US3894721A

US3894721A - Oscillatory mixing apparatus

Info

Publication number: US3894721A
Application number: US469399A
Authority: US
Inventors: Dietmar Boenisch
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-07-26
Filing date: 1974-05-13
Publication date: 1975-07-15
Anticipated expiration: 1992-07-15

Abstract

An orbitally oscillating mixing apparatus unit for fluent solid material such as foundry molding materials comprising an orbitally oscillated support for a vessel providing a mixingspace-enclosing wall perpendicular to the plane of support oscillation, and a series of spaced blade-like elements secured in the vessel to oscillate therewith, which are elongated perpendicular to the support and located and spaced on a common circular or elliptical curve with a somewhat rotary impeller-like configuration in a set cooperating in action on material as a mixing device; the widths of the blades having generally similar angular dispositions between radial and tangential to the curve, and slanted outwardly in the direction of orbital oscillation, whereby in addition to a main circulating flow induced in material in the vessel opposite to the orbital oscillation direction, the mixing device acts to set up a circulating flow in a path within the device and having also a component parallel to blade elongation, by deflecting on respective blades portions of material from the main flow path inwardly to a region of recombination within the mixing device, there being a constant exchange of materials between the two flow paths. Plural mixing devices within a vessel, plural apparatus units on a common support with feed from one to another, continuous and batch type apparatus, and both horizontally and vertically orbiting apparatus are disclosed.

Description

United States Patent 1 in] 3,894,721 Boenisch July 15, 1975 OSCILLATORY MIXING APPARATUS [57] ABSTRACT [76] Inventor: Dietmar Boenisch, Morillenhang 45, An Orbitall) osclllaling mixing apparatus unit for 5[ A h Germany ent solid material such as foundry molding materials com risin an orbital] oscillated su port for a vessel [22] plied: May 1974 prov i ding a mixing-spa ce-enclosing vFall perpendicular [21] App] No.: 469,399 to the plane of support oscillation, and a series of spaced blade-like elements secured in the vessel to os- Related Apphcauon Dam cillate therewith, which are elongated perpendicular l l COMiHUHIiOH-iD-Pa" of Sci Nov 7 1 y to the support and located and spaced on a common 1972- circular or elliptical curve with a somewhat rotary impeller-like configuration in a set cooperating in action [30] Foreign Application Priority Data on material as a mixing device; the widths of the July 26, 1971 Germany 2l37277 blades having generally similar angular dispositions between radial and tangential to the curve, and l l US. Cl. 259/2; 259/29; 259/5 slanted outwardly in the direction of orbital oscilla- 259/72 tion, whereby in addition to a main circulating flow {51] Int. Cl. BOlf 11/00; BOlf l5/O2 induced in material in the vessel opposite to the or- [58] Field 01' ear h 59/2, [2, 29, 54, 56, bital oscillation direction, the mixing device acts to set 259/72, 75, 80, 76, 63, DIG. 42 up a circulating flow in a path within the device and having also a component parallel to blade elongation, [56] References Cited by deflecting on respective blades portions of material UNITED STATES PATENTS from the main flow path inwardly to a region of re- 2,l43,6|0 1/1939 Muller 259/2 Combinatio Within the mixing being a 2340923 7/|958 Behrens 259/72 constant exchange of materials between the two flow 3,l84,222 5/1965 Arondwitz 5 t 259/72 P aarpenko i Y Plural mixing devices within a vessel, plural apparatus oore i 3,430,926 3/1969 Freedman 259/54 umts common supper Wnh feed from one to Primary ExaminerRobert W. Jenkins Attorney, Agent, or FirmP. D. Golrick another, continuous and batch type apparatus, and both horizontally and vertically orbiting apparatus are disclosed.

18 Claims, l4 Drawing Figures "."Ti-Ti" I 1 m. 1 5 13. 5

SHEET FIG. 3

FIG. 4

OSCILLATORY MIXING APPARATUS This application is a continuation-in-part of parent copending US. patent application Ser. No. 274,762, filed July 24, 1972, the disclosure of which are herein incorporated by reference.

This invention relates generally to improvements in apparatus for mixing materials, particularly foundry molding materials, by an orbitally oscillating vessel having therein a fixed mixing device, and whereby two or more circulating currents are established with a continual mixing exchange between said currents.

In various industrial processing technologies there is a continually increasing demand for short mixing times with efficient mixing of materials involved in the processes. Particularly important for the foundry industries in technical and economic aspects are the operations involved for the mixing of molding compositions, wherein quartz sands are ultimately bonded with a synthetic resin. Here the sand is intimately mixed with the resin and with added activators, catalysts or hardeners, the reaction of which, leading to a setting of the molding composition should take place first or to high degree in the molding flask rather than in the mixing apparatus. Obviously then fast thorough mixing is highly important.

In the prior art various applications of oscillating, gy ratory or orbitally driven mixing vessels are known for the mixing of quite diverse liquid materials, particulate or granular materials, and combinations thereof. The aforementioned pending application discloses an orbitally oscillated upright cylindrical vessel, driven with frequencies in the range of 1,500 to 10,000 cps, and having therein disposed one or more mixing devices affixed to and cooperating with the vessel to develop flows or currents of material with horizontal circulation and also vertical components to effect mixing between the flows.

By orbital vibration or oscillation, here is meant the movement ofa body, wherein each point thereof tends to move in a closed curved path about its respective distinct axis, but without any rotation of the body as a whole with all points thereof swinging coaxially about a common center or axis.

