US2817441A - Process for separating mixture of solid particles into fractions by means of a hydrocyclone - Google Patents

Process for separating mixture of solid particles into fractions by means of a hydrocyclone Download PDF

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Publication number
US2817441A
US2817441A US360464A US36046453A US2817441A US 2817441 A US2817441 A US 2817441A US 360464 A US360464 A US 360464A US 36046453 A US36046453 A US 36046453A US 2817441 A US2817441 A US 2817441A
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Prior art keywords
hydrocyclone
feed
apex
mixture
fractions
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Expired - Lifetime
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US360464A
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English (en)
Inventor
Jan N J Leeman
Freerk J Fontein
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Stamicarbon BV
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Stamicarbon BV
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B9/00—General arrangement of separating plant, e.g. flow sheets
    • B03B9/005—General arrangement of separating plant, e.g. flow sheets specially adapted for coal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
    • B03B5/28—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation
    • B03B5/30—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation using heavy liquids or suspensions
    • B03B5/32—Washing granular, powdered or lumpy materials; Wet separating by sink-float separation using heavy liquids or suspensions using centrifugal force
    • B03B5/34—Applications of hydrocyclones
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
    • B04C5/00—Apparatus in which the axial direction of the vortex is reversed
    • B04C5/08—Vortex chamber constructions
    • B04C5/081—Shapes or dimensions

