US3575321A

US3575321A - Solid particulate material blender

Info

Publication number: US3575321A
Application number: US773518A
Authority: US
Inventors: Glen W Fisher
Original assignee: Fisher Flouring Mills Co
Current assignee: Fisher Flouring Mills Co
Priority date: 1968-11-05
Filing date: 1968-11-05
Publication date: 1971-04-20
Anticipated expiration: 1988-04-20

Abstract

A blender for particularized solid material, such as cereal grain, comprises a discharge passageway and a plurality of segregated compartments extended into and terminating open ended within the passageway, such that a plurality of streams of material to be blended can be separately fed into the segregated compartments and therethrough into the discharge passageway.

Description

References Cited UNITED STATES PATENTS 8/1906 Strauss................. 2,455,572 12/1948 Evans.......

3,336,006 8/1967 Berg..... 3,448,968 6/1969 Primary Examiner-Stanley H. Tollberg Attorney-Seed, Berry & Dowrey Bellevue, Wash. [21] Appl.No. 773,518 [22] Filed Fisher Flouring Mills Company Seattle, Wash.

ENDER Glen W. Fisher Nov. 5, 1968 Apr. 20, 1971 United States Patent [72] Inventor [45] Patented [73] Assignee [54] SOLID PARTlCULATE MATERIAL BL ABSTRACT: A blender for particularized solid material, such as cereal grain, comprises a discharge passageway and a 222/145, plurality of segregated compartments extended into and 259/180 terminating open ended within the passageway, such that a B67d /60 plurality of streams of material to be blended can be 222/564, separately fed into the segregated compartments and Claims, 14 Drawing Figs.

[] Field of therethrough into the discharge passageway.

PATENIVTED APRZO um 3; 575321 SHEET 1 [IF 4 INVENTOR. GLEN W. FISHER ATTORNEYS pmminmzmen A 31575321 SHEET 3 0F 4 1 INVENTOR. [I GLEN w. FISHER SUlLllD FAIR'I'TCULATE MATERIAL BLENDER This invention relates to nonmechanical, volumetric blenders for particularized solid material. More particularly, this invention relates to blenders of the above-described type adapted to blend multiple continuously flowing streams of particulate solids such as cereal grains and other granular materials.

In the manufacture of flour, it is becoming common to temper the cereal grain in a continuously moving system. Thus, for example, moisture is added to cereal grain which is then continuously charged into the top of a vertical storage silo or bin. The volume of moisturized cereal grain is continuously discharged from the bottom of the bin, with the cereal grain being discharged therefrom only after it has tempered within the bin for a predetermined number of hours. The discharge rate of tempered grain from the bin, the volume of the bin, and the charge rate of moisturized grain into the bin are correlated such that the time period required for a layer of grain to move downwardly through the bin will equal the required tempering period.

A major problem associated with such a system is the difficulty in discharginggrain from the bin in a manner such that a cross-sectional layer of grain will move uniformly down through the bin. If a single axially positioned discharge opening were provided, for example, a generally cylindrical slug of grain above the opening would be discharged first with the grain around the sides of the bin feeding the cylindrical slug. In large, single-discharge opening bins, grain from the center of an upper cross-sectional layer can be discharged several hours ahead, by as much as 50 percent, of the discharge of grain from the edges of the cross-sectional layer. This is easily verified by placing numbered balls diametrically across the top layer of a filled bin and timing the periods that it takes the various balls to be discharged.

This problem has been solved by providing a plurality of uniformly spaced discharge openings across the bin bottom.

The openings must be of uniform size so that all discharge at an equal rate. The multiple discharge streams must then be recombined downstream in such a manner that the resulting single stream contains an equal amount of grain from each of the multiple streams. If one of the multiple streams feeds the resultant single stream at a faster rate than any of the others, for example, the discharge openingassociated with the stream, concommitently, will discharge grain faster than any of the other discharge openings. As a consequence, that faster discharging opening will function in much the same manner as the above-described single discharge opening, that is to say, the cylindrical slug above the faster discharging opening will be preferentially discharged. Thus, although the provision of multiple discharge openings can prevent unbalanced grain discharge, faulty recombination of the multiple discharge streams into a single resultant stream can render nil the effect of the multiple discharge openings.

