US3839802A - Desiccator for wet powder particles - Google Patents

Desiccator for wet powder particles Download PDF

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Publication number
US3839802A
US3839802A US00280205A US28020572A US3839802A US 3839802 A US3839802 A US 3839802A US 00280205 A US00280205 A US 00280205A US 28020572 A US28020572 A US 28020572A US 3839802 A US3839802 A US 3839802A
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US
United States
Prior art keywords
powder particles
hot gas
wet powder
cylinder
drying zone
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
US00280205A
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English (en)
Inventor
S Saito
H Nakamura
T Watanabe
H Wakamori
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Kureha Corp
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Kureha Corp
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Publication date
Application filed by Kureha Corp filed Critical Kureha Corp
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Publication of US3839802A publication Critical patent/US3839802A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/10—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers
    • F26B17/101—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers the drying enclosure having the shape of one or a plurality of shafts or ducts, e.g. with substantially straight and vertical axis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
    • B29B13/00—Conditioning or physical treatment of the material to be shaped
    • B29B13/06—Conditioning or physical treatment of the material to be shaped by drying
    • B29B13/065—Conditioning or physical treatment of the material to be shaped by drying of powder or pellets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
    • F26B3/10—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour carrying the materials or objects to be dried with it

Definitions

  • ABSTRACT Anderson Attorney, Agent, or FirmWenderoth, Lind & Ponack [5 7 ABSTRACT A desiccator for wet powder particles of synthetic high polymer substance, the main construction of which is a long vertical cylinder having a material feeding inlet at a lower part on the peripheral wall thereof and an inverse conical section forming the bottom part of the cylinder, a high speed hot gas current inlet being provided at the vertical angle of the inverse conical section, and the top end of the cylinder being communicated to a cyclone for collecting the dried product through a conveying tube.
  • This invention relates to a desiccator, or a drying apparatus. More particularly, it is concerned with a desiccator for wet powder particles of synthetic high polymer substances.
  • a desiccating device in which a dryer is combined with mechanical means for dividing the mass of wet powder particles such as, for instance, a cage mill, or other mechanical expedientprovided with a rotary body. While a remarkable effect of division can be obtained from this type of apparatus, if the mass to be divided is one that is highly agglomerative, there inevitably occur various problems such as notorious adherence of the wet, massive powder particles to the crusher main body or to the inner peripheral portion thereof.
  • such adhered material not only mixes into the final product later on to lower the quality of the product, but also causes inflammation and fire, when the adhered material is exposed in a high temperature circumstance for a long period of time, which is serious from the standpoint of operation and maintenance of the installation.
  • the present inventors conducted a long series of studies and experiments, as the result of which they have succeeded in building an improved desiccating apparatus free from these disadvanges.
  • FIGURE is a schematic structural diagram of an embodiment of the present invention.
  • the desiccator according to the present invention is much simpler in its construction than that of the known apparatus.
  • the main part of the apparatus is a vertical cylinder 3, the bottom part 1 of which is in an inverse conical shape with an inlet 2 for high speed hot gas current at the bottom center part thereof, and the upper part of which is connected with a conveying tube 5 for the desiccated product, which further communicates to a cyclone 6 for collecting the dried product therein and a gas exhaust tube 7.
  • the cylinder 3 is also provided at one position on its peripheral wall in the vicinity of the bottom part 1 with an inlet 4 for feeding raw material to be desiccated.
  • the cross-sectional area of the cylinder is necessarily from 10 to times as large as that of the inlet 2 for high speed hot gas current, and the total length (or height) of the cylinder 3 should be from 5 to 10 m long at least.
  • the interior of the cylinder 3 need not be provided with any special devices such as a crusher for agglomerated masses of wet powder particles or a sieve for screening such crushed powder particles.
  • the size of the agglomerates is reduced to a certain extent within a feeding apparatus before the desiccator, and an average diameter thereof is about 5 cm or less.
  • the required speed of the hot gas current to blow this size of the particles upwardly is at least 30- m/sec..
  • the hot gas current is the highest possible in speed to exert much more breaking force against the agglomerates of the wet powder particles
  • most of the masses of powder particles of synthetic high polymer can be sufficiently divided into individual particles at a current speed of 150 m/sec.
  • the hot gas current having an extremely high speed is obtained by an increased outlet pressure for a blower, and it is difficult to maintain constant the current speed within the cylinder.
