US2578805A

US2578805A - Mixing apparatus

Info

Publication number: US2578805A
Application number: US569719A
Authority: US
Inventors: Ethel H Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-12-26
Filing date: 1944-12-26
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18

Description

Dec. 18, 1951 J. JOHNSON 2,578,805

MIXING APPARATUS Filed Dec. 26. 1944 3 Sheets-Sheet l 4 l l H BY A TORNEY Dec. 18, 1.951 J, JOHNSON 2,578,805

MIXING APPARATUS Filed Dec. 26, 1944 5 Sheets-Sheet 2 j Y fr# H. 7a/ew vicar/ewa lTTORNEY reame-d Dec. 18,'71951 MIXING APPARATUS John Johnson, deceased, late of Morristown, N. J by vEthel H. Johnson. executrix, Morristown, N. J., assignor to John E. Johnson, Mount Kemble Lake, Morristown, N. J.

Application December 26, 1944, Serial No; 569,719

This invention relates to apparatus suitable for use in'thoroughly mixing, blending, emulsifying, homogenizing and/or dispersing mixtures of liquids with other liquids, gases and/or solids.

When mixing a liquid with another liquid of substantially the same viscosity and general character, or when mixing a liquid with a-solid which is already in a sufficiently finely divided condition, ordinary mixing apparatus usually suices. When, however, any of the materials to be mixed require emulsification, homogenization or attrition to insure the desired ultimate blending. ordinary mixing apparatus will not usually produce the desired ultimate result. The'present invention aims, therefore, to provide improved apparatus which is useful to effect the desired dispersion of one liquid in another or of a gas or of a solid in a liquid, as. for example, by providing for attrition of any solid particles which are in the liquid or the breaking up of any globules suspended in the liquid or such other treatment as may be necessary to secure complete blending, emulsiiication or homogenization of the materials to be treated.

An im.ortant feature of the invention is the provision of means for effecting a hydraulic shearing of the materials treated, this means serving to produce the hydraulic shearing action both by direct impact of liquid streams against shearing edges andpby mechanical movement of cooperating shearing edges through streams flowing thereacross.

Another important feature of the invention is the proviison of substantially contiguous relatively movable perforated plates or screens, which are so relatively movable to each other as to bring the openings in each screen gradually into and out of register with openings in the other, in combination with means for driving liquid to be treated through said screen openings during such relative movement and when and so long as any parts thereof are in register. It will be seen that this feature of the invention provides for a manifold shearing action which facilitates the blending, emulsifying and homogenizing action of the apparatus.

Still another important feature of the invention is the connection ofthe means for effecting the relative movements of the perforated screens to the means for effecting the liquid flow in such manner that these actions are synchronized, whereby the apparatus can readily be operated at various speeds to adapt it for use with liquids of different viscosities and with various combinations of materials to be treated.

5 Claims. (Cl. 2595-96) In apparatus for treting those mixtures to be blended, emulsied or homogenized in' which breaking up of solids into a more finely divided condition is essential to secure the desired ultimate result it is important that the apparatus include also attrition means. The invention therefore further contemplates the combination with the aforementioned means for effecting a. hydraulic shearing, of means for effecting an introduction of the solid particles between the surfaces over the edges of which the hydraulic shearinghas taken place whereby the solid particles are carried between the surfaces of the movable and stationary plates and a grinding thereof is effected by the relative movement of said plates.

Other objects and important features of the invention to which attention has not hereinabove specifically been directed will appear hereinafter when the following description and claims are considered in connection with the accompanying drawings, in which- Figure 1 is a section through combined mixing and homogenizing apparatus embodying the present invention;

Figure 2 shows a modification of the embodiment illustrated in Figure i in which two pairs of shearing screens are provided;

Figure 3 shows other means for effecting the relative movements of the shearing screens of apparatus embodying the present invention;

Figure 4 is a vertical section through another embodiment of the invention in which other means for effecting the relative movements of the shearing screens are provided;