The present invention is based first on the discovery that a three-dimensional array of elongated blades having, for example, a paddle wheel type configuration of blades as used in rotating impellers in air blowers or fans, e.g., for axial fan blowers, air turbines or trans verse blower fans, is eminently well suited to mix the materials in the shortest possible time, when arranged as a non-rotating but oscillating mixing device within a mixer vessel. This arrangement of oscillating" blades is so effective that in many cases, particularly with smaller mixer units, even with the mixer vessel stationary, it is sufficient merely to vibrate or oscillate the blades as a mixing device with circularly or elliptically orbital oscillations about axes extending substantially parallel with their lengths. In such array the blades are arranged along a closed curve, e.g., a circular or elliptical line, and at an angular disposition to the curve falling in a range between tangential and radial thereto, with spacing and other blade disposition variations as later detailed.

However, it is especially advantageous to oscillate the surrounding mixing vessel jointly with the blades by a common drive, as this achieves a certain further cooperative mixing effect imparted by the container walls, and a beneficial utilization of the drive. In this way, a quasi-fluidized bed" is created within the entire mixer vessel, promoting effective rapid mixing; and thereby also the mixed materials are effectively prevented from sticking to the vessel walls.

Consequently, additionally to a major current or main circulating movement imparted to a quite fluid bed of material to be mixed by the oscillating vessel walls, the oscillating blades also impel the material, and respectively, continually split off from a major current minor layer" currents or branch" currents, and direct them to recombine with relative displacement to a region central of the blade set there forming a new larger current. For this purpose it is particularly advantageous to provide more than two blades.

The current formed by recombination of the branch currents or layers derived from a main current is advantageously moved away in a direction different from, and preferably at about relative to, that of the main current from which derived for increasing mixing inten' sity by further turbulence. Thus, for example, from a main current circulating along the wall of an upright cylindrical vessel, a concentric array of oscillating blades divert branch currents, and conduct them to a central region within the array, that is, in a direction generally towards the axis of the oscillating vessel; and in that region in addition to other motion, a recom bined current advances also in the direction of the vessel axis.

The invention is more specifically explained relative to the accompanying drawings presenting some practical embodiments. It is however, not confined to the illustrated embodiments and many further modifications are conceivable within the general scope of this invention.

It is the general object of the present invention to provide improved apparatus for the mixing of fluent, principally particulate substances or materials, such as foundry molding materials, whereby a more thorough mixing, and even shorter mixing times are attained.

A more particular object is to improve mixing appa ratus of the type comprising an orbitally oscillated mixer vessel with a mixing device therein.

Another object is to provide a mixer apparatus which has a simple constructional design and basically has no relatively moving mixing elements.

Another object is to provide a mixing unit arrange ment which is applicable to batch mixers as well as to continuous mixers.

A further object is to provide at the same time a mixer which is rugged, largely maintenance-free and subject to little wear and tear.

Other objects and advantages will appear from the following description and the accompanying drawings, wherein:

FIG. 1 is a top plan view of a mixer unit comprising an upright cylindrical vessel and a mixing device emplaced therein;

FIG. 2 is a perspective and essentially diagrammatic illustration of a vane or blade assembly comprising the mixing device according to FlG. 1',

FIG. 3 is a vertical section taken along the line 3-3 in FIG. 1;

FIG. 4 shows a modification of the mixer vessel of FIG. 3, adapting the unit for core shooter and like use;

FIG. 5 is a top plan view of a modified mixer unit similar to that of FIG. I;

FIG. 6 is a somewhat schematic representation of a continuous horizontal mixer unit with a mixer vessel of an elongated trough shape;

FIG. 7 is a top plan view of yet another upright mixer unit;

FIG. 8 is a top plan view of a further mixer apparatus;

FIG. 9 is a top plan view of yet another mixing apparatus embodying a series of vessels and mixer devices similar to that of FIG. I, but with vessel modifications for continuous feed;

FIG. 10 is a perspective representation of a modification of the mixer shown in FIGS. 1-3;

FIG. 11 is a top plan view of a mixing apparatus embodying a plurality of mixer units each representing a modification of FIG. 10, to provide continuous through feed of distinct mixing streams, with final total mixing at a discharge point;

FIG. 12 is an irregular vertical section, taken principally along the line 12-12 in FIG. 11;

FIG. 13 is a top plan view of a further mixing unit modification;

FIG. 14 is a vertical section taken along the line 14-14 of FIG. 13.

In the following description of various mixer units or apparatus embodying the invention, generally only the basic dispositions of the principal components will be presented. Thus, with the exception of the driving means and mounting outlined in FIG. 11-12 for providing the orbital oscillation here commonly used, which is to be understood as applicable to the arrangements of the other figures of the drawings, the driving means, loading and discharge facilities, oscillating apparatus, etc., usually are not specifically described inasmuch as they form part of existing knowledge or prior disclosures.

FIGS. 1-3 Basic Structure and Operation For the mixing apparatus unit of FIGS. 1-3, in an orbitally oscillatable mixing vessel 10, an upright cylindrical, flat-bottomed container, a series of six like elongated flat vanes or blades 11 are arranged and secured to the vessel, equi spaced along a closed conic (here circular) curve center line 12 concentric with the vessel axis. The blades extend longitudinally substantially parallel to the vessel axis and are similarly located on the circle, with widths extending at like angles in the range between a tangential and radial disposition relative to said circle, so that here there is a six-fold rotational symmetry about an axis of symmetry which is the vessel axis.

The three-dimensional or spatial arrangement of the blades, as a set constituting what will here at times be called a mixing device M, corresponds to the paddlewheel-like rotary impeller configuration familiar in certain types of air fans or blowers. Here the circular reference line 12 is a convenient projection representation of an imaginary coaxial reference cylinder to which are referred the locations of corresponding parts of the blades.