The primary object of this invention is to provide a nonmechanical (i.e., no moving components) blender adapted to receive a plurality of streams from one bin and blend them into one resultant stream composed of proportioned parts from each inlet stream so that the resultant single outlet stream does not upset the flow rates of the inlet streams, thereby permitting the bin to be discharged in a balanced manner. Another object is to provide such a blender that can accept a plurality of inlet streams from more than one bin and blend the streams to provide a single outlet stream of desired composition.

A further object is to provide such a blender that can be installed within a bin to provide for uniform discharge from the bin in one or more outlet streams from the blender. These and other objects and advantages will become apparent from the following description and the accompanying drawings of which:

FIG. 1 is a vertical elevation of a preferred embodiment of the blender of this invention;

FIG. 2 is a top plan view of the FIG. I embodiment;

FIG. 3 is a partial vertical cross section through the FIG. I embodiment taken along the line 3-3 of FIG. 2;

FIG. 4 is a detail view of a gasket taken along the line 4-4 of FIG. 3;

FIG. 5 is a schematic illustrating the function of the blender of this invention as applied to a single bin;

FIG. 6 is a schematic illustrating the function of the blender of this invention as applied to a plurality of bins;

FIG. 7 is a cross section view of the blender discharge passageway taken along the line 7-7 of FIG. 3;

FIG. 8 is a side elevation view of a cylindrical bin with the blender of this invention incorporated within the bin;

FIG. 9 is a top plan view of the internal bin blender taken along the line 9-9 of FIG. 8;

FIG. 10 is a cross section of the discharge passageway of the internal bin blender taken along the line 10-10 of FIG. 8;

FIG. 11 is a vertical cross section detail of the internal bin blender taken along the line 11-11 of FIG. 8;

FIG. 12 is an enlarged detail of the encircled section of FIG. 1 l; a

FIG. 13 is a side elevation view of a rectangular bin with blenders incorporated both within and without the bin; and

FIG. 14 is a top plan view of the internal bin blender taken along the line Bil-l4 of FIG. 13.

In brief, the nonmechanical blender of this invention comprises outlet means providing a gravity discharge passageway for blended particulate solids having a certain minimum length, and blending means providing a plurality of segregated compartments extending into and terminating open ended within the gravity discharge passageway. Each stream of material to be blended is fed into one of the segregated compartments through an opening into the respective compartment and the material therein passes through the compartment into the gravity discharge passageway.

The flow rate through the discharge passageway must be less than the combined flow capacity into the segregated compartments. Thus under normal operating circumstances,

, the limiting flow rate through the discharge passageway will cause the segregated compartments of the blending means to be continuously full. Under operating conditions that keep the compartments filled, it has been discovered that particles in a cross-sectional layer across the vertical discharge passageway will flow unifonnly downward therethrough (under influence of gravity) regardless of the parameters existing upstream of the discharge passageway, provided that the discharge passageway is atleast a certain length. This being the case, material can only be fed into the blender of this invention at the rate at which it flows through the discharge passageway. Thus, any tendency of one of a plurality of discharge streams from the bottom of a single bin to feed more rapidly than another, for example, is eliminated. Consequently, the uniform blending of a plurality of discharge streams from a single bin can be achieved by dividing the segregated compartment outlets into equal cross-sectional areas. And, more broadly, a desired blending of a plurality of streams of particulate solid material can be achieved by dividing the segregated compartment outlets into cross-sectional areas proportional to blend. The overall result, therefore, is that equipment dimensions upstream of the entry section of thedischarge passageway (i.e., upstream of that section of the passageway that contains the segregated compartment ou' tlets) need not be matched with exactitude to ensure the desired blending.

The length of the discharge passageway is critical to the extent that for any given discharge passageway and its crosssectional area; there will exist a point above the outlet thereto where the particles across the passageway will not fall uniformly downward. Therefore, the passageway must be sufficiently long that the distance from the passageway outlet to the segregated compartment outlets will be greater than the distance from the passageway outlet to that point of nonuniform flow. If this condition is met, the particles will descend from the segregated compartment outlets uniformly thereby forming a blend equal to the relative cross-sectional areas of the segregated compartment outlets.