Figure 5 is a vertical section through still another,embodiment of the invention in which the shearing screens are arranged in horizontal planes;

Figure 6 is a transverse section through the perforated plates or screens of Figure 5 showing one construction and arrangement o! the screens or plates adapted to produce the desired attri.

tion of the materials to be treated, the parts being arranged for self cleaning;

Figure 'I is a section similar to Figure 6 showing a modification of the plate constructions for producing substantially the same results as are obtained by the construction shown in Figure 6;

Figure 8 is a view similar to Figure 6 showing still another modification of the plate constructions for securing substantially the same results as are obtained by the Figure 6 construction and arrangement;

Figure 9 is a composite view showing diierent shapes and sizes of apertures suitable for use in the screen plates of Figures 5, 6, '7 and 8;

Figure is a sectional view of another embodiment of the invention in which the shearing screens are `incorporated in a mixing apparatus of another type, the screens being inserted in the discharge end of the apparatus shown in this figure,

Figure l1 is a view similar to Figure 10 but showing the screens located in the intake endof the apparatus.

In the embodiment of the invention shown in Figure 1, mixing apparatus of the inclined :Ilow type, such as more fully disclosed in the copending application Serial No. 563.500, filed November 15, 1944, now Patent No. 2,450,802, dated' October 5, 1948, has incorporated therein the means for eiecting a hydraulic shearing of the materials being mixed which characterize the present invention, such means being preferably adapted to function also as an attrition mill. In this embodiment of the invention a liquid circulating rotor, comprising propeller blades 2 carried by a central hub 4 attached to a driving shaft 6, serves to effect the flow of the liquid or liquids through the mixing, blending, homogenizing or emulsifying apparatus. To insure the desired inclined flow of the propelled liquid the propeller blades 2 have their discharge edges 8 inclined to the axis of rotation of the shaft 6,-the inclination shown in Figure 1 being at an angle of substantially 35 to the axis of rotation of the shaft, or 55 to the horizontal. The liquid circulating rotor is also provided with a ilow directing shroud I0 carried upon the outer ends of the propeller blades 2, this flow director being shaped, as shown, to insure the desired inclined flow which, as also shown, is gradually converted into a substantially horizontal flow by reason of the impact of the liquid against the bottom I2 of the tank or other container in which the combined mixer and blender is located.

As in the mixer more fully shown and described in the Patent No. 2,450,802, hereinabove referred to, stator blades I4 are so located beneath the propeller blades 2 of the rotor that their liquid- Cil receiving edges I6 are parallel to the surface generated by the edges 8 of the blades 2 and lie substantially within the vertically projected periphery of the path of travel of the edges 8. Preferably theshroud I0 extends over the entire width of the stators I4 so as to insure direction of the flow through the stator part of the mixer.

Adjacent to the discharge side of the stator part' of the mixer a cylindrical plate or screen I8 is located which is provided with numerous perforations 20 so that the stream of liquid di- Irected against the screen is broken up into small jets. 'I'he walls of the holes or perforations 28 may be normal to the faces of the screen I8 or they may be inclined to the screen to secure any desired shearing and jet effect. As shown in Figure l, however, the openings 20 are so formed in the screen I8 that the walls of the openings are normal to the two faces of the screen for the major part of the length of opening. The screen I8 may be supported in fixed relation to the liquid circulating rotor in any suitable manner as, for example, connecting it directly to the outer edges of the stators I4 as shown at 22.

To increase the hydraulic shearing effect in the embodiment of the invention illustrated in Figure 1, means are provided for producing a mechanically shearing relative movement of registering jet openings in two screens relatively movable to each other. In the embodiment of the invention-shown in Figure l, a second cylindrical screen 28, in substantially con- 4tiguous or rubbing relation toV the screen I8. surrounds this screen and is so connected to an upturned flange 28 on the shroud I0 of the liquid circulating rotor by rivets 30 or other connecting means that it rotates with the liquid circulating rotor. The openings 32 in the screen 28 are so located that they may be brought into register with correspondingly located openings 20 in the screen I8 as the screens move relatively to each other.

