US3537591A - Continuously operating centrifuge - Google Patents

Continuously operating centrifuge Download PDF

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Publication number
US3537591A
US3537591A US779960A US3537591DA US3537591A US 3537591 A US3537591 A US 3537591A US 779960 A US779960 A US 779960A US 3537591D A US3537591D A US 3537591DA US 3537591 A US3537591 A US 3537591A
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US
United States
Prior art keywords
drum
scraper
solids
cake
centrifuge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US779960A
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English (en)
Inventor
Dirk Hoks
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STORK WERKSPOOR SUGAR NV
Original Assignee
STORK WERKSPOOR SUGAR NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by STORK WERKSPOOR SUGAR NV filed Critical STORK WERKSPOOR SUGAR NV
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Publication of US3537591A publication Critical patent/US3537591A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B3/00—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/08—Skimmers or scrapers for discharging ; Regulating thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/08—Skimmers or scrapers for discharging ; Regulating thereof
    • B04B2011/086—Skimmers or scrapers for discharging ; Regulating thereof with a plurality of scraper blades

Definitions

  • the invention relates to a continuously operating centrifuge for separating a given mixture of solid constituents and liquid,
  • the object of the invention is to'providea centrifuge of this type in which the above-problem is solvcd-ina simple manner.
  • the sieve drum maybe in the form of a cone or any other suitable body of revolution.
  • the inventiomeach scraper may have a porous or finely perforated part, behind the cutting edge, said part extending overthe entire'height of thescraper, and a pressure mediumcan besupplied to said part via the hollow scraper, said medium emerging uniformly over the entire surface of said part.
  • a pressure medium can besupplied to said part via the hollow scraper, said medium emerging uniformly over the entire surface of said part.
  • the speed and the pressure of the medium may be low so that standard blowers'and pumps can be used to deliver the medium.
  • A'centrifuge of this type is very suitablefor the treatment of sensitive material because there-is. no direct contact betweenthe. scraper and the material during transport, so that there is little chance of damage to the material.
  • the scraper part situated behind the cutting edge may bemadecfrorn such a material over the entire heightof the scraper and may have such a smooth finish that the coefficient of friction between the said part and the cake is less thanthe coeff cient of friction'betweenthe drum surface and the cake.
  • Acentrifuge'of thistype is simpler to construct because it is not; necessary to, use any medium under pressure although in that case there islthejdisadvantag ethat the material of the cake which is to be transported has to move along the scraper surface, thus increasing the chance ,of mechanical damage.
  • the, scraper part situated behind the cutting edge may form an angle, over the entire height of the scraper in a plane-through the axis of rotation, with said axis. such angle being-larger than the angleformed by the'wall of the drum with the said axis, and the tangent of this angle between the scraper surface and the axis is, greater than the coefficient of friction-between thecake and the scraper surface.
  • the scrap'ers constructed in the form of a hollow body may have a' channel which extends over the entire height, and the bottom of which forms the scraper part situated behind the cutting edge to allow the cake to slide off.
  • FIG. 1 is a vertical section of a centrifuge according to the invention
  • FIG. 2 is a-section on the line ll-II in FIG. 1;
  • FIG. 3 is a detail of FIG. 2 to an enlarged scale
  • FIG. 4 is a diagram showing the equilibrium of forces on the cake in the drum
  • FIG. 5 is a diagramshowing the equilibrium of forces on the cake on the scraper
  • FIG. 6 is a diagram showing the equilibrium of forces on the cake on the scraper in a slightly modified embodiment.
  • a hub 2 is fastened on a shaft I and bears a centrifuge drum 4 by means of spokes 3.
  • the inner wall of the drum 4 is formed by a sieve wall 5 constructed from rings or made from a perforate plate.
  • the liquid separated in the centrifuge is passed through small openings left between the rings, or through the perforations in the sieve wall' 5.
  • the latter is supported by rings 6 which are provided onthe inside of the drum and which have passages.
  • the drum extends conically so that the liquid passing through the ,sieve wall is conveyed downwards along the drum under the influence of centrifugal force.
  • the liquid flows out via openings7 and along the edge 8 to a channel 9 on the inside of the casing 10.
  • the channel 9 is provided with an outlet spigot 11 to discharge the liquid.
  • the shaft 1 is surrounded by a hollow shaft 12 which is guided on the shaft 1 by means of bearings 13 and 14.
  • the axial forces are talten by an axial bearing 15.
  • a drum 16 is connected to theshaft l2 by a baseplate 17.
  • the drum 16 has a volute portion and a cylindrical portion.
  • the volute portion 18 of the drum 16 has two chambers 19 at two diametrically opposite openings, the said chambers 19 extending over the entire height of the sieve wall 5 and having an outlet slot 20 near the sieve wall.
  • a chamber'22 is formed adjacent each chamber 19.
  • the chambers 22 are providedwith a scraper 23 which also extends over the entire height of the sieve wall.
  • the scrapers 23 have a channelshaped cavity over the entire height, with a base 24 extending parallel to the sieve wall 5.
  • a hose 30 is connected to the shaft 1 via a gland 29.
  • Agas for example air, at slight excess pressure, can be fedviathis hose to a bore 31 in the shaft 1, from which the gas is fedto chamber 28 via transverse bores 32.
  • the baseplate 17 has openings through'which-the product removed by the scraper can drop down into the funnel 34 connected to the casing 10.