It is to be emphasized that the mechanism by which the flow rate through the discharge passageway is restricted relative to the combined input flow capacity to the segregated compartments inherently will be controlling at an elevation below this critical point inasmuch as it is the existence of this mechanism that creates the critical point. And, the configuration of this mechanism will affect the elevation at which this critical point is created. It is also to be emphasized that the cross-sectional geometry of the discharge passageway is not critical so long as the geometry is uniform down to an elevation below the critical point. And in fact, a change in cross-sectional geometry below the discharge passageway may be employed to create the mechanism to impart flow rate limitation above.

The maximum height at which this critical point of nonuniform flow could be located under the worst conditions can be easily determined in the following manner. A discharge tube having the desired cross-sectional area is positioned such that its longitudinal axis is vertical. A plate is positioned to close off its open lower end and the tube is filled with the particulate solid material that is to be blended. The closure plate is then shifted to open a chordal segment of narrow width suflicient to permit the solid particulate material to gravitate downward and out through the segment opening in a free flowing manner. The point above the lower end of the tube at which the particles vertically above the segment opening begin to gravitate downward more rapidly than other particles in the same cross-sectional layer is the aforementioned critical point for that tube and that particulate solid material. lf the discharge tube length is greater than the critical distance between that point and the lower end of the tube, the flow rate across the entry section of the discharge tube will be uniform and independent of the upstream parameters. It has been observed that this critical point is reached at an elevation equal to about l-2 tube diameters for a smooth-walled cylindrical tube. Under more ideal conditions, as where the discharge tube outlet occupies substantially the full cross-sectional area of the tube, the critical point can be expected to exist below that point determined by the above-described test.

For completely accurate blending, the relative crosssectional areas of the sections of the segmented compartments within the entry section of the discharge tube must be as accurate as manufacturing tolerances will allow. ln one embodiment of this invention, for example, this accuracy is attainable by providing a mounting shaft extending axially into the entry section of the discharge tube and by providing divider plates dadoed radially into the mounting shaft and extended radially outward into abutment with the inner surface of the discharge tube. If an equal blend of eight streams is desired, for example, eight divider plates would be dadoed into the mounting shaft at 45 intervals around the mounting shaft. Likewise, if an equal blend of four streams is desired, four divider plates would be dadoed into the mounting shaft at 90 intervals. And if three streams are to be blended on a 50-25-25 basis, three divider plates would be dadoed into the mounting shaft at 90 intervals thereby providing one segregated compartment having an included angle relative to the mounting shaft of 180 and two segregated components each having included angles of 90.

The length of the entry section of the discharge tube is critical only to the extent that it must be sufliciently long to enable the solid material to enter the entry section under turbulent conditions, undergo a transition to substantially laminar flow, and exit the entry section under laminar flow conditions. For practical purposes, the outlet to the entry section should be above the aforementioned critical point. In the expected case, the solid particulate material would enter the discharge tube entry section in a plurality of streams, each being fed from a continuously replenished overhead body of segregated material within the main section of the blender means of large cross'sectional area, and thus the material will not enter the entry section under laminar flow conditions. However, by being confined in segregated streams, each of uniform cross section longitudinally (as occurs in the entry section), the material within each stream will assume laminar flow conditions within a very short distance. Upon reaching laminar flow conditions, the multiple streams can be recombined without material transfer from one stream to another by termination of the divider plates (delineating the exit to the discharge passageway inlet section).

