Abstract:
A sampler for acquiring a sample of blended powder from diverse locations within a bin is described. The sampler has a cylinder with a hollow chamber formed therein and is connected to a handle for rotation within a housing tube. Rotation causes the chamber to move into or out of alignment with an aperture in the housing tube. When the sampler is inserted axially into a batch of blended powder, the cylinder is rotated to align the chamber with the aperture in the housing cap, allowing powder to enter the chamber. The cylinder is rotated back to close the chamber, and the sampler is withdrawn from the powder batch. The cap is removed from the housing and the cylinder is removed from the housing to transfer the sample of powder for analysis.

Description:
FIELD OF THE INVENTION 
   The present invention relates to the field of samplers for acquiring samples of blended powder from various locations in a bin. 
   BACKGROUND OF THE INVENTION 
   Many pharmaceutical and food preparations are made by blending two or more powders together prior to further processing, such as compression into tablets or filling capsules, bottles, pouches, etc. Such powder blending must be thorough in order to avoid irregular distribution of the ingredients which equates to inconsistency in product quality. To verify uniformity of the powder blend, testing of powder properties must be conducted at the completion of the blending cycle prior to further manufacturing processes. The first step in testing is the acquisition of samples of a uniform size from various areas in the production batch for comparison with a standard. 
   If one of the ingredients in the blend is an active ingredient, such as a drug, deviation from the standard component ratio will render the dosage form non-uniform and potentially ineffective or dangerous. Therefore testing of powder blends for uniformity prior to further processing, handling, shipping, etc. is imperative. Uniformity in powder blends is usually studied both at the research and development stage and at the manufacturing stage by obtaining samples of the finished product, such as tablets or capsules. Samples are obtained at different time intervals throughout the processing batch and analyzed for content uniformity. However, since uniformity of the tablet or capsule is derived from uniformity of the powder blend, it is more efficient to test the powder blend, especially during production operations. 
   Thus, an apparatus to test powder blends for uniformity under production conditions of long run times would be an important tool for the blended powder product manufacturer. In particular, the test sample must be of a uniform size to enable comparison of results between batches. Since production conditions typically require large quantities, deep bins are often used, and there is a need for a sampling device able to acquire samples from diverse areas of the deep storage bin. 
   Prior powder sampling devices and methods are disclosed in U.S. Pat. Nos. 5,337,620, 5,440,941 and 6,339,966 to the present inventor. The inventions disclosed in these prior patents acquire samples through laterally open cavities that are perpendicular to the axis of the sampler. Powder samples thus are subject to shear forces as the powder enters the cavity and are thus not totally reliable. The invention disclosed herein provides a novel sampler especially adapted for acquiring samples of blended powder from various positions in a bin by a cavity parallel to the sampler axis to ensure uniformity. 
   SUMMARY OF THE INVENTION 
   The blended powder sampler apparatus described below has a long housing with an open upper end and a closable lower end. The lower end is closed with a cap having a hole therethrough. A rotatable cylinder resides within the housing. The cylinder has a chamber that is aligned with the cap hole in a first position and not aligned with the cap hole in a second position. The cylinder chamber is oriented parallel to the longitudinal axis of the sampler. The cylinder is turned by manipulation of a handle on the opposite end of a long shaft. In another embodiment of the invention, the cylinder is formed with multiple chambers to obtain several samples with one stroke. 
   In use, the sampler is inserted into a batch of blended powder that is stored in a bin. The cylinder is rotated to align the chamber in the cylinder with the hole in the cap, and the sampler is pushed further parallel to the axis to acquire a powder sample. The cylinder is then rotated back to close the chamber, the sampler is then withdrawn from the powder bin. The cap is removed from the housing and the sample taken for analysis. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is best understood in conjunction with the accompanying drawing figures in which like elements are identified by similar reference numerals and wherein: 
       FIG. 1  is a cross sectional elevation view of a bin containing blended powder into which the invention powder sampler is inserted. 
       FIG. 2A  is a front elevation view of the upper portion of the powder sampler of the invention, a portion thereof shown as a cutaway cross section. 
