US 4,067,494 A · Nozzle type centrifugal machine with improved slurry pumping chambers

Abstract

A nozzle type centrifugal machine designed for two-fraction separation of feed slurry, wherein the rotor has a light fraction overflow at the top, while feed slurry as well as underflow return slurry from the nozzles are introduced into the rotor from below into respective feed accelerating pumping chambers, and wherein improvements in the pumping chambers results in reduced power requirement and in improved overall performance of the machine.

Drawings

Drawings are temporarily unavailable. Open the PDF at USPTO

Drawings

Claims21

Dependent claims

A nozzle type centrifugal machine adapted for a two phase separation of a feed slurry into a nozzle discharge slurry and an overflow of separated liquid,

which comprises a rotor having a rotor bowl of double-conical configuration wherein the upper conical portion has a top opening at the narrow end providing an overflow for said separated liquid, wherein the inverted frusto-conical portion has a relatively wide bottom opening, and wherein a peripheral intermediate portion connects the wide ends of said conical portions, provided with discharge nozzles for said nozzle discharge slurry,
a hub member of hollow frusto-conical configuration, closing the bottom end of the rotor bowl, a rotor shaft rising from said hub member through said overflow opening, a spider member concentrically surrounding said shaft, and extending from said hub portion upward substantially to the level of said overflow, and having radial ribs presenting outer vertical edges, a stack of separating discs fitted over said vertical edges of the spider member and representing an inner separating zone, said ribs thus forming vertical channels for the separated liquid from said zone to flow upwardly to said overflow, said stack of discs and said intermediate portion of the rotor bowl defining between them an outer separating zone wherein concentrated material collects for delivery through said nozzles,
a set of vertical slurry feed pipes rising from the peripheral portions of said hub member, for delivering feed slurry to said stack of separating discs, said feed pipes being spaced evenly about the rotor axis,
a number of outwardly divergent return pipes equal to the number of said nozzles, and extending from the peripheral portion of said hub member into said outer separating zone for delivery of nozzle discharge slurry into said outer separating zone, said return pipes being spaced evenly about the rotor axis,
an upper annular partition member having a central feed opening coaxial with the rotor axis, and means for removably fastening said partition member to the underside of said hub member, surrounded by a peripheral portion of said hub member, said partition members thus constituting with the hollow of said hub member an upper pumping chamber,
an annular bottom closure plate having a central feed opening coaxial with the rotor axis, means for removably fastening the peripheral portion of said closure plate to said peripheral portion of said hub member, said closure plate being spaced downwardly from said partition member so as to constitute therewith and with said peripheral portion of the hub member a lower pumping chamber,
first conduit means for supplying one respective slurry to said upper pumping chamber,
second conduit means for supplying the other respective slurry to said lower pumping chamber,
one set of pumping vanes provided in one of said pumping chambers, said vanes being cooperatively associated with said vertical slurry feed pipes communicating with said one pumping chambers, and shaped so as to deviate in the direction of rotation of the rotor, and thus imparting to the incoming feed slurry outward acceleration, said vanes extending inwardly far enough to maintain delivery of separated liquid through the overflow,
complementary accelerator fins extending from the inner face of said hollow hub member radially inwardly, and in alignment with the outer ends of the pumping vanes, and constituting outward extension of said pumping vanes,
another set of pumping vanes provided in the other of said pumping chambers, said vanes being cooperatively associated with respective slurry return pipes communicating with said other pumping chamber, and shaped so as to deviate in the direction of rotation of the rotor, and thus imparting to the incoming return slurry outward acceleration, said vanes extending inwardly far enough to insure passage of said slurry through said divergent pipes, hydraulically balanced against the column of liquid reaching the top overflow,
and complementary accelerator fins extending from said peripheral portion of the hub member radially inwardly, and in alignment with respective outer ends of the pumping vanes.

9 more elements

A nozzle type centrifugal machine adapted for a two phase separation of a feed slurry into a nozzle discharge slurry and an overflow of separated liquid,