The blades here are secured to and extend from the vessel bottom longitudinally parallel to the vessel axis V and the axis 14 of vessel oscillation, upwardly in the charge 13 of materials to be mixed; but they also may be dependently secured to a vessel cover plate or lid to project downwardly into the charge, preferably with lower ends spaced slightly away from the vessel bottom.

Individually, or assembled as a structural unit mounted within the vessel, the blades 11 are rigidly secured to the vessel by screws or like fasteners, or by welding; or they may be formed integrally therewith as a single casting. They may consist of metal, synthetic material or rubber-coated metal, as may the vessel itself, depending upon usual engineering design considerations.

The angular disposition of the blades defines between each adjacent pair a passage or channel 15 in effect tapering or converging away from the cylindrically annular space defined between the vessel side wall and the outer vertical edges lle of the blades, or rather a cylindrical envelope of those edges, to open inwardly to a vertically elongated blade-enclosed region 16 interior of the blade inner vertical edges, conveniently considered as enclosed by the cylindrical envelope of those inner edges.

The vessel 10 and the mixing device rigidly secured thereto are set in high-speed orbital oscillation relative to a base by known means, such as an eccentric drive, as described in said parent patent application or as exemplified relative to FIGS. 11-12, or by an unbalanced rotating weight type drive.

For example, a counterclockwise eccentric rotation so drives the vessel 10 that it does not rotate about its own axis V, but that axis orbits on a small radius about the vertical axis 14 of rotation of the eccentric, which is here termed at times the axis of oscillation. Indeed, every point in a horizontal cross section of the vessel similarly orbits about a distinct vertical axis, as indicated in FIG. 1 for oscillation of the point B on the circle about axis line A; the diameter of which circle is determined by and is twice the drive eccentricity. Hence the walls of the vessel 10 and the mixing device M comprised of the blade set undergo these oscillations in the same manner.

With certain other useful drives the orbit may be elliptical and the resulting oscillation is comprehended in the term orbital oscillation. Such circular or elliptical oscillation is a pre-requisite condition for the functioning of all mixer apparatus with mixing devices according to this invention, and is to be understood as provided without a repeated description or representation thereof in discussing the individual examples of practical applications of the invention.

Assuming counterclockwise orbiting, the fluent charge will tend to circulate with a main flow in clockwise direction along a path in the aforementioned annular space, as shown by the arrow C. The rate of advancement or pumping of the material will increase with the diameter of the oscillation circle, i.e., with amplitudc, but will increase particularly with the oscillation frequency. Thus increased pumping speed means increased mixing speed. An oscillation drive rate of more than 1,000 rpm, hence a frequency exceeding 1,000 cps, has been found very efficient to assure high mixing performance; and oscillation amplitudes of a few millimeters have been found quite adequate.

The continual high-speed oscillation of the mixer unit as a whole, including the mixing vessel and the mixer device, on the one hand produces a very loose flowable condition of the charge, akin to a fluidized bed, owing to the rapidity of successive advance and retreat of the blades, and as well advances the material along the vessel internal wall surface and along the blades which exert a considerable impelling thrust.

The outer edge lie of each blade faces the direction from which the material approaches in flowing around the mixing device in the clockwise path along the vessel internal wall, so that the blades scoop or shave respective portions or upright layers from the main current or flow as layered branch currents deflected, as though in a vortex, through the channels 15, being rolled or turned inwardly to recombine under relative displacements thereof to form a further current internal of the mixer device, around the vessel axis V, in the middle region 16. In this recombined current, material is carried away also in an upward direction, as it were in an upward helical or vertical flow as shown in FIG. 3. Thus by virtue of the circular and upward components, molding material, which is flowing in a loose bulk condition engendered by the oscillation, continually emerges above and fans out away from the oscillating blades at the upper end of the mixing device to be scattered externally of the mixing device, (as also indicated by arrows in FIG. 3) over the top of the material circulating in the main flow path, where there is of course also a downward motion component involved. Thence it is redirected again inwardly and delivered upwardly by the bladed mixing device.

This continued high speed batch division and intermixing within and without the mixer device affords extremely high mixing efficiency without any movement of the mixer device within and relative to the mixing vessel. The mixing principal and action is simple and at the same time effective.

The internal space 16 enclosed by the blades or blade internal envelope, preferably should be smaller than the annular space defined as surrounding the device between the vessel wall and the external blade envelope. These conditions promote a higher velocity of flow for the materials within the mixing device.

For achieving a high mixer performance and efficiency, the plane of oscillation in the mixer device, as far as possible, is parallel with the direction of deliv ery required of the oscillating blades. Since in most cases the blades will be required. as in FIGS. 1-3, to deliver in a direction towards the mixer device interior 16, the plane of oscillation will then be similarly disposed relative to or at right angles to the longitudinal axis of the mixing device here coincident with that of the vessel. Inasmuch as the oscillating vessel and the mixing device each occupy space rather than a plane, the phrase plane of oscillation" is understood to mean an arbitrary reference plane perpendicular to the longitudinal axis or center line of the vessel or of the device as the case may be. For similar reasons, the axis of oscillation" of either, unless context dictates otherwise, signifies the axis about which the longitudinal center line of vessel or device is orbiting.

The mixing efficiency depends to a high degree on the setting angle and the width of the blades as well as on the gap width or relative spacing therebetween, in the mixing device. Preferably the number of blades is increased with the diameter of the vessel. A small mixer apparatus, having 5 litres capacity and the configuration of FIGS. 1-3, may manage with six blades as shown, for example, in FIGS. 1 to 4 and 10. The times for mixing to complete homogeneity, with frequencies as low as about 3,000 oscillations per minute, have been obtained in a range from only to seconds.