From the foregoing description it will be seen that the materials to be mixed, including the liquid or liquids constituting a part of the mixture, are drawn into the intake of the circulating rotor by the action of the propeller blades 2 and that as they leave the discharge edges 8 of the propeller blades 2 they strike the receiving edges I6 of the stator blades I4 and are directed by said stator blades I4 outwardly against the screen I8. As the force of the stream produced by the circulating rotor drives the liquid through the openings 20 in the screen I8 the liquid will pass through said openings 20 and into registering openings v32 of the screen 28 when these openings 32 are either wholly or partly in register with the openings 20. The rotation of the screen 26 with the liquid circulating rotor will ilrst bring the openings 32 into partial register with one set of the openings 20, then into complete register, then again into partial register and finally into non-registering relation thereto but into register with the succeeding set of openings, the result being that each of the jets through the registering

openings

28 and 32 are successively sheared and their cross-sectional dimensions constantly varied. This obviously increased the homogenizing and emulsifying action and at the same time, by reason of the projection of these jets into the slowly moving mass of liquid outside the screens. a thorough commingling and blending of all of the different materials in the mixture is brought about.

It is, of course, possible to so locate the successive sets of openings 20 in the screen I8fand the corresponding sets .of openings 32 in the screen 26 that there will be no complete shut off of the flow of the liquid through the two screens at any time. This, however, is more or less immaterial if the speed of the relative movement of the two screens is sulciently great, so that the registering of the openings is substantially continuous.

In Figure 2 of the drawings is illustrated a slight modification of the embodiment of the invention shown in Figure 1, in which two

stationary screens

34 and 38 are arranged in concentrically spaced relation to each other and are supported upon a plate 38 attached to the bottom of the tank in any suitable manner, this`p1ate-88 also carrying the stator blades I4. Two cooperating

rotary screens

40 and 42 are supported by studs 44 and 46, respectively, having reduced threaded ends extending through a horizontal flange 48 on the shroud I0 of the liquid circulating rotor and secured thereto by nuts 50 and 62. It will be seen that the jets, rst driven through the rotary screen'40 and the stationary screen 34, then strike the rotary screen 42 and pass through that and through the registering openings oi' the stationary screen 36.

In Figure 3 is shown a modification of the invention in which stator blades I4 are done away with and their place is taken by blades 84 carried upon a .floating rotary frame comprising arms I8 attached to a hub 58 mounted to turn freely on the shaft 8 of the liquid circulating rotor. The

arms 88 carry a section 88 of the flow directing.

f directing shroud. 1

From the foregoing description it will be seen that the movement of the

screens

48 and 42 relative to the

screens

84 and 38 is effected by the impact of the liquid discharged from the propeller blades 2 against the blades 84 carried by the shroud section 68. 'I'he blades 64 thus not only lll perform the function of the stator blades |4 in the form of the invention shown in Figure 1, but they also act to effect the rotation of the arm 58 and the parts connected thereto about the shaft 8 and thus produce the movement of the

screens

48 and 42 relative to the

stationary screens

84 and 38.

In the embodiment of the invention shown in Figure 4 the rotary screens are again brought outside the stationary screens, as in Figure l, but the

rotary screens

82 and 84 are mounted upon a rotary disk 86 having a central hub 88 secured to the upper end of a shaft 18 extending through the bottom I2 of the tank and the

stationary screens

12 and 14 are suspended from a horizontal plate 18 by

studs

18 and 88, similar to those employed in the construction shown in Figures 2 and 3, the plate 18 being itself supported on vertical studs 82 secured to the bottom |2 of the tank in which the mixing and blending apparatus is located.

In each of the forms of the invention so far described the screens or perforated plates, through which the mixture carrying liquid is forced in jets through registering openings, may also serve to effect attrition or grinding -of any solid.I constituents of the mixture or the breaking up of fat globules and to this end they may be constructed as more fully shown in Figures 6, 'I and 8, to which more specific reference will be made hereinafter. When, however, attrition is an important function of the apparatus a construction such as shown in Figure 5 is preferably employed.

