US3572654A - Apparatus for the continuous self-regulating gravity-flow mixing of pourable granular material - Google Patents

Apparatus for the continuous self-regulating gravity-flow mixing of pourable granular material Download PDF

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Publication number
US3572654A
US3572654A US822184A US3572654DA US3572654A US 3572654 A US3572654 A US 3572654A US 822184 A US822184 A US 822184A US 3572654D A US3572654D A US 3572654DA US 3572654 A US3572654 A US 3572654A
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Prior art keywords
discharge
granular material
feed
zone
container
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Expired - Lifetime
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US822184A
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English (en)
Inventor
Friedrich Jaeger
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Glanzstoff AG
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Glanzstoff AG
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Priority claimed from DE19681756344 external-priority patent/DE1756344C/de
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G69/00—Auxiliary measures taken, or devices used, in connection with loading or unloading
    • B65G69/10—Obtaining an average product from stored bulk material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/80—Falling particle mixers, e.g. with repeated agitation along a vertical axis
    • B01F25/82—Falling particle mixers, e.g. with repeated agitation along a vertical axis uniting flows of material taken from different parts of a receptacle or from a set of different receptacles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/80—Falling particle mixers, e.g. with repeated agitation along a vertical axis
    • B01F25/84—Falling-particle mixers comprising superimposed receptacles, the material flowing from one to the other, e.g. of the sandglass type