Though not exemplified in any of the drawings, it is noted that the individual blades ll may also be of upwardly tapering or twisted configuration or be inclined toward or away from the vessel axis, so that the radial length of the channels 15 will be enlarged or constricted along the direction parallel to the longitudinal axis of the mixer device M, whereby the mixing device zones of entry and exit of the fluent material may be deliberately located in the regions of the mixing unit most favorable for effective mixing under given circumstances.

It is also possible to reverse the mixing flow pattern from that shown in FIG. 3, by closing the top of the mixing device with a lid and spacing it, i.e., the lower ends of the blades, away from the vessel bottom.

FIGURE 4 Pneumatically Discharged Apparatus The modification, or elaboration, of FIG. 4 represents a particularly advantageous arrangement for pneumatically discharging material from or emptying the oscillatory mixer apparatus. This is based upon specific advantageous peculiarities of this invention, especially the fluidity condition of the material engendered by the high speed oscillation, and the consequent very rapid delivery of material into the mixer device interior 16, which create optimum conditions for expelling or aspirating the finished mixed batch from the vessel by compressed air or fan-induced suction,

For this purpose, at least during the emptying operation, the vessel 10 must be closed comparatively airtight by a lid or cover 17 carrying a compressed air feed pipe 18, and, depending toward the bottom region of mixer device space l6, a central discharge pipe 19. If desired. closable charging ports may be included in the cover structure. With the apparatus unit maintained in the previously described orbiting oscillation, the finish batch will flow out through pipe 19, even at comparatively low air pressures or pressure differentials and so may be transported directly to stations of further treatment or use.

Hence, for example, since the material may be expelled or air blasted in the quickest and shortest way directly into molds or core boxes, a very short reaction time may be used for chemically setting foundry mold ing compositions, comprising cold-setting mixtures of sand, resin and hardener. This obviously is highly advantageous as offering correspondingly increased productivity. The eminently high flowability or fluidity of the molding material within the mixer while oscillating will produce adequate core strengths even at shooting" pressures of about 2 atmospheres, in contrast with pressures of about 5 atmospheres currently normally used in conventional core-shooting machines. This means, that less pneumatic energy is involved in operations. and that the shooting machines may be much simplified and lighter in construction.

In this application of the invention to provide a mixer unit functioning also as a coreand mold-shooting machine for chemically setting foundry molding material, a further important advantage arises; namely, the prevention of compactions or agglomeration of setting mixtures within the oscillating apparatus. Particularly, residual excess mixture left over in the apparatus from the production of a given mold or core, which would inevitably cause blockage or constrictions in conventional mixers, is here prevented from baking or sticking together in the oscillating apparatus, since it is con stantly being turned over or sheared by the novel mixer device therein. Further, under the oscillatory impulses imparted thereto, the individual sand grains remain separate till after the end of the chemical reaction, and consequently can be absorbed without any disadvantage whatsoever in a subsequently charged batch of components for a fresh mixture.

The basic elements of the mixing device, shown in and described for the batch mixer unit of FIGS. 13, may be further adapted to special requirements by various possible modifications of which a few examples are hereinafter described.

FIGURE 5 Whereas in FIGS. 13, the width of the interspaces or passages between successive individual blades is generally constant from interspace to interspace, it may be unequal for achieving special mixing action or patterns, for example, as shown in the upright unit of FIGS. 5-6 where the relative blade spacing is notably larger resulting in a passage or channel 21 of considerable width. This causes the material impelled through the other narrower channels 15a-lSd into the mixing device interior 16, whence it emerges in greatest part laterally (as indicated by the arrows 22) through the wide channel 21 and along nearly the whole vertical length thereof to discharge into the surrounding annular space, rather than in the usually preferred manner, of axial emergence from the upper end of the mixer device, as shown in FIGS. 3, with discharge essentially above and across the surface of the rest of the mixture contained in the vessel.

FIGURE 6 Horizontal Continuous Flow Mixing Apparatus Though the examples thus far described have presented mixing apparatus units with upright cylindrical mixer vessels 10 and mixer devices M with vertically extending mixing blades, the invention may also be ap plied to horizontal apparatus, or generally horizontal, but somewhat inclined apparatus, with the plane of oscillation correspondingly vertical or nearly vertical.

Thus in FIG. 6, a mixer device M, designed somewhat similarly to that shown in vertical disposition in FIG. 5, is disposed horizontally in a horizontally elongated trough-like mixing vessel 10A with a semi-cylindrical bottom 10b merging upwardly into vertical longitudinal side walls 10.\', preferably spanned by a top wall 101. The several blades 11 extend over the whole of the vessel length to be rigidly secured to the flat vessel end walls 10d at which the vessel is resiliently supported and driven (for example, analogously to the under structure in FIGS. 11-12) to oscillate in a vertical oscillation plane." as indicated by the point B and its oscillation circle about a respective axis A extending parallel to the trough centerline or axis.

Moreover to provide a continuous mixer unit, a charging inlet 23 is provided at one end, which may be slightly elevated, as an inlet tube through a top wall 101 where used; through which individual mixture components, such as sand, resin and hardener may be supplied by a dispenser or supply device not here specifically indicated. A lateral discharge pipe or conduit 24 is then located on a side wall 10A, remotely from the feed inlet.

With the assumed indicated orbital oscillation direction, as shown by arrows in FIG. 6, the individual blades 11 again deliver branch" currents of material inwardly towards the mixing device central region, from which in effect the device opens upwardly owing to the large gap (corresponding to the channel 21 in FIG. 5), representing in effect an absence of blades in this direction; so that the mixed material emerges in this more or less upward direction along the length of the mixing device M. Again the material is continuously engaged and deflected by the blade outer edges, from place to place along an outer main flow circulating path adjacent the trough sides and bottom 10s, 10b, to be mixed again with an excellent mixing efficiency.