The divider plates, and the mounting shaft in the abovementioned embodiment, within the entry section of the discharge tube can be conveniently extended upward into the main part of the blending means to segregate the blending means into the aforesaid compartments, with the extended sections of the divider plates also being radially dadoed into the mounting shaft in the above-mentioned embodiment, and with their outer edges in abutment with the peripheral wall of the blending means. Also, the mounting shaft can be extended axially downward through the discharge tube to provide a means by which the bottom end of the tube can be positioned.

in general, the blending means will be peripherally defined by a peripheral wall structure of frustoconical geometry, typically of either a circular or rectangular base having an outlet at the end of smallest cross section, with divider plates extending from within the cone out through the outlet. The divider plates will be interconnected at the cone axis and abut the inner surfaces of the peripheral wall structure. The means providing the gravity discharge passageway comprises a tube, the upper interior of which, termed the inlet section, has a cross section matching the cross section of the cone outlet. The divider plate sections extending from the cone outlet extend into the discharge tube inlet section and abut the inner surfaces of the tube. The divider plate sections confined within the discharge tube will be of rectangular geometry.

The blender of this invention can be fabricated as a discrete structure or it can be incorporated into a bin bottom. In the latter, the bin bottom can be provided with one or a plurality of frustoconical bin bottom sections, the number depending on the cross-sectional area of the bin. ln general, the incorporation of the blender into the bin bottom structure will reduce the required numbers of bin bottom outlets by at least fourfold thereby markedly simplifying the bin bottom construction.

Referring now to FlGS. l4 and 7, the blender embodiment of this invention depicted is intended to blend eight streams of particulate solids, such as cereal grain, flowing at equal rates. This embodiment comprises discharge means 10, blender means 12, and inlet means 14. The discharge means comprises a vertical cylindrical discharge tube. The blender means comprises an outer shell or peripheral sidewall 16, an axial shaft 18, and a plurality (eight) of divider plates or walls 20. The inlet means comprises an outer shell or sidewall 22, a top cover plate or top wall 24, a plurality (eight) of spout flanges 26 secured to the sidewalls 22 and peripherally enclosing a plurality of inlet openings 28 therethrough, a plurality (eight) of inlet divider plates or walls 30, and an upper axial shaft 32.

The discharge tube 10 is smooth-walled interiorly and is preferably fabricated from a cast acrylic plastic tube stock. A mounting flange 34 is rabbeted onto the lower end of the discharge tube to retain the tube. A spider of three adjusting bolts 35 extending radially, l20 apart, from the shaft to the inner tube surface serves to position the tube and the shaft axially of one another. The sidewall 16 has a main intermediate section of frustoconical geometry with a 45 slope and an increasing cross section from bottom to top, a short cylindrical lower end section 16b rabbeted onto the upper end of the discharge tube such that the inner surface of the lower end section is flush with the inner surface of the discharge tube, and a radial annular upper or outer end connecting flange 160. The sidewall 22 has a main upper section of frustoconical geometry with increasing cross section from top to bottom, and a radial annular lower end connecting flange 22 b separated axially from flange 16c by an annular sealing gasket 36 and bolted thereto by a plurality of evenly spaced bolts 3%. The circular cover plate 24 closes the axial access opening 39 and is secured in place by an axially positioned bolt 40 extended therethrough and threaded into the upper end of the upper shaft 32.

The divider plates 211 are generally of triangular geometry with a depending vertical rectangular leg a and a radially extending horizontal tab 21112 at opposite ends of the outer 45 sloped edge. The vertical edge of each plate 20 is dadoed into the shaft 18 and each plate extends radially therefrom such that each of the eight compartments encompasses an angle of 45. The outer edges bear against the inner surface of the sidewall 22, the vertical legs 211a are slip fittedinto the upper end or entry section 22 of the discharge tube 10, and the radial tabs 20b fit into slots provided therefor in the gasket 36 and are contacted-top and bottomby the flanges 22b-16c.

The inlet divider plates 30 are of trapezoid configuration. The vertical edge of each plate 30 is dadoed into the upper shaft 32 and each plate extends radially therefrom such that each of the eight compartments encompasses an angle of 45 with a corresponding inlet 28 opening there into and such that each plate 311 overlays a plate 211 when the sidewall 22 is bolted to the sidewall 16. The lower radial edge of each plate 311 bears against the top edge of a corresponding plate 20, and the outer edge of each plate It bears against the sidewall 22. The upper shaft 32 is axially aligned with the shaft 18 and abuts the shaft 18 when the sidewall 22 is bolted to the sidewall 16.