       FIG. 2B  is a front cross sectional elevation view of the lower portion of the powder sampler of the invention. 
       FIG. 3  is an exploded perspective view of the internal components of the powder sampler of the invention. 
       FIG. 4  is a partial front elevation view showing a guide track formed in the powder sampler housing tube. 
       FIG. 5A  is a bottom plan view of assembled tip and cylinder internal components of the preferred embodiment in aligned orientation. 
       FIG. 5B  is a bottom plan view of the components of  FIG. 5A  with the tip pivoted into a non-aligned position. 
       FIG. 6  is a bottom plan view of an assembled tip and cylinder in aligned position according to a second embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In reference to  FIG. 1 , a production size bin  10  in a typical pharmaceutical manufacturing environment is illustrated as containing a quantity of blended powder  14 . Bin  10  may be of any standard shape and from 1 to 3 meters (3 to 10 feet) in depth. A blended powder sampler  20  of the invention is inserted into the batch of blended powder  14  in bin  10 . As discussed above, in order to verify the uniformity of component distribution in powder blend  14 , samples must be taken from various positions in bin  10  and analyzed for component content. Therefore, sampler  20  is sufficiently long to reach all areas within bin  10 , leaving an operator end of sampler  20  exposed above bin  10  for handling purposes. Sampler  20  is thus nominally adapted in length to the particular bin  10  being utilized. 
   Referring now to  FIG. 2A  and  FIG. 2B , the upper and lower portions of sampler  20 , respectively, are illustrated. A housing in the form of a long round cylindrical tube  22  contains and interacts with the operative internal components of sampler  20  as described below. Housing tube  22  has a longitudinal axis β. Handle  28  is affixed to shank  24  that partly resides rotatably in housing tube  22  and is attached to shaft  30  with transverse pin  32 ′. The upper end of housing tube  22  has a guide track  38  formed therethrough in the shape of the numeral “7”. Guide track  38  serves to control the rotation of handle  28 , and consequently shaft  30  to rotate through a selected angle. A lower end of tube  22  has an external thread  54  formed thereon. A cap  52  is provided with an internal thread  54  formed therein to be removably assembled to the lower end of housing tube  22 . Preferably, thread  54  is formed with a reduced diameter step cut into the exterior surface of tube  22  and an increased diameter step cut into the interior surface of cap  52  to allow the outside diameter of tube  22  to be substantially equal to the outside diameter of cap  52  eliminating any possible crevices that could collect residue. Other means of attaching cap  52  to housing tube  22  are considered within the scope of the invention. Cap  52  has a conical portion at its lower end to enable insertion of powder sampler  20  through depths of blended powder  14  (see  FIG. 1 ) with a minimum of effort or disturbance to the powder blend. Alternatively, the lower end portion of cap  52  may be formed as a convex rounded shape. Cap  52  has an aperture  58  formed through the conical or rounded lower end thereof. 
   As assembled within the lower end of sampler  20 , a tip  60  has a conical portion to nest rotatably within the conical interior portion of cap  52 . As will be understood, if the lower inner surface of cap  52  is rounded in form, tip  60  will be similarly rounded. Tip  60  may, optionally, have a cylindrical portion extensive with its conical portion, as seen in  FIG. 2B . As illustrated, the line dividing tip  60  from cylinder  48  may reside within cap  52  to enable removal of cylinder  48  when cap  52  has been removed. Tip  60  has a channel  62  formed therethrough that is sized and positioned to align with aperture  58  in cap  52  when tip  60  is rotated to a selected orientation. A cylinder  48  is configured to rotatably fit within housing tube  22  and is connected to tip  60  with a pivot pin  56  that resides in a pair of matching holes in the adjacent surfaces of tip  60  and cylinder  48 . As illustrated, the aligned holes are off center of cylinder  48  and tip  60  for reasons to be described below. Cylinder  48  has a chamber  50  formed therein in a location to extend coaxially from channel  62  of tip  60 . Thus, when tip  60  and cylinder  48  are properly rotated, aperture  58  of cap  52 , channel  62  of tip  60  and chamber  50  of cylinder  48  are in alignment with one another. Preferably, aperture  58 , channel  62  and chamber  50  are substantially equal in diameter. A plate  42  is assembled to the upper surface of cylinder  48  with a pair of pins  46  passing therebetween. Plate  42  has no hole other than the holes for pins  46 , thus plate  42  effectively blocks the upper end of chamber  50 . By providing plate  42  as an assembled component, plate  42  may be removed to allow thorough cleaning of chamber  50 . A plug  40  is assembled above plate  42  with pins  46 . Plug  40  is further formed with a cavity  36  to receive a lower end of shaft  30  and transverse connector pin  32  in perpendicular orientation thereto. In this configuration, rotation of shaft  30  causes plug  40 , plate  42 , cylinder  48  and tip  60  to rotate within housing tube  22  and cap  52 . 
