GB2183586A - Treatment of particulate materials - Google Patents

Treatment of particulate materials Download PDF

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Publication number
GB2183586A
GB2183586A GB08628307A GB8628307A GB2183586A GB 2183586 A GB2183586 A GB 2183586A GB 08628307 A GB08628307 A GB 08628307A GB 8628307 A GB8628307 A GB 8628307A GB 2183586 A GB2183586 A GB 2183586A
Authority
GB
United Kingdom
Prior art keywords
duct
zone
ofthe
mask
mobilisation
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.)
Granted
Application number
GB08628307A
Other versions
GB2183586B (en
GB8628307D0 (en
Inventor
Roland Clift
Roger William Hedge
Robert Legros
Clive Alan Millington
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.)
British American Tobacco Investments Ltd
Original Assignee
British American Tobacco Co Ltd
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
Priority claimed from GB858530020A external-priority patent/GB8530020D0/en
Application filed by British American Tobacco Co Ltd filed Critical British American Tobacco Co Ltd
Priority to GB8628307A priority Critical patent/GB2183586B/en
Publication of GB8628307D0 publication Critical patent/GB8628307D0/en
Publication of GB2183586A publication Critical patent/GB2183586A/en
Application granted granted Critical
Publication of GB2183586B publication Critical patent/GB2183586B/en
Expired legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
    • A24B3/00—Preparing tobacco in the factory
    • A24B3/04—Humidifying or drying tobacco bunches or cut tobacco
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/40—Mixers using gas or liquid agitation, e.g. with air supply tubes
    • B01F33/409—Parts, e.g. diffusion elements; Accessories
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/0015—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
    • B01J8/0025—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor by an ascending fluid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/1818—Feeding of the fluidising gas
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/245—Spouted-bed technique
    • 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
    • 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
    • F26B3/06—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 flowing through the materials or objects to be dried
    • F26B3/08—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 flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed
    • F26B3/092—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 flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed agitating the fluidised bed, e.g. by vibrating or pulsating
    • F26B3/0926—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 flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed agitating the fluidised bed, e.g. by vibrating or pulsating by pneumatic means, e.g. spouted beds
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Combustion & Propulsion (AREA)
  • Combined Means For Separation Of Solids (AREA)