which comprises a rotor having a rotor bowl of double-conical configuration wherein the upper conical portion has top opening at the narrow end providing an overflow for said separated liquid, wherein the inverted frusto-conical portion has a relatively wide bottom opening, and wherein a peripheral intermediate portion connects the wide ends of said conical portions, provided with discharge nozzles equally spaced about the rotor axis for said nozzle discharge slurry,
a hub member of substantially obtuse hollow frusto-conical configuration, closing the bottom end of the rotor bowl, a rotor shaft rising from said hub member through said overflow opening, a spider member concentrically surrounding said shaft, and extending from said hub portion upward substantially to the level of said overflow, and having radial ribs presenting outer vertical edges, a stack of separating discs fitted over said vertical edges of the spider member and representing an inner separating zone, said ribs thus forming vertical channels for the separated liquid from said zone to flow upwardly to said overflow, said stack of discs and said intermediate portion of the rotor bowl defining between them an outer separating zone wherein concentrated material collects for delivery through said nozzles,
a set of vertical slurry feed pipes rising from the peripheral portions of said hub member, for delivering feed slurry to said stack of separating discs, the number of said vertical feed pipes being equal to the number of said nozzles,
a set of outwardly divergent return pipes extending from the peripheral portion of said hub member into said outer separating zone for delivery of nozzle discharge slurry into said outer separating zone, the number of said return pipes being equal to the number of said nozzles as well as of said vertical slurry feed pipes, and arranged in alternation with said slurry feed pipes,
an upper annular partition member having a central feed opening coaxial with the rotor axis, and means for removably fastening said partition member to the underside of said hub member, surrounded by a peripheral portion of said hub member, said partition member thus constituting with the hollow of said hub member an upper pumping chamber,
an annular bottom closure plate having a central feed opening coaxial with the rotor axis, means for removably fastening the peripheral portion of said closure plate to said peripheral portion of said hub member, said closure plate being spaced downwardly from said partition member so as to constitute therewith and with said peripheral portion of the hub member a lower pumping chamber,
first conduit means for supplying one respective slurry to said upper pumping chamber,
second conduit means for supplying the other respective slurry to said lower pumping chamber,
one set of pumping vanes provided in one of said pumping chambers, equal to the number of vertical feed pipes communicating with said one pumping chamber, said vane comprising long vanes alternating with at least one short vane interposed between two long vanes, and arranged so that any two mutually adjacent vanes will impel feed slurry to a respective associated vertical feed pipe, the long vanes being shaped so as to deviate in the direction of rotation of the bowl, and thus imparting to the incoming feed slurry outward radial acceleration, said long vanes extending inwardly far enough to maintain delivery of separated liquid through the top overflow,
complementary accelerator fins extending from the inner face of said hollow hub member radially inwardly, and in alignment with the outer ends of said pumping vanes, and constituting radial outward extensions of said pumping vanes,
another set of pumping vanes provided in the other pumping chamber, equal to the number of said divergent slurry return pipes communicating with the other of said pumping chambers, said vanes comprising long vanes alternating with at least one short vane interposed between two long vanes, and arranged so that any two mutually adjacent vanes will impel return slurry to a respective associated divergent pipe, the long vanes being shaped so as to deviate in the direction of rotation of the bowl, and thus imparting to the incoming feed slurry outward radial acceleration, said long vanes extending inwardly far enough to insure passage of said slurry through said divergent pipes, hydraulically balanced against the column of liquid reaching the top overflow,
and complementary accelerator fins extending from the peripheral portion of said hub member radially inwardly and in alignment with the outer ends of said pumping vanes.

9 more elements

Dependencies are inferred from the claim text.

Description5,648 words

Summary1,732 words

#This invention relates to centrifugal machines of the nozzle type wherein a double-cone shaped rotor bowl has a separating chamber containing a stack of separating discs for effecting a two-fraction separation of a feed slurry into a heavy nozzle discharge slurry or socalled underflow fraction or concentrate delivered by the nozzles, and a light fraction or separated liquid delivered by overflow from the top end of the machine. Provision is made for a part of the underflow fraction to be returned to the separating chamber at a controllable rate, by introduction through the lower end of the rotor bowl.

#In the type of rotor embodying the invention, both the nozzle discharge return material and the feed slurry are introduced by injection upwardly into the rotor, and into respective annular pumping chambers located one above the other. These pumping chambers herein termed the pumping section of the rotor, deliver the respective slurries upwardly into the separating chamber in the rotor bowl.

#The two pumping chambers communicate respectively with a set of upright slurry feed tubes delivering into the stack of separating discs in an inner separating zone, and with a set of outwardly divergent underflow return tubes delivering a portion of the nozzle discharge slurry into an outer annular separating zone which surrounds the discs in the rotor bowl.

Brief description of the drawings16 figures

#FIG. 1 is a vertical sectional view of the rotor, embodying one form of the invention, wherein the upper and the lower pumping chamber are related to the vertical feed pipes and the divergent return pipes respectively in the rotor bowl.

#FIG. 2 is a vertical sectional view of the rotor similar to FIG. 1, embodying a reversal of parts.

#FIG. 3 is a cross-sectional view taken on line 3--3 in the FIG. 1 embodiment showing the relationship between the pumping vanes, the pipe system within the rotor bowl and the nozzles, in that embodiment. (Note: A similar cross-sectional view taken in FIG. 2 would be identical).

Detailed description3,505 words

#The centrifugal machine embodying one form of the invention in FIG. 1, is of the type constructed for a two phase separation of a feed slurry or solids suspension into the heavy fraction of a desired solids concentration, delivered by the rotor nozzles, and a light overflow fraction delivered at the top end of the rotor bowl. In this type of machine, feed slurry is introduced through the rotor bottom end, instead of downward through the top end of the rotor. Such bottom feed arrangement leaves the top overflow end unencumbered, thus avoiding what might be an undesirably large overflow diameter required for accommodating the top feed supply facilities.

#Furthermore, since recirculation of a portion of the nozzle discharge product or underflow material back into the separating chamber of the rotor is normally required, provision is also made for the introduction thereof through the bottom end of the rotor into the outer centrifugal separating zone of the nozzles, that is the zone that surrounds the stack of separating discs.

#The two slurries, that is the feed slurry and the return slurry to undergo separation, are pushed upwardly through the rotor by the pumping or impeller vanes of the respective annular pumping chambers. These pumping chambers presenting substantially identical pumping problems, occupy the smaller bottom end portion of the rotor, being located below the much greater centrifugal separating chamber or separating zones contained in the rotor bowl.

Nozzle type centrifugal machine with improved slurry pumping chambers

Life of this patent

Nozzle type centrifugal machine with improved slurry pumping chambers

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims21

Description5,648 words

Drawings

Classification3 codes

Life of this patent

Description5,648 words