Power filling apparatus and methods for their use

Information

  • Patent Grant
  • 6182712
  • Patent Number
    6,182,712
  • Date Filed
    Thursday, September 17, 1998
    26 years ago
  • Date Issued
    Tuesday, February 6, 2001
    23 years ago
Abstract
The invention provides methods, systems and apparatus for the metered transport of fine powders into receptacles. According to one exemplary embodiment, an apparatus is provided which comprises a hopper having an opening. The hopper is adapted to receive a bed of fine powder. At least one chamber, which is moveable to allow the chamber to be placed in close proximity to the opening, is also provided. An element having a proximal end and a distal end is positioned within the hopper such that the distal end is near the opening. A vibrator motor is provided to vibrate the element when within the fine powder.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates generally to the field of fine powder processing, and particularly to the metered transport of fine powders. More particularly, the present invention relates to systems, apparatus and methods for filling receptacles with unit dosages of non-flowable but dispersible fine powdered medicaments, particularly for subsequent inhalation by a patient.




Effective delivery to a patient is a critical aspect of any successful drug therapy. Various routes of delivery exist, and each has its own advantages and disadvantages. Oral drug delivery of tablets, capsules, elixirs, and the like, is perhaps the most convenient method, but many drugs have disagreeable flavors, and the size of the tablets makes them difficult to swallow. Moreover, such medicaments are often degraded in the digestive tract before they can be absorbed. Such degradation is a particular problem with modern protein drugs which are rapidly degraded by proteolytic enzymes in the digestive tract. Subcutaneous injection is frequently an effective route for systemic drug delivery, including the delivery of proteins, but has a low patient acceptance and produces sharp waste items, e.g. needles, which are difficult to dispose. Since the need to inject drugs on a frequent schedule such as insulin one or more times a day, can be a source of poor patient compliance, a variety of alternative routes of administration have been developed, including transdermal, intranasal, intrarectal, intravaginal, and pulmonary delivery.




Of particular interest to the present invention are pulmonary drug delivery procedures which rely on inhalation of a drug dispersion or aerosol by the patient so that the active drug within the dispersion can reach the distal (alveolar) regions of the lung. It has been found that certain drugs are readily absorbed through the alveolar region directly into blood circulation. Pulmonary delivery is particularly promising for the delivery of proteins and polypeptides which are difficult to deliver by other routes of administration. Such pulmonary delivery can be effective both for systemic delivery and for localized delivery to treat diseases of the lungs.




Pulmonary drug delivery (including both systemic and local) can itself be achieved by different approaches, including liquid nebulizers, metered dose inhalers (MDI's) and dry powder dispersion devices. Dry powder dispersion devices are particularly promising for delivering protein and polypeptide drugs which may be readily formulated as dry powders. Many otherwise labile proteins and polypeptides may be stably stored as lyophilized or spray-dried powders by themselves or in combination with suitable powder carriers. A further advantage is that dry powders have a much higher concentration than medicaments in liquid form.




The ability to deliver proteins and polypeptides as dry powders, however, is problematic in certain respects. The dosage of many protein and polypeptide drugs is often critical so it is necessary that any dry powder delivery system be able to accurately, precisely and repeatably deliver the intended amount of drug. Moreover, many proteins and polypeptides are quite expensive, typically being many times more costly than conventional drugs on a per-dose basis. Thus, the ability to efficiently deliver the dry powders to the target region of the lung with a minimal loss of drug is critical.




For some applications, fine powder medicaments are supplied to dry powder dispersion devices in small unit dose receptacles, often having a puncturable lid or other access surface (commonly referred to as blister packs). For example, the dispersion devices described in U.S. Pat. Nos. 5,785,049 and 5,740,794, the disclosures of which are herein incorporated by reference, are constructed to receive such a receptacle. Upon placement of the receptacle in the device, a multi-flow ejector assembly having a feed tube is penetrated through the lid of the receptacle to provide access to the powdered medicament therein. The multi-flow ejector assembly also creates vent holes in the lid to allow the flow of air through the receptacle to entrain and evacuate the medicament. Driving this process is a high velocity air stream which is flowed past a portion of the tube, such as an outlet end, to draw powder from the receptacle, through the tube, and into the flowing air stream to form an aerosol for inhalation by the patient. The high velocity air stream transports the powder from the receptacle in a partially de-agglomerated form, and the final complete de-agglomeration takes place in the mixing volume just downstream of the high velocity air inlets.




Of particular interest to the present invention are the physical characteristics of poorly flowing powders. Poorly flowing powders are those powders having physical characteristics, such as flowability, which are dominated by cohesive forces between the individual units or particles (hereinafter “individual particles”) which constitute the powder. In such cases, the powder does not flow well because the individual particles cannot easily move independently with respect to each other, but instead move as clumps of many particles. When such powders are subjected to low forces, the powders will tend not to flow at all. However, as the forces acting upon the powder are increased to exceed the forces of cohesion, the powder will move in large agglomerated “chunks” of the individual particles. When the powder comes to rest, the large agglomerations remain, resulting in a non-uniform powder density due to voids and low density areas between the large agglomerations and areas of local compression.




This type of behavior tends to increase as the size of the individual particles becomes smaller. This is most likely because, as the particles become smaller, the cohesive forces, such as Van Der Waals, electrostatic, friction, and other forces, become large with respect to the gravitational and inertial forces which may be applied to the individual particles due to their small mass. This is relevant to the present invention since gravity and inertial forces produced by acceleration, as well as other effected motivators, are commonly used to process, move and meter powders.




For example, when metering the fine powders prior to placement in the unit dose receptacle, the powders often agglomerates inconsistently, creating voids and excessive density variation, thereby reducing the accuracy of the volumetric metering processes which are commonly used to meter in high throughput production. Such inconsistent agglomeration is further undesirable in that the powder agglomerates need to be broken down to the individual particles, i.e. made to be dispersible, for pulmonary delivery. Such de-agglomeration often occurs in dispersion devices by shear forces created by the air stream used to extract the medicament from the unit dose receptacle or other containment, or by other mechanical energy transfer mechanisms (e.g., ultrasonic, fan/impeller, and the like). However, if the small powder agglomerates are too compacted, the shear forces provided by the air stream or other dispersing mechanisms will be insufficient to effectively disperse the medicament to the individual particles.




Some attempts to prevent agglomeration of the individual particles are to create blends of multi-phase powders (typically a carrier or diluent) where larger particles (sometimes of multiple size ranges), e.g. approximately 50 μm, are combined with smaller drug particles, e.g. 1 μm to 5 μm. In this case, the smaller particles attach to the larger particles so that under processing and filling the powder will have the characteristics of a 50 μm powder. Such a powder is able to more easily flow and meter. One disadvantage of such a powder, however, is that removal of the smaller particles from the larger particles is difficult, and the resulting powder formulation is made up largely of the bulky flowing agent component which can end up in the device, or the patient's throat.




Current methods for filling unit dose receptacles with powdered medicaments include a direct pouring method where a granular powder is directly poured via gravity (sometimes in combination with stirring or “bulk” agitation) into a metering chamber. When the chamber is filled to the desired level, the medicament is then expelled from the chamber and into the receptacle. In such a direct pouring process, variations in density can occur in the metering chamber, thereby reducing the effectiveness of the metering chamber in accurately measuring a unit dose amount of the medicament. Moreover, the powder is in a granular state which can be undesirable for many applications.