With constant feed additions at 23, the entire charge mass also moves as a whole longitudinally while being subjected to strong mixing action in the arcuate currents or circulating flows, therefore helically through the mixer trough, ultimately to leave through the lateral discharge pipe or conduit 24.

Special advantages may be obtained by disposing several of these continuous horizontal mixer units in a parallel arrangement. Thus for example, sand and resin may be thoroughly pre-mixed in a first mixer unit, and sand and hardener in a second, so that no reactions can occur within the individual mixer troughs. The homogeneous pre-mixed materials may then be continuously discharged to and quickly intermixed in a simple postmixer device, such as a similar horizontal mixer.

FIGURE 7 Higher Capacity Batch Apparatus The upright batch mixers of FIGS. 1-3, or 4 can effectively handle only moderate batch volumes at higher mixing speeds. However, operating on the same principles higher capacity mixers may utilize two or more mixer devices, arranged in a common vessel laterally adjacent or within one another, in number as required for the batch size and for higher mixing speeds.

Thus in FIG. 7 what amounts to a more complex mixing device M-] is provided in upright cylindrical mixing vessel 10, by two mutually interfitted or coaxially arranged mixer devices consisting of a first set M of blades arranged along the inner circle 12; and, arranged along the outer circle 26, a second set including a majority of flat blades 11, but others 11a shown to be radiussed, i.e., curved in horizontal cross section.

FIGURE 8 Upright Continuous Feed Mixer Unit In FIG. 8, groups of blades, representing respective mixing devices M (each such as that of FIG. 1), are equally spaced as groups successively on a circle concentric with the vessel axis, where another mixing device M is centered in the upright cylindrical vessel 10; the latter being orbitally oscillated as a mixer apparatus unit in the manner previously described. This unit as thus far described may be operated as a high capacity batch mixer apparatus.

However, the construction of FIG. 8 may be simply adapted for, and is shown as, a continuously fed mixer apparatus, by inclusion of a radially disposed vertical baffle or damming wall 28 extending over the full height of the cylindrical vessel wall and projecting therefrom inwardly between two adjacent mixing devices M, in combination first with a discharge trough at 29, or other delivery device, at an opening. e.g., in the top margin of the vessel side wall counterclockwise of and closely adjacent to baffle 28; and secondly with feed or supply inlet troughs or conduits 3t) and 31, lo cated on the clockwise side of dam 28.

Owing to the oscillation of the wall 10, the general mass of the material will move clockwise in the direction of the arrows C-] from the supply stations to encounter baffle 28 and discharge at outlet 29; with mixing action occurring locally at each of the mixing de vices M both in the outer series along the path and also at the central device relative to the flows C in the annular paths thereabout. The mixer apparatus will deliver finished mixed material at a rate corresponding to the rate of component feed.

FIGURE 9 Continuous Feed Mixing Apparatus A high capacity, continuous feed mixing apparatus of great mixing efficiency is obtained in FIG. 9 by what is in effect a circular arrangement of several successively communicating vertical cylindrical mixer units of the basic design shown in and previously described for FIGS. I-3 as a batch unit.

Therein what maybe considered 12 circularly adjacent mixer sections on a common support, the intersecting mixing vessel cylindrical walls are interrupted by vertical passages or

openings

32a, 32b, 32c, etc., excepting where the common wall 38 occurs between two adjacent sections, resulting in what is actually an annular vessel 36 with scalloped internal and external walls. Mixture components are fed by supply conduits or troughs at 33, 34, 35 into the mixer sections immediately clockwise of wall 38; and at 37 a lateral outlet through the vessel wall counterclockwise of 38 has an associated discharge trough.

The entire unit with the several mixing devices M secured centrally in the respective sections is orbitally driven and mixing occurs in each section generally as previously described. The fed material passes in the as sumed direction of arrow C with thorough mixing at each individual mixing unit" successively through the whole vessel finally to discharge well mixed at 37. The mixing efficiency of such a continuous mixer apparatus increases with the mixing intensity of the individual mixer devices and with their number.

FIG. Mixing Device Modification In FIG. 10, a perspective schematic illustration, there appears a mixing device M-2 modified from the arrangement shown in FIGS. 1-3, by terminating the blades at their upper ends at or in an annular member such as a short pipe or tube. Member 20 prevents in the upper region of the mixing device that lateral or radial transfer of material described by the shorter arrows below the blade tops in FIG. 3.

This arrangement intensifies the vertical component of the overall mixing circulation, inasmuch as the material is always stripped off from the flow in the annular space between side wall and mixing device at the level of the exposed blade edges in the mixer bottom region; and is delivered upwardly therefrom through the length of member 20 either to be scattered onto the upper surface of the material batch in the vessel 10, where the FIG. 10 structure is used in a batch apparatus, or else delivered from the top of member 20 to a discharge chute or the like where the unit of FIG. 10 is used in a larger apparatus as next described.

FIGS. 11-12 Continuous Feed Parallel Mixing Apparatus In FIGS. 11-12, there is shown another apparatus incorporating the invention, which is especially adapted for continuous feed mixing of a foundry molding composition comprised of quartz sand, with a reactive binder resin and hardener.

Two series arranged in right and left hand rows of vertical cylindrical mixer units, each representing an elaboration of the type shown in FIG. 10, are rigidly secured on a flat rigid horizontal round support member 46, forming as shown (see FIG. 12) a common bottom for the several vessels 10a, ltlb, lOc', in the right row 10d, lOe, lOf in the left row; the support member in turn being non-rotationally, but orbitally oscillatably mounted through conventional sturdy resilient or elastic post units P. The support 46 is orbitally oscillatorilly actuated by an electric motor Em secured in the base Z and driving the eccentric in an appropriate eccentric bearing housing H secured to the bottom of the support plate 46.