  • a preferable speed of the hot gas current is therefore from 30 to 150 m/sec..
  • the average speed of the hot gas current within the cylinder is determined by the particle size, specific gravity and shape of the material to be desiccated. It is necessary that the average current speed be chosen within a range between the end speed of the largest powder particles in the material to be dried and the end speed plus 2 m/sec.. If a current speed lower than this range is selected, any powder particles having higher end speed than the current speed within the cylinder remain in the cylinder without being discharged therefrom. On the contrary, when a current speed higher than this range is selected, thepowder particles are discharged out of the cylinder without sufficiently dcssicated and without masses of powder particles being completely broken up. Generally, in the case of synthetic high polymer particles, effective dividing and drying of the powder particles can be attained at the selected current speed of from 1.5 to 5 m/sec..
  • the cylinder should have a sharp expansion of the space at the apex of the inverse conical section constituting the inlet for high speed hot gas current into the cylinder main body where the current speed somewhat slows down, whereby violent turbulence occurs at the expanded portion of the cylinder to flush the inner surface of the inverse conical section so as to prevent the wet powder particles from adhering thereonto.
  • the apex angle of the inverse conical section is preferably in the range of 60
  • the total length of the cylinder constitutes the third important point.
  • the height at which the blown-up masses lose their speed and drop downward depends on the flow-rate of the high speed hot gas current, and size, shape and weight of the agglomerated mass.
  • the total length of the cylinder should be made greater than a value represented by a relationship of(0.05V 3m), where V is from to 150 meters and the numerical value thereof corresponds to the numerical value of the distance of the flow of the high speed hot gas current per second.
  • length of the cylinder portion from the material feeding inlet to the outlet at the top thereof should be at least 3 meters, and the position of the material feeding inlet on the peripheral wall of the cylinder should preferably be at a distance of from k to l/20 of the diameter of the cylinder but not exceeding l/ 10 of the total length of the cylinder from the bottom end thereof.
  • hot air is blown into the cylinder 3 constituting the dryer main body from the hot gas current inlet 2 at the bottom thereof at a high speed hot gas current of from to 150 m/sec..
  • wet powder particles of synthetic high polymer are continuously fed from the material feeding inlet 4.
  • the powder particles thus fed into the cylinder 3 are dispersed and dried in the cylinder by the high speed hot gas current from the inlet 2.
  • agglomerated masses in the wet powder particles are also divided by this high speed hot gas current into individual fine particles.
  • the entrance speed of the high speed hot gas current as well as the average speed of the same within the cylinder according to the present invention may be varied.
  • high speed hot gas current 40 to 150 m/sec. and an average speed within the cylinder of 1.5 to 5 m/sec. can effectively carry out the drying.
  • EXAMPLE 1 M resin having a particle size range of from 44 to 1,000 microns and a moisture content of 50% was fed at a rate of 18 kg/hr. into a desiccator constructed with a cylinder main body of 30 cm in diameter and 800 cm in height, the bottom part of which forms an inverse conical section having an apex angle of 60.
  • the bottom center of the inverse conical section is provided with a high speed hot gas current inlet of 5.5 cm in diameter.
  • a material feeding inlet of 8 cm in diameter is provided at a position 10 cm away from the bottom end of the cylinder main body.
  • the drying operation was conducted under the following conditions.
  • ABS resin having particle size range of from 44 to 500 microns and a moisture content of 40% was fed at a rate of 40 kg/hr. into a desiccator constructed with a cylinder main body of 30 cm in diameter and 600 cm in height, the bottom part of which forms an inverse conical section having a the vertical angle of 60.
  • the bottom center of the inverse conical section is provided with a high speed hot gas current inlet of 10 cm in diameter.
  • a material feeding inlet of 8 cm in diameter is provided at a position 10 cm away from an bottom end of the cylinder main body.
  • the drying operation was conducted under the following conditions.
  • a method for desiccating wet powder particles of synthetic high polymer substance which comprises the steps of:
  • a method for desiccating wet powder particles of synthetic high polymer substance which comprises the steps of:
  • blowing into the defined drying zone a stream of high speed hot gas at a temperature of from 70 to 200C at a flowrate of 30 to m/sec. and having a cross-section from l/lO to l/ 100 the crosssectional area of the defined zone to cause fluidization of said powder particles within the defined drying zone for dividing the agglomerated masses into individual fine particles, dispersing and sufficiently drying the fine particles within the drying zone;
  • the speed of the hot gas stream being sufficient to maintain the average speed of the hot gas through the defined drying zone at 1.5 to 5.0 m/sec.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Drying Of Solid Materials (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
US00280205A 1971-08-18 1972-08-14 Desiccator for wet powder particles Expired - Lifetime US3839802A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6231471A JPS5551723B2 (fr) 1971-08-18 1971-08-18