Definitions

  • Hafer A tt0rney-JOhnSt0I1, Root, Okeeffe, Keil, Thompson and Shurtleff ABSTRACT A combination of apparatus for the continuous, self-regulating, gravity-flow mixing of different component streams of a pourable or flowing granular material wherein a plurality of individual discharge conduits from different supply vessels and/or supply zones open into a grid of feed compartments at the upper end of a vertical receiving container of rectangular cross section having a unidimensionally narrowing discharge zone terminating in a discharge slot at the lower end of the container and an unobstructed stabilizing zone interconnecting the discharge zone with the feed compartments, with means to adjust the flow of granular material through the discharge slot.
  • This invention generally relates to apparatus for the continuous withdrawal and gravity-flow mixing of a pourable, granular material as it is discharged in fractional or component amounts from different supply or storage vessels and/or different supply zones of one or more vessels.
  • Such apparatus may also be referred to as a gravity-flow solids blender and provides a means of improving the homogeneity of a granular mixture.
  • pourable granular material is applied to particles or granules of a wide variety of substances which exhibit a substantially uniform particle or grain size and are normally resistant toward adhesion, i.e. there are no adhesive forces sufficient to cause an uncontrollable agglomeration or thermal growth of particle size.
  • the expression pourable granular material includes all particles or granulates as described in the periodical chemic-lngenieur-Technik," Vol. 30, 1958, No. 3, pages l44-l46.
  • the apparatus of the invention is particularly suitable for the gravity-flow mixing of thermoplastic polymer granulates,'e.g.
  • the apparatus is also adapted to handle particulated or pelletized foodstuffs or fertilizers as well as seed grains and the like.
  • One object of the present invention is to provide apparatus for the gravity-flow withdrawal and recombination of a large number of component streams of pourable granular material such that this mixing procedure can be accomplished without the use of complicated and expensive measuring and regulating devices which are highly susceptible to disturbances or malfunctioning in their operation.
  • Another object of the invention is to provide a gravity-flow mixing apparatus which is easily constructed and maintained with an absolute minimum of moving parts.
  • Yet another object of the invention is to provide a gravityflow mixing apparatus which is adapted to handle a wide variety of pourable granular materials under continuous, selfregulating feed supply from different supply vessels and/or supply zones.
  • a uniform and self-regulating continuous flow of the pourable granular material can be achieved in a gravity-flow mixing apparatus which comprises in combination: at least one supply vessel associated with a plurality of discharge conduits for gravity-flow withdrawal of the granular material from different supply zones thereof; an elongated vertical receiving container of rectangular cross section arranged below said supply vessel, said container having a unidimensionally narrowing discharge zone at its lower end formed by oppositely disposed walls slanting downwardly and inwardly with a narrow discharge slot at their bottom end, the angle of aperture formed by said slanting walls being smaller than 0.8 times the difference between and twice the angle of slide of the granular material, and said container having a feed grate arranged at its upper end composed of a plurality of individual compartments subdividing the rectangular cross section of the container into a grid of feed zones in feed connection with said discharge conduits, that portion of the rectangular container between its discharge zone and said feed zones being essentially free of any obstruction to fonn
  • angle of aperture is employed herein to define the angle between the two slanting or converging walls of the discharge zone which present an unidimensionally narrowing rectangular cross section terminating in an elongated discharge slot or narrow rectangular aperture at the bottom of an otherwise uniformly rectangular receiving vessel.
  • This discharge slot is preferably combined with means to regulate the discharge of granular material therethrough, e.g. a movable gate or door which permits the effective width of the discharge slot to be varied, preferable together with means to convey the granular material away from the discharge slot such as a rotating drum, a conveyor belt or any similar moving surface.
  • the widt or breadth of various rectangular cross sections of the receiving container are measured in the direction in which the discharge zone is narrowed by its slanting walls.
  • the "length" or depth of the rectangular vessel remains constant and is thus measured in the longitudinal direction of the discharge slot, while the height" of the receiving container and its stabilizing and discharge zones are measured inthe'vertical direction.
  • angle of slide has reference to the granular material being mixed and is sometimes referred to as the angle of slope" or pour angle" which is formed by pouring a conically-shaped mass of particles in which the individual particles freely slide or fall down the outer surface of the cone, the angle being measured between this conical surface and the horizontal.
  • the angle of slide may also be defined as the angle of minimum slope, measured from the horizontal, at which any pourablegranular material or similar loose solid will flow.
  • a polyethylene terephthalate granulate with a uniform particle size of 2X3X4 mm has an angle of slide of approximately 40. This angle of slide can be readily determined for any other granular material.
  • the entire receiving container of the invention is adapted to provide a discharge bed or plurality of superimposed discharge layers in which the granular material is moved downwardly solely by the force of gravity, i.e. so as to pass slowly through the container from top to bottom as controlled by the constricted discharge zone and removal of material through the narrow discharge slot.
  • a stabilization of this discharge bed it will be understood that the velocity of the individu'al granular particles in all lines of stream over a given cross section is nearly constant. in the ideal case, such a stabilized stream presents a so-called coherent or graft" stream.
  • the receiving container Le. a stabilized discharge bed, it is essential to employ a rectangular container with particular dimensions as noted above which are dependent upon the angle of slide of the granular material.
