Patent Publication Number: US-9427740-B2

Title: Vertical top-fed grain mill

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND 
     1. Field 
     The present disclosure pertains to a vertical top-fed grain mill (degermer). More particularly, the present disclosure relates to a grain milling machine which causes intermittent compression of grains while reducing potential overmilling. 
     2. Description of the Related Art 
     Milling machines are well known wherein grains, such as corn kernels, are debranned and the germ freed or exposed by application of impact force. Grains are supplied from a feeding inlet to a milling chamber having a milling roll, which serves as an impeller and which typically has an abrasive surface. The grains are then circulated by the milling roll, induced to move due to contact with the milling roll&#39;s abrasive surface, and are milled until exiting. The milling roll may include one or more agitating projections or stirring bars mounted on the milling roll within the milling chamber and/or may be elliptical to circulate the grains within the mill. During circulation, the grains rub one another, causing the bran layer to separate from the endosperm and germ. If the distance between the exterior of the milling roll and the milling chamber varies, such as by use of an elliptical milling roll or by use of a polygonal screen defining the exterior of the milling chamber, the grains within the milling chamber are additionally intermittently compressed, increasing the friction between the grains and increasing the internal stresses within the grains, thereby speeding bran removal and grain fracturing, respectively. Typically, a screen defines the extent of the milling chamber. The screen includes perforations to permit grain fragments, generally referred to as brokens, which may be germ, endosperm, bran or a combination thereof, of less than a maximum size, to exit the milling chamber. The force applied to the grains and the associated speed of processing may also be affected by selection of the size, density and direction of the perforations. Additionally, breaks or breaker bars may be installed about the screen that produce further localized areas of compression, which result in further fracturing of the kernels, or propagation of existing fractures within the kernels. Sufficient milling for exposing germ or for reduction of the grain broken size may be controlled by requiring a minimum force be applied to a discharge gate by or through the adjacent grains. Removal of sufficiently milled kernel brokens prior to reaching the top of the milling chamber may be permitted by sufficiently sized perforations in the screen. Those brokens passing through the screen are known as throughs. The grains and brokens passing through the mill to the output are known as overtails. 
     Various milling systems are known in the art for milling of grains. Some mills are horizontally aligned, wherein grains are input at one end of a horizontal-oriented mill, travel horizontally during milling and then exit. The Beall-type degermer is one such well-known horizontally-oriented mill. In a Beall-type degermer, corn is fed into and through the annulus at one end and between a rotating, conical rotor and a stationary concentric screen made of perforated metal. Both rotor and screen are textured with large nodes, which impede motion of the kernels as they are impelled by the rotor. 
     Other mills are vertically-aligned, wherein grains are input at the top or the bottom of a vertically-oriented mill, travel downward or upward, respectively, during milling and then exit One such machine is the Satake Maize Degermer VBF. During rotation of the milling rotor in a vertical degermer, the corn is circulated horizontally by the milling rotor and is retained by the surrounding screen while moving in the vertical plan. 
     In both type of mills, as bran layers may remain with the pieces of endosperm after processing, further refinement may be necessary to reduce the fiber content of the endosperm product. 
     Problematically, grains that are sufficiently fractured early in the milling process continue to be milled with insufficiently fractured grains, often resulting in excessive milling and thereby degradation of products. It is generally desirable to minimize the production of fine particles, known as “fines” as these fines are difficult to separate in order to recover as a marketable product. One resolution has been the positioning of breaker bars at the section of the screen adjacent the discharge to accelerate fracturing of the kernels immediately prior to discharge. The breaker bars may substantially affect the output and milling time, as well as the power applied by the milling roll to the grains. 
     In horizontal mills and vertical bottom-fed mills, a substantial amount of energy is required for milling, which includes the energy needed to introduce grains to the machine and to drive already-present grains toward discharge. Vertical top-fed mills may avoid this issue by introducing grains at the top, but must then address the problem of increased milling resulting from the weight of the newly introduced grains atop those grains already being processed in connection with the abrasive roll. 
