US2592709A - Mixing and homogenizing apparatus - Google Patents

Description

A ril 15, 1952 w. R. KINNAIRD 2,592,709

MIXING AND HOMOGENIZING APPARATUS Filed Feb. 25. 19.50

Patented Apr. 15, 1952 2,592,709 f MIXING AND HOMOGENIZING APPARATUS William R. Kinnaird, Riverside, 111., assignorto Universal Oil Products Company, Chicago, 11].,1

a corporation of Delaware Application February 25, 1950, Serial No. 146,273

1 Claim.

This invention relates to improved apparatus suitable for the mixing of different fluid streams, and more particularly to a mixer which is constructed in a manner to be operated continuously to effect the thorough mixing of miscible liquids, or alternately, the dispersion or homogenization of immiscible fluid mediums.

It is an object of the present invention to provide a mixer of relatively simple construction which combines flow mixing, jet stream or spray mixing, and paddle mixing to effect eiiicient and thorough mixing of different fluid streams.

It is also, an object of the present invention to provide a mixing apparatus which incorporates therewith means for effecting a shearing action onfa fluid stream and a resulting homogenization or emulsification of immiscible fluid streams, or alternatively the dispersion of finely divided solids in a liquid medium to provide a quasi-homogeneous product.

In a broad aspect, the present apparatus for mixing different fluid streams comprises in combination, a cylindrical housing, a hollow shaft held rotatably within and extending axially through said housing, with one. end of the hollow shaft extending exteriorally of the housing, fluid inlets connecting to the exterior end ofrthe rotating hollow shaft, a plurality of sets :of fluid orifices from the hollow shaft at spaced distances along the latter within thehousing, each of the orifices of each set being constructed and positioned angularly with respect to the hollow shaft in a manner causing theimpinge- ,ment of a plurality of jet-like streams against an adjacent dish shaped baflle plate, there being one bafile plate for each of the sets of orifices and each plate having a diameter substantially smaller than that of the interior diameter of the cylindrical housing, adjacent sets of orifices being constructed and positioned at divergent angles with respect to the hollow shaft and the accompanying dish shaped baffles are positionedin opposition to one another, whereby the resulting' fluid streams sprayed from the sets of orifices and subsequently from the periphery of each of the dish shaped baflles provide a plurality of crossing streams, a mixed fluid outlet the blades extending radially from the hollow shaft .to within a short distance of the interior wall of the cylindrical housing and provide thereby additional mixing and turbulence within the housing.

The housing and the hollow shaft extending longitudinally therethrough may be positioned horizontally or vertically, depending upon the particular type of fluid mediums to be mixed. 'In any case, a single rotating hollow shaft is utilized, with a suitable motor or driving means attaching to the exterior end of the shaft so as to continuously rotate the latter within the cylindrical housing. The apparatus thus provides a relatively simple form of construction, with only one member being rotated mechanically. There is utilized to advantage a confined fluid passageway, orifices, baffles, centrifugal rotation, and mixing blades to combine many types of mixing and provide; a very efficient overall means of effecting the mixing of either miscible or immiscible fluid streams.

In a modified embodiment, a cone-shaped member is attached to the end of the rotating shaft and is positioned in close proximity toa matching cone-shaped head or end member of the housing so as to develop a shearing action on the fluid stream, resulting from the relative rotation of one surface with respect to another, to in turn be effective in the emulsifying or homogenizing of immiscible streams or mixtures. In this embodiment, the cylindrical housing is preferably placed in a vertical position and the homogenizing cone is attached to the rotating hollow shaft at the lower end of the unit. The unmixed fluidstreams being introduced to the interior of the hollow shaft at the upper end of the mixing apparatus, become mixed in a series of recrossing sprayed streams during their downward passage through the mixer, and subsequently homogenized by the rotating cone member and closely placed coneshaped end of the housing to permitthe withdrawal of a homogenized or quasi-homogeneous product stream from the center of the lower end of the unit, v

The construction and operation of the improved mixer will be more apparent upon reference to the accompanying drawing and the lindrical housing I, held on a base 23,- anda ver- 7 the, periphery of the individual'bafiles.

tically positioned rotatable hollow shaft 2. The

shaft 2 is held in axial alignment within the housing I by means of a bearing 3 and a packing gland 4, maintained within the upper head or closure member 5, and by means of a lower internal bearing 5 which is in turn supported by suitable spokes or web members 1 that connect with the inside of the cylindrical housing I. Preferably the lower bearing 6 is of a thrusttype roller bearing suitable to accommodate the load of the hollow shaft and its attachments.

A suitable seal 8 is utilized at the top of the rotating hollow shaft in order to connect there-' with a stationary conduit. 9 ,and' fluid inletslll;

and II. 'Also, a suitable sheave-orgearing l-2, or

the likepis attached to the upper end of the hollow shaft externally of the cylindrical housing in order that a motor or other power driven means may connect with the shaft and rotate-the"- latter within the housing.