The branches of a bifurcated sand supply chute or trough 40 feed into the annular space about the mixer device of the respective

first mixer vessels

10a and 10d of the right and left rows. Resin and hardener feed pipes or

conduits

41 and 42 likewise feeding into

mixer vessels

10a and 10d afford simultaneous supply of resin and hardener with the sand to these vessels respectively.

As shown more clearly in FIG. 11, each bladed mixer device M-3 has three curved mixer blades 11c, though at times two blades suffice, and, if necessary, more than three can be provided: and the rather stubby annular member 20 of FIG. 10 here is modified to an elongated tubular riser 20a, bearing at its top end above the top of the vessel wall a sloping lateral discharge chute 43. For sturdy simple mounting, the riser bottom end and blades are secured to the vessel floor. and the blades also to margins of riser side apertures.

Whereas the first two chutes 43 are relatively short to overhang the walls to discharge into the annular space of the next unit, for the final units of each row the discharge chutes or

troughs

44 and 44a are elongated to discharge into a final mixer vessel 45 which, in its interior, is equipped with similar mixer device (not shown). Preferably, as shown in FIG. 12, the final mixer vessel 45 has its own base and drive; but it can also be secured to the support plate 46 to eliminate the individual drive.

Within each mixer vessel, the material to be mixed moves upwardly within the blades 11c and the coaxial shaft formed thereabove by the riser 20a (as explained relative to 20in FIG. 10), and discharges from the riser top through the sloped trough or chute 43, to enter the annular space between the vessel wall and the mixer device of the adjacent mixer unit.

In this way, the fed resin and sand are conveyed with mixing from mixer vessel 10a to mixer vessel 10c, and the fed hardener and sand from 10d to 10f, resulting in preliminary mixed streams delivered from the third units via

chutes

44 and 44a for final mixing in 45; from which in turn by a like mixing device such as M-3 (not shown in 45) the final composition is mixed and continuously delivered for use.

FIGS. 13-14 Instantaneous Continuous Mixer A very efficient high-capacity continuous vertical mixer apparatus is shown at FIGS. 13-14 respectively in top plan and in vertical axial section.

In an external cylindrical upright housing 10x, there are located and embraced six like nearly cylindrical elements 11g each closed by a bottom wall 39b. These elements may be conceived of as being as it were, each a longitudinally slotted tube with one reflected outwardly bent slot edge 1111; and with the tubular elements disposed in a circle with the straight slot edge of each longitudinally engaging and preferably secured to an outer surface of adjacent element at a line spaced from its respective bent slot edge. By this disposition the elements successively conjointly form vertical tubular or cylindrical chambers, each now having a quite narrow vertical outlet slot 15x opening into a vertically elongated central space or region F functionally akin to interior region 16 in a FIG. 1 type device. This central space (see FIG. 14) preferably has a closed top 390 and a downwardly convergent funnel-like bottom discharge opening 3a, in the housing bottom wall 39 for gravity discharge. The unit is oscillated by means and in the manner previously described about its axis.

Plan view FIG. 13 shows the resemblance to the basic type of FIG. 1, which can be considered to have merely been modified in that pairs of mutually adjacent blades 113 are combined on the outside to present a closed chamber having a rounded cross sectional configuration for dynamic flow reasons. In effect an element por tion from its bent slot edge 1 1h out to the line of attachment with the straight edge of a counterclockwise adjacent element, then continues in the latter as a blade which, at the wall of 10):, is then reflected inwardly to the left to meet the next element.

By means of dispensing or conveying devices, (not here shown; e.g., plastic tubes of larger diameter), components for the desired mixture are continuously fed to the respective individual alternating mixer chambers D,E,D, etc.; for example, the chambers D receiving the supply feed of sand and resin, and the chambers E receiving the supplied sand and hardener.

Hence under oscillation the mixture components which emerge from D and E layerwise through the loftgitudinal slots 151:, will continually successively overlap one another, and as shown by the spirals in FIG. 14, will descend in a helical movement and be turbulently combined. This continuous vertical mixer with its drive unit may be conveniently movable or portable, so that it may be moved to a spot directly adjacent a work station for filling a foundry mold box located therebeneath. When this mixer serves as a final or post'mixcr apparatus for combining preliminary mixtures of sand with resin and of sand with hardener, the preliminary mix tures may be prepared by using other continuous mixing devices, e.g., those shown in FIGS. 6, 8 or 9.

This mixing apparatus is suited and preferred for damp or more or less cohesive or adhesive components or pre-mixed materials, which will not run or trickel out of narrow slots, when the mixer oscillation is stopped. It is suitable, for example, for the final or postmixing of previously prepared sand-resin and sandhardener preliminary mixtures, because it will combine the preliminary mixtures only at the moment when it is switched on, so that in the stationary mixer, there can be no appreciable chemical reactions.

A further important advantage derives from the fact that the further running in or supply of the prelimiinary mixtures is immediately interrupted on switching the unit off, and the finished mixture will drop out of the apparatus leaving no reactive residual mixture within the mixer. It is possible to extract instantaneously any required amounts of finished mixture in precisely measured quantities which are readily available at all times. Hence, this type of mixer is excellently suited for special purposes, for example, in the foundry industry for making molds and cores by the so-called cold-setting process.