     Frequent screen replacement is typical in these mills, particularly as the screen surrounding the milling chamber wears, and often wears unevenly, particularly adjacent the point of introduction of the grains. The constant abrasion of the grains wears the periphery of the perforations of the screen. Such wear requires frequent screen replacement even though the remaining portions of the screen remain usable. 
     Thus, there is a need in the art for vertical grain mill which sufficiently mills grain at high rates of processing while addressing shortcomings of the prior art. 
     SUMMARY 
     The present disclosure therefore meets the above needs and overcomes one or more deficiencies in the prior art by providing a vertical grain mill which sufficiently mills grain at high rates of processing while addressing shortcomings of the prior art. In a first embodiment, the top-fed vertical grain mill includes a main shaft, a roll assembly, a bran removal cylinder, a resistor bar, a grain inlet and an overtails outlet. The main shaft is vertical, rotatable and has an upper portion. The roll assembly includes a plurality of rolls concentrically, removably affixed to the upper portion of the main shaft. Each of the rolls has a smooth, metal vertical outer periphery, a horizontal round cylindrical body of common diameter, a top surface and a bottom surface. On the outer periphery of each roll is a vertically-aligned stirring bar. The bran removal cylinder is vertically aligned and concentrically positioned distant the outer periphery of the plurality of rolls and has a plurality of perforations therethrough below the bottom surface of the top-most of the plurality of rolls. The resistor bar is substantially vertical and positioned on an interior of the bran removal cylinder. The grain inlet, above the roll assembly, permits the provision of grain to the milling chamber between the roll assembly and the bran removal cylinder. The overtails outlet, below the roll assembly, permits the provision of overtails from the milling chamber. 
     In a second embodiment, the top-fed vertical grain mill includes a main shaft, a roll assembly, a bran removal cylinder, a resistor bar, an grain inlet and an overtails outlet. The main shaft is vertical, rotatable and has an upper portion. The roll assembly is removably concentrically affixed to the upper portion of the main shaft and includes a plurality of metal rolls removably concentrically affixed to the upper portion of the main shaft. Each of the plurality of rolls having a smooth, metal vertical outer periphery, a horizontal round cylindrical body of common diameter, a top surface and a bottom surface. On the outer periphery of each of the plurality of metal rolls, a vertically-aligned stirring bar is provided. The bran removal cylinder, which is internally round and vertical concentrically positioned distant the roll assembly, has a plurality of perforations therethrough. The resistor bar is substantially vertical and positioned on an interior of the bran removal cylinder. The grain inlet, above the roll assembly, permits the provision of grain to the milling chamber between the roll assembly and the bran removal cylinder. The overtails outlet, below the roll assembly, permits the provision of overtails from the milling chamber. 
     The present disclosure provides a mill which provides for efficient removal of bran from a grain, such as corn, while simultaneously breaking the endosperm into fractions, also know as grits, maximizing “large grit” while minimizing “small grit.” The present disclosure further provides a mill which aids in separation of germ from endosperm fractions so as to minimize fat or oil contamination of the grits. 
     Additional aspects, advantages, and embodiments of the disclosure will become apparent to those skilled in the art from the following description of the various embodiments and related drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the described features, advantages, and objects of the disclosure, as well as others which will become apparent are attained and can be understood in detail; more particular description of the disclosure briefly summarized above may be had by referring to the embodiments thereof that are illustrated in the drawings, which drawings form a part of this specification. It is to be noted, however, that the appended drawings illustrate only typical preferred embodiments of the disclosure and are therefore not to be considered limiting of its scope as the disclosure may admit to other equally effective embodiments. 
       In the drawings: 
         FIG. 1  is an illustration of one embodiment of the present disclosure along its center illustrating the various components. 
         FIG. 2  is an illustration of the embodiment of  FIG. 1  taken along plane A-A. 