Some attempts have been made to minimize density variations by compacting the powder within, or prior to depositing it in the metering chamber. However, such compaction is undesirable, especially for powders made up of only fine particles, in that it decreases the dispersibility of the powder, i.e. reduces the chance for the compacted powder to be broken down to the individual particles during pulmonary delivery with a dispersion device.




It would therefore be desirable to provide systems and methods for the processing of fine powders which would overcome or greatly reduce these and other problems. Such systems and methods should allow for accurate and precise metering of the fine powder when divided into unit doses for placement in unit dose receptacles, particularly for low mass fills. The systems and methods should further ensure that the fine powder remains sufficiently dispersible during processing so that the fine powder may be used with existing inhalation devices which require the powder to be broken down to the individual particles before pulmonary delivery. Further, the systems and methods should provide for the rapid processing of the fine powders so that large numbers of unit dose receptacles can rapidly be filled with unit dosages of fine powder medicaments in order to reduce cost.




2. Description of the Background Art




U.S. Pat. No. 5,765,607 describes a machine to meter products into containers and includes a metering unit to supply the product into containers.




U.S. Pat. No. 4,640,322 describes a machine which applies sub-atmospheric pressure through a filter to pull material directly from a hopper and laterally into a non-rotatable chamber.




U.S. Pat. No. 4,509,560 describes a granular material processing apparatus employing a rotating paddle to stir the granular material.




U.S. Pat. No. 2,540,059 describes a powder filling apparatus having a rotating wire loop stirrer for stirring powder in a hopper before directly pouring the powder into a metering chamber by gravity.




German patent DE 3607187 describes a mechanism for the metered transport of fine particles.




Product brochure, “E-1300 Powder Filler” describes a powder filler available from Perry Industries, Corona, Calif.




U.S. Pat. No. 3,874,431 describes a machine for filling capsules with powder. The machine employs coring tubes that are held on a rotatable turret.




British Patent No. 1,420,364 describes a membrane assembly for use in a metering cavity employed to measure quantities of dry powders.




British Patent No. 1,309,424 describes a powder filling apparatus having a measuring chamber with a piston head used to create a negative pressure in the chamber.




Canadian Patent No. 949,786 describes a powder filling machine having measuring chambers that are lipped into the powder. A vacuum is then employed to fill the chamber with powder.




SUMMARY OF THE INVENTION




The invention provides systems, apparatus and methods for the metered transport of fine powders into unit dose receptacles. In one exemplary method, such fine powders are transported by first agitating the fine powders with a vibrating element, and then capturing at least a portion of the fine powder. The captured fine powder is then transferred to a receptacle, with the transferred powder being sufficiently uncompacted so that it can be substantially dispersed upon removal from the receptacle. Usually, the fine powder will comprise a medicament with the individual particles having a mean size that is less than about 100 μm, usually less than about 10 μm, and more usually in the range from about 1 μm to 5 μm.




The fine powder will preferably be placed into a hopper having an opening at a bottom end. The element is vibrated to agitate the fine powder. Vibration of the powder in the vicinity of the opening assists in the transfer of a portion of the fine powder through the opening where it may be captured into a chamber. Vibration of the element also assists in de-agglomerating powder within the metering chamber so that the metering chamber may more uniformly be filled.




The vibratable element is preferably vibrated in an up and down, i.e. vertical, motion relative to the powder in the hopper. In one aspect, an ultrasonic horn is employed to vertically vibrate the element. Alternatively, the element may comprise a rod that is vibrated back and forth, i.e. laterally, within the powder. In another alternative, the vibratable element is vibrated in an orbital manner. In one aspect, the rod is operably attached to a piezoelectric motor which vibrates the rod. Preferably, the element is vertically vibrated at a frequency in the range from about 1,000 Hz to about 180,000 Hz, and more preferably from about 10,000 Hz to about 40,000 Hz, and most preferably from about 15,000 Hz to about 25,000 Hz. The rod is preferably vibrated laterally at a frequency in the range from about 50 Hz to about 50,000 Hz, and more preferably in the range from about 50 Hz to about 5,000 Hz, and most preferably in the range from about 50 Hz to about 1,000 Hz.




In another aspect, the element has a distal end which is placed near the opening. Further, the distal end has an end member which is vibrated over the chamber to assist in transfer of the fine powder from the hopper to the chamber. The end member preferably projects laterally outward from the element. In one aspect, the end member comprises a cylinder when the element is vibrated vertically. In another aspect, the end member comprises a cross-member when the rod is laterally vibrated. Preferably, the end-member is vertically spaced apart from the chamber by a distance in the range from about 0.01 mm to about 10 mm, and more preferably from about 0.5 mm to about 3.0 mm. Such a distance assists in keeping the powder uncompacted when transferred to the chamber.




In still another aspect, the element is preferably moved across the opening while being vibrated. For instance, the element may be translated along the opening at a rate that is preferably less than about 100 cm/s. However, the particular rate of translation will typically depend on the vibrational frequency of the element. In this way, the element is swept across the chamber while being vibrated.




Movement of the element along the opening is particularly preferable when multiple chambers are aligned with the opening. In this way, the element may be employed to assist in the transfer of fine powder from the hopper into each of the chambers. Optionally, a plurality of elements or rods may be vibrated within the hopper in the vicinity of the openings. Preferably, the rods will be aligned with each other and will be translated along the opening while being vibrated, although in some cases the rods or elements may remain stationary over each chamber.




To assist in the capture of the fine powder in the chamber, air is preferably drawn through the chamber bottom to draw the fine powder into the chamber. Following capture of the fine powder, the powder is preferably transferred to a receptacle. Transferring of the fine powder is preferably accomplished by introducing a compressed gas into the chamber to expel the captured powder into the receptacle.




In another aspect of the method, the powder in the hopper is periodically levelled. As one example, the powder may be levelled by placing a projecting member above the distal end of the vibratable element. In this way, the projecting member vibrates along with the vibratable element. As the element is translated along the hopper, the projecting member tends to level the powder in the hopper. In one aspect, transfer of the powder is performed in a moisture controlled environment.




In still another aspect, the powder captured by the chamber is adjusted to be a unit dose amount. This may be accomplished by placing a thin plate (or doctor sheet) between the hopper and the chamber. The plate has an aperture to allow for the transfer of the powder from the hopper and into the chamber. The chamber is then moved relative to the plate, with the plate scraping any excess powder from the chamber. Alternatively, a doctor blade may be employed to scrape any excess powder from the chamber as the chamber is rotated.




In one particular aspect, the powder is transferred to the hopper from a secondary hopper. Preferably, the secondary hopper is vibrated to transfer the powder onto a chute where it passes into the primary hopper. In still yet another aspect, the chamber is periodically removed and replaced with a chamber of a different size to adjust the volume of the chamber. In this way, different unit dosages may be produced by the invention.




