Abstract:
The subject matter of this specification can be embodied in, among other things, a rotary mixer with a housing defining a mixing chamber defining a rotation axis, the housing being rotatable about the rotation axis in a rotation direction and having a longitudinal midpoint, a set of blades within the housing, wherein at least one pair of blades of the set of blades forms an angle with respect to each other, and at least one blade of the set of blades is shorter than another blade of the set of blades in the rotation direction, and a splitter blade located within the housing with respect to the longitudinal midpoint and the angle to divide material in the mixing chamber between the at least one blade of the set of blades and the other blade of the set of blades, as the cylindrical housing is rotated about the rotation axis.

Description:
TECHNICAL FIELD 
       [0001]    This specification relates to apparatus for mixing particulate matter. 
       BACKGROUND 
       [0002]    Mixing of solids, such as powders and aggregates, is a common operation in many industries. Examples can be found in the manufacturing of chemical products (gas-solid reaction), pharmaceuticals (preparation of drugs), foods (freeze-dried products), cosmetics (preparation of makeup), construction products (concrete in truck mixers), and detergents (homogenization of washing powders). The aim of these operations is to homogenize two or more components. Such homogenization can be difficult due to the diversity of products in terms of size (particles, granules or lumps), shape (spheres, pellets, flakes, filaments, blocks, crystals or irregularly shaped particles), moisture (dry product, wet product or paste), and surface nature (cohesive or non-cohesive powder). 
       SUMMARY 
       [0003]    In general, this document includes systems, apparatus and techniques for mixing particulate matter. 
         [0004]    In a first aspect, a rotary mixer includes a cylindrical housing having a peripheral wall defining a mixing chamber having a first axial end and a second axial end and defining a rotation axis, the cylindrical housing being rotatable about the rotation axis in a rotation direction and having a longitudinal midpoint, a set of blades within the cylindrical housing, wherein at least one pair of blades of the set of blades forms an angle with respect to each other, and at least one blade of the set of blades is shorter than another blade of the set of blades in the rotation direction, and a splitter blade located within the cylindrical housing with respect to the longitudinal midpoint and the angle to divide material in the mixing chamber between the at least one blade of the set of blades and the other blade of the set of blades, as the cylindrical housing is rotated about the rotation axis. 
         [0005]    Various embodiments can include some, all, or none of the following features. The at least one pair of blades can include a first wedge blade and a second wedge blade, the first wedge blade being attached to the peripheral wall proximal to the first axial end to a location on the peripheral wall away from the first axial end and extending inward toward the rotation axis, and the second wedge blade being attached to the peripheral wall proximal to the second axial end to a location on the peripheral wall away from the second axial end and extending inward toward the rotation axis. The at least one pair of blades can include a third wedge blade and a fourth wedge blade, the third wedge blade being attached to the peripheral wall proximal to the first axial end to a location on the peripheral wall away from the first axial end and extending inward toward the rotation axis, and the fourth wedge blade being attached to the peripheral wall proximal to the second axial end to a location on the peripheral wall away from the second axial end and extending inward toward the rotation axis. The at least one pair of blades can include the at least one blade of the set of blades and the other blade of the set of blades, which are a first lifter blade and a second lifter blade that come together to form a v-channel. The set of blades can include a first wedge blade and a second wedge blade, the first wedge blade being attached to the first lifter blade and to the peripheral wall proximal to the first axial end, and the second wedge blade being attached to the second lifter blade and to the peripheral wall proximal to the second axial end. The v-channel can be a first v-channel, and the at least one pair of blades can include a third lifter blade and a fourth lifter blade that come together to form a second v-channel suspended radially between the first v-channel and the cylindrical housing. The at least one pair of blades can include a third lifter blade and a fourth lifter blade that come together to form a second v-channel. The set of blades can include a first wedge blade and a second wedge blade, the first wedge blade being attached to the third lifter blade and to the peripheral wall proximal to the first axial end, and the second wedge blade being attached to the fourth lifter blade and to the peripheral wall proximal to the second axial end. The at least one pair of blades can include a fifth lifter blade and a sixth lifter blade that come together to form a third v-channel suspended radially between the second v-channel and the cylindrical housing. 