Description

SPECIFICATION Improvements relating to the treatment of particulate materials This inventionn relates to the treatment of particulate materials. The invention is particularly reievantto the treatment offibrous particulate materials such as, for example, cut lamina tobacco.
As used herein the term "fibrous particulate material" means particulate material a substantial proportion at least of which comprises individual particles of which one length dimension is large by comparison with the other two length dimensions.
Because of the presence of such elongate particles, within a body of fibrous particulate material there is a propensityforentanglement.
As used herein the term "mobilisation" means a controlled process in which in a body of particulate material individual particles are maintained in a separate condition so that the particles are free to move relatively to each other. With reference to fibrous particulate material, mobilisation further means that the material is wholly or substantially disentangled and maintained in a disentangled, particle separated condition.
As used herein the term "mobilising apparatus" means apparatus comprising wall means bounding a mobilisation zone, said wall means being upwardly divergent from the vertical, whereby the horizontal cross-sectional area of the mobilisation zone increases in an upward direction thereof, first, mobiiisation nozzle means operable to supply gaseous mobilising medium at a multiplicity of sites ofthewall means and second, acceleration nozzle means operable to supply gaseous accelerating medium in an upward direction from a location ata lower region ofthe mobilisation zone.
The horizontal cross-section ofthe mobilisation zone can be of various shapes, including square, rectangular, circular, elliptical and polygonal. The shape may be constant or may vary from one height location ofthe mobilisation zoneto another.Thewall means may in vertical cross-section be straight; alternatively the wall means may be curved, in concave or convex fashion, over a part or the whole ofthe upward extent thereof.If the horizontal cross-section ofthe mobilisation zone is of square shape, or of other shape having oppositely situated and parallel wall members ofthe wall means, such wall mernbers are preferably symmetrically configured with reference to a central vertical plane or axis The angle of upward divergence of such wall members is suitably in the region of 30 degrees if the apparatus is to be used for the treatment of cut lamina tobaccos.
At the bottom of the mobilisation zone the horizontal cross-section thereof should preferably be small in comparison with the horizontal cross-section at the top ofthe zone.
Suitably, the mobilisation nozzle means takes the form ofan array of perforations in the wall means.
The perforated wall means may bound plenum chamber means with which the perforations directly communicate.
As used herein the term "a method of treating particulate material", means a method wherein particulate material, fibrous particulate material for example, is maintained in a mobilised state in a mobilisation zone bounded by wall means upwardly divergent from the vertical, whereby the horizontal cross-sectional area ofthe mobilisation zone increases in an upward direction thereof, gaseous mobilising medium being supplied ata multiplicity of sites of the wall meanstothemobilisationzone whereby there obtains in said zone a circulatory pattern comprising downward flow atthe wall means and upwardflowfrom a lower region ofthe zone.
Advantageously, gaseous accelerating medium is supplied to the mobilisation zone in an upward direction from a location at a lower region ofthe zone.
The treatments of particulate materials which may be practised using the method or mobilisation apparatus ofthe type defined include drying, moistening, heating, cooling, blending, mixing, expanding or applying a flavourant or other additive.
The treatments may also include chemical treatments.
Air is a practicable mobilising medium and a practicable accelerating medium. Steam or other vapour or gas may be injected into the mobilised bed of particulate material, either directly or with the mobilising medium and/or accelerating medium.
Steam or othervapour or gas may be employed as mobilising and/or accelerating medium.
When the method of treating particulate material is carried out utilising an accelerating flow as well as a mobilisingflow,themobilisingflowservesto mobilise the fibrous or other particulate material and the accelerating flow serves to enhance the circulation, and thereby the mixing, of the mobilised body of particulate material. It has been found that when the only gaseous flow employed is an upward flow, fibrous particulate materials remain or become entangled and so are not mobilised in the sense above defined. For any one particulate material or mobilising apparatus constructed in accordance with the present invention there will be a finite range of mobilising and accelerating flow rates within which controlled operation is possible. These ranges may be readily ascertained by simple experiment.
The present invention provides mobiiising apparatus comprising discharging means, said discharging means comprising discharge duct meansandfurthercomprising mask means movable between an obturating position and a non-obturating position, said mask means when in said obturating position providing a gas-flow barrier extending outwardly of said duct means at the upper end ofthe mobilisation zone.
Preferably, the discharge duct means comprises a first, fixed duct and a second duct arranged for telescopic sliding movement with the first duct,the mask means being fixed to and extending from a lower end ofthe second duct.
When the mask means is in the obturating position thereof the mask means advantageously contacts walls ofthe mobilising apparatus.
The mask means may be of flat configuration.
Alternatively the mask means may in section be of a curved, or partly curved configuration.
The present invention also provides a method of treating particulate material, wherein gaseous accelerating medium is supplied to the mobiiisation zone in an upward direction from a location ata lower region of said zone and mask means is moved to an upper location of the mobilisation zone, at which location the mask means extends outwardly from a lower, open end of upwardly extending duct means, whereby the particulate material is pneumatically transported upwardly through the duct means.