The invention further provides an exemplary apparatus for transporting a fine powder. The apparatus comprises a hopper for holding the fine powder. The apparatus further includes at least one chamber which is moveable to allow the chamber to be placed in close proximity to an opening in the hopper. A vibratable element is also provided having a proximal end and a distal end, with the element being placed within the hopper such that the distal end is near the opening. A vibrator is provided to vibrate the element when within the fine powder. In this way, the element may be vibrated to agitate the fine powder to assist in its transfer from the hopper to the chamber. Preferably, the vibrator comprises an ultrasonic horn which vibrates the element in an up and down or vertical motion. Alternatively, a piezoelectric motor may be employed to laterally vibrate the element.




In one exemplary aspect, the apparatus further includes a mechanism for translating the vibratable element or rod over the chamber as the element is vibrated. Such a mechanism is particularly advantageous when a plurality of chambers are provided in a rotatable member which is rotated to align the chambers with the opening. The translating mechanism may then be employed to translate the element over the rotatable member so that the vibrating element passes over each chamber to assist in the filling of each with powder. The translating mechanism preferably comprises a linear drive mechanism which translates the rod along the opening at a rate that is less than about 100 cm/s.




In another aspect, the vibrator is configured to vibrate the element in an up and down motion at a frequency in the range from about 1,000 Hz to about 180,000 Hz, and more preferably in the range from about 10,000 Hz to about 40,000 Hz, and most preferably in the range from about 15,000 Hz to about 25,000 Hz. When vibrated up and down, the vibratable element preferably comprises a cylindrical shaft having a diameter in the range from about 1.0 mm to about 10 mm. When vibrated laterally, the element preferably comprises a rod or wire having a diameter in the range from about 0.01 inch to about 0.04 inch.




An end-member is preferably operably attached to the distal end of the vibratable element to assist in agitation of the fine powder. The end-member is preferably vertically spaced apart from the chamber by a distance in the range from about 0.01 mm to about 10 mm, and more preferably from about 0.5 mm to about 3.0 mm. In one alternative, the apparatus is provided with a plurality of vibratable elements so that multiple elements may be vibrated within the fine powder.




In still another aspect, the chamber is disposed within a rotatable member which is placed in a first position having the chamber aligned with the opening in the hopper, and a second position having the chamber aligned with a receptacle. In this way, the chamber may be filled with powder when in the first position. The rotatable member is then rotated to the second position to allow the powder to be expelled from the chamber and into the receptacle. The chamber preferably includes a port which is in communication with a vacuum source to assist in drawing the fine powder from the hopper and into the chamber. A filter is preferably disposed across the port to assist in capturing the powder. A source of compressed gas is preferably also in communication with the port to eject the captured powder from the chamber and into the receptacle. A controller may be provided for controlling actuation of the gas source, the vacuum source and operation of the vibrator.




The apparatus may also include a mechanism for adjusting the amount of captured powder in the chamber due to the chamber volume. In this way, the captured amount will be a unit dose amount. Such an adjustment mechanism may comprise an edge for removing fine powder extending above the chamber. In one embodiment, the adjustment mechanism comprises a thin plate having an aperture which may be aligned with the chamber during filling. As the rotatable member is rotated, the edge of the aperture scrapes the excess powder from the chamber.




In one particular aspect, the vibratable element includes a projecting member which is spaced above the distal end. The projecting member serves as a leveller to level powder within the hopper as the vibratable element is translated along the hopper.




In another aspect, a secondary hopper is provided to store the powder until delivered to the primary hopper. A shaking mechanism is provided to vibrate the secondary hopper when powder is to be transferred to the primary hopper. Preferably, the powder passes down a chute so that the powder may be transferred without interfering with the translation of the vibratable member along the primary hopper.




In still another aspect, the chamber is formed in a change tool. In this way, the size of the chamber may be varied simply by attaching a change tool with a different sized chamber to the rotatable member.




The invention further provides an exemplary system for transporting fine powders. The system comprises a plurality of rotatable members which each include a row of chambers. A hopper is disposed above each rotatable member and has an opening to allow powder to be transferred to the chambers. A vibratable element is disposed in each hopper, and vibrators are provided to vibrate the elements in an up and down motion. A translation mechanism is further provided to translate the vibratable members along the hoppers to assist in transferring the powder from the hoppers and into the chambers. Conveniently, a controller may be provided to control operation of the rotatable members, the vibrators, and the translation mechanism.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a cross-sectional side view of an exemplary apparatus for transporting fine powders according to the invention.





FIG. 2

is an end view of the apparatus of FIG.


1


.





FIG. 3

is a more detailed view of a chamber of the apparatus of

FIG. 1

showing a vibrating rod being translated over the chamber according to the invention.





FIG. 4

is a left front perspective view of an exemplary system for transporting powder according to the invention.





FIG. 5

is a right front perspective view of the system of FIG.


4


.





FIG. 6

is a cross-sectional view of the system of FIG.


4


.





FIG. 7

is a schematic view of an alternative apparatus for transporting fine powders according to the invention.





FIG. 8

is a schematic view of still another alternative apparatus for transporting fine powders according to the invention.





FIG. 9

is a schematic view of still another alternative apparatus for transporting fine powders according to the invention.





FIG. 10

is a perspective view of a further embodiment of an apparatus for transporting fine powders according to the invention.





FIG. 11

is a cross-sectional view of the apparatus of

FIG. 10

taken along lines


11





11


.





FIG. 12

is a cross-sectional view of the apparatus of

FIG. 10

taken along lines


12





12


.





FIG. 13

is an exploded view of a rotatable member of the apparatus of FIG.


10


.





FIG. 14A

is a schematic view of a scraping mechanism for scraping excess powder from a chamber of a rotatable member.





FIG. 14B

is an end view of the scraping mechanism of

FIG. 14A

as mounted above the rotatable member.





FIG. 14C

is a perspective view of an alternative mechanism for scraping excess powder from a chamber of a rotatable member according to the invention.





FIG. 15

is a perspective view of a particularly preferable system for transporting powders according to the invention.











DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS




The invention provides methods, systems, and apparatus for the metered transport of fine powders into receptacles. The fine powders are very fine, usually having a mean size in the range that is less than about 20 μm, usually less than about 10 μm, and more usually from about 1 μm to 5 μm, although the invention may in some cases be useful with larger particles, e.g., up to about 50 μm or more. The fine powder may be composed of a variety of constituents and will preferably comprise a medicament such as proteins, nucleic acids, carbohydrates, buffer salts, peptides, other small biomolecules, and the like. The receptacles intended to receive the fine powder preferably comprise unit dose receptacles. The receptacles are employed to store the unit dosage of the medicament until needed for pulmonary delivery. To extract the medicament from the receptacles, an inhalation device, such as those described in U.S. Pat. Nos. 5,785,049 and 5,740,794, previously incorporated herein by reference, may be employed. However, the methods of the invention are also useful in preparing powders to be used with other inhalation devices which rely on the dispersement of the fine powder.