What is claimed is:

1. An orbitally oscillating mixing apparatus unit for fluent soldi material, such as foundry molding materials, comprising: a support mounted for, and driven with, an orbital oscillation in a plane,

a vessel secured on the support for oscillation therewith, and providing a mixing space enclosing wall substantially perpendicular to the plane of support oscillation,

a plurality of blade-like elements secured as a set to the vessel to move therewith,

and elongated in direction away from the support, and located and spaced along a closed conic curve the plane of which is parallel to the plane of oscillation, the widths of said blades having similar angular dispositions between radial and tangential to the curve, and slanted outwardly toward the direction of orbital oscillation, said blades thereby forming a set of somewhat impeller-like configuration cooperating in action on material as a mixing device, whereby, in addition to a main flow induced in material in the vessel tending to circulate in a path along the enclosing wall oppositely to the orbital oscillation direction, the mixing device acts to set up at least a second flow circulating within the device and having also a component perpendicular to the plane of oscillation, by each blade deflecting material, from a portion circulating in the main flow path, inwardly to a path of recombination within the mixing device and with a constant exchange of material between the two circulating flow paths.

2. An apparatus unit as described in claim 1, wherein the length of said blades is greater than half the length of the vessel.

3. An apparatus unit as described in claim 2, wherein said plurality comprises at least three blades.

4. An apparatus unit as described in claim 1, wherein said vessle is an upright vessel and said support and plane are horizontal;

and further including a removable lid closing the top of the vessel,

an air supply pipe opening through the lid into the vessel, and

a discharge tube extending through the lid toward the vessel bottom,

whereby the unit constitutes a coreor mold-shooting apparatus, discharging a finished composition mixture while oscillating and under an air pressure differential between the air supply pipe and an outer end of the discharge tube.

5. An apparatus unit as described in claim 1, wherein said vessel is an upright cylinder on a horizontal support, and said curve is a circle concentric with the vessel axis, and further including a cylindrical member coaxial within the vessel and joined to and extending upwardly from the upper ends of the blades.

6. Apparatus comprising a plurality of successively adjacent apparatus units as described in claim 5 sharing a common support and wherein each said cylindrical member at its upper end has a lateral discharge opening and bears a lateral discharge conduit at said opening for discharging and conveying mixed material into the space between the wall and the mixing device of the succeeding adjacent vessel, and from a last unit to serve as the apparatus discharge for finished mixed material;

and thereby being adapted to serve as a continually fed and continually discharging mixing apparatus.

7. Apparatus as described in claim 6, comprising two said pluralities of apparatus units, arranged in two respective rows on a said common support, and with the discharge conduits of the last units of said rows discharging into a common subsequent orbiting mixer vessel.

8. An apparatus unit as described in claim 1, wherein the blades of said set are spaced and arranged on a circle as said closed curve,

and within said set there is located a second set of similar blades arranged along a closed curve concentric with the said circle, and disposed in the range between tangential and perpendicular to the curve.

9. An apparatus unit as described in claim 1, including as said vessel, an upright cylindrical vessel with the plane ofoscillation perpendicular to the vessel axis; and

a plurality of said mixing devices located on and spaced along a circle which is coaxially spaced within the cylindrical wall of the vessel.

10. Apparatus as described in claim 9, including a damming partition extending upwardly from the bottom to the top of the vessel and projecting from the vessel cylindrical wall inwardly between two adjacent said mixing devices;

lateral discharge conduit means associated with a lateral opening in the upper part of the vessel wall adjacent to one side of the partition; and

feed conduit means on the other side of said partition for supplying to said vessel material to be mixed;

whereby said apparatus is adapted to operate as a continuously fed and discharging mixer.

11. Apparatus as described in claim 1, wherein said vessel comprises a generally horizontal trough of elongated oblong plan configuration and having a longitudinal center line; and

said blades are disposed horizontally extending longitudinally of the trough and substantially over the length thereof; and arranged on a circle as said closed curve;

said trough being oscillatable orbitally about an oscillation axis parallel to its longitudinal center line.

12. Apparatus as described in claim 11, wherein said trough has a bottom rounded in transverse cross section, and a closed configuration;

said mixing device has the blades thereof spaced more widely at the top of the set;

and including material feed conduit means opening into one end of said trough, and a lateral discharge conduit opening from the other end of the trough; whereby the apparatus is adapted to serve as a continuous mixer. 13. Apparatus as described in claim 1, wherein said vessel is an upright cylindrical vessel, and has said mixing device disposed concentrically therein with said blades longitudinally upright. 14. An apparatus comprising a plurality of apparatus as described in claim 13 with the vessels thereof arranged on a common support successively in a circle and with the cylindrical walls of successively adjacent vessels intersecting at the regions of intersections affording communicating openings between at least all but one adjacent pair of vessels, and thereby forming a larger generally annular material containing space.

15. An apparatus as described in claim 14, including one pair of adjacent vessels which at the region of intersection have a common wall portion blocking communication therebetween', a lateral opening and associated discharge conduit extending outwardly from said annular material containing space from one vessel of said pair; and supply conduit means feeding at least into the other vessel of said pair. 16. Apparatus as described in claim 1, wherein said vessel is an upright cylindrical vessel: said blades are each curved at its outer end to turn back inward to the next in the direction of orbital movement thereby conjointly to form a plurality of generally cylindrical mixing chambers, the inner end of each said blade leading into a central space surrounded by said mixing chambers, and

defining with an adjacent blade a narrow elongated vertical slot opening from a respective chamber to said central space;

said central space being closed at the top and having a bottom wall aperture as a discharge outlet of the apparatus;

whereby with different materials to be mixed fed to successively alternatingly located chambers, the apparatus delivers from said bottom wall aperture a composition of said materials mixed in said central space, upon orbital oscillation of the apparatus.

17. Apparatus as described in claim 16, wherein the said discharge outlet comprises a bottom wall central opening surrounded by a downwardly con vergent funnel-like flange.

