The rods 33 extend downwardly around the impeller 23. Sleeves 34 of resilient material such as a rubber composition that will resist the action of the reagents employed in flotation, are mounted on the rods 33 to take the wear of the pulp thrown out from the impeller. The sleeves 34 may be of natural rubber or of a synthetic rubber particularly designed to withstand the conditions under which they are used. They can be rota-ted as they become worn and replaced when no longer serviceable.

' The follower plate 30 is supported by four stand pipes 35 which are connected together by a flange member 36 that is bolted directly to the follower plate 30 by bolts 37. The upper ends of the stand pipes 35 are joined to a manifold member 38 which has a lower flange 39 receiving the stand pipes 35, an upper flange 40 which is bolted to the bearing quill 24 and, a cylindrical portion 41 that joins the flanges 39 and 40 and surrounds the shaft 19. A shield 42 encloses the flanges 39 and 40 so as to provide an air ring in communication with all of the stand pipes 35. The stand pipes 35 are set equidistant from each other and are spaced from the axis of the shaft 19 and the stem 26 radially outwardly a distance equal to about 70 percent of the radius of the impeller 23. The

follower plate 30 has apertures 30a aligned with the stand pipes 35 so the air may flow down through the stand pipes to the blades 25 of the impeller.

The four stand pipes 35 are provided with threaded studs 43 which are used to mount four plates 44, 4-5, 46 and 47 to make the cell an enclosed unit whenever that is desired. When the cell is used as an open unit, the threaded studs are replaced by plugs which do not extend out beyond the surfaces of the stand pipes. The plate 46 is shown as provided with an inlet pipe 48 which can be used to return pulp to the closed cell for recleaning. The plate 47 is shown as provided with an inlet pipe 49 for supplying the initial pulp feed to the closed cell. As an example of the way in which the machine is convertible at the option of the operator to any combination of closed and open cells, Figure 1 shows cells 7 and 9 operating as closed cells and cells 8 and 10 operating as open cells. The air space at the top of the stand pipe in cell 7 is The plate 30 has a shown as connected by a pipe 50 and a valve 51 to the support pipe 16 to receive air under pressure.

The mounting and assembly of the operating parts of the machine is simplified by providing the pipe 16 with a plurality of mounting brackets 52 for mounting the bearing quills 24. Each bearing quill 24 is provided with 'tWO diametrically opposed flanges 53 which are bolted to flanges 54 on the brackets 527 The pipe 16 also has motor mounting brackets 55 thereon. These brackets have slidable motor mounts 56 secured thereon by bolts 57 and the mounts 56 have flanges 53 to which motors 59 can be bolted. The mounts 56 have elongated slots 56a therein to receive the bolts 57 and they carry blocks 60 to receive adjusting rods 61 that are threaded into the upstanding member 62 on each of the brackets 55. The motors 59 are connected by pulleys 63 and belts 64 to pulleys 65 on the adjacent shaft 19 for driving the impeller shafts 19. The motor mount 56 and the rod 61 provide a convenient means of tightening the belts 64.

The construction just described provides a flotation machine which may be operated in any of a plurality of combinations to produce the best results for the particular mineral matter to be processed. As hereinbefore described there are three general types of flotation cells, the closed cell type, the open cell type having a pressurized air supply, and the open cell type having no pressurized air supply but operable to draw air by impeller action. Each of these designs is particularly useful for certain operations. Often times it is desirable to combine in one ore treating process a combination of open cells and closed cells. For example it may be desirable to carry on a flotation process using a number of open cells to handle a particular quantity of ore, and then to re-treat the froth from those cells in a closed, cleaning cell. With my invention, a bank of cells, such as shown in Figure 1 may be utilized for this purpose. Cell 7, for example, may be used as a closed cleaning cell and cells 8, 9 and 10 may be used as open cells in a common flotation bath. When cells 8, 9 and 10 are so used, the pulp in the bath is free to circulate from each impeller 23 around and through each impeller 23 again in a continuous, closed circuit. The froth produced from these cells is spilled out over the lip 12 and collected. The cell 7 is separated from the cells 8, 9 and 10 by the usual partition, and the panels 44-47 are placed on the standpipes 35 to make cell 7 a closed cell. The froth from the remaining cells 8, 9 and 10 is led into the inlet pipe 49 and into cell 7. This cell being used as a closed cell, the froth is cleaned once and cannot recirculate. Thus only the cleaned froth from a single cycle is produced from cell 7.

It should be understood that any of cells 7, 8, 9 or 10 may be used as any of the three types of flotation cells. By the addition of the panels 44-47 any cell may be converted to a closed cell, and by the addition of the shield 42 and pipe 50 connecting to the air supply pipe 16 any cell may be provided with a pressurized air supply. By removing the shield 42, any cell may be converted to the type which utilizes only the impeller action to draw air into the pulp.

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:

In a flotation cell having an impeller shaft depending into the cell from the top thereof and having an impeller secured to the shaft at its lower end, said cell also having a bearing rotatably supporting the shaft, the improvement comprising an air manifold beneath the bearing encircling the shaft, a plurality of standpipes suspended from the manifold and open to it, a follower plate fixed to the lower ends of thestandpipes and overlying the impeller, the follower plate having a central aperture around the shaft and apertures therethrough from the standpipes to the impeller, and enclosure plates bolted to said standpipes enclosing the space between the standpipes.

References Cited in the file of this patent UNITED STATES PATENTS 2,054,249 Fagergren "Sept. 15, 1936 2,189,779 Daman Feb. 13, 1940 2,352,767 Booth at al July 4, 1944 2,393,976 Daman et al. Feb. 5, 1946 2,466,037 McNeill Apr. 5, 1949 FOREIGN PATENTS 462,441 Canada Jan. 17, 1950