The receptacles are preferably each filled with a precise amount of the fine powder to ensure that a patient will be given the correct dosage. When metering and transporting the fine powders, the fine powders will be delicately handled and not compressed, so that the unit dosage amount delivered to the receptacle is sufficiently dispersible to be useful when used with existing inhalation devices. The fine powders prepared by the invention will be especially useful with, although not limited to, “low energy” inhalation devices which rely on manual operation or solely upon inhalation to disperse the powder. With such inhalation devices, the powder will preferably be at least 20% (by weight) dispersible or extractable into a flowing air stream, more preferably be at least 60% dispersible, and most preferably at least 90% dispersible as defined in U.S. Pat. No. 5,785,049, previously incorporated by reference. Since the cost of producing the fine powder medicaments are usually quite expensive, the medicament will preferably be metered and transported into the receptacles with minimal wastage. Preferably, the receptacles will be rapidly filled with the unit dosage amounts so that large numbers of receptacles containing the metered medicament can economically be produced.




According to the invention, the fine particles are captured in a metering chamber (which is preferably sized to define a unit dosage volume). A preferable method of capturing is by drawing air through the chamber so that the drag force of the air will act upon the small agglomerates or individual particles as described in U.S. Pat. No. 5,775,320, the complete disclosure of which is herein incorporated by reference. In this way, the fluidized fine powder fills the chamber without substantial compaction and without substantial formation of voids. Further, capturing in this manner allows the fine powder to be accurately and repeatably metered without unduly decreasing the dispersibility of the fine powder. The flow of air through the chamber may be varied in order to control the density of the captured powder.




After the fine powder is metered, the fine powder is ejected into the receptacle in a unit dosage amount, with the ejected fine powder being sufficiently dispersible so that it may be entrained and aerosolized in the turbulent air flow created by an inhalation or dispersion device. Such an ejection process is described in U.S. Pat. No. 5,775,320, previously incorporated by reference.




Agitation of the fine powders is preferably accomplished by vibrating a vibratable member within the fine powder in the vicinity just above the capture chamber. Preferably, the element is vibrated in an up and down, i.e., vertical, motion. Alternatively, the element may be laterally vibrated. A variety of mechanisms may be employed to vibrate the elements including an ultrasonic horn, a piezoelectric bending motor, a motor rotating a cam or a crank shaft, an electric solenoid, and the like. Alternatively, a wire loop may be rotated within the fine powder to fluidize the powder. Although agitation is preferably accomplished by vibrating the vibratable member within the fine powder, in some cases it may be desirable to vibrate the vibratable member just above the powder to fluidize the powder.




Referring to

FIGS. 1 and 2

, an exemplary embodiment of an apparatus


10


for metering and transporting unit dosages of a fine powder medicament will be described. Apparatus


10


comprises a trough or hopper


12


having a top end


14


and a bottom end


16


. At bottom end


16


is an opening


18


. Held within hopper


12


is a bed of fine powder


20


. Positioned below hopper


12


is a rotatable member


22


having a plurality of chambers


24


about its periphery. Rotatable member


22


may be rotated to align chambers


24


with opening


18


to allow powder


20


to be transferred from hopper


12


and into chambers


24


.




Positioned above hopper


12


is piezoelectric bending motor


26


having a rod


28


attached thereto. Piezoelectric motor


26


is positioned above hopper


12


such that a distal end


29


of rod


28


is placed within the fine powder bed


20


while being spaced apart from rotatable member


22


. Bottom end


16


of hopper


12


is positioned just above rotatable member


22


so that powder held within hopper


12


will not escape between bottom end


16


and rotatable member


22


. At distal end


29


of rod


28


is a cross-member


30


which is generally perpendicular to rod


28


. Cross-member


30


will preferably be at least as long as the top diameters of chambers


24


to assist in agitating fine powder into the chambers as described in greater detail hereinafter.




As best illustrated in

FIG. 1

, upon actuation of piezoelectric bending motor


26


, rod


28


is caused to vibrate back and forth as indicated by arrows


32


. Further, as illustrated by arrow


34


, piezoelectric bending motor


26


is translatable along the length of rotatable member


22


to allow cross-member


30


to be vibrated over each of the chambers


24


.




Referring now to

FIG. 3

, the transfer of powder from hopper


12


(see

FIG. 1

) to chamber


24


will be described in greater detail. Disposed within chamber


24


is a top filter


36


and a back-up filter


38


. Top filter


36


is disposed in rotatable member


22


such that it is at a known distance relative to the top of chamber


24


. A line


40


is in communication with chamber


24


to provide suction within chamber


24


during filling and compressed gas when expelling the powder from chamber


24


in a manner similar to that described in copending U.S. patent application Ser. No. 08/638,515, the disclosure of which is herein incorporated by reference.




When ready for filling, a vacuum is created within line


40


to draw air through chamber


24


. Further, rod


28


is vibrated as shown by arrows


32


when positioned above chamber


24


to assist in agitating powder bed


20


. Such a process assists in transferring the powder from bed


20


and into chamber


24


. While vibrating, rod


28


is translated over chamber


24


as indicated by arrow


34


. In this way, agitation of the powder bed


20


will occur over substantially the entire opening of the chamber


24


. Further, translation of rod


28


will also move rod


28


over other chambers so that they may be filled in a similar manner.




As illustrated by arrows


42


, rod


28


will preferably be vertically spaced from rotatable member


22


by a distance in the range from about 0.01 mm to about 10 mm, and more preferably from about 0.1 mm to about 0.5 mm. Such vertical spacing is preferred to ensure that the powder immediately above the cavity is fluidized and can be drawn into the chamber


24


. Referring now to

FIGS. 4-6

, an exemplary embodiment of a powder transferring and metering system


44


will be described. System


44


is patterned after the principles previously set forth in connection with apparatus


10


of

FIGS. 1-3

. System


44


comprises a base


46


and a frame


48


for rotatably holding a rotatable member


50


. Rotatable member


50


includes a plurality of chambers


52


(see FIG.


6


). Rotatable member


50


, including chambers


52


, will preferably be provided with vacuum and compression lines similar to that previously described in copending U.S. patent application Ser. No. 08/638,515, previously incorporated by reference. In brief, a vacuum is created to assist in drawing powder into chambers


52


. Upon filling of chambers


52


, rotatable member


50


is rotated until chambers


52


are facing downward. At that point, compressed gas is forced through chambers


52


to eject the captured powder into receptacles, such as blister packages as are commonly used in the art.




Positioned above rotatable member


50


is a hopper


54


having an elongate opening


56


(see FIG.


6


). Operably mounted to frame


48


are a plurality of piezoelectric bending motors


58


. Attached to each of piezoelectric bending motors


58


is a rod


60


. An exemplary piezoelectric bending motor is commercially available from Piezo Systems, Inc., Cambridge, Mass. Such bending motors comprise two layers of a piezoceramic, each having an outer electrode. An electric field is applied across the two outer electrodes to cause one layer to expand while the other contracts.