   Referring further to  FIGS. 2A and 2B , the upper end of shaft  30  resides in a cavity  36 ′ in shank  24  and is held in engagement therewith by a connector pin  32 ′. Connector pins  32  and  32 ′ through the lower and upper ends of shaft  30  are preferably spring pins, as are known. A handle  28  is fixedly assembled to shank  24  in perpendicular relation thereto. A guide pin  34  is assembled to extend radially out from shank  24  in a position to engage guide track  38 . As will be understood, guide pin  34  holds shank  24 , shaft  30  and the components connected to the lower end of shaft  30  in a selected orientation to be aligned or to close hole  58  over channel  62 . Housing tube  22  has a length L T  and shaft  30  has a length L S  that places tip  60  in sliding contact with the inner surface of the conical portion of cap  52 . When sampler  20  of the present invention is used to obtain a blended powder sample from a storage bin of a different depth, both length L T  and length L S  are changed by a similar amount. 
   Referring now to  FIG. 3 , the several components intended to function within the lower end of housing tube  22  are illustrated in exploded perspective view. Tip  60  has channel  62  formed therethrough at a location between a centerline and the periphery of tip  60  to be exposed on an angled portion of the cone. The upper surface of tip  60  has a pivotal socket  66  provided for insertion of pivot pin  56  that also engages a pivotal socket  66 ′ formed in the lower surface of cylinder  48 . Pivotal sockets  66  and  66 ′ are located off-center of cylinder  48  and tip  60 . Socket  66  in tip  60  is preferably sized to create an interference fit with pin  56 , essentially permanently holding pin  56  in assembly with tip  60 . Socket  66 ′ is of a larger diameter than socket  66  to receive a resilient bushing and allow pin  56  to rotate therein. Cylinder  48  has a chamber  50  that is positioned in alignment with channel  62  of tip  60  when assembled. Chamber  50  may, optionally, have a capacity equal to a volume of one unit dose of the blended powder being tested. If one unit dose is the sample size, a tablet may be pressed of the blended powder in a separate device, or a capsule may be filled. When assembled, chamber  50  resides substantially parallel to axis β of housing tube  22  (see  FIG. 2B ) so that thrusting sampler  20  axially into powder blend  14  (see  FIG. 1 ), with chamber  50  and channel  62  aligned with aperture  58  (see  FIG. 2B ), forces a sample quantity of blended powder  14  into chamber  50 . Cylinder  48  has a pair of drive sockets  68  in its upper surface to snugly receive drive pins  46  that further pass snugly through drive sockets  68 ′ in plate  42  to terminate slidingly in holes  68 ″ in plug  40 . According to the preferred embodiment, a highly frictional annular insert, for example a short length of synthetic resin tubing, is inserted into drive sockets  68  and  68 ′ in order to securely anchor drive pins  46  and minimize metal contact wear between drive pins  46  and drive sockets  68 ,  68 ′. Plug  40  also includes an axial cavity  36  for receiving the lower end of shaft  30  (see  FIG. 2B ) and connector pin hole  72  to pass connector pin  32  (see  FIG. 2B ). Plate  42  is only breached by holes  68 ′ therethrough. Pin holes  68 ,  68 ′ and  68 ″ in cylinder  48 , plate  42  and plug  40  are formed so that pins  46  snugly hold plate  42  to cylinder  48 , and slidingly connect to plug  40 . When assembled, these components of  FIG. 3  form a stack held in the lower end of housing tube  22  (see  FIG. 2B ) by cap  52 . 