         FIG. 3  is an illustration of a side view of an embodiment of a stirring bar of the present disclosure. 
         FIG. 4  is an illustration of a screen segment of the bran removal cylinder of the present disclosure. 
         FIG. 5  is an illustration of an exploded view of various components of the present disclosure for a second embodiment of the disclosure. 
         FIG. 6  is an illustration of a side view of an embodiment of resistor bar of the present disclosure. 
         FIG. 7  is an illustration of an actual test result comparing the output of an embodiment of a disclosure to an existing bottom-fed mill for two types of corn. 
         FIG. 8  is an illustration of a screen segment of the bran removal cylinder with a wear plate. 
     
    
    
     DESCRIPTION 
     Referring to  FIG. 1 , the top-fed vertical grain mill  100  according to the present disclosure is illustrated. The top-fed vertical grain mill  100  includes a main shaft  102 , a roll assembly  104 , a bran removal cylinder  106 , a resistor bar  108 , a grain inlet  110  and an overtails outlet  112 . The main shaft  102  is vertical, rotatable and has an upper portion  114 . The roll assembly  104  includes a plurality of rolls  116   a - 116   g  concentrically, removably affixed to the upper portion  114  of the main shaft  102 . Referring to  FIGS. 1, 2, and 5 , each of the rolls  116   a - 116   g  has a smooth, metal substantially-vertical outer periphery  150   a - 150   g , a horizontal round cylindrical body  202  of common maximum diameter, a top surface  204  and a bottom surface  152 . On the outer periphery  150  of each roll  116  is a vertically-aligned stirring bar  118 . The bran removal cylinder  106  is vertically aligned and concentrically positioned distant the outer periphery  150   a - 150   g  of the plurality of rolls  116   a - 166   g  and has a plurality of perforations  120  therethrough, in one embodiment limited to a position below the bottom surface  152  of the top-most of the plurality of rolls  116   a  and the bottom  154  of the bran removal cylinder  106 . The resistor bar  108  is substantially vertical and positioned on an interior of the bran removal cylinder  106 . The grain inlet  110 , above the roll assembly  104 , permits the provision of grain to the milling chamber  122  between the roll assembly  104  and the bran removal cylinder  106 . The overtails outlet  112 , below the roll assembly  104 , permits the provision of overtails from the milling chamber  122 . 
     Referring to  FIG. 1 , the top-fed vertical grain mill  100  may also include a frame  124 , wherein the main shaft  102 , and therefore also the roll assembly  104 , is supported. A motor  126  may be affixed to the frame  124  and coupled to the main shaft  102  to cause rotation of the main shaft  102 , and therefore of the roll assembly  104 , during operation of the top-fed vertical grain mill  100 . The frame  124  may include a horizontal surface  128  below the roll assembly  104  to define the bottom of the milling chamber  122 . The overtails outlet  112 , positioned below the horizontal surface  128 , may be affixed to the frame  124 , which may include an orifice through the horizontal surface  128  of the frame  124  for communication between the milling chamber  122  and the overtails outlet  112 . Referring to  FIG. 2 , the bran removal cylinder  106  may be attached to the frame  124  by attachment to pillars  206  of the frame  124 . Referring to  FIGS. 1 and 2 , an outer wall  130  may be attached to the frame  124  and may be placed external to the bran removal cylinder  106 , defining an annular bran removing chamber  132 . This annual bran removing chamber  132  may communicate with a throughs outlet  156  for removal of the throughs from the top-fed vertical grain mill  100 . Referring again to  FIG. 1 , the grain inlet  110  is connected to the frame  124  and provides the inlet for gravity-supplied grain to enter the top-fed vertical grain mill  100 . The frame  124  may also support a guide body  136 . When falling grain enters the top-fed vertical grain mill  100  through the grain inlet  110 , it first contacts the guide body  136 , then is guided to a spiral rotor, or conveyor,  134  mounted to the main shaft  102 . The spiral rotor  134  then provides grain from the grain inlet  110  to the milling chamber  122  so as to be generally equivalently dispersed in the milling chamber  122 . 
