US3575709A - Method of cleaning sugar crystals - Google Patents

Method of cleaning sugar crystals Download PDF

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Publication number
US3575709A
US3575709A US753966A US3575709DA US3575709A US 3575709 A US3575709 A US 3575709A US 753966 A US753966 A US 753966A US 3575709D A US3575709D A US 3575709DA US 3575709 A US3575709 A US 3575709A
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United States
Prior art keywords
crystals
bowl
liquid
magma
sugar
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Expired - Lifetime
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US753966A
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English (en)
Inventor
Francis X Ferney
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Bird Machine Co Inc
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Bird Machine Co Inc
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Publication date
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    • 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
    • B04B3/04—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering discharging solid particles from the bowl by a conveying screw coaxial with the bowl axis and rotating relatively to the bowl
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B15/00—Other accessories for centrifuges
    • B04B15/12—Other accessories for centrifuges for drying or washing the separated solid particles
    • C—CHEMISTRY; METALLURGY
    • C13—SUGAR INDUSTRY
    • C13B—PRODUCTION OF SUCROSE; APPARATUS SPECIALLY ADAPTED THEREFOR
    • C13B30/00—Crystallisation; Crystallising apparatus; Separating crystals from mother liquors ; Evaporating or boiling sugar juice
    • C13B30/04—Separating crystals from mother liquor
    • C13B30/06—Separating crystals from mother liquor by centrifugal force