   Referring now to  FIG. 4 , a brief description of the operation of the present invention follows in conjunction with  FIGS. 2A and 2B . Guide track  38  is formed in the upper end of housing tube  22  in the shape of the numeral “7”. When guide pin  34  resides at position A, channel  62  (see  FIG. 2B ) in tip  60  is not in alignment with aperture  58  through cap  52 , causing chamber  62  to be closed. Sampler  20  (see  FIG. 1 ) is pushed axially through the batch of blended powder  14  in bin  10 . When the lower end of sampler  20  approaches the position for obtaining a sample of blended powder, handle  28  (see  FIG. 2A ) is rotated to place guide pin  34  at position B, to open channel  62  (see  FIG. 2B ) by aligning channel  62  with aperture  58 . Sampler  20  (see  FIG. 1 ) is pushed further linearly into the batch of blended powder  14  in a direction parallel to axis β (see  FIG. 2B ) to fill channel  62  and chamber  50  with blended powder  14 . Handle  28  (see  FIG. 2A ) is returned to the position at which guide pin  34  is at point A, closing channel  62  (see  FIG. 2B ) within cap  52 . Sampler  20  is then withdrawn from bin  10 . Next, sampler  20  is inverted to place cap  52  (see  FIG. 2B ) on top, and cap  52  is unscrewed at threads  54  and removed from tube  22 . Then, handle  28  moves guide pin  34  again to position B and on to position C to further extend cylinder  48  out from the end of tube  22 . Cylinder  48  and tip  60  are grasped by a user and removed from tube  22  along with plate  42 . Plug  40 , being fixedly connected to shaft  30  and slidingly connected to plate  42 , remains in tube  22 . 
   In removing the assembly comprising plate  42 , cylinder  48  and tip  60  from tube  22 , care is taken to hold cylinder  48  upright with tip  60  on top, as seen in  FIG. 5A , so as to avoid spilling the acquired sample of blended powder  14 . As seen in regard to  FIG. 2B  and  FIG. 3 , plate  42  remains in contact with cylinder  48  to keep the blended powder  14  in chamber  50 . Next, tip  60  is pivoted around pivot pin  56  in the direction indicated by arrow F to the position shown in  FIG. 5B . By this movement of tip  60  relative to cylinder  48 , the blended powder that was in channel  62  is discarded and the residual blended powder sample in chamber  50  is preserved. The preserved blended powder sample in chamber  50  has a defined volume that may, optionally, be equal to a unit dose of blended powder  14 . Last, cylinder  48  is inverted with tip  60  and the blended powder sample  14  is transferred to another container for analysis. In case a unit dose size sample is selected, the acquired sample of blended powder may be compressed into a tablet or a capsule filled for further powder evaluation. Guide pin  34  (see  FIG. 4 ) is moved past position D to position A. When removing all internal components from housing tube  22 , pin  34  is moved past position E and out through the open channel above. 
   Referring now to  FIG. 6 , a further embodiment of the invention is illustrated as a top view of a tip  60   a . Tip  60   a  and the cylinder (not shown) on which it pivots around pin  56   a  provide 3 chambers  62   a ,  62   a ′ and  62   a ″. A sampler having 3 chambers is particularly beneficial in order to acquire 3 samples during a single insertion into blended powder  14 . Chambers  62   a ,  62   a ′ and  62   a ″ are all oriented substantially parallel to axis β of housing tube  22  (see  FIG. 2B ). The 3 samples may be used for the purposes of present analysis, backup in case of loss, and an archive sample. 
   While the description above discloses preferred embodiments of the present invention, it is contemplated that numerous variations and modifications of the invention are possible and are considered to be within the scope of the claims that follow.