In the embodiment of the invention shown in Figure 5 the movable perforated plates or screens are shown as arranged in horizontal planes and the stationary perforated plates or screens/are likewise, of course,.arranged in horizontal planes. Each movable perforated plate or screen may be arranged to cooperate with a single stationary platel or screen associated therewith, as in Fig-A ures l to 4 inclusivepbut where, as above suggested, attrition is an important function of the apparatus, it is preferred to arrange each movable plate so that it cooperates with two stationary plates, or vice versa. As shown in Figure 5, four movable perforated plates or screens are shown as arranged to cooperate with four pairs of hori- 'zontal plates or screens so arranged with respect to the movable plates or screens that each movable plate rotates between the two stationary plates of its associated pair.

.nuts 88. The four perforated annular or segmental plates or

screens

82, 84, 88 and 88 are mounted on the studs 88 in any suitable manner to secure them in the desired vertically spaced relations to each other thereon and also' in the desired relations to the stationary per-r forated blades or screens. As herein shown each screen is provided with upper and lower collars |88 and |82 fitting on the stud 88 and adapted to be pinned, welded or otherwise secured in position thereon to hold the associated movable perforated plate or screen in its proper position on said stud 88.

As above suggested, each movable perforated plate or screen is arrangedV to cooperate with two stationary plates or screens or Vice versa, the movable plate in each case being located between the two stationary plates.` In the embodiment of the invention shown in Figure 5, the movable perforated plate 82 moves between two contiguous stationary plates |84 and |88; movable plate 94 moves between two contiguous stationary plates |88 and ||8; movable plate 88 moves between two contiguous stationary plates ||2 andl ||4 and movable plate 88 moves between two contiguous stationary plates ||8 and I8. As also shown, all of these stationary plates are mounted on stationary studs |28, each having a head at one end and a nut at the other end to clamp the plates and their separating washers and collars and the flow directors in position on the studs. The studs |28 may be held in stationary position in any suitable manner such, for example, as attaching them to supports in turn secured to the bottom of the container |22 in which the apparatus is located.

Associated with each group of plates, that is,

with each movable plate and its associated pair of stationary plates, is a flow director. The ow director |24 for the uppermost group of perforated plates or screens is shown as mounted on the studs |28 and having its inner edge adjacent to the outer edge of the overhanging part 84 of the shroud i8 of the liquid circulating rotor. The flow director |24 thus serves to guide that part of the stream of liquid discharged from the rotor, which passes over the. upper movable plate or screen 82,7through the perforations in the screen, the space provided between the flow director |24 and the uppermost stationary screen |84 being tapered as shown to insure substantially equal distribution of the liquid among and substantially uniform velocity of iiow thereof through the perforations in the uppermost group of perforated plates or screens.

The flow directors |28, |28 and |38 for the respective groups of perforated plates or screens below the uppermost group are shaped as shown with a bent-up portion near their inner ends which engages the inner margin of the associated lower stationary plate of the respective groups, in order not only to insure the direction of the flow of a part of the rotor driven stream toward this group but to assist somewhat in supporting the inner edge of the lower plate of .the group and maintain it in rubbing contact with the movable plate. It will be seen that the flow director |28 maintains the lower plate |88 7f in engagement with the under face of the movable plate 82 of the Auppermost group.

These various elements which are mounted on the studs are suitably spaced thereon as follows:

Spacing-collars |32, |34 and |36 are located respectively between the lowermost plate |06 of the uppermost group and the flow director |26,

between the lowermo'st plate llo of the next group and the flow director |28, and between tlie lowermost plate ||4 of the third group from the top and the iiow director |30. Spacing sleeves |38, |40, |42 and |44 extend between the respective flow directors |24. |26, |28 and |30 and the bottom plates of the respective groups, namely. |06, ||0, ||4 and ||8. The upper plates |04, |08, ||2 and ||6 are freely slidable on the sleeves |38, |40, |42 and |44 so that the uppermost stationary plate of each group is permitted to bear with its own weight against the upper face of the associated movable' plate.