         [0006]    In a second aspect, a method of mixing particulate matter includes providing a particulate mix including one or more particulates within a cylindrical housing having a peripheral wall defining a mixing chamber having a first axial end and a second axial end and defining a rotation axis, the cylindrical housing being rotatable about the rotation axis extending between the first axial end and the second axial end and having a longitudinal midpoint, and at least one set of blades within the cylindrical housing, rotating the cylindrical housing about the rotation axis, separating, by rotational motion of the set of blades about the rotation axis, the particulate mix into a first portion and a second portion, lifting, by rotational motion of the set of blades about the rotation axis, the first portion above the second portion, directing, by rotational motion of the set of blades about the rotation axis, the first portion toward the midpoint, directing, by rotational motion of the set of blades about the rotation axis, the second portion toward the midpoint, and depositing, by rotational motion of the set of blades about the rotation axis, the first portion on top of the second portion. 
         [0007]    Various embodiments can include some, all, or none of the following features. The set of blades can include a first wedge blade attached to the peripheral wall proximal to the first axial end to a location on the peripheral wall away from the first axial end and extending inward toward the rotation axis, a second wedge blade attached to the peripheral wall proximal to the second axial end to a location on the peripheral wall away from the second axial end and extending inward toward the rotation axis, at least one pair of blades forming a v-channel, and a splitter blade attached to the v-channel and oriented substantially perpendicular to the rotation axis and substantially dividing the mixing chamber. The at least one pair of blades includes a first lifter blade having a planar surface having a first lifter blade edge, a second lifter blade edge opposite the first lifter blade edge, a third lifter blade edge in contact with the first wedge blade, and a fourth lifter blade edge, and a second lifter blade having a planar surface having a fifth lifter blade edge, a sixth lifter blade edge opposite the fifth lifter blade edge, a seventh lifter blade edge in contact with the second wedge blade, and an eighth lifter blade edge in contact with the fourth lifter blade edge. The method can also include separating, by rotational motion about the rotation axis of a second set of blades within the cylindrical housing, the particulate mix into a third portion and a fourth portion, lifting, by rotational motion of the second set of blades about the rotation axis, the third portion above the fourth portion, directing, by rotational motion of the second set of blades about the rotation axis, the third portion toward the midpoint between the first axial end and the second axial end, directing, by rotational motion of the second set of blades about the rotation axis, the fourth portion toward the midpoint, and depositing, by rotational motion of the second set of blades about the rotation axis, the third portion on top of the fourth portion. The cylindrical housing can be rotated n times and the particulate mix can be mixed with a blending effect of 2 n . The second set of blades can include a third wedge blade attached to the peripheral wall proximal to the first axial end to a location on the peripheral wall away from the first axial end and extending inward to the rotation axis, a fourth wedge blade attached to the peripheral wall proximal to the second axial end to a location on the peripheral wall away from the second axial end and extending inward to the rotation axis, at least one pair of blades forming a v-channel, and a splitter blade attached to the v-channel and oriented substantially perpendicular to the rotation axis and substantially dividing the mixing chamber. The at least one pair of blades can include a third lifter blade having a planar surface having a ninth lifter blade edge, a tenth lifter blade edge opposite the ninth lifter blade edge, an eleventh lifter blade edge in contact with the third wedge blade, and a twelfth lifter blade edge, and a fourth lifter blade having a planar surface having a thirteenth lifter blade edge, a fourteenth lifter blade edge opposite the thirteenth lifter blade edge, a fifteenth lifter blade edge in contact with the fourth wedge blade, and a sixteenth lifter blade edge in contact with the twelfth lifter blade edge. 
         [0008]    In a third aspect, a rotary mixer includes a cylindrical housing defining a mixing chamber and a rotation axis, the cylindrical housing being rotatable about the rotation axis in a rotation direction and having a longitudinal midpoint, means for splitting a material into two parts along the rotation axis during rotation of the material in the rotary mixer, means for moving the material toward the longitudinal midpoint during the rotation of the material in the rotary mixer, and means for depositing the material in one of the two parts over the material in another of the two parts during the rotation of the material in the rotary mixer to cause the mixing of the material. 
         [0009]    Various embodiments can include some, all, or none of the following features. The cylindrical housing can include a peripheral wall defining a main mixing chamber having a first axial end and a second axial end, the cylindrical housing being rotatable about the rotation axis. The means for moving the material toward the longitudinal midpoint can include a collection of wedge blades attached to the peripheral wall proximal to the first axial end and proximal to the second axial end to locations on the peripheral wall away from the first axial end and the second axial end, and extending inward to the rotation axis. The means for depositing the material can be one or more v-channels. The means for splitting a material into two parts can be a splitter blade attached to at least one of the one or more v-channels substantially perpendicular to the horizontal rotation axis and substantially dividing the mixing chamber. 