     Referring to  FIGS. 1 and 2 , each roll  116  of the roll assembly  104  provides a smooth, metal substantially-vertical outer periphery  150   a - 150   g  rather than an abrasive surface, such as an emery stone typically used as an abrasive grinding stone. While some surface imperfections of the outer periphery  150   a - 150   g  may result in some friction between the grains and the roll  116   a - 116   g , the coefficient of friction is negligible and therefore does not provide sufficient friction to aggressively wear the bran from the exterior of the grain. Any change in the application of force applied to the grains by the roll  116   a - 116   g  itself is further reduced by using rolls  116   a - 116   g  which are round, rather than elliptical. Each of these rolls  116   a - 116   g  is then attached to the main shaft  102 , and each  116   a - 116   g  may be separated from an adjacent vertically-adjacent roll  116   a - 116   g  by a spacer inserted between the rolls  116   a - 116   g  or by a gapping system intended to provide positive airflow such as from main shaft  102 , if a hollow main shaft is used, to the milling chamber  122 . Once each roll  116   a - 116   g  is affixed to the main shaft  102 , an integral unit—the roll assembly  104 —is formed. The outer periphery  150   a - 150   g  of the rolls  116   a - 116   g  in the roll assembly  104  defines the inner diameter of the milling chamber  122 . As can be appreciated, in the roll assembly  104 , the topmost roll  116   a  might not have an outer periphery  150   a  which is entirely vertical, but rather may have an outer periphery  150   a  which is only substantially vertical, such that the top surface of the topmost roll  116   a  may be smaller in diameter than the bottom surface  152  of the topmost roll  116   a , producing a canted periphery  150   a  which aids in the downward flow of the grains introduced to the top-fed vertical grain mill  100 . Preferably, the outer periphery  150   a - 150   g  of each of the rolls  116   a - 116   g  is formed of steel, which is sufficiently smooth as to prevent undesirably grain rubbing and which is sufficiently durable to resist the wearing forces from the grain passing through the top-fed vertical grain mill  100 . 
     At least one vertically-aligned stirring bar  118  is affixed, such as by one or more bolts, or other fastening systems, to each roll  116   a - 116   g  of the roll assembly  104  on its outer periphery  150   a - 150   g , preferably having a height equal to that of the roll  116   a - 116   g  such that the stirring bar  118  extends from the top surface  204  to the bottom surface of the roll assembly  104 . More than one stirring bar  118  may be utilized, provided sufficient spacing about the periphery of the roll  116   a - 116   g  is provided so that grains may be contacted by and impelled by the stirring bar  118 . The thickness of the stirring bar  118  is selected to ensure the quantity, size, and type of grain in the mill, such as corn, barley, or wheat, is induced to move about the milling chamber  122  during operation. Barley, for example, provides a grain notably smaller than corn, and therefore would require a milling chamber  122  and stirring bar  118  sized differently than a milling chamber  122  and stirring bar  118  for use in connection with corn. The various rolls  116   a - 116   g  preferably, but not necessarily, are positioned on the main shaft  102  so that the associated stirring bars  118  are not aligned vertically. Each stirring bar  118  is made of a durable material, such as steel, sufficient to endure the force of the grains on its surface during rotation. Each stirring bar  118  provides a profile extending sufficiently from the outer periphery  150   a - 150   g  of each roll  116   a - 116   g  to induce movement of the grains adjacent the roll  116   a - 116   g . Referring to  FIGS. 2 and 3 , this profile may be a trapezoidal prism. Alternatively, the profile of the stirring bar  118  may be another shape sufficient to induce movement, such as half an elliptical cylinder—which may be used to avoid the generation of an edge which may cause localized stresses in the grains from the stirring bar  118 . The stirring bar  118  has a height substantially equal to the height of the roll  116 . Referring to  FIGS. 2 and 3 , each stirring bar  118  may be mounted on a roll  116   a - 116   g  such that its vertically extending chamfer  302  is found on the forward side  304  in the rotational direction  208  of the roll assembly  104  and that its vertically extending edge portion (rising portion)  306  is found on the rear side  308 . By mounting stirring bar  118  such that the chamfer  302  is on the forward side  304  in the rotational direction  208  of the roll assembly  104 , a comparatively gentle stirring action is obtainable. 