Rod


60


will preferably comprise a stainless steel wire rod having a diameter in the range from about 0.005 inch to about 0.10 inch, and more preferably from about 0.02 inch to about 0.04 inch. However, it will be appreciated that other materials and geometries may be used when constructing rod


60


. For example, a variety of rigid materials may be employed, including other metals and alloys, a steel music wire, a carbon fiber, plastics, and the like. The shape of rod


60


may also be non-circular and/or non-uniform in cross section, with an important feature being the ability to agitate the powder near the distal end of the rod to fluidize the powder. A perpendicular cross-member


62


(see

FIG. 6

) will preferably be attached to the distal end of rod


60


. One or more cross-members may optionally be positioned above the distal cross-member to help collapse any trenches created in the powder bed during operation. When actuated, rods


60


will preferably be vibrated at a frequency in the range from about 5 Hz to about 50,000 Hz, and more preferably in the range from about 50 Hz to about 5,000 Hz, and most preferably in the range from about 50 Hz to about 1,000 Hz.




Piezoelectric bending motors


58


are attached to translation mechanism


64


which translates rods


60


along hopper


54


. When translated, cross-member


62


will preferably be vertically spaced above chambers


52


by a distance in the range from about 0.01 mm to about 10 mm, and more preferably from about 0.1 mm to about 0.5 mm. Translation mechanism


64


comprises a rotary drive pulley


66


which rotates a belt


68


, which in turn is attached to a platform


70


. Piezoelectric bending motors


58


are attached to platform


70


which is translated over a shaft


72


when pulley


66


is actuated. In this way, rods


60


may be translated back and forth within hopper


54


so that rods


60


will be vibrated over each of the chambers


52


. Translation mechanism


64


may be employed to pass rod


60


over chambers


52


as many times as desired when filling chambers


52


. Preferably, rod


60


will be translated at a speed that is less than about 200 cm/s, and more preferably less than about 100 cm/s. Rod


60


will preferably pass over each chamber at least one time, with two passes being preferred.




In operation, hopper


54


is filled with fine powder that is to be transferred into chambers


52


. A vacuum is then drawn through each of chambers


52


while they are aligned with opening


56


. At the same time, piezoelectric bending motors


58


are actuated to vibrate rods


60


. Translation mechanism


64


is actuated to translate rods


60


back and forth within hopper


54


while rods


60


are vibrating. Vibration of rods


60


agitates the fine powder to assist in its transfer into chambers


52


. When chambers


52


are sufficiently filled, rotatable member


50


is rotated 180° to place chambers


52


in a downward position. As rotatable member


50


is rotated, a blade at the bottom edge of hopper


54


scrapes off any excess powder to ensure that each chamber contains only a unit dose amount of fine powder.




When in the downward position, a compressed gas is forced through each of chambers


52


to eject the fine powder into receptacles (not shown). In this way, a convenient method is provided for transferring fine powder from a hopper into receptacles in a metered amount.




Referring now to

FIG. 7

, an alternative embodiment of an apparatus


74


for transferring metered doses of fine powder will be described. Apparatus


74


comprises a housing


76


and a piezo substrate


78


operably attached to housing


76


. piezo substrate


78


includes a plurality of holes


80


(or a screen). Positioned above substrate


78


is a hopper


82


having a bed of fine powder


84


. Attached to substrate


78


is a pair of electrical leads


86


for actuation of piezo substrate


78


. When electrical current is alternately supplied to leads


86


, substrate


78


is caused to expand and contract to produce a vibration mode as illustrated by arrow


88


. In turn, holes


80


are caused to vibrate to assist in agitating powder bed


84


to more effectively allow the powder to fall through holes


80


and into a chamber. A rotatable member having chambers in communication with a vacuum source and a pressure source as described in previous embodiments may also be used in connection with apparatus


74


to assist in capturing the fine powder and expelling the captured powder into receptacles.




A further embodiment of an apparatus


100


for transferring metered doses of fine powder is illustrated in FIG.


8


. Apparatus


100


operates similar to apparatus


10


as previously described, except that the piezoelectric bending motor has been replaced with a motor


102


having a crank


104


which drives a linkage shaft


106


. As shaft


106


is reciprocated, a rod


108


is vibrated within a hopper


110


that is filled with powder


112


. The agitated powder is then captured in a chamber


114


in a manner similar to that previously described. Further, rod


108


may be translated over chamber


114


during vibration in a manner similar to that previously described with other embodiments.




Another embodiment of an apparatus


120


for transferring metered doses of fine powder is illustrated in FIG.


9


. Apparatus


120


comprises a motor


122


which rotates a wire loop


124


. As shown, wire loop


124


is disposed within a bed of fine powder


126


just above a chamber


128


. In this way, when wire loop


124


is rotated, the powder will be fluidized and drawn into chamber


128


in a manner similar to previous embodiments. Further, loop


124


may be translated over chamber


128


during its rotation in a manner similar to that previously described with other embodiments.




Referring now to

FIG. 10

, another embodiment of an apparatus


200


for transporting fine powders will be described. Apparatus


200


operates in a manner similar to the other embodiments as previously described in that powder is transferred from a hopper into metering chambers of a rotatable member. From the rotatable member, the powder is expelled into receptacles in unit dosage amounts.




Apparatus


200


comprises a frame


202


which holds a rotatable member


204


such that rotatable member


204


may be rotated by a motor (not shown) held on frame


202


. Frame


202


also holds a trough or primary hopper


206


above rotatable member


204


. Positioned above hopper


206


is a vibrator


208


. As shown in

FIGS. 11 and 12

, a vibratable element


210


is coupled to vibrator


208


. Vibrator


208


is coupled to an arm


212


by a clamp


214


. Arm


212


in turn is coupled to a translation stage


216


. A screw motor


217


is employed to translate stage


216


back and forth relative to frame


202


. In this way, vibratable element


210


may be translated back and forth within hopper


206


.




Referring also now to

FIGS. 11 and 12

, apparatus


200


further includes a secondary hopper


218


disposed above primary hopper


206


. Conveniently, hopper


218


includes wings


219


to allow it to be removably coupled to frame


202


by inserting wings


219


into slots


220


. Hopper


218


comprises a housing


222


and a tubular section


224


for storing powder. A chute


226


extends from housing


222


and into hopper


206


when hopper


218


is attached to frame


202


. Tubular section


224


includes an opening


228


to allow powder to flow from tubular section


224


and down chute


226


. A screen


230


is disposed over opening


228


to generally prevent the flow of powder down chute


226


until housing


222


is shaken or vibrated.




Conveniently, a latch


232


is employed to secure secondary hopper


218


to frame


202


. To remove secondary hopper


218


, latch


232


is disengaged from hopper


218


and hopper


218


is lifted from slots


220


. In this way, hopper


218


may be conveniently removed for refilling, cleaning, replacement, or the like.




To transfer powder from hopper


218


, an arm


234


is placed into contact with housing


222


and is shaken or vibrated to vibrate housing


222


. A motor (not shown) is employed to shake or vibrate arm


234


. As shown in

FIG. 12

, housing


222


may optionally include an internal opening


236


containing a block


238


. As housing


222


is shaken, block


238


vibrates within opening


236


. As block


238


engages the walls of housing


222


, it sends shock waves through housing


222


to assist in transferring the powder from tubular section


224


, through opening


228


, and through screen


230


. The powder then slides down chute


226


until it falls within hopper


206


. Use of chute


226


is also advantageous in that it allows tubular section


224


to be laterally offset from vibrator


208


so that it will not interfere with the motion of vibrator


208


. One particular advantage of including block


238


within opening


236


is that any particulate generated as block


238


is vibrated will be maintained within opening


236


and will not contaminate any of the powder.