  • the depth of the receiving container remains constant over both the stabilizing and discharge zones thereof.
  • the breadth or width also remains constant in the stabilizing zone while becoming narrower in the discharge zone to provide the unidimensionally narrowing rectangular cross section.
  • the discharge slot must be sufficiently narrow to have a damming or delaying effect on the rate of flow of granular material through the receiving container.
  • the width of the discharge slot should be smaller than approximately 0.1 of the width of the rectangular receiving container, i.e. the width of the stabilizing zone corresponding to the maximum width of the discharge zone.
  • FIG. I is a partly schematic side elevational view of the receiving container with its associated discharge conduits feeding into the top end and suitable discharge means at the bottom end, selected portions being cut away at the top and bottom;
  • FIG. 2 is a partly schematic top plan view of the receiving container of FIG. 1;
  • FIG. 3 is a partly schematic side elevational view of the receiving container (shown in cross section) in combination with the required discharge elements and illustrating the use of two different supply vessels in which partial amounts of a granular material are drawn off from different supply zones and then reunited with each other in the receiving container.
  • the apparatus of the invention essentially includes the elongated and vertically positioned receiving container 1 with an upper feed or dosing zone 2, an intermediate stabilizing zone 3 and a lower or bottom discharge zone 4 with two oppositely disposed walls 8 slanting or converging inwardly at the required angle of aperture down to the discharge slot 5.
  • a feed grate or grid insert 6 is contained within the four vertically positioned walls I of the receiving container so as to form the feed zone 2 with a total of 30 individual grid or feed compartments 11, all of which have the same quadratic cross section and extend vertically downwardly from the open top of the container 1.
  • discharge conduits 9 are inserted vertically downwardly into the top of the receiving container 1 so as to open into the individual feed zones formed by each grid compartment ll, preferably so as to terminate at about the same vertical level on a plane intermediate the top and bottom of each of the compartments and located centrally or symmetrically within the quadratic crosssectional area of each compartment.
  • These discharge or individual feed conduits 9 can come from two supply bins or vessels (shown only in FIG. 3), one of which contains a granular component A and the other of which contains a different granular component B.
  • each discharge or feed conduit 9 is not important in terms of a self-regulating and equalized dosage of the partial amounts of each components. Therefore, when further homogenization is not a serious problem, it is sufficient to permit the 15 discharge conduits from each supply vessel to open into an 15 randomly positioned grid or feed compartments.
  • the bottom ends of the discharge tubes or conduits 9 lie at about the same height.
  • an exact placement of these bottom ends of the conduits 9 is not a critical feature. Good results are achieved even if the discharge conduits 9 terminate at random heights or vertical levels within the grid compartments 1], and this greatly simplifies the installation of the tubular conduits.
  • tubular discharge conduits having a circular cross section, and although they are most suitably arranged in fixed positions laterally or horizontally of one another to fall within their respective grid compartments, they can be adjustably or randomly fastened in their vertical position so that they need not have an extremely accurately measured length or be fastened so as to place undesirable strains or stresses on the container or the conduits themselves.
  • FIG. 3 The arrangement of two or even more supply bins or vessels 10 above the receiving container 1 and in feed connection therewith through a plurality of discharge conduits 9 is illustrated in FIG. 3.
  • the pourable granular material is not only withdrawn from different supply vessels 10 but also from different supply zones within each vessel where the discharge conduits open into the vessel at random heights and preferably at random cross-sectional positions in a manner which is conventional for obtaining random samples from a single supply vessel.
  • the top ends of the conduits 9 preferably project inwardly and upwardly into the interior of the vessels 10 so as to terminate at different levels or in different supply zones.
  • This combination of withdrawing pourable granular material from different supply zones as well as different supply vessels is especially advantageous if the components A and B in each of the supply vessels 10 are themselves already mixtures of two or more components.
  • conduits 9 In order to avoid repetitive details of the feed supply through conduits 9, only a few of these conduits at one vertical cross section of the receiving container 1 are shown in their entirety in FIG. 3 as they extend from the supply vessels I0 downwardly into the compartments ll of the feed grate 6. It will be understood that all of these conduits 9 provide a complete feed connection as schematically illustrated in FIG. 2 with reference to the components A and B.
  • the form of the feed grate or grid insert 6 with its quadratic compartments 11 extending vertically downwardly from the top of container 1 represents an especially preferred embodiment.
  • These grid compartments 11 can naturally assume other cross-sectional shapes, e.g. rectangular, circular, elliptical, hexagonal, etc., and may also be of different sizes.
  • a second feed grate or grid insert can be arranged below that shown such that its vertical walls intersect and separate the streams flowing downwardly from the first feed grate. It is extremely important, however, to avoid any such baffles, stream guiding inserts or similar obstruction in the stabilizing zone 3 which must have a predetermined vertical height within the container 1 above the discharge zone 4.
  • the pourable granular material arrives from the supply vessel or vessels 10, i.e. from the different supply zones, in the direction of the arrows A and B as shown in FIG. 1 to represent two different components.
  • the granular material initially falls into the empty receiving container 1 where the discharge slot 5 is closed off by a suitable gate or sliding door 12 in cooperation with the rotatable discharge drum 7.
  • the container 1 is thus completely filled up to the level of the bottom ends of the discharge conduits 9 and these remain filled up into the supply vessels It).