Definitions

  • the present invention relates to a methodsfor separating zmixturesofsolidtparticles into fractionsbyumeans of :a hydrocyclone.
  • ihydrocyclone as used in this. specification and-the: claims: hereof designates apparatus known. per se .comprisinga chamber which is peripherallybounded by .asmooth' surface of revolution (by which we mean a .surfacetgeneratedlby the rotation of a straightor a curved line aboutgancaxis) xandmtapering towards one end, the apparatus including one or more feedpassages'leading substantially tangentially into the chambernear the wider end thereoftand twouaxial discharge apertures, viz.,. one :atfithe apex ofthe chamber and hereinafter called the apexaaperture. and one intthe wider end of the chamber and hereinafter called the overflow aperture.
  • the chamber may; comprise conjoined cylindrical and conical portions :and the tapering wall may conformrto the wall of a true cone or may beslightly. curved to present'a. concave or convex surface to the inside of the chamber. .
  • the overflow aperture may be and preferably is defined by a short, conduit, hereinaftercalled a vortex, finder extendingaxially into the wider end of the chamber.
  • the dimensionsl ,of a hydrocyclone and the diameters of the feed apertures and outlets are such that, when a liquidis con tinuously introduced into the feed conduit(s) at a suffi- "c'iently high pressure, arotary current is generated in the chamber, which current has an inner vortex directed to- Wardsthe vortex finder and another vortex around the first one, which moves axiallyin the opposite direction.
  • the chamber which generally is substantially conical, preferably has a mean angleof'taper of from 5 to 30,but angles up to .9.0.also havebeen successfully employed.
  • hydrocyclones for the separation of solid ,particlesaccordingto grain size (classification) and for separation according to specific gravity (washing).
  • a.mixture ofsolidparticles-is to be classified the mixture .is fed continuously under pressure into a hydrocyclone of suitable dimensions, together with a liquid whose specific gravity is lower than thatof the particles to be .classificd.
  • tThe-expres'sion liquid separating medium as used above means an entirely liquid medium havinganintermediate specific, gravity, i. e., a specific gravity which is higher than the specific gravity of the specifically light particles and lower than the specific gravity of the specifically heavy particles constituting the fractions to *be separated, or a mediumvcomprising a liquid with-solid particles considerably smaller than the particles to be separated in suspension,'and having an intermediate specific gravity as aforesaid at a concentration'ofthe suspension: particles of: fifty percent or less.
  • specific gravity i. e., a specific gravity which is higher than the specific gravity of the specifically light particles and lower than the specific gravity of the specifically heavy particles constituting the fractions to *be separated
  • The: suspension iparticles utilized in a: separating medium of thesecond of the aforesaid kinds arewgenerallysmaller than '200. microns and are often of a "size of 60-microns or less, depending on :the size. of the particles to be sepa- 'rated,:the specificitgravity oflthecparticles in the suspension and the. conditions under which the separation takes place.
  • the invention is based on the discovery that the reason why big hydrocyclones which are positioned vertical need a comparatively high feed pressure is that, owing to their great length, these hydrocyclones contain such a tall liquid column that gravity becomes an important factor and influences the operation of the hydrocyclone. If, however, the hydrocyclone is given a sufficient tilt this phenomenon cannot occur.
  • the hydrocyclone is put with its axis substantially horizontal (or about 90
  • the influence of gravity is then as small as possible and the ratio of H to L cos a is infinitely large. It goes without saying that under those circumstances H cannot be made arbitrarily small, but must be great enough so that a rotary current is generated in the hydrocyclone.
  • a special advantage of a hydrocyclone which is positioned more or less horizontal is that, when this cyclone is fed from a tank situated higher than the cyclone, the feed conduit to the hydrocyclone may be straight.
  • the feed conduit to a vertically arranged hydrocyclone usually has a bend in practice, which causes wear.
  • a conical hydrocyclone is so positioned that 90 ot is substantially equal to half of the apex angle and that the apex of the hydrocyclone is lower than its overflow aperture. This position otters the advantage that all the liquid can flow out of the hydrocyclone, which is of importance in case of shut-down and revision.
  • the invention which is especially suitable for making separations by means of hydrocyclones having an axial length between 0.7 and 9 m. with a feed head in the range from 0.4 to 5.7 times the axial length of the hydrocyclone will be further explained with the help of the drawings.
  • Figure l is a section through a hydrocyclone which is so positioned that the lowest generatrix is horizontal.
  • Figure 2 is a view of a washing apparatus comprising a deep wash box and a hydrocyclone with its axis positioned horizontal.
  • 1 is a hydrocyclone, consisting of a cylindrical section 2 and a conical section 3.
  • the feed conduit 4 discharges tangentially into the cylindrical section 2 through the feed aperture 5, the cylindrical section being closed by a plate 6 in which the vortex finder finder 7 is provided.
  • the conical section 3 is provided with an apex aperture 8.
  • the hydrocyclone is fed from the feeder tank 21.
  • the level of the liquid in this tank is at a height H above the feed aperture 5.
  • the axial length of the hydrocyclone is denoted by L, the angle between the axis of the hydrocyclone and the vertical by a.
  • 11 is a collecting tank for the light fraction discharged through the vortex finder 7 and 12 is a collecting tank for the heavy fraction discharged through the apex aperture 8.
  • the collecting tank 11 is so constructed that the fraction removed through vortex finder 7 cannot flow back to pipe 7.
  • Example 1 Different samples of raw bituminous coal having particle sizes ranging from 0.5 to 10 mm., from Popemijn Emma, were washed in a conical hydrocyclone of the following dimensions:
  • Example 2 Raw coal fines were washed in a conical hydrocyclone of the following dimensions:
  • Axial length of the hydrocyclone -mm 1780 Diameter of the cylindrical section mm 700 Length of the cylindrical section mm 420 Feed aperture mm 86 176 Diameter of the vortex finder mm 300 Length of the vortex finder "mm” 420 Diameter of the apex aperture mm 220 Apex angle "degrees" 20
  • the axis of the hydrocyclone was horizontal and the hydrocyclone was fed from a tank situated at a height of 5.90 m. above the cyclone.
  • the separating suspension had a specific gravity of 1.53 and consisted of Water and magnetite, 95% by weight of which was smaller than 50
  • the feed contained a large percentage of slush, owing to which the viscosity of the suspension was high, which had an unfavourable influence on the result.
  • the enclosed area of the Tromp curve of the particles of 1-2 mm. was 62 cm. and the probable deflection amounted to 0.08, which, under the given conditions may be called very good.
  • Example 3 A mixture of sand and loess in water was classified in a conical hydrocyclone of the following dimensions:
  • the hydrocyclone was so positioned that its axis was horizontal and it was fed from a tank situated at a height of 3 m. above the cyclone. Under these conditions its capacity amounted to 53.3 in. per hour.
  • the suspension contained 50 grams of solid material per litre.
  • the grain distribution in the feed and the results of the classification appear from the following table:
  • Fig. 2 shows a diagram of an attractive application of the invention.
  • the feed conduit of the horizontal hydrocyclone 13 is directly coupled, via valve 14, to the short discharge pipe 15 of the deep wash box 16.
  • the column of suspension from the feed aperture of hydrocyclone 13 to the overflow trough 17 of wash box 16 provides the feed pressure H.
  • the mixture to be separated e. g. raw coal
  • the coal fraction is removed through the overflow trough 17, the shales and iniddlings through the discharge pipe 15.
  • the latter fraction is subsequently separated in hydrocyclone 13 into a waste fraction, caught in the collecting tank 19, and a fraction consisting of middlings, caught in collecting tank 20.
  • the amount of energy required to make the separation between the waste and the middlings is very small.
  • a process of separating a mixture of solid particles into fractions which comprises the steps of continuously feeding the mixture together with a liquid medium under pressure tangentially into a hydrocyclone having an axial length of at least 0.7 metre, whereby separated fractions are discharged from axial overflow and apex apertures at opposite ends of said hydrocyclone, the axis of said hydrocyclone being inclined relative to the vertical at a considerable angle, and adjusting the feed pressure of said mixture and medium to a value, expressed in head of feed, substantially less than six times the axial length of said hydrocyclone but large enough to maintain a central air column in said hydrocyclone.
  • a process of separating a mixture of solid particles into fractions which comprises the steps of continuously feeding the mixture together with a liquid medium under pressure tangentially into a hydrocyclone having an axial length of at least 0.7 metres, whereby separated fractions are discharged from axial overflow and apex apertures at opposite ends of said hydrocyclone, the axis of said hydrocyclone being inclined relative to the vertical at a considerable angle, and adjusting the feed pressure of said mixture and medium to a value expressed in head of feed, within the range of from 0.4 to 5.7 times the axial length of the hydrocyclone.