18. Apparatus as described in claim 1, wherein inward channels, from the circumferential region exterior of the mixing device to the interior region thereof, as channels defined between mutually adjacent blades, are of relatively different width. l IF

Claims

1. An orbitally oscillating mixing apparatus unit for fluent soldi material, such as foundry molding materials, comprising: a support mounted for, and driven with, an orbital oscillation in a plane, a vessel secured on the support for oscillation therewith, and providing a mixing space enclosing wall substantially perpendicular to the plane of support oscillation, a plurality of blade-like elements secured as a set to the vessel to move therewith, and elongated in direction away from the support, and located and spaced along a closed conic curve the plane of which is parallel to the plane of oscillation, the widths of said blades having similar angular dispositions between radial and tangential to the curve, and slanted outwardly toward the direction of orbital oscillation, said blades thereby forming a set of somewhat impeller-like configuration cooperating in action on material as a mixing device, whereby, in addition to a main flow induced in material in the vessel tending to circulate in a path along the enclosing wall oppositely to the orbital oscillation direction, the mixing device acts to set up at least a second flow circulating within the device and having also a component perpendicular to the plane of oscillation, by each blade deflecting material, from a portion circulating in the main flow path, inwardly to a path of recombination within the mixing device and with a constant exchange of material between the two circulating flow paths.

4. An apparatus unit as described in claim 1, wherein said vessle is an upright vessel and said support and plane are horizontal; and further including a removable lid closing the top of the vessel, an air supply pipe opening through the lid into the vessel, and a discharge tube extending through the lid toward the vessel bottom, whereby the unit constitutes a core- or mold-shooting apparatus, discharging a finished composition mixture while oscillating and under an air pressure differential between the air supply pipe and an outer end of the discharge tube.

6. Apparatus comprising a plurality of successively adjacent apparatus units as described in claim 5 sharing a common support and wherein each said cylindrical member at its upper end has a lateral discharge opening and bears a lateral discharge conduit at said opening for discharging and conveying mixed material into the space between the wall and the mixing device of the succeeding adjacent vessel, and from a last unit to serve as the apparatus discharge for finished mixed material; and thereby being adapted to serve as a continually fed and continually discharging mixing apparatus.

8. An apparatus unit as described in claim 1, wherein the blades of said set are spaced and arranged on a circle as said closed curve, and within said set there is located a second set of similar blades arranged along a closed curve concentric with the said circle, and disposed in the range between tangential and perpendicular to the curve.

9. An apparatus unit as described in claim 1, including as said vessel, an upright cylindrical vessel with the plane of oscillation perpendicular to the vessel axis; and a plurality of said mixing devices located on and spaced along a circle which is coaxially spaced within the cylindrical wall of the vessel.

10. Apparatus as described in claim 9, including a damming partition extending upwardly from the bottom to the top of the vessel and projecting from the vessel cylindrical wall inwardly between two adjacent said mixing devices; lateral discharge conduit means associated with a lateral opening in the upper part of the vessel wall adjacent to one side of the partition; and feed conduit means on the other side of said partition for supplying to said vessel material to be mixed; whereby said apparatus is adapted to operate as a continuously fed and discharging mixer.

11. Apparatus as described in claim 1, wherein said vessel comprises a generally horizontal trough of elongated oblong plan configuration and having a longitudinal center line; and said blades are disposed horizontally extending longitudinally of the trough and substantially over the length thereof; and arranged on a circle as said closed curve; said trough being oscillatable orbitally about an oscillation axis parallel to its longitudinal center line.

12. Apparatus as described in claim 11, wherein said trough has a bottom rounded in transverse cross section, and a closed configuration; said mixing device has the blades thereof spaced more widely at the top of the set; and including material feed conduit means opening into one end of said trough, and a lateral discharge conduit opening from the other end of the trough; whereby the apparatus is adapted to serve as a continuous mixer.

13. Apparatus as described in claim 1, wherein said vessel is an upright cylindrical vessel, and has said mixing device disposed concentrically therein with said blades longitudinally upright.

14. An apparatus comprising a plurality of apparatus as described in claim 13 with the vessels thereof arranged on a common support successively in a circle and with the cylindrical walls of successively adjacent vessels intersecting at the regions of intersections affording communicating openings between at least all but one adjacent pair of vessels, and thereby forming a larger generally annular material containing space.

15. An apparatus as described in claim 14, including one pair of adjacent vessels which at the region of intersection have a common wall portion blocking communication therebetween; a lateral opening and associated discharge conduit extending outwardly from said annular material containing space from one vessel of said pair; and supply conduit means feeding at least into the other vessel of said pair.

16. Apparatus as described in claim 1, wherein said vessel is an upright cylindrical vessel; said blades are each curved at its outer end to turn back inward to the next in the direction of orbital movement thereby conjointly to form a plurality of generally cylindrical mixing chambers, the inner end of each said blade leading into a central space surrounded by said mixing chambers, and defining with an adjacent blade a narrow elongated vertical slot opening from a respective chamber to said central space; said central space being closed at the top and having a bottom wall aperture as a discharge outlet of the apparatus; whereby with different materials to be mixed fed to successively alternatingly located chambers, the apparatus delivers from said bottom wall aperture a composition of said materials mixed in said central space, upon orbital oscillation of the apparatuS.

17. Apparatus as described in claim 16, wherein the said discharge outlet comprises a bottom wall central opening surrounded by a downwardly convergent funnel-like flange.

18. Apparatus as described in claim 1, wherein inward channels, from the circumferential region exterior of the mixing device to the interior region thereof, as channels defined between mutually adjacent blades, are of relatively different width.