To insure entrance of the particles Ito 'be broken up between the stationary and the movable plates, the openings 20 in the stationary plates or the openings 32 in the movable plates or both may have their marginal edges cut back to provide recesses between the plates and adjacent to the openings, into which recesses the particles can enter to cause their introduction between the plates. The

openings

20 and 32 may be either circular, elliptical, square or of any other desired shape, such as shown in Figure 9, but for ease of production they are preferably circular. When circular openings are provided it is comparatively easy to ream them to provide beveled recesses between the plates adjacent to the openings. Even when the openings are of other shapes, if the plate be made by die stamping or die casting the beveling of the edges of the openings to provide the cutback margins is a comparatively simple operatiom As shown in Figures 6, 7 and 8, the provision of the particle-receiving recesses adjacent to the plate or screen openings is accomplished in three different Ways. In Figure 6 the lower margins of the openings 20 in the upper stationary plate of each group are shown as cut back at |46 and the upper margins ofthe openings 20 in the lower stationary plate of each group are likewise shown as cut back at |48. The margins of the openings 32 in the rotary plate of each group are shown as flush with the surfaces of the plate. In Figure 7 the margins of the openings 20 in the stationary plates are kept flush with the operative surfaces of the plates while both the upper andlower margins of the openings 32 in the movable plate of each group are shown as cut back at |50 and |52, respectively. In Figure 8 substantially the Vsame result is produced by leavingfthe margins of the openings 20 in the lower plate flush with its operative surface, cutting back the lower margins of the openings 32 in the movable plate on one side only of the openings, that is, the trailing side as shown at |54, and cutting-back one side only of the margins of the opening 20 in the upper stationary plate, likewise on` the side last engaged, or trailing side, as shown at |56.

It will be apparent that other arrangements of the recesses on the respective plates may be made to facilitate the introduction of solid particles to be ground between the faces of the stationary and movable plates.

.In Figures 1 to 5 inclusive of the drawings the 8` present invention has been shown as incorporated in a mixer of the type disclosed in the Patent No, 2,450,802.. In Figures 10 and 11 there has been shown the invention as incorporated in a somewhat different type of mixer, that is, a mixer known commercially as the Stevens type of mixer converging flow-directing stator blades |58, projecting inwardly from the wall of a hopper-like flow-directing tube |60, direct the liquid to the blades |62 of a rotary propeller having a hub |64 mounted on a shaft |68.

To produce the desired homogenizing or emulsifying action in the embodiment of the invention shown in Figure 10, a stationary perforated plate or screen |68 is fixed in the discharge end of the flow directing tube |60 and a contiguous cooperating screen |10 is mounted on the shaft |66 to cause its perforations 32 to move into and out of register with the perforations 20 of the stationary screen |68. l

In Figure 11 the stationary screen |68, instead of being located at the discharge end of the Stevens type mixer, is located at the intake end, as shown at |10, and the rotary screen |12 is mounted on the outside of the stationary screen |10 instead of being upon the inside, as shown in Figure 10.

From the foregoing description it will be seen that the invention provides improved means for insuring not only a thorough mixing of a liquid with another liquid or of a liquid with a solid or agas, but also such a dispersion of the materials yto be mixed throughout the mixture as to insure the desired complete blending of the materials. It will further be seen that the hydraulic shearing effect produced by the relative movement of the contiguous perforated plates or screens insures homogenization and emulsification of those .mixtures requiring such treatment and that where attrition of solid particles is essential to the complete ultimate blending of the materials, such attrition is insured both by the shearing action and by the grinding of the materials between the contiguous plates.

In designing the apparatus to insure adequate attrition, it will be understood that the contiguous faces of the stationary and movable plates may be provided with abrading surfaces and also, if desired, with suitable grooves in order further to facilitate the introduction of thematerials to be ground between the abrading surfaces, where considerable attrition is important.