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  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Cyclones (AREA)
US360464A 1953-03-02 1953-06-09 Process for separating mixture of solid particles into fractions by means of a hydrocyclone Expired - Lifetime US2817441A (en)

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NL726510X 1953-03-02

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US (1) US2817441A (en(2012))
BE (1) BE526735A (en(2012))
DE (1) DE1022532B (en(2012))
FR (1) FR1097313A (en(2012))
GB (1) GB726510A (en(2012))

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2917173A (en) * 1957-08-21 1959-12-15 Rakowsky Victor Centrifugal method and apparatus for separating solids
US2982409A (en) * 1958-06-10 1961-05-02 Nichols Engineering And Res Co Separation of foam and other materials from liquid mixtures
US3008574A (en) * 1958-06-30 1961-11-14 Int Minerals & Chem Corp Method of treating ores
US3019901A (en) * 1959-07-01 1962-02-06 Bauer Bros Co Vacuum receiver and separator
US3456789A (en) * 1966-03-11 1969-07-22 Floatex Separations Ltd Classifiers for grading solid particles in a liquid suspension
US3901725A (en) * 1971-09-15 1975-08-26 Staley Mfg Co A E Size classified cereal starch granules
US4795037A (en) * 1986-05-07 1989-01-03 Rich Jr John W Process for separating high ash coal from refuse
US5676710A (en) * 1996-04-29 1997-10-14 Cli International Enterprises, Inc. Coal preparation system
US6638433B2 (en) 2002-03-12 2003-10-28 Sedgman, Llc System and method for controlling water-only cyclones
US8506824B1 (en) * 2012-05-16 2013-08-13 Charles M. Schloss Method for separating putrescible organic matter from inorganic grit suspended in waste water and sewage

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2588780B1 (fr) * 1985-10-17 1988-06-24 Sames Sa Installation de poudrage de pieces a cabine de poudrage maintenue en depression

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2639862A (en) * 1949-07-08 1953-05-26 Simon Ltd Henry Pneumatic elevator for flour mill stocks
US2668620A (en) * 1948-12-15 1954-02-09 Stamicarbon Multiple hydrocyclone

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE490371A (en(2012)) * 1948-11-29 1949-07-10

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2668620A (en) * 1948-12-15 1954-02-09 Stamicarbon Multiple hydrocyclone
US2639862A (en) * 1949-07-08 1953-05-26 Simon Ltd Henry Pneumatic elevator for flour mill stocks

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2917173A (en) * 1957-08-21 1959-12-15 Rakowsky Victor Centrifugal method and apparatus for separating solids
US2982409A (en) * 1958-06-10 1961-05-02 Nichols Engineering And Res Co Separation of foam and other materials from liquid mixtures
US3008574A (en) * 1958-06-30 1961-11-14 Int Minerals & Chem Corp Method of treating ores
US3019901A (en) * 1959-07-01 1962-02-06 Bauer Bros Co Vacuum receiver and separator
US3456789A (en) * 1966-03-11 1969-07-22 Floatex Separations Ltd Classifiers for grading solid particles in a liquid suspension
US3901725A (en) * 1971-09-15 1975-08-26 Staley Mfg Co A E Size classified cereal starch granules
US4795037A (en) * 1986-05-07 1989-01-03 Rich Jr John W Process for separating high ash coal from refuse
US5676710A (en) * 1996-04-29 1997-10-14 Cli International Enterprises, Inc. Coal preparation system
US6638433B2 (en) 2002-03-12 2003-10-28 Sedgman, Llc System and method for controlling water-only cyclones
US8506824B1 (en) * 2012-05-16 2013-08-13 Charles M. Schloss Method for separating putrescible organic matter from inorganic grit suspended in waste water and sewage

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Publication number Publication date
DE1022532B (de) 1958-01-16
BE526735A (en(2012))
FR1097313A (fr) 1955-07-04
GB726510A (en) 1955-03-16

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