  • a number of sprays 35 are also secured to the drum 16 and co-rotate therewith and with the hollow shaft 12.
  • the sprays 35 distribute a washing liquid over the centrifuged product and can be adjusted .so that the washing time can be varied with respect to the centrifuging time according to the required washing effect.
  • the washing liquid can be fed to the sprays 35 in a manner not shown, via a gland 36.
  • a channel 38 leads into the cylinder part 37 of the drum 16 and the material to be centrifuged can be fed to the volute casing 18 via said channel.
  • a gearbox 41 is secured to the bearing block 39 and can follow oscillations of the shafts 1 and 12.
  • Shaft l bears a gearwheel 42 coupled via two intermediate gearwheels 43 and 44 to gearwhcel 45 secured .on the hollow shaft 12.
  • the transmission ratio between the gcarwheels 42 and 45 is such that the speed difference between the shafts 1 and 12 is very small. This speed difference determines the centrifuging time. The latter can be adjusted as required by varying the transmission ratio of these gearwheels.
  • the centrifuge operates as follows: the mixture to be contrifuged is fed to the cylindrical chamber 37 via the channel 38 and then flows to the volute chamber 18 and is then deposited on the sieve wall 5 via the supply chambers 19 and the outlet apertures 20.
  • the thickness of the layer deposited on the sieve wall 5 is determined by the width of the slots 20. Since the chambers 19 move slowly with respect to the sieve wall, material is continually deposited on the sieve wall 5 and is lifted off said wall after some time by the scraper 23 situated diametrically opposite.
  • the liquid emerges from the centrifuged mixture through the sieve wall 5 and passes to the discharge channel 9, from which the liquid is discharged via the spigot 11.
  • FIG. 4 illustrates the forces acting on a small portion 46 of the cake deposited on the sieve wall.
  • the drum wall forms an angle a with said axis.
  • the centrifugal force C acts on part 46 in the outward direction and this force can be divided up into a component C,. directed at right angles to the sieve wall and a component C,, directed along the wall.
  • the particle 46 is retained by the frictional force W acting along the wall.
  • the frictional force W is equal to the force N extending at right angles to the wall, multiplicd by the coefficient of friction fhctwcen the wall and the particle 46.
  • the force N is equal to C...
  • the angle a is so selected that the coefficient of frictionfis equal to or slightly greater than tan a. This means that the particle 46 just continues to remain on the sieve wall 5 during the centrifuging process.
  • FIG. 6 shows another embodiment.
  • the surface 24 of the scraper in this case forms a larger angle with the axis of rotation than the sieve wall 5. This means that for a constant coefficient of friction the component C,, of the centrifugal force becomes larger than the opposing frictional force W. The particle 46 is again no longer in equilibrium and will slide down along the surface 24.
  • the constructions shown in FIGS. and 6 can be combined. in which case the driving force C increases and the counteracting frictional force W decreases.
  • a centrifuge assembly for continuous recovery of solids from a liquid-solids mixture comprising in combination:
  • scraper means within said drum for removing said cake and discharging the removed solids of the cake toward one end ofthe drum;
  • said scraper means including a surface facing inwardly with respect to the axis of rotation and against which said removed solids of the cake are engaged by centrifugal force, said surface being inclined along its length outwardly with respect to its axis of rotation toward said one end of the drum by an amount sufficient to produce, due to its rotation, a component of centrifugal force acting on the removed solids of the cake parallel to said surface toward said one end of the drum which exceeds the frictional resistance to movement of said removed solids ulong suid surface due to the own ponent of centrifugal force acting normal to such surface whereby to feed the removed solids of the cake continuously therealong to a region outside said drum.
  • a centrifuge for continuous recovery of solids from a liquid-solids mixture comprising in combination:
  • scraper means within said drum for removing said cake and discharging the removed solids of the cake toward one end ofthe drum;
  • said scraper means including a surface facing inwardly with respect to the axis of rotation and receiving the removed solids, such surfucc being inclined ulong its length outwurdly with respect to the axis of said drum towurd said one end ofthe drum sufficiently to cause migration of the removed solids therealong due to that component of the centrifugal force which is parallel to such surface.
  • a centrifuge for continuous recovery of solids from a liquid-solids mixture comprising in combination:
  • a drum of porous material having a frusto-conical inner surface; means for feeding the liquid-solids mixture against the inner surface of said drum;
  • the coefficient of friction between said solids and the inner surface of said drum being sufficient to prevent axial migration of said solids relative to said drum whereby said solids tend to build up as a cake upon the inner surface of said drum; scraper means within said drum; and means for rotating said scraper means at a speed slightly different from the speed of rotation of said drum so that said scraper means moves slowly with respect to said drum continuously to remove said cake, and said scraper means including a surface portion extending axially within said drum and facing inwardly with respect'to the axis of rotation for receiving the cake as it is removed and said surface portion being inclined along its length in the same direction as the inner surface of said drum by an amount sufficient to produce a component of centrifugal force acting on the removed solids parallel to said surface which exceeds the frictional resistance to movement of said removed solids along said surface, to feed the removed solids outwardly of the drum under the influence of the centrifugal force acting thereon.

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  • Centrifugal Separators (AREA)
US779960A 1967-12-02 1968-11-29 Continuously operating centrifuge Expired - Lifetime US3537591A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6716436A NL6716436A (xx) 1967-12-02 1967-12-02

Publications (1)

Publication Number Publication Date
US3537591A true US3537591A (en) 1970-11-03

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ID=19801885

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Application Number Title Priority Date Filing Date
US779960A Expired - Lifetime US3537591A (en) 1967-12-02 1968-11-29 Continuously operating centrifuge

Country Status (8)

Country Link
US (1) US3537591A (xx)
JP (2) JPS4840505B1 (xx)
BE (1) BE724783A (xx)
CH (1) CH495781A (xx)
FR (1) FR1595895A (xx)
GB (1) GB1252893A (xx)
NL (2) NL6716436A (xx)
SE (1) SE347441B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140256528A1 (en) * 2011-11-24 2014-09-11 Bma Braunschweigische Maschinenbauanstalt Ag Discontinuous centrifuge with a scraper for scraping a product
CN107876219A (zh) * 2017-10-27 2018-04-06 无锡艾科瑞思产品设计与研究有限公司 一种上悬式离心机
CN110665283A (zh) * 2019-10-29 2020-01-10 朱海艳 一种果汁饮料生产用果渣过滤装置

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50146967A (xx) * 1974-05-17 1975-11-25
JPS5312469U (xx) * 1976-07-12 1978-02-01
JPH05319421A (ja) * 1992-05-13 1993-12-03 Shichizun Shoji Kk 小物セット製品の包装方法及び包装された小物セット製品
CN110124882B (zh) * 2019-06-24 2020-12-25 陕西陕煤韩城矿业有限公司 一种调节矿用离心机筛篮与刮刀间隙的方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140256528A1 (en) * 2011-11-24 2014-09-11 Bma Braunschweigische Maschinenbauanstalt Ag Discontinuous centrifuge with a scraper for scraping a product
US9764337B2 (en) * 2011-11-24 2017-09-19 Bma Braunschweigische Maschinenbauanstalt Ag Discontinuous centrifuge with a scraper for scraping a product
CN107876219A (zh) * 2017-10-27 2018-04-06 无锡艾科瑞思产品设计与研究有限公司 一种上悬式离心机
CN110665283A (zh) * 2019-10-29 2020-01-10 朱海艳 一种果汁饮料生产用果渣过滤装置

Also Published As

Publication number Publication date
NL131232C (xx)
FR1595895A (xx) 1970-06-15
SE347441B (xx) 1972-08-07
JPS4840505B1 (xx) 1973-11-30
CH495781A (de) 1970-09-15
BE724783A (xx) 1969-05-16
GB1252893A (xx) 1971-11-10
JPS4938664B1 (xx) 1974-10-19
NL6716436A (xx) 1969-06-04
DE1812030A1 (de) 1969-07-03

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