The grinding plates may, if desired, be made of powdered metal with diamond dust, powdered Stellite, silicon, carbide or other abrasives mixed with the powder before compacting and sintering' and the grinding surfaces of the plates may be treated in any suitable Way, as by etching to expose the abrasive materials. The plates might also be made of steel faced with a softer material,

such as copper, having the abrasive pressed into the face thereof, or the platesv could be faced with a mixture of powdered metal and abrasive,

compacted and sintered as above described. In

fact, any of the commercial methods of embedding abrasive materials in the surfaces of surface grinders might be employed to increase the attritive effect of the perforated plates or screens of the present invention.

What is claimed as new is:

l. In homogenizing apparatus or the like, the combination with substantially contiguous screens so relatively movable as to bring the openings in each gradually into and out of register with openings -in the other, of means'for" effecting such relative movement and means operating while such relative movement is taking place to drive liquid to be treated through said screen openings when and so long as any parts thereof are in register, including direction changing means between the driving means and the screens for positively directing the driven liquid toward the screen openings in directions substantially normal to the screen surfaces, said relatively movable substantially contiguous screens having tapered passages leading away from at least some of the screen openings in the direction to effect by the relative screen movement the gradual introduction of the liquid or liquids and any other materials suspended therein between the substantially contiguous screen surfaces to insure attrition of the materials thus brought into rubbing relation to said surfaces.

2. In homogenizing apparatus or the like, the combination with substantially contiguous screens so relatively movable as to bring the openings in each gradually into and out of regster with openings in the other, of means for effecting such relative movement and means operating while such relative movement is taking place to drive liquid to be treated through said screen openings when and so long as any parts thereof are in register, including direction changing means between the driving means and the screens for positively directing the driven liquid toward the screen openings in direction substantially normal to the screen surfaces, the substantially contiguous screen surfaces being faced with abrasive material and provision being made for gradually introducing liquid or liquids and any materials suspended therein between said substantially contiguous screen surfaces.

3. In homogenizing apparatus or the like, the combination with substantially contiguous screens so relatively movable as to bring the openings in each gradually into and out of register with openings in the other, of means for effecting such relative movement and means operating while such relative movement is taking place to drive liquid to be treated through said screen openings when and so long as any parts thereof are in register, including direction changing means between the driving means an'd the screens for positively directing the driven liquid towardA the screen openings in directions substantially normal to the screen surfaces, said substantially contiguous screens being arranged in a plurality of segregated banks of three screens each in the path of flow of the liquid, each of said banks comprising inner and outer screens and an intermediate screen substantially contiguous; to each of said inner and outer screens and relatively movable with respect to both and each having an intake and a, discharge independent of the others.

4. In homogenizing apparatus or the like, the combination with substantially contiguous 10 screens so relatively movable as to bring the openings in each gradually into and out of register with openings in the other, of means for effecting such relative movement and means operating while such relative movement is taking place to drive liquid to be treated through said screen openings when and so lcng as any parts thereof are in register, including direction changing means between the driving means and the screens for positively directing the driven liquid toward the screen openings in directions substantially normal to the screen surfaces, the liquid driving means comprising a rotor having propeller blades and the relatively movable substantially contiguous screens lying in a plane I substantially perpendicular to the rotor axis.

5. In homogenizing apparatus or the like the combination with substantially contiguous screens so relatively movable as to bring the openings in each gradually into and out of register with openings in the other, of means for effecting such relative movement and means operating while such relative movement is taking place to drive liquid to be treated through said screen openings when and so long as any parts thereof are in register, including direction changing means between the driving means and the screens for positively directing the driven liquid toward the screen openings in directions substantially normal to the screen surfaces, the substantially contiguous screens having portions of the contiguous face of at least one screen so cut away adjacent to the screen openings therein as to provide tapered passages leading away from said openings in the direction to effect by the relative screen movement the gradual introduction of the materials to be mixed between the contiguous faces to effect attrition thereof.

ETHEL H.A JOHNSON.

Executri of the Estate of John Johnson,

Deceased.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS