Classifying – separating – and assorting solids – Fluid suspension – Liquid
Reexamination Certificate
2001-03-12
2003-03-25
Lithgow, Thomas M. (Department: 1724)
Classifying, separating, and assorting solids
Fluid suspension
Liquid
C209S164000
Reexamination Certificate
active
06536596
ABSTRACT:
The present invention relates to a line formed by cells used in the treatment of flotatable materials, in which line the cells are installed with respect to each other, so that at least one cell can be withdrawn from the process without essentially deteriorating the operation of the flotation cell line.
In a flotation cell, there are treated slurry-like materials in order to remove from the rest of the material the desired ingredients that can be utilized. The main task of the flotation cell is to keep the flotatable material in suspension, to feed air into the suspension and to disperse the suspension into small air bubbles, as well as to conduct the utilizable ingredients, i.e. the concentrate, and the rest of the material, to separate locations. However, with respect to the recovered concentrate, the efficiency of the flotation cell is essentially low. Consequently, in order to achieve the desired degree of concentration for the utilizable ingredient, the flotation cells are usually coupled in series, so that the waste from the preceding flotation cell serves as the feed for the successive flotation cell. The concentrates obtained from the cells of the accordingly created flotation cell line are then combined and conducted to further treatment.
In a conventional flotation cell line, the cells are coupled in series with respect to each other, so that the whole flotation cell line must be stopped and production interrupted even in a case where only one cell in the flotation cell line needs repairs or maintenance. Because the capacity of the flotation cells as such has increased, and because respectively the number of parallel flotation cell lines has decreased, the relative capacity share of each flotation cell line becomes large. When this type of a flotation cell line must be stopped, for instance in order to maintain or repair one cell in the line, the procedure remarkably cuts the degree of utilization of the flotation process, and thus causes high extra expenses for the process.
The object of the present invention is to eliminate some of the drawbacks of the prior art and to achieve an improved flotation cell line, where the withdrawal of one flotation cell from the line does not cause any essential changes in the operation of the flotation cell line, and whereby it is possible to reduce the space needed for the flotation cell line. The essential novel features of the invention are apparent from the appended claims.
According to the invention, the flotation cell line is formed of flotation cells, which are provided with inlet and outlet apertures for the flotatable material, so that the flotatable material can be conducted from a flotation cell to at least two flotation cells that are located in succession to said flotation cell, when seen in the flowing direction of the flotatable material. Thus the flotatable material can be conducted alternatively either to the cell in the flotation cell line that is located next in the flowing direction of the flotatable material, or past the cell located next in the flowing direction, to at least one cell following in succession in the flowing direction of the flotatable material. In case the cell in question is the cell that is located last but one in the flowing direction of the flotatable material, the flotatable material can only be conducted to the last cell or to further treatment after the flotation cell line. Moreover, when feeding the flotatable material to the flotation cell line, the material can be fed either to the cell located first in the flowing direction of the flotatable material, or past the first cell to the cell located second in the flowing direction of the flotatable material.
When the flotatable material, according to the invention, is conducted past that cell in the flotation cell line that is located next in the flowing direction of the flotatable material, the flotatable material can in the flotation cell line be further conducted, irrespective of the flotation cell that is withdrawn from usage, so that the flotation cell line still can be used in the treatment of the flotatable material. Moreover, in a flotation cell line according to the invention, the flotation cells are installed at least partly in parallel, so that space can advantageously be saved in the flowing direction of the flotation cell line, and simultaneously the interval between two flotation cells is reduced, when the flotatable material is conducted past the cell that needs repairs or maintenance.
In the flotation cell line according to the invention, the cells are interconnected by means of conduits, so that in the outlet aperture of the cell, or in between the cells, there is installed a flow control member, which guides the flotatable material to the feed inlet of the cell that is located next in the flowing direction of the flotation cell line, or alternatively to the feed inlet of the cell that is located nearest to the next cell. Advantageously the number of inlet and outlet apertures of the cells provided in the flotation cell line is one or two. However, a larger number can also be applied, when desired. In the flotation cell line according to the invention, the number of the inlet and outlet apertures of individual flotation cells can alter, in which case different types of flotation cells can be combined in a flotation cell line.
According to the invention, when using both two inlet and two outlet apertures in the cells of the flotation cell line, the passage of the flotatable material either to the next cell or to the conduit passing the next cell is controlled already in the flotation cell itself, by keeping one outlet aperture and the inlet aperture provided in the receiving flotation cell open by means of the flow control members, so that the flotatable material flows from one cell to another.
The passage of the flotatable material from one flotation cell to the cell located next in the flotation cell line, or past the next cell, can also be arranged so that the flotatable material is discharged through the same outlet irrespective of the fact whether the flotatable material passes to the next flotation cell or to the conduit passing the next cell. Now the flow control member of the flotatable material is installed outside the flotation cell, in the conduit connecting the cells. When using only one outlet in the flotation cell, it is possible in the next receiving flotation cell to use either one or two inlets, because the flotatable material conduit meant for the passing of one flotation cell can be connected either to that conduit piece which provides for the flotatable material a direct contact between two successive flotation cells, or the conduit can be connected directly to the flotation cell as a separate inlet aperture.
In the flotation cell line according to the invention, the cells that are located successively in the flowing direction of the flotatable material are installed at least partly in parallel with respect to each other. Thus the distance of the first and last cell in the flotation cell line, when seen in the flowing direction of the flotatable material, is reduced, and the flotation cell line as such takes up less space than a conventional flotation cell line. Now also the distance between a cell and the cell located next in succession, when seen in the flowing direction of the flotatable material, is essentially reduced. Likewise, the conduit arranged between a cell and the cell located next in succession, when seen in the flowing direction, also is essentially short and easily installed in place. The distance proceeded by the flotatable material in the flotation cell line remains essentially the same as in a conventional flotation cell line, in case the flotatable material passes via all cells in the flotation cell line, but said distance is essentially shortened, in case the flotatable material is conducted past one or several flotation cells.
REFERENCES:
patent: 4121945 (1978-10-01), Hurst et al.
patent: 4477338 (1984-10-01), Hellmann
patent: 4915706 (1990-04-01), Daley
patent: 1 197 403 (1965-07-
Niitti Timo
Tarvainen Matti
Lithgow Thomas M.
Outokumpu Oyj
Smith-Hill and Bedell
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