Publications (1)

Publication Number Publication Date
US3839802A true US3839802A (en) 1974-10-08

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ID=13196534

Family Applications (1)

Application Number Title Priority Date Filing Date
US00280205A Expired - Lifetime US3839802A (en) 1971-08-18 1972-08-14 Desiccator for wet powder particles

Country Status (8)

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US (1) US3839802A (fr)
JP (1) JPS5551723B2 (fr)
BE (1) BE787784A (fr)
DE (1) DE2240524A1 (fr)
FR (1) FR2151878A5 (fr)
GB (1) GB1379833A (fr)
IT (1) IT964093B (fr)
NL (1) NL158608B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3998596A (en) * 1973-06-04 1976-12-21 Onoda Cement Company, Ltd. Apparatus for treating by-product gypsum to be used as an inhibitor for setting of cement
US4118196A (en) * 1973-06-13 1978-10-03 Onoda Cement Company, Limited Apparatus for calcining wet powdery gypsum

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60115032U (ja) * 1984-01-13 1985-08-03 松下電工株式会社 ミラ−キヤビネツト
DE58906032D1 (de) * 1988-12-23 1993-12-02 Buehler Ag Verfahren und Vorrichtung zum kontinuierlichen Kristallisieren von Polyestermaterial.
JPH03195888A (ja) * 1989-12-26 1991-08-27 Sanii Package:Kk 粉粒体の乾燥方法ならびにその装置
JP5943256B2 (ja) * 2013-04-15 2016-07-05 沖縄パウダーフーズ株式会社 バガス粉末の製造方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486346A (en) * 1945-02-21 1949-10-25 Rca Corp Apparatus for plasticating thermoplastic materials
US2786280A (en) * 1954-03-12 1957-03-26 Ca Nat Research Council Method of contacting solid particles with fluids
US2903800A (en) * 1955-07-05 1959-09-15 Svenska Flaektfabriken Ab Turbulent pneumatic driers for granular and pulverulent material
US3066017A (en) * 1953-07-28 1962-11-27 Exxon Research Engineering Co Control of flow of particulate solids
US3263338A (en) * 1963-09-26 1966-08-02 Combustion Eng Flash drying system for fine coal
US3273257A (en) * 1963-07-09 1966-09-20 Rietz Mfg Co Air lift drier
US3399462A (en) * 1965-08-04 1968-09-03 Hauni Werke Koerber & Co Kg Apparatus for treating tobacco and the like

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486346A (en) * 1945-02-21 1949-10-25 Rca Corp Apparatus for plasticating thermoplastic materials
US3066017A (en) * 1953-07-28 1962-11-27 Exxon Research Engineering Co Control of flow of particulate solids
US2786280A (en) * 1954-03-12 1957-03-26 Ca Nat Research Council Method of contacting solid particles with fluids
US2903800A (en) * 1955-07-05 1959-09-15 Svenska Flaektfabriken Ab Turbulent pneumatic driers for granular and pulverulent material
US3273257A (en) * 1963-07-09 1966-09-20 Rietz Mfg Co Air lift drier
US3263338A (en) * 1963-09-26 1966-08-02 Combustion Eng Flash drying system for fine coal
US3399462A (en) * 1965-08-04 1968-09-03 Hauni Werke Koerber & Co Kg Apparatus for treating tobacco and the like

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3998596A (en) * 1973-06-04 1976-12-21 Onoda Cement Company, Ltd. Apparatus for treating by-product gypsum to be used as an inhibitor for setting of cement
US4118196A (en) * 1973-06-13 1978-10-03 Onoda Cement Company, Limited Apparatus for calcining wet powdery gypsum

Also Published As

Publication number Publication date
JPS4828557A (fr) 1973-04-16
JPS5551723B2 (fr) 1980-12-26
NL158608B (nl) 1978-11-15
IT964093B (it) 1974-01-21
FR2151878A5 (fr) 1973-04-20
DE2240524A1 (de) 1973-02-22
BE787784A (fr) 1972-12-18
GB1379833A (en) 1975-01-08
NL7211246A (fr) 1973-02-20

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