  • the entire apparatus is then filled completely with granular material while further flow from the discharge conduits 9 is blocked off where the granular material itself closes off their bottom ends.
  • the gate 12 is then opened to such an extent that the total efiective area of the discharge slot opening 5 is less than or at the most equal to the free or open cross section of all of the discharge conduits 9.
  • the granular material then flows or streams through the container 1 so as to temporarily unblock the bottom ends of the discharge conduits 9, thereby permitting a continuous but controlled flow of the various partial streams from the supply vessels 10.
  • the self-regulating feed is essentially imposed at the moment at which the bottom ends of these tubes or conduits 9 are unblocked.
  • Fresh granular material is continuously supplied to the vessels It) to maintain a level which is consistently above the uppermost feed intake or feed zone of the supply vessels where granular material is being withdrawn through conduits 9.
  • This discharge drum represents the only moving element of the apparatus aside from the gate 12, and this drum can be modified or even removed if the granular material is discharged directly into another container or other transporting means.
  • the gate 12 is usually opened to provide a predetermined or easily adjustable discharge gap and requires little or not adjustment during operation.
  • the entire apparatus operates essentially only by gravity-flow with a selfregulating proportioning of the partial streams of each component.
  • the stabilizing zone 3 of the receiving container 1 is essential and requires a certain minimum vertical height above the discharge zone 4 in order to ensure a uniform vertical rate of flow of the granules or particles across a horizontal cross section at the upper end of the containerl and especially within the individual feed zones 2.
  • the bed or horizontal layers of particles in the container 1 must be sufficiently stabilized so that their downward movement uniformly unblocks the lower rims of the discharge conduits 9.
  • Each portion or partial stream of the granular material then slides or flows in equal proportions in the individual compartments ll of the feed grate 6.
  • the stabilization of the discharge bed or layers in container 1 occurs to the desired extend provided that the width of the stabilizing zone 3 is less than 1500 mm. and preferably less than 800 mm., i.e the width measured in the same direction as the width of the discharge slot 5 or the direction in which the discharge zone 4 converges inwardly down to the discharge slot.
  • the width of the stabilizing zone 3 is less than 1500 mm. and preferably less than 800 mm., i.e the width measured in the same direction as the width of the discharge slot 5 or the direction in which the discharge zone 4 converges inwardly down to the discharge slot.
  • stabilizing zone widths of more than l500 mm. the stream or flow of granular material tends to become unstable, i.e. every high stabilizing zone is not longer successful in achieving an essentially coherent stream or constant rate of vertical flow of the bed below the feed zone and hence within the individual grid or feed compartments.
  • the angle of aperture of the slanting walls of the discharge zone and the height of the stabilizing zone is essential for the angle of aperture of the slanting walls of the discharge zone and the height of the stabilizing zone to have the prescribed dimensions dependent upon the angle of slide of the granular material being mixed. preferably with all components of this granular material having the same or uniform particle size.
  • the uniform square or rectangular cross section over the entire height of the container 1, especially in the stabilizing zone 3 is an essential feature of the apparatus.
  • the upper end of the receiving container 3 and its vertical feed compartments ll can remain open or a suitable cover with openings for the conduits 9 can be incorporated to avoid contamination from the surrounding atmosphere or to provide a dusttight closure where this is deemed necessary.
  • the feed grate 6 should have a vertical height to receive the bottom ends of the conduits 9 at a distance above the lower end or edge of the grate sufficient to ensure an at least partial filling of the feed compartments during continuous operation. This distance is determined in part by the relative cross-sectional areas of the conduits 9 and compartments ll, respectively, and in part by the angle of slide of the granular material itself.
  • the rate of withdrawal of the granular material may also affect this placement of the conduit discharge openings, but this withdrawal rate is usually sufficiently-slow as to avoid a complete emptying of a feed compartment. Otherwise, the maximum height of the feed zone is limited by practical considerations of maintaining the overall height of the receiving container as small as possible within a given space.
  • the apparatus of the invention provides means of setting up definite proportions between the cross-sectional areas of the individual compartments or feed zones so as to effect a similar proportioning by weight or by volume of the interspersed amounts of granular material being introduced solely by gravity-flow from different supply vessels and/or supply zones. Furthermore, the proportioned rate of flow of the separate granular streams as they are discharged into the individual feed compartments are completelyv self-regulating without 1.
  • Apparatus for the continuous, self-regulating, gravityflow mixing of a pourable granular material comprising in combination:
  • At least one supply vessel associated with a plurality of discharge conduits for gravity-flow withdrawal of the granular material from different supply zones thereof;
  • each individual discharge conduit extends vertically downwardly to open into and within a vertically positioned feed zone formed by one of said individual compartments.
  • said feed grate is composed of quadratic compartments of equal size extending vertically downwardly from the top of said container, a single discharge conduit of approximately circular cross section extending vertically downwardly within each compartment such that the bottom open end of the discharge tube terminates above the lower end of the compartment.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fertilizers (AREA)
  • Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
US822184A 1968-05-10 1969-05-06 Apparatus for the continuous self-regulating gravity-flow mixing of pourable granular material Expired - Lifetime US3572654A (en)