Vibrator


208


is configured to vibrate element


210


in an up and down or vertical motion. Vibrator


208


preferably comprises any one of a variety of commercially available ultrasonic horns, such as a Branson TWI ultrasonic horn. Vibratable element


210


is preferably vibrated at a frequency and range from about 1,000 Hz to about 180,000 Hz, and more preferably from about 10,000 Hz to about 40,000 Hz, and most preferably from about 15,000 Hz to about 25,000 Hz.




As best shown in

FIG. 12

, vibratable element


210


includes an end member


240


which is appropriately shaped to optimize agitation of the fine powder during vibration of element


210


. As shown, end member


240


has an outer periphery which is greater than that of element


210


. Element


210


is preferably cylindrical in geometry and preferably has a diameter in the range from about 0.5 mm to about 10 mm. As shown, end member


240


is also cylindrical in geometry and preferably has a diameter in the range from about 1.0 mm to about 10 mm. However, it will be appreciated that vibratable element


210


and end member


240


may be constructed to have a variety of shapes and sizes. For example, vibratable element


210


may be tapered. End member


240


may also have a reduced profile to minimize the lateral movement of powder as vibrator


208


is translated through hopper


206


. Preferably, end member


240


is vertically spaced above rotatable member


204


by a distance in the range from about 0.01 mm to about 10 mm, and more preferably from about 0.5 mm to about 3.0 mm.




Vibrator


208


is employed to assist in the transfer of powder into metering chambers


242


of rotatable member


204


in a manner similar to that described with previous embodiments. More specifically, motor


217


is employed to translate stage


216


so that vibratable element


210


may be translated laterally back and forth along hopper


206


. At the same time, vibratable element


210


is vibrated in an up and down motion, i.e., radial to rotatable member


204


, as it passes over each of metering chambers


242


. Preferably, vibrator


208


is laterally translated along hopper


206


at a rate that is less than about 500 cm per second, and more preferably less than about 100 cm per second.




As vibratable element


210


is moved laterally within hopper


206


, there may be a tendency for vibratable element


210


to push or plow some of the powder towards the ends of hopper


206


. Such movement of the powder is mitigated by providing a radiating surface or projecting member


244


on vibratable element


210


just above an average powder depth within the hopper. In this way, accumulated powder that is higher than the average depth is preferentially mobilized and moved to areas in the hopper having a smaller powder depth. Preferably, projecting member


244


is spaced apart from end member


240


by a distance in the range from about 2 mm to about 25 mm, and more preferably from about 5 mm to about 10 mm. As an alternative, various plowing mechanisms, such as rakes, may be attached to vibrator


208


(or be separately articulatable) so that they will drag over the top of the powder to assist in leveling the powder as vibrator


208


is translated along the hopper. As another alternative, an elongate vibratory element, such as a screen, may be disposed within the powder bed to assist in levelling the powder.




As shown in

FIGS. 11 and 12

, rotatable member


204


is in a filling position where metering chambers


242


are aligned with hopper


206


. As with the other embodiments described herein, once metering chambers


242


are filled, rotatable member


204


is rotated 180° where the powder is ejected from metering chambers


242


into receptacles. A Klöckner packaging machine is preferably employed to supply apparatus


200


with a sheet containing the receptacles.




Referring now to

FIG. 13

, construction of rotatable member


204


will be described in greater detail. Rotatable member


204


comprises a drum


246


having a front end


248


and a back end


250


. Bearings


252


and


254


are insertable over ends


248


and


250


to allow drum


246


to rotate when attached to frame


202


. Rotatable member


204


further includes a collar


256


, a rear slip ring


258


and a front slip ring


259


which are fitted with gas tight seals. Air inlets


260


and


261


are provided in collar


256


. Air inlet


260


is in fluid communication with a pair


242




a


of metering chambers


242


while inlet


261


is in fluid communication with a pair


242




b


of metering chambers


242


. In this way, pressurized air or a vacuum may be produced in either pair of chambers


242




a


or


242




b.






More specifically, air from inlet


260


passes through slip ring


258


, through a hole


264


in a gasket


270


and into a hole


265


in a manifold


262


. The air then passes through manifold


262


and exits manifold


262


through a pair of holes


265




a


and


265




b


. Holes


265




c


and


265




d


in bracket


272


then route the air into chambers


242




a


. In a similar manner, air from inlet


261


passes through slip ring


259


, through a hole


266


in gasket


270


and into a hole (not shown) in manifold


262


. The air is routed through various holes in manifold


262


and gasket


270


in a manner similar to that previously described with inlet


260


until passing through chambers


242




b


. In this manner, two separate air circuits are provided. Alternatively, it will be appreciated that one of the air inlets could be eliminated so that a vacuum or pressurized gas may be simultaneously provided to all of metering chambers


242


.




Also disposed above manifold


262


is a change tool


274


. Metering chambers


242


are formed in change tool


274


, and filters


276


are disposed between change tool


274


and air bracket


272


to form a bottom end of metering chambers


242


. Air may be drawn into chambers


242


by attaching a vacuum to air inlets


260


or


261


. Similarly, a compressed gas may be forced through metering chambers


242


by coupling a source of compressed gas to air inlets


260


or


261


. As with other embodiments described herein, a vacuum is drawn through metering chambers


242


to assist in drawing the powder into metering chambers


242


. After drum


246


is rotated 180°, a compressed gas is forced through metering chambers


242


to expel the powder from metering chambers


242


.




Drum


246


includes an aperture


278


into which manifold


262


, gasket


270


, air bracket


272


and change tool


274


are inserted. A cam


280


is also provided and is insertable into aperture


278


. Cam


280


is rotated within aperture


278


to secure the various components within drum


246


. When loosened, it is possible to slide change tool


274


from aperture


278


. In this way, change tool


274


may easily be replaced with another change tool having different sized metering chambers. In this manner, apparatus


200


may be provided with a wide assortment of change tools which allows a user to easily change the size of the metering chambers simply by inserting a new change tool


274


.




Apparatus


200


further includes a mechanism for doctoring any excess powder from metering chambers


242


. Such a doctoring mechanism


282


is illustrated in

FIGS. 14A and 14B

and is also referred to as a doctoring sheet. For convenience of illustration, doctoring mechanism


282


has been omitted from the drawings of

FIGS. 10-12

. In

FIGS. 14A and 14B

, rotatable member


204


is shown in schematic view. Doctoring mechanism


282


comprises a thin plate


284


having apertures


286


which are aligned with metering chambers


242


when rotatable member


204


is in the filling position. Apertures


286


preferably have a diameter that is slightly larger than the diameter of metering chambers


242


. In this way, apertures


286


will not interfere with the filling of metering chambers


242


. Plate


284


is preferably constructed of brass and has a diameter of approximately 0.003 inches. Plate


284


is sprung against rotatable member


204


so that it is generally flush against the outer periphery. In this way, plate


284


is generally sealed against rotatable member


204


to prevent excess powder from escaping between plate


284


and rotatable member


204


. Plate


284


is attached to frame


202


and remains stationary while rotatable member


204


rotates. In this way, after powder has been transferred to metering chambers


242


, rotatable member


204


is rotated toward the dispensing position. During rotation, the edges of apertures


286


scrape any excess powder from metering chambers


242


so that only a unit dose amount remains in metering chambers


242


. Configuration of doctoring mechanism


282


is advantageous in that it reduces the amount of movable parts, thereby reducing the build up of static electricity. Further, the removed powder remains within hopper


206


where it will be available for transfer into metering chambers


242


after they have been emptied.




Illustrated in

FIG. 14C

is an alternative mechanism for scraping or doctoring excess powder from metering chambers


242


. The mechanism comprises a pair of doctoring blades


290


and


292


which are coupled to hopper


206


, it being appreciated that only one blade may be needed depending on the direction of rotation of rotatable member


204


. Blades


290


and


292


are preferably constructed of a thin sheet material, such as 0.005 inch brass, and are sprung lightly against rotatable member


204


. The edges of blades


290


and


292


coincide approximately with the edges of the opening in hopper


206


. After metering chambers


242


are filled, rotatable member


204


is rotated, with blades


290


or


292


(depending on the direction of rotation) scraping any excess powder from metering chambers


242


.




Referring back now to

FIGS. 10-12

, operation of apparatus


200


to fill receptacles with unit dosages of fine powder will be described. Initially, the fine powder is placed into tubular section


224


of secondary hopper


218


. Conveniently, hopper


218


may be removed from frame


202


during filling. Housing


222


is then shaken or vibrated for a time sufficient to transfer a desired amount of powder through opening


228


, through screen


230


and down chute


226


where it falls into primary hopper


206


. Rotatable member


204


is placed in the filling position where metering chambers


242


are aligned with hopper


206


. A vacuum is then applied to air inlets


260


and


261


(see

FIG. 13

) to draw air through metering chambers


242


. Under the influence of gravity, and with the assistance of the vacuum, the powder tumbles into the metering chambers


242


and generally fills metering chambers


242


. Vibrator


208


is then actuated to vibrate element


210


. At the same time, motor


217


is operated to translate vibratable element


210


back and forth within chamber


206


. As element


210


is vibrated, end member


240


creates a pattern of air flow at the bottom of hopper


206


to agitate the powder. As end member


240


passes over each metering chamber


242


, an aerosol cloud is produced that is drawn into the metering chamber


242


by vacuum and by gravity. As end member


240


passes over metering chambers


242


, ultrasonic energy radiates down into metering chambers


242


to agitate the powder already inside the metering chamber. This in turn allows flow within the cavity to even out any irregularities in density that may exist during previous filling. Such a feature is particularly advantageous in that agglomerates or chunks of powder which may create voids in the metering chamber may be broken down to more evenly fill the metering chamber.




After passing one or more times over each of the metering chambers


242


, rotatable member


204


is rotated 180° to a dispensing position where metering chambers


242


are aligned with receptacles (not shown). As rotatable member


204


rotates, any excess powder is scraped from metering chambers


242


as previously described. When in the dispensing position, a compressed gas is supplied through air inlets


260


and


261


to expel unit dosages of powder from metering chambers


242


and into the receptacles.




The invention also provides a way to adjust fill weights by modulating the ultrasonic power supplied to vibrator


210


as it passes over metering chambers


242


. In this way, fill weights for the various metering chambers may be adjusted to compensate for powder weight discrepancies that may periodically occur. As one example, if the fourth metering chamber was consistently producing a dosage amount that was too low in weight, the power to vibrator


208


could be increased slightly each time it passed over the fourth metering chamber. In conjunction with an automated (or manual) weighing system and a controller, such an arrangement may be used to make an automated (or manual) closed-loop weight control system to adjust the power level of the vibrator for each of the metering chambers to provide more accurate fill weights.




Referring now to

FIG. 15

, an exemplary embodiment of a system


300


for metering and transporting a fine powder will be described. System


300


operates in a manner similar to apparatus


200


but includes multiple vibrators and multiple hoppers for simultaneously filling a plurality of receptacles with unit dosages of fine powder. System


300


comprises a frame


302


to which are rotatably coupled a plurality of rotatable members


304


. Rotatable members


304


may be constructed similar to rotatable member


204


and include a plurality of metering chambers (not shown) for receiving powder. The number of rotatable members and metering chambers may be varied according to the particular application. Disposed above each rotatable member


304


is a primary hopper


306


which holds the powder above rotatable members


304


. A vibrator


308


is disposed above each hopper


306


and includes a vibratable element


310


to agitate the powder within hopper


306


in a manner similar to that described in connection with apparatus


200


. Although not shown for convenience of illustration, a secondary hopper which is similar to secondary hopper


218


of apparatus


200


will be disposed above each of primary hoppers


306


to transfer powder into hoppers


306


in a manner similar to that described in connection with apparatus


200


.




A motor


312


(only one being shown for convenience of illustration) is coupled to each of rotatable members


304


to rotate rotatable members


304


between a filling position and a dispensing position similar to apparatus


200


.




Each vibrator


308


is coupled to an arm


314


by a clamp


316


. Arms


314


are in turn coupled to a common stage


318


which having slides


319


which are translatable over tracks


321


by a screw


320


of a screw motor


322


. In this way, the vibratable elements


310


may simultaneously be moved back and forth in hoppers


306


by operation of screw motor


322


. Alternatively, each of vibrators could be coupled to a separate motor so that each vibrator may independently be translated.




Frame


302


is coupled to a base


324


which includes a plurality of elongate grooves


326


. Grooves


326


are adapted to receive bottom ends of a plurality of receptacles


328


which are formed in a sheet


330


. Sheet


330


is preferably supplied from a blister maker, such as a commercially available Uhlmann Packaging Machine, Model No. 1040. Rotatable members


304


preferably include a number of metering chambers that correspond to the number of receptacles in each row of sheets


330


. In this way, four rows of receptacles may be filled during each cycle of operation. Once four of the rows are filled, the metering chambers are again refilled and sheet


330


is advanced to align four new rows of receptacles with hoppers


306


.




One particular advantage of system


300


is that it may be fully automated. For example, a controller may be coupled to the packaging machine, vacuum and pressurized gas sources, motors


312


, motor


322


and vibrators


308


. By use of such a controller, sheet


330


may automatically be advanced to the proper position whereupon motors


312


are actuated to align the metering chambers with hoppers


306


. A vacuum source is then actuated to draw a vacuum through the metering chambers while vibrators


308


are actuated and motor


322


is employed to translate vibrators


308


. Once the metering chambers are filled, the controller is employed to actuate motors


312


to rotate rotatable members


304


until they are aligned with receptacles


328


. The controller then sends a signal to send a pressurized gas through the metering chambers to expel the metered powder into receptacles


328


. Once filled, the controller causes the packaging machine to advance the sheet


330


and to repeat the cycle. When needed, the controller may be employed to actuate motors (not shown) to vibrate the secondary hoppers to transfer powder into primary hoppers


306


as previously described.




Although shown with vibrators which comprise ultrasonic horns, it will be appreciated that other types of vibrators and vibratable elements may be employed, including those previously described herein. Further, it will be appreciated that the number of vibrators and size of the troughs may be varied according to the particular need.