As stated above, the positions of the divider plate sections 2110 within the discharge tube entry section 23 are critical in that the volumetric proportions of the discharged composite stream is detemiined by the relative cross-sectional areas of the segregated compartment sections within the entry section 23. Thus, it may be desirable to provide the divider plate sections 211a separate from the main divider plate section 20, thus to minimize the fabrication cost of the main divider plate sections.

in addition to providing a mounting or joining means, the cylindrical shaft section 180 within the discharge tube entry section presents a curved surface substantially at each apex of adjoining divider plates such that particles cannot become wedged between the adjacent plates and disrupt the flow characteristics through the entry section. Extension of the shaft 1% through the main section of the discharge tube also promotes uniform flow characteristics in that no void is created, by its premature termination, to be filled by nonlaminar flowing particles. By terminating at the bottom end of the discharge tube, which is below the above-described critical point, any effects caused by its termination are not going to have any effect on the flow rate and blending conditions at the upper end of the discharge tube.

The blended material is typically delivered by the discharge tube to a variable output feeder for further transfer. Therefore, the material flow rate through the discharge tube can be conveniently controlled by adjusting the feeder output such that gravity flow through the discharge tube will not exceed the flow input to the discharge tube entry section.

in the F16. 5 system, a solid particulate material such as cereal grain is drawn from a bin 1011 through a plurality of discharge chutes 1112 mounted in the bottom wall of the bin. The streams of grain are gravity fed through ducts 11M and discharged therefrom into the blender 1% of this invention wherein the streams are blended and discharged as a unitary stream from the blender. ln this system, the plurality of streams from the bin should be recombined in equal proportions. Means 1107 for effecting a discharge flow rate of the blender 1% is also provided in the form of a feeder, for

example.

in the FIG. 6 system, a plurality of

bins

120, 122, 124 and 126 are provided with a discharge chute, or

chutes

128, 130, 132 and 1315, respectively. The stream of grain from each bin is gravity fed through ducts 11%, 13%, M0 and M2, respectively, into the blender 1 of this invention wherein the streams are blended and discharged as a unitary stream from the blender. If multiple streams are withdrawn from each bin, they may be directed by ducts separately to the blender of this invention, or they may be first combined by a blender of this invention, and then discharge streams therefrom directed to the blender 1%. Means 1415 for effecting a discharge flow rate of the blender 144 is also provided, in the form of a feeder, for example.

The blender of this invention may be incorporated within the bin to provide for uniform particulate material discharge through a single bin outlet (FIGS. fl12) or through multiple bin outlets (FIGS. 13-14). A single bin outlet internal blender is particularly suited for cylindrical bins and a multiple bin outlet blender is particularly suited for rectangular or square bins.

Referring to FlGS. 812, the single bin outlet internal blender for a cylindrical bin depicted is designed to blend streams of particulate solids into a single stream. This embodiment comprises discharge means 110, and blender means 112 and inlet means 114. The discharge means comprises a cylindrical discharge tube that constitutes thesingle bin outlet. The blender means comprises an outer shell or peripheral sidewall 116 that constitutes the bin bottom wall, and a plurality (four) of divider plates or walls 120. The inlet means comprises a double apex cone assembly providing a first cone 121 with a downwardly pointing apex and a second cone 123 with an upwardly pointing apex, the cone bases having identical diameters and being joined together at their peripheries. Also, means (not shown) for effecting a discharge flow rate limitation of the blender 112 would be provided.

The sidewall 116 has a frustoconical geometry with a slope angle steeper than the angle of repose of the particulate solids to be stored in the bin, an external upper annular rim 125 bolted to a corresponding rim 127 on the base of the main bin cylinder 129, and an external lower annular rim 131 bolted to a corresponding rim 133 on the upper end of the discharge tube.