     The bran removal cylinder  106 , which defines the outer boundary of the milling chamber  122 , is internally-round, vertical cylinder concentrically positioned distant the outer periphery  150   a - 150   g  of each of the plurality of rolls  116   a - 116   g . The bran removal cylinder  106  may be formed of two or more segments  210  which may be joined together to provide the uprightly-formed round cylinder  106 , and is formed of a durable material, such as steel, sufficient to endure the force of the grains on its surface  212  during rotation. 
     The bran removal cylinder  106  has a plurality of perforations  120  therethrough. In the first embodiment, these perforations  120  may be limited to the area below the bottom surface  152  of a top-most roll  116   a  of the plurality of rolls  116   a - 116   g . The size, alignment, direction, and shape of the perforations  120  may be selected depending on a number of factors, including grain type, water content, desired bran size, and rate of milling. Perforations  120  may be round or elliptical and, in the case of elliptical perforations may be angled relative to the screen surface  212 . Thus, the bran removal cylinder  106  has a porous wall portion and is uprightly formed. Perforations  120  therefore are laterally present about the entire inner circumference of the bran removal cylinder  106 . As depicted in  FIG. 4 , in connection with a four piece bran removal cylinder  106 , such as depicted in  FIG. 2 , the perforations  120  may be slotted perforations  402 , essentially elliptical in shape and angled upwards from the horizontal plan when viewed from direction of rotation  208 . Other sizes (width, height, orientation, and shape) and arrangements of perforations  120  may be used, subject to the restriction that none are operable above the bottom surface  152  of the top roll  116   a  of the plurality of rolls  116   a - 116   g . Where slotted perforations  402  are used, each may be 25 millimeters in length with a 0.9 millimeter height, on 3.5 millimeter centers, at an angle of not more than 7.5 degrees and not less than 2.7 degrees, and preferably about 4.6 degrees. These perforations  402  may be grouped to address the second and third rolls  116   b ,  116   c  in a first perforation group  404 , to address the fourth and fifth rolls  116   d ,  116   e  in a second perforation group  406 , and the sixth and seventh rolls  116   f ,  116   g  in a third perforation group  408 , if seven rolls are used. As depicted in  FIGS. 1 and 4 , in one embodiment, the perforations  120  are not found above the bottom surface  152  of the top roll  116   a  of the plurality of rolls  116   a - 116   g  should the milling obtained by a top-fed vertical grain mill  100  using a smooth roll with a stirring bar  118 , a round screen  106 , and a resistor bar  118  cause the bran removal cylinder  106  to wear out rapidly at the portion adjacent the top roll  116   a . Alternatively, the perforations  120 ,  402  may be found throughout the bran removal cylinder  106 , including above the bottom surface  152  of the top roll  116   a  of the plurality of rolls  116   a - 116   g    
     Additionally, referring to  FIG. 8 , a wear plate  802  may be affixed to the bran removal cylinder  106  in the area opposite the first roll  116   a  when the bran removal cylinder  106  is installed. The wear plate  802  is provided without any perforations and is sized to fit to and within the bran removal cylinder  106  without interfering with operation of the top-fed vertical grain mill  100 , particularly with regard to the stirring bar  118  associated with the first roll  116   a  and the resistor bar  108 . Thus, an internally-round, vertical wear plate  802  is affixed internally to the internally-round, vertical bran removal cylinder  106  above the bottom surface  152  of the top-most of the plurality of rolls  116   a . The internally-round, vertical bran removal cylinder  106  may therefore include the limitation of the perforations  120  being only below the bottom surface  152  of a top-most  150   a  of the plurality of metal rolls  150   a - 150   g  or may include perforations  120  above the bottom surface  152  of a top-most  150   a  of the plurality of metal rolls  150   a - 150   g  which are then masked from contact with product by the wear plate  802 . 