In orderthatthe present invention may be clearly understood and readily carried into effect, reference will now be made, byway of example, to the accompanying drawings, in which Figure 7 shows, diagrammatically and in vertical section, mobilisation apparatus; Figure2 shows diagrammatically a perspective view of major parts ofthe apparatus of Figure 1; Figure 3 is a graph indicating the ranges of mobilising gasvelocity(axisA) andaccelerating gas velocity (axis B) for which controlled operation is possible when the apparatus of Figures 1 and 2 is used for drying a cut lamina tobacco; and Figure 4shows a view similarto that of lower portions of Figure 1 but also including an indication of a circulatory pattern in mobilisation zone ofthe apparatus.
The mobilisation apparatus of Figures 1 and 2 comprises an upwardly extending casing 1 of square horizontal section, the side walls ofthe casing 1 being designated by reference numerais 2-5. In Figure 2 parts of walls 2 and 3 have been removed. A lower part 6 of the casing 1 comprises upwardly diverentwalls, three of which walls are designated by reference numerals 7, 8 and 9 in Figures 1 and 2.
Trunking 10 extends downwardly from the lower end ofthe part 6 ofthe casing 1.
Disposed inwardly of and extending parallel to eachofthewallsofthepart6ofthecasing lisa diffuser plate, those of these plates observable in Figures 1 and 2 being designated by reference numerals 11, 12 and 13. Along the upper edge thereof each ofthese four diffuser plates contacts, in gas-tight fashion, a respective one ofthe side walls 2-5 ofthe casing 1. Each of the diffuser plates comprises an array of perforations, the perforations in plate 12 being designated 14 and those of plate 13 being designated 15. The diffuser plates bound a mobilisation zone.
A pipe 16 extends through the wall of the trunking 10 and, as is indicated in Figure 1, joins at its upper end the lower convergent ends of the diffuser plates.
Fitted across the pipe 1-6 at its upper end is an orifice plate 17.
Discharging means of the mobilisation apparatus comprisesatrunking 18, providing afirst partof discharge duct means, and a movable, gas impervious flange member 19 providing mask means.
The trunking 18, which is fixed relative to the casing 1, extends from a location within the casing 1, which location is vertically spaced above the lower part8 of the casing 1,through an upper end wall 20 of the casing 1.
The flange member 19 is attached to and extends horizontally from the periphery of a length of inner trunking 21, providing a second partofthedischarge duct means, at a lower end of the trunking 21, to the foursidewalls 2-5 ofthe casing 1. The outer side edges of the member 19 are provided with gas-tight seal means designated 19'. As depicted in Figure 1, the member 19 is at an upper position thereof and the trunking 21 is disposed wholly within the trunking 18,from which itis held in spaced relationship by spacing means 22 and 23 attached to thetrunking21.
The discharging means further comprises actuation means operable to move the flange means 19, together with the innertrunking 21, between the upper position thereof and a lower position thereof, which lower position, shown in broken line in Figure 1, is close above the lower part 6 ofthe casing 1. The actuation means, which for the sake of simplicity is not shown in Figure 2, may comprise, for example, two pneumatic cylinder and piston or other linear actuation units 24 and 25. Cylinders 26 and 27 of the units 24,25 are disposed, in vertical orientation, at locations above and fixed relatively ofthe casing 1.
Extended rods pass downwardly through glands 30 and 31, located in the top wall 20 ofthe casing 1, into attachment with the flange member 19.
In use ofthe mobilisation apparatusforthe purpose of, for example, drying moist cut lamina tobacco, a quantity of the tobacco is disposed within the space jointly defined bythefourdiffuser plates.
Suitably, the tobacco is introduced into the casing 1 via the trunking 18 and 21 from tobacco charging means (not shown).
With the flange member 19 in the upper position thereof, warm mobilising air is supplied under low pressure to thetrunking 10, from which it passes to the spaces between the walls of part 6 ofthe casing 1 and the associated diffuser plates and from there through the diffuser plate perforations into contact with the tobacco. Concurrently, warm accelerating air is supplied under low pressure to the pipe 16, from which it issues in a vertically upward direction into the tobacco charge. When starting up the process, it is preferable for the mobilising flowto be established before initiation of the accelerating flow.
As a result of the geometry of the mobilisation zone and ofthe provision of mobilising air and accelerating airthere is obtained a controlled mobilisation of the cut tobacco. Such mobilisation results in adisentanglementoftheelongatefibres and the attainment of a close approach to a perfect mixing condition.
The hatched area shown in Figure 3 represents the zone of controlled operation of the mobilisation apparatus in terms of the superficial velocity ofthe accelerating air (abscissa B).
In Figure 4there is indicated the circulatory pattern of air and entrained tobacco particles which obtains in the mobilised bed. It may be observed thatthere are downward flows at the sloping walls defining the mobilisation zone and an upward flow centrally of the zone. The circulatory pattern further comprises outward flows from the central zone. The mobilised bed is located substantiallywhollywithin the space defined by the divergent walls, i.e. diffuser plates, although, as shown, the bed does extent two a location above the upper ends ofthe diffuser plates.
The basic circulatory pattern just referred to is established by the mobilising flow, but is enhanced by the presence of the accelerating flow.
The circulatory flow is, of course, superimposed upon a general upward flow ofairwithin the apparatus.
When it is desired to discharge the tobacco from the mobilisation apparatustheflange member19is moved to the lower position thereof under action of the cylinder and piston units 24,25. When the member 19 occupies its lower position the member 19 obturates the space between lower end ofthe trunking 21 and the side walls 2-5 ofthe casing 1 ata vertical location of the casing 1 such that the above mentioned circulatory pattern is destroyed. As a resultthe upward airflow in the central zone isso significantly increased that the tobacco becomes subject to pneumatic transport upwardly th rough thetrunking 18and21.Thetrunking 18mayatitsend remote the casing 1 be connected to an air/tobacco separator (not shown).
Whereas as shown in Figures 1 and 2 the walls 2-5 ofthe casing 1 extending vertically, it could be arranged for these walls to be gently downwardly convergent such thatthe outer edges ofthe flange member 19 contact the walls only when the flange member has been lowered to its lower, circulatory-pattern destroying position.