Definitions

  • This invention relates to a method of treating a magma of sugar crystals.
  • the invention features a method for treating a magma of sugar crystals wherein the magma is continuously fed to a rotary impervious centrifuge bowl to form therein a pool in which most of the sugar crystals of the magma separate from the liquid under centrifugal force to form a bed of the crystals held against the inner surface of the bowl by the centrifugal force. Liquid is drained from the pool at a rate to maintain the pool volume substantially constant and the crystals in the bed are scrubbed by pushing and tumbling them along the surface of the bowl and against one another in the pool for sufficient time to remove a substantial amount of impurities therefrom into V the liquid of the pool.
  • the crystal bed is conveyed out of the pool onto an axially sloped drainage section of the bowl and the crystals are further scrubbed by pushing and tumbling the same along the surface of the drainage slope while draining a substantial part of the liquid from the bed.
  • the crystal bed is conveyed from the smaller radius end of the drainage slope to the inlet end of a rotating screen and further scrubbed by pushing and tumbling the crystals over the inner surface of the screen drum to the outlet end thereof while draining further liquid from the bed through the screen drum.
  • a wash is applied to the crystal bed during its residence in the screen drum; wherein the Wash is Water of the order of 1% by weight of the crystal bed in the screen drum; and wherein the crystal bed has a residence time in the pool of at least 8 seconds, a residence time on the drainage section sufficient to reduce the surface liquor content to about or less, and a residence time in the screen drum of at least 9 seconds.
  • FIG. 1 is a schematic illustration of a typical afiination process in the refining of cane sugar
  • FIG. 2 is a longitudinal section of a centrifuge as used in the method of the invention.
  • the afiination process is a suitable process for the application of the method of treatment of the invention. It comprises crystallization, hot mingling, and a processing of the resulting magma to wash the sugar crystals and separate them from the syrup.
  • FIG. 2 is a longitudinal section of such a centrifuge.
  • the centrifuge shown in FIG. 2 comprises a base 10 carrying at one end a bracket arm 12 supporting a fixed feed pipe 14 through the inlet end 16 of which is introduced the magma.
  • the centrifuge 'bowl indicated generally by the numeral 18 is mounted for rotation about a central axis.
  • Bowl 18 comprises imperforate cylindrical portion 20, imperforate frustoconical portion 22, and cylindrical screen portion 24.
  • a conveyor 26 mounted for rotation and having helical flights 28 secured to a hollow cylindrical core 30.
  • the conveyor 26 is a double helix having a live inch lead length.
  • Inlet pipe 14 extends into the interior of hollow core 30 which is provided with apertures 32 to permit the feed magma to pass from feed pipe 14 into the interior of bowl 18.
  • a pipe 34 for Wash fluid extends concentrically through the center of feed pipe 14 and discharges into a compartment in core 30 provided with nozzle outlets.
  • Bowl 18 and conveyor 26 are driven by drive mechanism (indicated at the left hand end of FIG. 2) in the same direction but at different speeds so that conveyor 26 rotates slowly with respect to bowl 18.
  • This arrangement causes the conveyor to advance the layer of solid particles deposited upon the inner surface of the bowl from the inlet end of the bowl toward the left hand or solids discharge end as seen in FIG. 2.
  • a casing 36 is mounted around the outside of bowl 18 and is provided with a solid discharge opening 38 and a liquid discharge opening 40.
  • a customary baflle system serves to maintain the solids discharge separate from the liquid discharge and the liquid discharges from the imperforate and screen sections separate.
  • annular baffles 46, 48, 50 fixed to the inside of casing 36 mate with corresponding baffles 46, 48, 50 secured to the outer face of bowl 18 for thi purpose.
  • an additional baflle 52 can be provided inside the casing 36 along with outlets 54 and 56 to segregate the liquid dis charges (wash liquid or mother liquor) from the various parts of the screen portion.
  • magma As the magma is introduced into bowl 18 it is formed into a pool by centrifugal force against the imperforate inner surface.
  • the surface of the pool intercepts the conical surface of the bowl at a zone A, the location of which is determined by the position of liquid overflow port 42.
  • a system of spray nozzles 58 connected to a suitable header or manifold 60 may be mounted on the part of casing 36 radially outwardly of screen portion 24. By supplying water or steam to the manifold when desired the nozzles may be used to clean the screen portion 24.
  • the bowl 18 and conveyor 26 are driven at appropriate differential speeds while the magma is introduced through inlet opening 16 and flows through inlet pipe 14 thence through apertures 32 in core member 30 to form a liquid pool by centrifugal force against the inner surface of the imperforate conical portion of bowl 18.
  • the liquid overflows into casing 36 and thence through a liquid discharge opening 40 in the bottom of the casing.
  • the solid particles in the magma being of greater density than the liquid, form a layer directly against the inner surface of bowl 18 and are urged along it by flights 28 of conveyor 26 from right to left as seen in FIG. 2.
  • wash liquid or vapor e.g. water or steam
  • pipe 34 may be introduced through pipe 34 to wash and/or dry the solid particles passing across screen portion 24.
  • the invention has been successfully practiced with a centrifuge as just described wherein the bowl 18 was 28 inches in length and had a diameter, at its widest point, of 18 inches. Bowl 18 was rotated at a speed of about 2000 rpm, developing a centrifugal force of about one thousand times gravity at the l8 inch diameter.
  • the feed rate and rate of rotation of the conveyor relative to the bowl were such as to provide a residence time of the crystals in cylindrical portion 20 of bowl 18 above about 8 seconds and in cylindrical screen portion 24 above about 9 seconds, the preferred minimum residence times in the practice of the process.
  • the drainage time between the pool and the screen section was such as to reduce the liquid content of the solids bed to 10% or less, as is desirable.
  • the size and speed of rotation of the bowl can of course be varied substantially while still observing the above preferred residence times provided sufiicient centrifugal force is developed to effect efficient solids separation from the liquid in the imperforate portion and liquid separation from the solids in the screen portion.
  • the centrifuge chosen to implement the method according to the invention entirely circumvents these difficulties and, in fact, operates best with thinner magma.
  • the typical 5 to 7 inch thick crystal cake in a batch centrifuge is most difficult to wash, due both to the thickness and the stationary aspect of the crystals in the bed (which results in channeling of wash water through the cake).
  • the centrifuge as used herein attained results superior to those of a batch machine (in terms of resultant crystal purity and color) using only one third the wash water typically required with the batch machine (1% vs. 3% of the weight of the crystals to be washed) while avoiding the control complications and processing time loss inherent in loading and unloading the batch machines.
  • Method for treating a magma of sugar crystals which comprises:
  • magma is of the order of 40 to 50 brix in sugar content.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • Organic Chemistry (AREA)
  • Centrifugal Separators (AREA)
  • Saccharide Compounds (AREA)
US753966A 1968-08-20 1968-08-20 Method of cleaning sugar crystals Expired - Lifetime US3575709A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US75396668A 1968-08-20 1968-08-20