     At least one substantially vertical resistor bar  108  is positioned on the interior of the bran removal cylinder  106 , preferably spanning the entire height of the bran removal cylinder  106 . The resistor bar  108  may be affixed to a portion of the frame  124  surrounding the bran removal cylinder  106 , as illustrated in  FIG. 1 , or directly to the bran removal cylinder  106 , as illustrated in  FIG. 5 . Each resistor bar  108  may be inserted or extracted using a plurality of knob bolts  138 . Each resistor bar  108  is made of a durable material, such as steel, sufficient to endure the force of the grains on its surface during contact. Each resistor bar  108  provides a profile extending sufficiently from the screen surface  212  of the bran removal cylinder  106  to retard movement of the grains adjacent the bran removal cylinder  106  in the milling chamber  122 . This may be accomplished by a rectangular profile, such as illustrated in  FIG. 2 , or a trapezoidal prism profile which may include a parallel top  602  and bottom  604  and chamfers front  606  and rear  608  of equal cant, such as depicted in  FIG. 6 , or another shape sufficient to retard movement, such as half an elliptical cylinder. The sum of the height  310  of a stirring bar  118  and the height  610  of a resistor bar  108  is greater than the distance between the outer periphery  150   a - 150   g  of the plurality of rolls  116   a - 116   g  and screen surface  212  of the bran removal cylinder  106 , so that a stirring bar  118  may rotate past a resistor bar  108  without interference other than that caused the intermediate grains. 
     The overtails outlet  112  is disposed at the lower end of the milling chamber  122  so as to discharge the grain milled by the top-fed vertical grain mill  100 . The overtails outlet  112  includes a discharge port  140  that is formed by opening a part of the bran removal cylinder  106 , an outlet opening  142  that is connected to the discharge port  140 , a weight lever  144  that is fixed to a shaft  146  transversely suspended on the outlet opening  142 , a resisting plate  148  that is pivoted to one end of the weight lever  144  and faces the discharge port  140  so as to block it, and a weight  145  that is movably attached to the other end of the weight lever  144 . 
     In operation, the motor  126  causes the main shaft  102  to rotate, during which grain, particularly corn, is introduced to the top-fed vertical grain mill  100  via the grain inlet  110 . Various systems are known in the art for distribution of downwardly falling grain from a source to the milling chamber  122 . In one embodiment, prior to introduction to the top-fed vertical grain mill  100 , the grain may be stored any various systems known in the art, including a raw material tank, which may be associated with a valve to control flow of grain into the top-fed vertical grain mill  100 . The downwardly flowing grain introduced to top-fed vertical grain mill  100  is somewhat equally dispersed circumferentially by the guide body  136 , which provides a cone for distribution of grain, and which them conveys the grain to the spiral rotor  134 . The grain is then introduced to the milling chamber  122  by the spiral rotor  134 . 
     The grain enters the milling chamber  122 , which may including impinging on the outer periphery  150   a  of the first roll  116   a  plurality of rolls  116 . Grain then at least partially fills the milling chamber  122 , potentially until the entire milling chamber  122  is full and grain is standing in the grain inlet  110 . It is therefore desirable to provide a canted outer periphery  150   a  of the first roll  116   a  of the plurality of rolls  116   a - 116   g  to aid in efficient introduction of grain to the milling chamber  122  and to avoid undesirable overwear of the portion of the bran removal cylinder  116  adjacent thereto. During this filling and afterward during operation, the rolls  116   a - 116   g  are being rotated due to their connection to the main shaft  102 . Due to the rotation of the rolls  116  in the roll assembly  104 , the stirring bars  118  are rotating about the main shaft  102  in the milling chamber  122 , impelling grains circumferentially about the roll assembly  104 . 
     Because the bran removal cylinder  116  is round, rather than a polygonal screen, the bran removal cylinder causes no localized areas of varying stress and force within the grains. Polygonal screens, because of the varying distance between the screen and roll assembly, generate areas of low force and inter-grain friction—at the point of greatest distance between the screen and roll assembly, and areas of high force and inter-grain friction—at the point of least distance between the screen and roll assembly. Instead, because the distance between the bran removal cylinder  106 , and particularly the bran removal chamber outer wall  132 , is constant, the width of the milling chamber  122  is constant, with the exception of localized areas about the resistor bars  108  and the stirring bars  118 , the force applied among the grains, which initially will cause inter-grain friction and separation of bran by rubbing and then will cause propagation of fractures through the remaining germ/endosperm/bran of the grains, has a substantially smaller variance. The smooth, durable outer periphery  150   a - 150   g  of each of the plurality of rolls  116   a - 116   g  reduces the rotational force and rubbing introduced by the rolls  116   a - 116   g  to a negligible value. 
     As the rolls  116   a - 116   g  are being rotated and the stirring bars  118  impel grains circumferentially about the roll assembly  104  within the milling chamber  122 , the movement of the grains, broken grains and debranned grains, is retarded by the resistor bar  108 , which increases the inter-grain force and provides a localized area of higher force and stress in the milling chamber  122  which increases the separation of bran by rubbing and the propagation of fractures through the remaining germ/endosperm/bran of the grains, i.e., grain milling. 
     Coupled with the lack of rubbing from the smooth rolls  116 , the increases in inter-grain rubbing from the stirring bars  118  and the resistor bar  108 , the construction of the perforations  120  in the bran removal cylinder  106  increases the rate of milling while avoiding overmilling. The perforations  120  permit the throughs, including bran and any overmilled “fines”, to exit the milling chamber  122 , while retaining the remaining grain components. Additionally, the perforations  120  in the bran removal cylinder  106  present surfaces which cause impact forces to be applied to passing grains, causing those grains to fracture into desirable components. 
     The milled grain components not exiting the milling chamber  122  but rather exiting via the overtails outlet  112  are, as a result of a top-fed mill with beneficially sufficiently milled without issues of overmilling or undermilling. 
     Beneficially, the combination of the smooth roll  116   a - 116   g  with a stirring bar  118 , a round screen  106  where the perforations are limited to the area below the bottom surface  152  of a top-most roll  116   a  of the plurality of rolls  116   a - 116   g , and a resistor bar  118  result in a more desirable output. The output of the top-fed vertical grain mill  100  for two corn types  702   a ,  704   a , is better in size and distribution for mesh sizes than the output from a conventional mill for the same corn two types  702   b ,  704   b  as illustrated in  FIG. 7 . 
     Thus, the top-fed vertical grain mill  100  provides for efficient removal of bran from a grain, such as corn, while simultaneously breaking the endosperm into fractions, also known as grits, maximizing “large grit” while minimizing “small grit.” The top-fed vertical grain mill  100  aids in separation of germ from endosperm fractions so as to minimize fat or oil contamination of the grits. Referring to  FIG. 7 , the top-fed vertical grain mill  100  provides a desirable granulation distribution of corn grits. The top-fed vertical grain mill  100  produces higher percentages of larger grit (+4 Mesh, +5 Mesh, +6 Mesh) while simultaneously reducing the percentage of large unbroken kernels (grains) (+3.5 Mesh). This improved distribution impacts the requirements for further processing or recycling of the +3.5 Mesh Fraction, particularly the need for additionally machine content, horsepower and the like. 
     The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof. It will be evident to those skilled in the art that various modifications and changes can be made thereto without departing from the broader spirit or scope of the disclosure. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense. It is therefore, contemplated that various alternative embodiments and modifications may be made to the disclosed embodiments without departing from the spirit and scope of the disclosure defined by the appended claims and equivalents thereof.