Claims (8)

1. Mobilising apparatus comprising discharging means, said discharging means comprising upwardly extending discharge duct means and further comprising mask means movable between an obturating position and a non-obturating position, said mask means when in said obturating position providing a gas-flow barrier extending outwardly of said duct means at the upper end ofthe mobilisation zone.
2. Apparatus as claimed in Claim 1, wherein said duct means comprises a first, fixed duct and a second duct telescopically slidable relative to said first duct.
3. Apparatus as claimed in Claim 1 or 2, wherein said mask means is secured to said duct means.
4. Apparatus as claimed in Claim 1,2 or3, wherein when said mask means is in said obturating position, the outer edges of said mask means are in contactwith wall means of said apparatus.
5. Apparatus as claimed in any one of the preceding claims in which said discharging means further comprises actuation means operable to move said flange means between the obturating and non-obturating positions thereof.
6. A method of treating particulate material, wherein gaseous accelerating medium is supplied to the mobilisation zone in an upward direction from a location at a lower region of said zone and mask means is moved to an upper location ofthe mobilisation zone, at which location the mask means extends outward ly from a lower, open end of upwardly extending duct means, whereby the particulate material is pneumaticallytransported upwardly th rough the duct means.
7. Mobilisingapparatussubstantiallyas hereinabove described with reference to Figures 1,2 and 4 hereof.
8. A method of discharging particulate material from mobilising apparatus, substantially as hereinabove described with reference to the drawings hereof.
GB8628307A 1985-12-05 1986-11-26 Improvements relating to the treatment of particulate material Expired GB2183586B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8628307A GB2183586B (en) 1985-12-05 1986-11-26 Improvements relating to the treatment of particulate material

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB858530020A GB8530020D0 (en) 1985-12-05 1985-12-05 Treatment of particulate materials
GB8628307A GB2183586B (en) 1985-12-05 1986-11-26 Improvements relating to the treatment of particulate material

Publications (3)

Publication Number Publication Date
GB8628307D0 GB8628307D0 (en) 1986-12-31
GB2183586A true GB2183586A (en) 1987-06-10
GB2183586B GB2183586B (en) 1989-10-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8628307A Expired GB2183586B (en) 1985-12-05 1986-11-26 Improvements relating to the treatment of particulate material

Country Status (1)

Country Link
GB (1) GB2183586B (en)

Also Published As

Publication number Publication date
GB2183586B (en) 1989-10-04
GB8628307D0 (en) 1986-12-31

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PCNP Patent ceased through non-payment of renewal fee