Each divider plate has a vertical rectangular leg 1200 depending from a main section, the outer edge of which abuts the inner surface of the discharge tube 110. Each plate main section has an inclined outer edge abutting'the inner surface of wall 116, an inclined inner edge abutting the outer surface of cone 121, and an upper edge flush with the bottom edge of the bin cylinder 129 and with the bases of

cones

121 and 123. The vertical edges of the divider plates 120 are welded together with weld bead material therebetween providing a rounded comer to minimize jamming of particulate solids at the corners. The outer surface of the lower cone 121 has a slope angle no steeper than the angle of repose of repose of the particulate solids to be stored in the bin and therefore segregated compartments defined by the divider plates have throats of increasing cross section down to the apex of the lower cone 121. The outer surface of the upper cone 123 has a slope angle steeper than the angle of repose of the particulate solids to be stored in the bin.

With four divider plates positioned equidistant from one another, the opening into the segregated compartments of the bin bottom at the lower end of the bin cylinder 129 is subdivided into four quadra-annular sections, one for each compartment (see FlG. 9). Consequently, particulate solids in the bin overhead will be directed by the surface of the upper cone 123 in equal amounts into the segregated compartments and from them into the discharge passageway inlet section wherein the streams are recombined. This stream division and recombination within the bin bottom results in uniform solids wthdrawal from the bin, in contrast to the nonuniform withdrawal experienced by other single outlet bin bottom designs.

Referring to NUS. 13-14, the multiple bin outlet internal blender depicted is designed to blend streams of particulate solids in four streams. This embodiment comprises four discharge means 210 and blender means 212. Each discharge means comprises a discharge tube that constitutes one of four equispaced bin outlets. The blender means comprises four conical shells or walls 216 of rectangular cross section, four main bin divider plates or walls 219 and l6 bin bottom divider plates or walls 220. The main bin divider plates extend from the base of the vertical bin walls 229 upward into the in to subdivide the bin into four main zones of equal rectangular cross section. The bin bottom divider plates extend from the bin base into the respective bin bottom cone to subdivide each bin bottom into four segregated compartments of equal rectangular cross section. The bin bottom divider plates are provided with vertical rectangular legs depending from a main section, the outer edges of which abut the inner surface of the discharge tube 210. Each plate main section has an outer edge abutting the inner surface of the respective wall 216. The upper ends of the bin bottom divider plates may be extended upwardly into the bin to brace both the walls 229 and the bin divider plates 219. If desired, the four bin outlet streams in discharge tubes 210 may be recombined by an external blender 250 of the H08. 13 and 7 type into a single stream 260, the blender 250, in this case, providing discharge flow rate restriction for the blender means 212. Another discharge flow rate restricting means (not shown) would be provided for blender 250.

In most applications of the blender of this invention, particulate solid material to be blended will be gravity fed into the blender. In some applications, however, it may be desirable to force feed material to the blender, as by means of a screw feeder. In this latter case, the principles of operation defined above will still be applicable.

It is believed that the invention will have been clearly understood from the foregoing detailed description of my now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly my intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

lclaim:

1. Apparatus which comprises means providing a discharge passageway for blended particulate solids; blending means for introducing segregated streams of said solids into the discharge passageway and combining the solids into a common stream in the passageway at a point of combination; said passageway having an elongated section of at least a minimum length and of substantially uniform cross-sectional area commencing at said point of combination and extending downstream from said point of combination; and means downstream of said elongated section for restricting the flow through said elongated section to a rate less than the combined maximum flow rates of the segregated streams to obtain a uniform movement of cross-sectional segments of said solids at said point of combination, said minimum length being greater than the distance between said restricting means and the critical point upstream of said restricting means at which the flow begins to be nonuniform across the elongated section.

2. Apparatus according to claim 1 wherein said blending means comprises a plurality of divider members extended into said discharge passageway so as to divide an entry section thereof into said segregated compartments.

3. Apparatus'according to claim 1 wherein said blending means comprises a mounting shaft; a plurality of divider plates mounted to said shaft and extending outward therefrom, the lower end sections of said divider plates extended into said discharge passageway so as to divide an entry section thereof into said segregated compartments; and a peripheral wall member enclosing the sections of said divider plates above said discharge passageway so as to provide with said divider plates extensions of said segregated compartments above said discharge passageway.

4. Apparatus according to claim 3 wherein each divider plate comprises a main generally triangular section with a vertical inner edge and a horizontal upper edge, and a vertically depending rectangular section adapted to fit into said discharge passageway; and wherein said peripheral wall member comprises a conical section enclosing the main sections of said divider plates and axially connected at its lower end to said discharge means.

5. A storage bin structure for particulate solids which comprises a vertical peripheral wall structure providing a vertical storage zone for particulate solids; a bin bottom structure having a peripheral wall member and discharge means providing at least one bin outlet passageway; blending means providing a plurality of segregated compartments within said bin bottom structure and extending into and terminating within said bin outlet passageway for introducing segregated streams of solids into the bin outlet passageway and combining the solids into a common stream in the passageway at a point of combination, said bin outlet passageway having an elongated section of at least a minimum length and of substantially uniform cross-sectional area commencing at said point of combination and extending downstream from said point of combination; and means downstream of said elongated section for restricting the flow through said elongated section to a rate less than the combined flow rates of the segregated streams to obtain a uniform movement of cross-sectional segments of the solids at said point of combination, said minimum length being greater than the distance between said restricting means and the critical point upstream of said restricting means at which the flow begins to be nonuniform across the elongated section.

6. Apparatus according to claim 5 wherein said blending means comprises a plurality of divider members extended into said discharge passageway so as to divide the entry section thereof into said segregated compartments.

7. Apparatus according to claim 5, wherein each divider plate comprises a main generally triangular section with a vertical inner edge and a horizontal upper edge, and a vertically depending rectangular section adapted to fit into said discharge passageway; and wherein said peripheral wall member comprises a conical section enclosing the main section of said divider plates and axially connected at its lower end to said discharge means.

8. Apparatus according to claim 5 including means mounted within said storage zone for directing particulate solids into said compartments.

9. Apparatus according to claim 8, wherein the means mounted within said storage zonecomprises a first cone having a downwardly pointed apex and a second cone having an upwardly pointed apex, said first and second cones being joined together at their bases and oriented such that said first cone depends into the bin bottom and such that said second cone extends upward into said storage zone to provide in conjunction with said blending means semiannular peripheral openings into said segregated compartments.

10. Apparatus according to claim 5, wherein said bin bottom structure provides a plurality of bin outlet passageways, and said peripheral wall member provides a plurality of cones terminating in said bin outlet passageways; and wherein said blending means comprises a plurality of sets of divider members, the divider members of each set extended into a bin outlet opening so as to divide the entry section thereof into segregated compartments.

11. Apparatus which comprises means providing a discharge passageway for blended particulate solids; blending means for introducing segregated streams of said solids into the discharge passageway and combining the solids into a common stream in the passageway at a point of combination, said blending means comprising a plurality of divider members extended into an upper entry section of said discharge passageway and terminating at said point of combination and dividing the entry section thereof into a plurality of segregated compartments and means for delivering a surplusage of said solids into each segregated compartment; said passageway having an elongated section of at least a minimum length and of substantially uniform cross-sectional area commencing at said point of combination and extending downstream from said point of combination, said minimum length being greater than the distance between the downstream outlet from said elongated section and the critical point upstream at which particle flow begins to be nonuniform across the elongated section.

12. A storage bin structure for particulate solids which comprises a vertical peripheral wall structure providing a vertical storage zone for particulate solids; a bin bottom structure having a peripheral wall member and a plurality of bin outlets; a blender comprising means providing a discharge passageway for blended particulate solids, blending means providing a plurality of segregated compartments extending into and terminating open ended within an entry section of said discharge passageway for introducing segregated streams of solids into the discharge passageway and combining the solids into a common stream in the passageway at a point of combination, said passageway having an elongated section of at least a minimum length and of substantially uniform crosssectional area commencing at said point of combination and extending downstream from said point of combination, and means downstream of said elongated section for restricting the flow through said elongated section to a rate less than the combined flow rates of the segregated streams to obtain a uniform movement of cross-sectional segments of the solids at said point of combination, said minimum length being greater than the distance between said restricting means and the critical point upstream of said restricting means at which the flow begins to be nonunifonn across the elongated section; and inlet means connecting said bin outlets to said segregated compartmentsv 13. The method of blending particulate solids comprising providing a supply of solids to be blended, discharging the solids from said supply in segregated paths, combining the paths downstream in a common discharge path, the discharge path having an elongated section commencing at said point of combination and extending downstream from the point of combination, and restricting the flow of solids in said common path to a rate less than the combined maximum flow rates in the segregated paths to obtain a uniform movement of crosssectional segments of said solids at the point of combination, the flow restricting occurring sufficiently downstream of the point of combination that the critical point at which the flow begins to be nonuniform across the common path is downstream of the point of combination and of no influence on the flow at the point of combination.

14. The method of claim 13, wherein said supply constitutes a single bin and said method is employed to uniformly draw the solids down in the bin, further comprising dividing the bin into zones, discharging the solids from said zones in said segregated paths, the ratio of the cross-sectional area of each said segregated path to, I the cross-sectional area of the common path at the point of combination being equal to the ratio of the cross-sectional area of each corresponding zone to the total cross-sectional area of the bin.

15. The method of claim 13, wherein said supply constitutes a plurality of bins and said method is employed to blend the solids from the bins, and said segregated paths constituting outlets from said bins.

Claims

3. Apparatus according to claim 1 wherein said blending means comprises a mounting shaft; a plurality of divider plates mounted to said shaft and extending outward therefrom, the lower end sections of said divider plates extended into said discharge passageway so as to divide an entry section thereof into said segregated compartments; and a peripheral wall member enclosing the sections of said divider plates above said discharge passageway so as to provide with said divider plates extensions of said segregated compartments above said discharge passageway.

9. Apparatus according to claim 8, wherein the means mounted within said storage zone comprises a first cone having a downwardly pointed apex and a second cone having an upwardly pointed apex, said first and second cones being joined together at their bases and oriented such that said first cone depends into the bin bottom and such that said second cone extends upward into said storage zone to provide in conjunction with said blending means semiannular peripheral openings into said segregated compartments.

12. A storage bin structure for particulate solids which comprises a vertical peripheral wall structure providing a vertical storage zone for particulate solids; a bin bottom structure having a peripheral wall member and a plurality of bin outlets; a blender comprising means providing a discharge passageway for blended particulate solids, blending means providing a plurality of segregated compartments extending into and terminating open ended within an entry section of said discharge passageway for introducing segregated streams of solids into the discharge passageway and combining the solids into a common stream in the passageway at a point of combination, said passageway having an elongated section of at least a minimum length and of substantially uniform cross-sectional area commencing at said point of combination and extending downstream from said point of combination, and means downstream of said elongated section for restricting the flow through said elongated section to a rate less than the combined flow rates of the segregated streams to obtain a uniform movement of cross-sectional segments of the solids at said point of combination, said minimum length being greater than the distance between said restricting means and the critical point upstream of said restricting means at which the flow begins to be nonuniform across the elongated section; and inlet means connecting said bin outlets to said segregated compartments.

13. The method of blending particulate solids comprising providing a supply of solids to be blended, discharging the solids from said supply in segregated paths, combining the paths downstream in a common discharge path, the discharge path having an elongated section commencing at said point of combination and extending downstream from the point of combination, and restricting the flow of solids in said common path to a rate less than the combined maximum flow rates in the segregated paths to obtain a uniform movement of cross-sectional segments of said solids at the point of combination, the flow restricting occurring sufficiently downstream of the point of combination that the critical point at which the flow begins to be nonuniform across the common path is downstream of the point of combination and of no influence on the flow at the point of combination.

14. The method of claim 13, wherein said supply constitutes a single bin and said method is employed to uniformly draw the solids down in the bin, further comprising dividing the bin into zones, discharging the solids from said zones in said segregated paths, the ratio of the cross-sectional area of each said segregated path to the cross-sectional area of the common path at the point of combination being equal to the ratio of the cross-sectional area of each corresponding zone to the total cross-sectional area of the bin.