Publications (1)

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US3575709A true US3575709A (en) 1971-04-20

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US753966A Expired - Lifetime US3575709A (en) 1968-08-20 1968-08-20 Method of cleaning sugar crystals

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US (1) US3575709A (xx)
BE (1) BE737639A (xx)
DE (1) DE1942136A1 (xx)
FR (1) FR2016986A1 (xx)
GB (1) GB1268972A (xx)
NL (1) NL6912713A (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4298161A (en) * 1978-10-23 1981-11-03 Wilkinson Rubber Linatex Limited Centrifuge
US4303192A (en) * 1979-07-05 1981-12-01 Hide Katsume Full jacket-worm centrifuge
DE3518885A1 (de) * 1985-05-25 1986-11-27 Bayer Ag, 5090 Leverkusen Vollmantelschneckenzentrifuge mit nachklaervorrichtung
US6290636B1 (en) * 2000-04-28 2001-09-18 Georg Hiller, Jr. Helix centrifuge with removable heavy phase discharge nozzles
US20050192173A1 (en) * 2004-02-07 2005-09-01 Thomas Broadbent & Sons Limited Washing of separated solids in solid bowl and screen bowl decanting centrifuges
US20090050036A1 (en) * 2007-08-20 2009-02-26 Card-Monroe Corp. Gauging element modules
US20120010065A1 (en) * 2008-11-28 2012-01-12 Alfa Laval Corporate Ab Decanter centrifuge with a hinged lid
US20180065129A1 (en) * 2015-03-10 2018-03-08 Ecofast Italia S.R.L. - Tecnologie Ambientali Separator for separating chopped food waste material

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0341433B1 (de) * 1988-05-11 1993-08-04 Flottweg Gmbh Vollmantel-Schnecken-Zentrifuge

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4298161A (en) * 1978-10-23 1981-11-03 Wilkinson Rubber Linatex Limited Centrifuge
US4303192A (en) * 1979-07-05 1981-12-01 Hide Katsume Full jacket-worm centrifuge
DE3518885A1 (de) * 1985-05-25 1986-11-27 Bayer Ag, 5090 Leverkusen Vollmantelschneckenzentrifuge mit nachklaervorrichtung
US6290636B1 (en) * 2000-04-28 2001-09-18 Georg Hiller, Jr. Helix centrifuge with removable heavy phase discharge nozzles
US20050192173A1 (en) * 2004-02-07 2005-09-01 Thomas Broadbent & Sons Limited Washing of separated solids in solid bowl and screen bowl decanting centrifuges
US7448992B2 (en) * 2004-02-07 2008-11-11 Thomas Broadbent & Sons Limited Washing of separated solids in solid bowl and screen bowl decanting centrifuges
US20090050036A1 (en) * 2007-08-20 2009-02-26 Card-Monroe Corp. Gauging element modules
US20120010065A1 (en) * 2008-11-28 2012-01-12 Alfa Laval Corporate Ab Decanter centrifuge with a hinged lid
US8235882B2 (en) * 2008-11-28 2012-08-07 Alfa Laval Corporate Ab Decanter centrifuge with a hinged lid
US20180065129A1 (en) * 2015-03-10 2018-03-08 Ecofast Italia S.R.L. - Tecnologie Ambientali Separator for separating chopped food waste material
US10589294B2 (en) * 2015-03-10 2020-03-17 Ecofast Italia S.R.L.—Tecnologie Ambientali Separator for separating chopped food waste material

Also Published As

Publication number Publication date
BE737639A (xx) 1970-02-19
DE1942136A1 (de) 1970-02-26
FR2016986A1 (xx) 1970-05-15
GB1268972A (en) 1972-03-29
NL6912713A (xx) 1970-02-24

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