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Application Number Priority Date Filing Date Title
DE19681756344 DE1756344C (de) 1968-05-10 Vorrichtung zum kontinuierh chen Abziehen einander zugeordneter, gleichbleibender Teilmengen von schuttfahigem, kornigem Gut

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US (1) US3572654A (enExample)
AT (1) AT285549B (enExample)
BE (1) BE731511A (enExample)
CH (1) CH495164A (enExample)
ES (1) ES366382A1 (enExample)
FR (1) FR2008260A1 (enExample)
GB (1) GB1219257A (enExample)
LU (1) LU58526A1 (enExample)
NL (1) NL6907122A (enExample)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977657A (en) * 1973-10-23 1976-08-31 Charles John Shearer Apparatus for mixing particulate solids
US20110036866A1 (en) * 2009-08-16 2011-02-17 Leon Han Apparatus and method for synchronized flow from volumetric tanks
CN110155759A (zh) * 2019-06-17 2019-08-23 苏州捷赛机械股份有限公司 仓顶分料器
US11167252B2 (en) * 2017-02-07 2021-11-09 Loramendi, S. Coop. Solid component mixing apparatus and associated method

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2231534C2 (de) * 1972-06-28 1985-09-12 Chantiers Navals de la Ciotat, Le Trait, Seine-Maritime Homogenisierungsvorrichtung für Schüttgüter
DE2500784C3 (de) * 1975-01-10 1982-04-08 Claudius Peters Ag, 2000 Hamburg Doppelstock-Mischsilo
DE19606721A1 (de) * 1996-02-23 1997-08-28 Du Pont Deutschland Verminderung von dynamischen Effekten bei der Entleerung von Silos

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US829127A (en) * 1905-10-03 1906-08-21 Julian B Strauss Mixing apparatus.
US2486200A (en) * 1946-12-17 1949-10-25 Lummus Co Clay flow baffle
US3155377A (en) * 1963-02-25 1964-11-03 Warren L Godman Destratifying uniform blender
US3158362A (en) * 1962-06-07 1964-11-24 Acheson Ind Inc Method of blending granular materials

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US829127A (en) * 1905-10-03 1906-08-21 Julian B Strauss Mixing apparatus.
US2486200A (en) * 1946-12-17 1949-10-25 Lummus Co Clay flow baffle
US3158362A (en) * 1962-06-07 1964-11-24 Acheson Ind Inc Method of blending granular materials
US3155377A (en) * 1963-02-25 1964-11-03 Warren L Godman Destratifying uniform blender

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977657A (en) * 1973-10-23 1976-08-31 Charles John Shearer Apparatus for mixing particulate solids
US20110036866A1 (en) * 2009-08-16 2011-02-17 Leon Han Apparatus and method for synchronized flow from volumetric tanks
WO2011022120A1 (en) * 2009-08-16 2011-02-24 Chemflow Systems, Inc. Apparatus and method for synchronized flow from volumetric tanks
US8292123B2 (en) * 2009-08-16 2012-10-23 ZhangJiaGang Chemflow Technology Co., Ltd. Apparatus and method for synchronized flow from volumetric tanks
US11167252B2 (en) * 2017-02-07 2021-11-09 Loramendi, S. Coop. Solid component mixing apparatus and associated method
CN110155759A (zh) * 2019-06-17 2019-08-23 苏州捷赛机械股份有限公司 仓顶分料器

Also Published As

Publication number Publication date
LU58526A1 (enExample) 1969-07-29
ES366382A1 (es) 1971-02-01
NL6907122A (enExample) 1969-11-12
CH495164A (de) 1970-08-31
GB1219257A (en) 1971-01-13
DE1756344A1 (de) 1970-03-19
FR2008260A1 (enExample) 1970-01-16
BE731511A (enExample) 1969-09-15
AT285549B (de) 1970-10-27

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