Although the foregoing invention has been described in some detail by way of illustration and example, for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims.



Claims
  • 1. A method for transporting a fine powder, comprising:placing the fine powder into a hopper having an opening therein; vibrating a vibratable element within the fine powder, wherein the vibratable member has a distal end in the vicinity of the opening, and wherein the vibratable member is vibrated in an up and down motion relative to the powder in the hopper; moving the distal end of the vibratable element laterally through the fine powder while the vibratable element is vibrating; and capturing at least a portion of the fine powder exiting the opening within a chamber, wherein the captured powder is sufficiently uncompacted so that it may be dispersed upon removal from the chamber.
  • 2. A method as in claim 1, wherein the vibratable element is coupled to an ultrasonic horn, and wherein the vibrating step comprises actuating the ultrasonic horn.
  • 3. A method as in claim 1, wherein the vibratable element is vibrated at a frequency in the range from about 1,000 Hz to about 180,000 Hz.
  • 4. A method as in claim 1, wherein the distal end has an end-member attached thereto which is vibrated over the chamber.
  • 5. A method as in claim 4, wherein the end-member is vertically spaced apart from the chamber by a distance in the range from about 0.01 mm to about 10 mm.
  • 6. A method as in claim 5, wherein the end-member is vertically space apart from the chamber by a distance in the range from about 0.01 mm to about 10 mm.
  • 7. A method as in claim 1, further comprising moving the distal end of the element across the opening while vibrating the element.
  • 8. A method as in claim 7, further comprising periodically levelling the powder within the hopper.
  • 9. A method as in claim 8, wherein the levelling step comprises placing a projecting member on the vibratable element at a location spaced apart from a distal end of the vibratable element.
  • 10. A method as in claim 1, wherein multiple chambers are aligned with the opening, and further comprising moving the vibratable element along the opening to pass over each chamber.
  • 11. A method as in claim 1, wherein the fine powder comprises a medicament composed of individual particles having a mean size in the range from about 1 μm to 100 μm.
  • 12. A method as in claim 1, wherein the capturing step further comprises drawing air through the chamber which is positioned below the opening, wherein the drawn air assists in drawing the fine powder into the chamber.
  • 13. A method as in claim 1, further comprising transferring the captured powder from the chamber to a receptacle.
  • 14. A method as in claim 13, wherein the transferring step comprises introducing a compressed gas into the chamber to expel the captured powder into the receptacle.
  • 15. A method as in claim 1, further comprising adjusting the amount of captured powder to be a unit dosage amount.
  • 16. A method as in claim 15, wherein the adjusting step comprises providing a thin plate below the hopper, with the plate having an aperture that is aligned with the chamber, and further comprising moving the chamber relative to the plate to scrape the excess powder from the chamber.
  • 17. A method as in claim 1, wherein the hopper is a primary hopper, and wherein the placing step comprises transferring the powder from a secondary hopper to the primary hopper.
  • 18. A method as in claim 17, further comprising vibrating the secondary hopper to transfer the powder to the primary hopper.
  • 19. A method as in claim 1, further comprising dispensing the powder from the chamber and changing the size of the chamber.
  • 20. Apparatus for transporting a fine powder, comprising:a hopper having an opening therein, the hopper being adapted to receive the fine powder; at least one chamber which is movable to allow the chamber to be placed in close proximity to the opening; a vibratable member having a proximal end and a distal end, the vibratable member being positionable within the hopper such that the distal end is near the opening; a vibrator motor to vibrate the vibratable member when within the fine powder in an up and down motion; and a mechanism for moving the vibratable member over the chamber while the vibratable member is vibrating.
  • 21. An apparatus as in claim 20, further comprising a rotatable member having a plurality of chambers about its periphery which are alignable with the opening, and wherein the moving mechanism is configured to translate the vibratable member along the opening so that the vibratable member passes over each chamber.
  • 22. An apparatus as in claim 20, wherein the moving mechanism comprises a linear drive mechanism which translates the vibratable member along the opening at a rate that is less than about 100 cm/s.
  • 23. An apparatus as in claim 20, wherein the vibrator motor vibrates the vibratable member at a frequency in the range from about 1,000 Hz to about 180,000 Hz.
  • 24. An apparatus as in claim 20, wherein the vibrator motor comprises an ultrasonic horn which vibrates the element in said up and down motion relative to the powder.
  • 25. An apparatus as in claim 24, wherein the vibratable element is cylindrical in geometry and has a diameter in the range from about 1.0 mm to about 10 mm.
  • 26. An apparatus as in claim 25, further comprising an end member at the distal end of the vibratable member.
  • 27. An apparatus as in claim 26, wherein the end member radially extends from the vibratable element.
  • 28. An apparatus as in claim 26, further comprising a powder levelling member spaced above the end member.
  • 29. An apparatus as in claim 20, wherein the chamber is disposed within a rotatable member which is placed in a first position having the chamber aligned with the opening, and a second position having the chamber aligned with a receptacle.
  • 30. An apparatus as in claim 29, further comprising a plurality of hoppers disposed above a plurality of rotatable members which each include a plurality of chambers, and further comprising a plurality of vibratable elements and a plurality of vibrators to vibrate the elements.
  • 31. An apparatus as in claim 29, wherein the chamber is formed in a change tool, and wherein the change tool is removably coupled to the rotatable member.
  • 32. An apparatus as in claim 21, further comprising a port in the bottom of the chamber, and a vacuum source in communication with the port to assist in drawing the fine powder from the hopper and into the chamber.
  • 33. An apparatus as in claim 32, further comprising a filter disposed across the port.
  • 34. An apparatus as in claim 32, further comprising a source of compressed gas in communication with the port to eject the captured powder from the chamber and into the receptacle.
  • 35. An apparatus an in claim 34, further comprising a controller for controlling actuation of the gas source and the vacuum source.
  • 36. An apparatus as in claim 20, further comprising a plate disposed below the hopper, with the plate having an aperture that is aligned with the chamber, and wherein the chamber is movable relative to the plate to allow excess powder to be scraped from the chamber.
  • 37. An apparatus as in claim 20, wherein the hopper is a primary hopper and further comprising a secondary hopper disposed above the primary hopper to transfer powder to the primary hopper.
  • 38. An apparatus as in claim 37, further comprising a snaking mechanism to vibrate the secondary hopper.
  • 39. A system for transporting a fine powder, comprising:a plurality of rotatable members each having a row of chambers about their periphery; a hopper disposed above each rotatable member, wherein each hopper includes an opening; a vibratable element that is positionable within each of the hoppers, wherein each vibratable element has a distal end near the opening; a vibrator coupled to each vibratable element to vibrate the elements in an up and down motion; and a mechanism to translate each vibratable element along each of the hoppers while the elements are vibrating.
  • 40. A system as in claim 39, further comprising a controller to control rotation of the vibratable members, the vibrators, and the translation mechanism.
CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of and claims the benefit of U.S. Provisional Patent Application Ser. No. 60/100,437, which was converted from U.S. patent application Ser. No. 08/949,047, filed Oct. 10, 1997, the complete disclosures of which are herein incorporated by reference.

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Provisional Applications (1)
Number Date Country
60/100437 Jul 1997 US