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AssigneeGlatt Air Techniques, Inc.
InventorsDavid M. Jones, Richard Andrew Smith, John Patrick Kennedy, Frank Maurer, Matthias Georg Tondar, Bernhard Luy, Markus J. Baettig
Estimating the term…
A fluidized bed apparatus for applying a coating liquid onto the surface of particles includes a vertically disposed cylindrical product container having a peripheral wall, at least one cylindrical partition defining a centrally located up bed region and a peripherally located down bed region. The product container further includes an upper end connected to an expansion chamber and a lower end including an orifice plate having a plurality of openings for passage of fluidized air or gas. A nozzle is centrally located through the orifice plate and is adapted to generate a spray of coating liquid upwardly into the up bed. Particles located within the product container circulate upwardly through the partition and the coating liquid spray, between the up bed and the down bed. A plurality of inwardly directed discharge jets are positioned along the periphery of the product container and generally adjacent to the orifice plate. A source of pressurized air or gas is connected to the plurality of discharge jets and provide a radially inwardly directed flow of air or gas through the particles of the down bed so that the particles located adjacent to the peripheral wall of the product container are displaced radially inwardly along the orifice plate towards the nozzle and the up bed. A partition having an outer wall surface and an outwardly directed flared lower end defining a lower rim. The partition further includes an inwardly and upwardly directed ramp surface extending between the lower rim and the up bed. The improved partition encourages particles located within the down bed adjacent to the outer wall surface to move outwardly away from the up bed until reaching the lower rim, at which point the particles are atraumatically and gradually directed inwardly and upwardly along the inwardly and upwardly directed ramp surface into the up bed to continue the coating process. A nozzle ramp is provided around the nozzle. The nozzle ramp is generally cusp shaped and includes nozzle-ramp surface. The nozzle ramp is centrally positioned around the nozzle and is directed upwardly towards the partition so that the nozzle-ramp surface directs particles moving generally horizontally across the orifice plate from the down bed upwardly into the partition and the up bed. The nozzle ramp may further include air passages for passing fluidized air upwardly to the nozzle-ramp surface. A central discharge assembly is provided at the lower end of the product containers for emptying particles from the machine. Air is preferably discharged from the manifold during the emptying process to help direct particles towards the discharge assembly.
An improved Wurster-type fluidized bed apparatus for applying a coating liquid onto the surface of particles, said apparatus being of the type including a vertically disposed generally cylindrical product container having a peripheral wall, at least one cylindrical partition defining a centrally located up-bed region and a peripherally located down-bed region, said product container further including an upper end connected to an expansion chamber, a lower end including an orifice plate having a plurality of openings for passage of fluidized air, a nozzle centrally located through said orifice plate and being adapted to generate a spray of said coating liquid upwardly into said up-bed, wherein said particles located within said product container circulate upwardly through said partition and said spray of coating liquid, between said up-bed and said down-bed, said improvement comprising:
An improved Wurster-type fluidized bed apparatus for applying a coating liquid onto the surface of particles, said apparatus being of the type including a vertically disposed generally cylindrical product container having a peripheral wall, at least one cylindrical partition having a lower rim and defining a centrally located up bed region and a peripherally located down bed region, said product container further including an upper end connected to an expansion chamber, a lower end including an orifice plate having a plurality of openings for passage of fluidized air, a nozzle centrally located through said orifice plate and being adapted to generate a spray of said coating liquid upwardly into said up bed, wherein said particles located within said product container circulate upwardly through said partition and said spray of coating liquid, between said up bed and said down bed, said improvement comprising:
An improved Wurster-type fluidized bed apparatus for applying a coating liquid onto the surface of particles, said apparatus being of the type including a vertically disposed cylindrical product container having a peripheral wall, at least one cylindrical partition defining a centrally located up bed region and a peripherally located down bed region, and product container further including an upper end connected to an expansion chamber, a lower end including an orifice plate having a plurality of openings for passage of fluidized air, a nozzle centrally located through said orifice plate and being adapted to generate a spray of said coating liquid upwardly into said up bed, wherein said particles located within said product container circulate upwardly through said partition and said spray of coating liquid, between said up bed and said down bed, said improvement comprising:
An improved Wurster-type fluidized bed apparatus for applying a coating liquid onto the surface of particles, said apparatus being of the type including a vertically disposed cylindrical product container having a peripheral wall, at least one cylindrical partition defining a centrally located up bed region and a peripherally located down bed region, said product container further including an upper end connected to an expansion chamber, a lower end including an orifice plate having a plurality of openings for passage of fluidized air, a nozzle centrally located through said orifice plate and being adapted to generate a spray of said coating liquid upwardly into said up bed, wherein said particles located within said product container circulate upwardly through said partition and said spray of coating liquid, between said up bed and said down bed, said improvement comprising:
The improved Wurster-type fluidized bed apparatus for applying a coating liquid onto the surface of particles, said apparatus being of the type including a vertically disposed generally cylindrical product container having a peripheral wall, at least one cylindrical partition defining a centrally located up-bed region and a peripherally located down-bed region, said product container further including an upper end connected to an expansion chamber, a lower end including an orifice plate having a plurality of openings for passage of fluidized air, a nozzle centrally located through said orifice plate and being adapted to generate a spray of said coating liquid upwardly into said up-bed, wherein said particles located within said product container circulate upwardly through said partition and said spray of coating liquid, between said up-bed and said down-bed, said improvement comprising:
Dependencies are inferred from the claim text.
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Being subject to a circulatory movement only: internally, i.e. the particles rotate within the vessel
Processes or devices for granulating materials , e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g.…
Processes or devices for granulating materials , e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g.…
According to "fluidised-bed" technique: fluidisation grids
Term end not estimated
A. Field of the Invention
The present invention generally relates to coating machines and, in particular, to fluid-bed coating machines used for the coating of tablets.
B. Description of the Prior Art
FIG. 1 is a sectional side view schematic (labeled PRIOR ART) of a prior art Wurster-type bottom spray particle-coating machine showing a product container, a partition, a nozzle, a down-bed, and a up-bed, a nozzle sleeve, and a plurality of tablets or pills (represented by spheres) being coated as they circulate through the machine.
FIG. 2 is an enlarged sectional view (labeled PRIOR ART) of a portion of the prior art Wurster-type coating machine of FIG. 1 (shown without the numerous particles, for clarity) including particle-flow arrows representing the flow of particles during their transition from the down-bed into the up-bed air-stream, and further including a dashed line representing a “dead-zone” within the product container;
FIG. 3 is a sectional side view schematic of an improved Wurster-type bottom spray particle-coating machine showing a product container, a partition having a peripheral skirt, a nozzle, a down-bed, an up-bed, a nozzle sleeve, a truncated cusp-shaped nozzle-ramp, and a plurality of tablets or pills (represented by spheres) being coated as they circulate through the machine, according to the present invention;
By way of background and introduction, the present invention provides improvements relating to tablet flow and handling during the coating process of an otherwise conventional Wurster-type bottom-spray particle coating machine (hereinafter referred to as “Wurster machine”). To better understand and appreciate the improvements of the present invention, a detailed description of the structure and operation of a conventional Wurster machine is first provided.
A. Description of a Conventional Wurster Machine
Referring to FIGS. 1 and 2 (labeled PRIOR ART), a conventional Wurster machine is shown, including a generally conical product container 12, an orifice plate 14, a lower plenum 16, a central nozzle 18 projecting upwardly through a central opening 20 located within orifice plate 14, a nozzle sleeve 22, and a cylindrical partition 24. The product container 12 may be cylindrical or conical in shape and is mounted to an upper surface 26 of orifice plate 14, while the lower plenum 16 connects with a lower surface 28 of orifice plate 14. The upper end of the product container 12 is connected to an expansion chamber (not shown).