         [0010]    The systems, apparatus and techniques described here may provide one or more of the following advantages. First, an apparatus can provide rapid homogenization of disparate solid particulate materials. Second, the apparatus&#39; operating principles enable the devices to mix materials of widely varying particle sizes, densities, and shapes. Third, the apparatus can reliably achieve a substantially homogeneous and/or uniform mixture in a relatively short period of time. 
         [0011]    The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0012]      FIGS. 1-6  are views of an example of a rotary mixer for mixing particulate matter. 
           [0013]      FIGS. 7-12  are views of another example of a rotary mixer for mixing particulate matter. 
           [0014]      FIG. 13  is a diagram of an example of an apparatus for manipulating a rotary mixer. 
           [0015]      FIG. 14  is flow chart that shows an example of a process for mixing particulate matter. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In general, the apparatus use a technique of splitting and recombination that promotes efficient and effective mixing. The apparatus implement a collection of blades arranged within a cylindrical housing (e.g., a drum, barrel). The design is such that the material to be mixed is split into two substantially equal halves, and then as the cylinder rotates one of the halves continues to slide on the outer drum wall while the other half is raised above and over the first half, and is then dropped on top of the first half, completing a precise, controlled recombination of the material. In general, the mixing apparatus are implemented as industrial right circular cylindrical drums (e.g., 55 gallon steel drum) although in some embodiments the design can be implemented in cylindrical housings made of plastic, fiberboard, steel, stainless steel, or any other appropriate material. The cylindrical housings are fitted with blades positioned at predetermined positions and angles to accomplish the splitting and recombination of the material being mixed. In some embodiments, the cylindrical housings can range in size from as small as a quart or smaller, up to as large as the mixing requirements may require (e.g., dozens, hundreds, or thousands of cubic feet). 
         [0017]      FIGS. 1-6  are views of an example of a rotary mixer (e.g., drum mixer) for mixing particulate matter. The rotary mixer  100  includes an outer housing  102 . The outer housing  102  is formed as a hollow cylinder that defines a mixing chamber, the ends of which are covered by a pair of end caps  104 . In some embodiments, the outer housing  102  may be a standard industrial drum. In some embodiments the end caps  104  can be standard industrial drum ends and/or lids. In some embodiments, one or both of the end caps  104  may be removable. 
         [0018]    The rotary mixer  100  has two sets of blades  110   a  and  110   b  that split and recombine particulate matter twice for each rotation of the outer housing  102  along its cylindrical longitudinal axis  106 . The set of blades  110   a  includes a pair of wedge blades  120   a,    120   b  that are substantially in contact with the outer housing  102  and extend radially inward toward the axis  106 . In some embodiments, one or both of the wedge blades  120   a,    120   b  can be at least partly connected to the outer housing  102  (e.g., welded, glued, fastened). The wedge blades  120   a,    120   b  are arranged as a wedge shape with its wide end open relative to the direction of rotation of the rotary mixer  100  as indicated by arrow  108 . In some embodiments, the wedge blades  120   a  and  120   b  can be oriented relative to each other at angles ranging from about 1 degrees to 179 degrees. In some embodiments, the end caps  104  may be used without the wedge blades  120   a  and  120   b.    
         [0019]    A pair of lifter blades  122   a,    122   b  extend between the wedge blades  120   a,    120   b  to define a shallow v-channel  125   a.  The lifter blades  122   a,    122   b  are arranged such that the v-channel  125   a  is radially further away from the axis  106  than the points from which the lifter blades  122   a,    122   b  extend from the wedge blades  120   a,    120   b.  The lifter blade  122   a  includes a leading edge  124   a  and a trailing edge  126   a.  In some embodiments, the lifter blades  122   a  and  122   b  can be arranged to contact each other at angles ranging from about 90 degrees to about 179 degrees. 
         [0020]    The lifter blade  122   b  includes a leading edge  124   b  and a trailing edge  126   b.  The leading edges  124   a  and  124   b  lead the lifter blades  122   a  and  122   b  relative to rotation of the rotary mixer  100  in the direction of the arrow  108 , and the trailing edges  126   a  and  126   b  follow the lifter blades  122   a  and  122   b  relative to rotation of the rotary mixer  100 . The combined longitudinal width of the leading edges  124   a  and  124   b  is wider than the combined longitudinal width of the trailing edges  126   a  and  126   b.    
         [0021]    A pair of lifter blades  123   a,    123   b  extends longitudinally between the wedge blades  120   a,    120   b  to define another shallow v-channel  126   a.  The lifter blades  123   a,    123   b  are arranged such that the v-channel  126   a  is radially further away from the axis  106  than the points from which the lifter blades  123   a,    123   b  extend from the wedge blades  120   a,    120   b,  and such that the v-channel  126   a  is suspended radially between the v-channel  125   a  and the outer housing  102 . In some embodiments, the lifter blades  123   a  and  123   b  can be configured to meet at angles ranging from about 0 degrees to about 90 degrees. For example, a v-channel with a zero degree angle can be configured as a substantially planar lifting surface. 
         [0022]    A splitter blade  130   a  extends radially inward from the v-channel  125   a  proximal to a midpoint  190  of the outer housing  102 , partly into the interior of the outer housing  102 . The splitter blade  130   a  is oriented substantially perpendicular (e.g., +/−20 degrees) to the axis  106 . A leading aperture  142   a  is defined by the wedge blades  120   a,    120   b,  the splitter blade  130   a,  and the outer housing  102  proximal the leading edge  124   a.    
         [0023]    The set of blades  110   b  includes a pair of wedge blades  120   c,    120   d  that are substantially in contact with the outer housing  102  and extend radially inward toward the axis  106 . In some embodiments, one or both of the wedge blades  120   c,    120   d  can be at least partly connected to the outer housing  102  (e.g., welded, glued, fastened). The wedge blades  120   c,    120   d  are arranged as a wedge shape with its wide end open relative to the direction of rotation of the rotary mixer  100  as indicated by arrow  108 . In some embodiments, the wedge blades  120   c  and  120   d  can be oriented relative to each other at angles ranging from about 1 degree to 179 degrees. In some embodiments, the end caps  104  can be used without the wedge blades  120   c  and  120   d.    
         [0024]    A pair of lifter blades  122   c,    122   d  extend between the wedge blades  120   c,    120   d  to define a shallow v-channel  125   b.  The lifter blades  122   c,    122   d  are arranged such that the v-channel  125   b  is radially further away from the axis  106  than the points from which the lifter blades  122   c,    122   d  extend from the wedge blades  120   c,    120   d.  The lifter blade  122   c  includes a leading edge  124   c  and a trailing edge  126   c.  The lifter blade  122   d  includes a leading edge  124   d  and a trailing edge  126   d.  The leading edges  124   c  and  124   d  lead the lifter blades  122   c  and  122   d  relative to rotation of the rotary mixer  100  in the direction of the arrow  108 , and the trailing edges  126   c  and  126   d  follow the lifter blades  122   c  and  122   d  relative to rotation of the rotary mixer  100 . The combined longitudinal width of the leading edges  124   c  and  124   d  is wider than the combined longitudinal width of the trailing edges  126   c  and  126   d.  In some embodiments, the lifter blades  122   c  and  122   d  can be arranged to contact each other at angles ranging from about 90 degrees to about 179 degrees. 
         [0025]    A pair of lifter blades  123   c,    123   d  extends longitudinally between the wedge blades  120   c,    120   d  to define another shallow v-channel  126   b.  The lifter blades  123   c,    123   d  are arranged such that the v-channel  126   b  is radially further away from the axis  106  than the points from which the lifter blades  123   c,    123   d  extend from the wedge blades  120   c,    120   d,  and such that the v-channel  126   b  is suspended radially between the v-channel  125   b  and the outer housing  102 . In some embodiments, the lifter blades  123   c  and  123   d  can be configured to meet at angles ranging from about 0 degrees to about 90 degrees. For example, the lifter blades  123   c  and  123   d  can be configured as a single plate, forming a v-channel with zero angle. 
         [0026]    A splitter blade  130   b  extends radially inward from the v-channel  125   b  proximal to the midpoint  190  of the outer housing  102 , partly into the interior of the outer housing  102 . The splitter blade  130   b  is oriented substantially perpendicular (e.g., +/−20 degrees) to the axis  106 . A leading aperture  142   b  is defined by the wedge blades  120   c,    120   d,  the splitter blade  130   b,  and the outer housing  102  proximal the leading edge  124   c.    
         [0027]    The blade set  110   a  and the blade set  110   b  are near mirror configurations of each other across the axis  106 , except that the leading aperture  142   a  and the leading aperture  142   b  are on opposite sides of their respective splitter blades  130   a,    130   b  relative to each other along the axis  106 . 
         [0028]    In operation, the rotary mixer  100  is at least partly filled with one or more forms of particulate matter (not shown). The end caps  104  are used to enclose the particulate matter within the interior of the outer housing  102 . The rotary mixer  100  is oriented such that the axis  106  is substantially perpendicular to the pull of gravity (e.g., +/−5 to 10 degrees from horizontal relative to gravity). The particulate matter within the rotary mixer  100  falls under the pull of gravity, partly settling at the lowest points within the outer housing  102 . 
         [0029]    The rotary mixer  100  is then rotated about the axis  106 . The particulate matter within the rotary mixer  100  is partly captured (e.g., scooped) by the wide end of the wedge formed by the wedge blades  120   a,    120   b.  As the rotary mixer  100  continues to rotate, the splitter blade  130   a  divides the particulate matter substantially into two halves (e.g., approximately a 50%-50% split, +/−30%), with one half passing through the leading aperture  142   a  onto the lifter blades  123   a  and  123   b,  and the other half being lifted away from the outer housing  202  lifter blades  123   a,    123   b  by the lifter blades  122   a  and  122   b.    
         [0030]    As the rotary mixer  100  continues to rotate, the half of the particulate on the lifter blades  122   a,    122   b  will slide toward the trailing edges  126   a  and  126   b.  As the particulate matter slides, the wedge blades  120   a  and  120   b  and the slopes of the lifter blades  122   a  and  122   b  urge the material towards the v-channel  125   a.  The other half of the particulate on the lifter blades  123   a  and  123   b  will slide toward a pair of trailing edges  128   a  and  128   b  at the rotationally rearward ends of the lifter blades  123   a,    123   b.  The particulate on the lifter blades  123   a  and  123   b  will also be urged towards the v-channel  126   a  by the wedge blades  120   a  and  120   b  and the slopes of the lifter blades  123   a  and  123   b.    
         [0031]    The lifter blades  122   a  and  122   b  act as a rotating shelf to raise one of the halves of the particulate matter above the other half relative to gravity. Eventually, the lifted half of the particulate matter will fall off the trailing edges  126   a  and  126   b  on top of the other half of the particulate matter (e.g., on the lifter blades  123   a  and  123   b ). The aforementioned processes occur during substantially one half of a rotation of the rotary mixer  100 . 
         [0032]    As the rotary mixer  100  continues to rotate, the blade set  110   b  performs substantially the same actions as the blade set  110   a,  scooping, splitting, lifting, and depositing the particulate material to cause further mixing. In some embodiments, because the rotary mixer  100  is recombining substantially equal halves of a quantity of particulate matter, the blending effect can be quantified as 2 to the nth power. For example, since the rotary mixer  100  contains two blade sets  110   a,    110   b  that have substantially equal effect, the mixing achieved by one rotation of the rotary mixer  100  can be expressed mathematically as 2 2 =4, with 4 being the number of effective layers created by the rotation of the drum through one revolution. With 10 rotations of the rotary mixer  100  the effect (e.g., number of layers) can be 2 10 =1,048,576 (e.g., over a million). Similarly, with 20 rotations of the rotary mixer the effect can be 2 40 =1.099×1012 (e.g., over 1 trillion). 
         [0033]      FIGS. 7-12  are views of another example of a rotary mixer  200  for mixing particulate matter. The rotary mixer  200  includes an outer housing  202 . The outer housing  202  is formed as a hollow cylinder, the ends of which are covered by a pair of end caps  204 . In some embodiments, the outer housing  202  may be a standard industrial drum. In some embodiments the end caps  204  can be standard industrial drum ends and/or lids. In some embodiments, one or both of the end caps  204  may be removable. 
         [0034]    The rotary mixer  202  has two sets of blades  210   a  and  210   b  that split and recombine particulate matter twice for each rotation of the outer housing  202  along its cylindrical longitudinal axis  206 . The set of blades  210   a  includes a pair of wedge blades  220   a,    220   b  that are substantially in contact with the outer housing  202  and extend radially inward toward the axis  206 . In some embodiments, one or both of the wedge blades  220   a,    220   b  can be at least partly connected to the outer housing  202  (e.g., welded, glued, fastened). The wedge blades  220   a,    220   b  are arranged as a wedge shape with its wide end open relative to the direction of rotation of the rotary mixer  200  as indicated by arrow  208 . 
         [0035]    A lifter blade  222   a  extends substantially parallel (e.g., +/−20 degrees) to the axis  206  between the wedge blades  220   a,    220   b.  The lifter blade  222   a  includes a leading edge  224   a  and a trailing edge  226   a.  The leading edge  224   a  leads the lifter blade  222   a  relative to rotation of the rotary mixer  200  in the direction of the arrow  208 , and the trailing edge  226   a  follows the lifter blade  222   a  relative to rotation of the rotary mixer  200 . The leading edge  224   a  is wider than the trailing edge  226   a.    
         [0036]    A splitter blade  230   a  extends substantially perpendicular (e.g., +/−20 degrees) from the lifter blade  222   a  proximal to a midpoint  290  of the outer housing  202 , and extends radially inward from the outer housing  202  partly into the interior of the outer housing  202 . The splitter blade  230   a  is oriented substantially perpendicular (e.g., +/−20 degrees) to the axis  206 . A blocker blade  240   a  extends substantially perpendicular (e.g., +/−20 degrees) from the lifter blade  222   a  partly into the interior of the outer housing  202 . The blocker blade  240   a  is oriented substantially parallel (e.g., +/−20 degrees) to the axis  206 . 
         [0037]    A leading aperture  242   a  is defined by the wedge blades  220   a,    220   b,  the splitter blade  230   a,  the blocker blade  240   a,  and the outer housing  202  proximal the leading edge  224   a.  A trailing aperture  244   a  is defined by wedge blades  220   a,    220   b,  and the outer housing  202  proximal the trailing edge  226   a.    
         [0038]    The set of blades  210   b  diagonally mirrors the set of blades  210   a  across the axis  206 . The set of blades  210   b  includes a pair of wedge blades  220   c,    220   d  that are proximal to, or at least partly in contact with, the outer housing  202  and extend radially inward toward the axis  206 . In some embodiments, one or both of the wedge blades  220   c,    220   d  can be at least partly connected to the outer housing  202  (e.g., welded, glued, fastened). The wedge blades  220   c,    220   d  are arranged as a wedge shape relative to the direction of rotation of the rotary mixer  200  as indicated by arrow  208 . 
         [0039]    A lifter blade  222   b  extends substantially parallel (e.g., +/−20 degrees) to the axis  206  between the wedge blades  220   c,    220   d.  The lifter blade  222   b  includes a leading edge  224   b  and a trailing edge  226   b.  The leading edge  224   b  leads the lifter blade  222   b  relative to rotation of the rotary mixer  200  in the direction of the arrow  208 , and the trailing edge  226   b  follows the lifter blade  222   b  relative to rotation of the rotary mixer  200 . The leading edge  224   b  is wider than the trailing edge  226   b.    
         [0040]    A splitter blade  230   b  extends substantially perpendicular (e.g., +/−20 degrees) from the lifter blade  222   b  proximal to the midpoint  290  of the outer housing  202 , and extends radially inward from the outer housing  202  partly into the interior of the outer housing  202 . The splitter blade  230   b  is oriented substantially perpendicular (e.g., +/−20 degrees) to the axis  206 . A blocker blade  240   b  extends substantially perpendicular (e.g., +/−20 degrees) from the lifter blade  222   b  partly into the interior of the outer housing  202 . The blocker blade  240   b  is oriented substantially parallel (e.g., +/−20 degrees) to the axis  206 . 
         [0041]    A leading aperture  242   b  is defined by the wedge blades  220   c,    220   d,  the splitter blade  230   b,  the blocker blade  240   b,  and the outer housing  202  proximal the leading edge  224   b.  A trailing aperture  244   b  is defined by wedge blades  220   c,    220   d,  and the outer housing  202  proximal the trailing edge  226   b.    
         [0042]    The blade set  210   a  and the blade set  210   b  are near mirror configurations of each other across the axis  206 , except that the leading aperture  242   a  and the blocker blade  240   a,  and the leading aperture  242   b  and the blocker blade  240   b  are on opposite sides of their respective splitter blades  230   a,    230   b  relative to each other along the axis  206 . 
         [0043]    In operation, the rotary mixer  200  is at least partly filled with one or more forms of particulate matter (not shown). The end caps  204  are used to enclose the particulate matter within the interior of the outer housing  202 . The rotary mixer  200  is oriented such that the axis  206  is substantially perpendicular to the pull of gravity (e.g., +/−10 degrees from horizontal relative to gravity). The particulate matter within the rotary mixer  200  falls under the pull of gravity, partly settling at the lowest points within the outer housing  202 . 
         [0044]    The rotary mixer  200  is then rotated about the axis  206 . The particulate matter within the rotary mixer  200  is partly captured (e.g., scooped) by the wide end of the wedge formed by the wedge blades  220   a,    220   b.  As the rotary mixer  200  continues to rotate, the splitter blade  230   a  divides the particulate matter substantially into two halves (e.g., approximately a 50%-50% split, +/−30%, with one half passing through the leading aperture  242   a  and remaining proximate the outer housing  202 , and the other half being lifted away from the outer housing  202  by the lifter blade  222   a.    
         [0045]    As the rotary mixer  200  continues to rotate, the half of the particulate on the lifter blade  222   a  will slide toward the trailing aperture  244   a.  As the particulate matter slides, the wedge blades  220   a  and  220   b  urge the material towards the longitudinal midpoint  290  of the rotary mixer  200 . The other half of the particulate along the outer housing  202  will slide toward the trailing aperture  244   a  as well, and will be urged towards the longitudinal midpoint  290  of the rotary mixer  200  by the wedge blades  220   a  and  220   b  as well. The lifter blade  222   a  acts as a rotating shelf to raise one of the halves above the other relative to gravity. Eventually, the lifted half of the particulate matter will fall though the trailing aperture  244   b  on top of the other half of the particulate matter. The aforementioned processes occur during substantially one half of a rotation of the rotary mixer  200 . 
         [0046]    As the rotary mixer  200  continues to rotate, the blade set  210   b  performs substantially the same actions as the blade set  210   a,  scooping, splitting, lifting, and depositing the particulate material to cause further mixing. In some embodiments, because the rotary mixer  200  is recombining substantially equal halves of a quantity of particulate matter, the blending effect can be quantified as 2 to the nth power. For example, since the rotary mixer  200  contains two blade sets  210   a,    210   b  that have substantially equal effect, the mixing achieved by one rotation of the rotary mixer  200  can be expressed mathematically as 2 2 =4, with 4 being the number of layers through one revolution. With 10 rotations of the rotary mixer the effect (e.g., number of layers) can be 2 10 =1,048,576 (e.g., over a million). Similarly, with 20 rotations of the rotary mixer the effect can be 2 40 =1.099×10 12  (e.g., over 1 trillion). 
         [0047]      FIG. 13  is a diagram of an example of an apparatus  300  for manipulating a rotary mixer  301 . In some embodiments, the rotary mixer  301  can be the rotary mixer  100  of  FIGS. 1-6  or the rotary mixer  200  of  FIGS. 7-12 . 
         [0048]    The apparatus  300  includes a support base  310  and a collection of rollers  320 . In some embodiments, the support base  310  can include power, control, structural supports, and motors for the operation of the rollers  320 . The rollers  320  are arranged to support and rotate the rotary mixer  301  about an axis  302 . A first pair of the rollers  320  is arranged to rotate about a common axis  322   a,  and a second pair of the rollers  320  is arranged to rotate about a common axis  322   a  spaced apart and parallel to the common axis  322   a.    
         [0049]    In use, particulate matter can be placed in the rotary mixer  301 . The rotary mixer  301  is placed horizontally upon the rollers  320 . In some embodiments, the rotary mixer  301  can be oriented within a range of about +/−5 to 10 degrees from horizontal (e.g., perpendicular to gravity). The rollers  320  are then actuated to roll the rotary mixer  301  about the axis  302 . The rotation of the rotary mixer  301  causes the particulate matter to interact with blades arranged within the interior of the rotary mixer  301  to cause a mixing of the particulate matter. 
         [0050]    The rotary mixer  301  can also include a spout  330 . The spout  330  can be opened and closed to allow for the entry and exit of particulate matter into and out of the interior of the rotary mixer  301 . In some embodiments, the rotary mixer  301  may be rotated to locate the spout  330  at the relative top of the rotary mixer  301  (e.g., relative to gravity as the rotary mixer  301  rests horizontally). For example, the spout  330  may be rotated upward when particulate matter is to be introduced into the rotary mixer  301 . In some embodiments, the rotary mixer  301  may be rotated to locate the spout  330  at the relative bottom of the rotary mixer  301  (e.g., relative to gravity as the rotary mixer  301  rests horizontally). For example, the spout  330  may be rotated downward when particulate matter is to be removed from the rotary mixer  301  (e.g., to flow or pour out). 
         [0051]      FIG. 14  is flow chart that shows an example of a process  400  for mixing particulate matter. In some implementations, the process is performed using the rotary mixers  100 ,  200 , or  300  of  FIGS. 1-13 . At  410  a particulate mix including one or more particulates is provided within a cylindrical housing having a peripheral wall defining a mixing chamber having a first axial end and a second axial end and at least one collection of mixing blades, the cylindrical housing being rotatable about a substantially horizontal (e.g., +/−5 to 10 degrees perpendicular to gravity) rotation axis extending between the first axial end and the second axial end. For example, the rotary mixer  100  can be provided, and the rotary mixer can hold a mixture of one or more particulates. 
         [0052]    At  420 , the cylindrical housing is rotated about the horizontal rotation axis. For example, the rotary mixer  100  can be rotated about the axis  106 . 
         [0053]    At  430 , the particulate mix is separated into a first portion and a second portion by rotational motion of a first collection of mixing blades. For example,  FIG. 1  shows the splitter blade  130   a  in a position that can divide the particulate mix as the rotary mixer  100  rotates. 
         [0054]    At  440 , the first portion is lifted above the second portion by rotational motion of the first collection of mixing blades. For example, as shown in  FIG. 2 , one of the portions divided by the splitter blade  130   a  can be lifted by the lifter blades  122   a  and  122   b  above the other portion as the rotary mixer  100  rotates. 
         [0055]    At  450  the first portion is directed toward a midpoint between the first axial end and the second axial end by rotational motion of the first collection of mixing blades. For example, as shown in  FIG. 2 , the wedge blades  120   a,    120   b,  and the slopes of the lifter blades  122   a,    122   b  can direct the upper portion of the particulate mix toward the v-channel  125   a  as the rotary mixer  100  rotates. 
         [0056]    At  460 , the second portion is directed toward the midpoint by rotational motion of the first collection of mixing blades. For example, as shown in  FIG. 2 , the wedge blades  120   a,    120   b,  and the slopes of the lifter blades  123   a,    123   b  can direct the upper portion of the particulate mix toward the v-channel  126   a  as the rotary mixer  100  rotates. 
         [0057]    At  470 , the first portion is deposited on top of the second portion by rotational motion of the first collection of mixing blades. For example,  FIG. 3  shows the set of blades  110   a  in a position in which the portion of the particulate mix on the lifter blades  122   a  and  122   b  can slide off the trailing edges  126   a  and  126   b  onto the portion of the particulate mix supported by the lifter blades  123   a  and  123   b.    
         [0058]    In some implementations, steps  420 - 470  may be repeated a predetermined number of times or until a predetermined amount of mixing has been achieved. For example, with  10  rotations of the rotary mixer the effect can be 2 10 =1,048,576 (e.g., over a million). In some implementations, after  470 , the particulate mix may be removed from the rotary mixer. For example, one or both of the end caps  104  may be removed to provide access to the particulate mix, or the particulate mix may be poured out through a spout such as the spout  330  of  FIG. 3 . 
         [0059]    In some embodiments, the process  400  can also include separating by rotational motion of a second collection of mixing blades the particulate mix into a third portion and a fourth portion, lifting by rotational motion of the third collection of mixing blades the third portion above the fourth portion, directing by rotational motion of the second collection of mixing blades the third portion toward the midpoint between the first axial end and the second axial end, directing by rotational motion of the second collection of mixing blades the fourth portion toward the midpoint, and depositing by rotational motion of the second collection of mixing blades the third portion on top of the fourth portion. For example, the set of blades  110   b  can split, lift, direct, and deposit the particulate matter a second time per rotation of the rotary mixer  100 , in addition to the mixing done by the set of blades  110   a.  In some embodiments, the rotary mixer  100  can be rotated n times and the particulate mix can mixed with a blending effect of 2 n . For example, the sets of blades  110   a  and  110   b  can both be used, and if the rotary mixer  100  is rotated ten times then the mixing effect can be 2 10 =1,048,576. 
         [0060]    In some embodiments, the rotary mixers  100 ,  200 , and  300  of  FIGS. 1, 2, and 3  can be modified for continuous (e.g., flow-through) operation. For example, one or more of the rotary mixers  100 , with the end caps  104  omitted, can be assembled end-to-end along a shared rotational axis. The assembly can be elevated at one axial end relative to gravity and rotated about the shared rotational axis. One or more particulates can be poured into the upper end of the assembly, and the particulates can be mixed by rotation of the assembly as the mix is also drawn longitudinally downward by gravity along the assembly. The mix can then exit the assembly at the lower axial end. 
         [0061]    Although a few implementations have been described in detail above, other modifications are possible. For example, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.