The fluid streams which are to be mixed, and being introduced by way of inlets l0 and H, and

through; the shaft seal 8 into the interior of the 'hollowshaft 2, pass in a mixed fluid stream continuously downwardly through the entire shaft and outwardly through. a plurality of sets or .-orifices, i-ndicatedby the numerals I 3 and 14. As

will be noted upon reference to the drawing, the various orifices l3 are drilled or otherwise placed through the wall oi the hollow shaft 2 so that jet like streams of fluid pass upwardly and outwardly to. impinge against the inner face of a dishshapedbaille l5, while the jetllike streams from the orifices H} are projected-downwardly and outwardly from the hollow shaft 2, to impinge The baille pinging jet streams; so that the fluid streams subsequently leave the periphery of each oflthe dished baffle plates in a thin sheet-like stream or continuous film. Th setsof orifices l3 and I4 and the accompanying baflles l5 and I6, for each of the respective sets of orifices, are spaced longitudinally along the hollow shaft 2,'such that the resulting sheet-like fluid streams from the periphery of each. of the baffles will cross with 'another, within the cylindrical housing 2.

The jet streams from, the orifices and the resulting. crossing of sprayed. streams from the .peripheries of the bafiie plates [5 and I6 takes placein a continuous manner and during the continuous rotation of the hollow shaft and the attachedbaflles, so that there is a combination .of methods of mixing. Flow mixing through the inside of the. hollow shaft 2 and the orifices I3 and M, with spray mixing resultingfrom the impingement of. the jet orifices against the accompanying bafile plates andfrom'the crossing of the streams after the fluid is allowed to flow from i It is to be noted, thatthe sets of orifices, which are adjacent one another, are positioned or constructed in a manner to cause diverging jet streams of fluid, and the adjacent bafiles l5 and I6 oppose vone another', .to provide a plurality of pairs of crossing streams or films of fiuid and thus effect a high degree of mixing within thehousing, Also, in a vertically disposed embodiment of the appa- The present embodiment has a plurality of blades or curved propeller-like blades H which project radially from the hollow shaft 2. Such blades are efiective in the breaking up and further mixing of such liquid as may be raining or flowing downwardly through the housing. 'Alternatively, where the mixing chamber is lying in a horizontal position, the blades are efiective in stirring and mixing the liquid'whichj accumulates in the lower portion of the unit. While the pres- 1 ent drawing indicates the curved blades in sets of i, it is' not intended to limit the mixer to any particular number'of blades, or to any particular shape. The spacing of the sets of orifices and attached. to the lower end of the. hollow. shaft 2,

suchthat it isr-otated therewith, The member H 18 in this particularmixerlalso serves to caper block the. fiuidlfl'ow fromtheend of the hollow shaft 2 such that all of the fluid medium is passed outwardly through the pluralityiof orifices l3 and f4. Th cone-shaped member lja'provides a conical surface of revolution whichfis 'injelose proximity to a' cone-shaped head l9 at the lower end of the cylindrical housing and" thus provides j in turn a relatively thin conically shaped passageway for the fluid stream tobe passed through prior to reaching thejoutletZ'O; atthe lOWQnfil'ld of the chamber The. rotating surface, provided by the surfaceof the cone member [8 develops a shearing action on the fluids to produce a. fine dispersion or emulsion of non-miscible fluids, 'or

alternatively, to provide a homogeneous or quasihomogeneous product, depending upon thetype of streams beingmixed.

, Adjustment means are preferably provided to regulate the spacing between the cone member I8 and the lower head liland in turn permit adjustability in the homogenizing action on the fluid stream passing from the mixing sectionto the outlet 20. The present embodiment provides a plurality of bolts 01' cap screws 21 and slotted holes 22 in the head l9 so that thelattercan be moved up and down with respect tothe cone member I8 and regulate the spacing therebetween, however, other more readily operated mechanical means may be utilized to advantage to provide the desired adjustment.

It is not intended to limit the present mixing I and homogenizing apparatus to any one use, for

obviously, it may be utilized to advantage in many types of contacting and mixing operations. For example, with petroleums, it may be utilized to effect 7 the dispersion between a gasoline and caustic stream'in a treating process, oralternatively, with an acid to provide a catalytic conversion. The apparatus may also be used "to advantage to mix a liquid and solid, such as a finely divided pigment in a suitable vehicle. as in the manufacture of paint, or the mixture of other finely divided solid material in thefformation of slurry streams.

Particularly advantageous features of the improved unit, reside in the simple construction using'a single rotating shaft, sothat the power or driving means may be connected with'the shaft externally of the mixing housing or chainof the bafiles l5 and It, as well as the diameter" of they latter, is correlated with respect to the her I, and there is no necessity to attach or connect driving or rotating means to an internal portion of the unit. The hollow shaft also permits the introduction of the streams to be mixed, into the center of the chamber and throughout the entire length of the unit in a simultaneous manner to thus maintain uniformity of mixing over long sustained periods of operation.

As briefly pointed out hereinbefore, a plurality of the well known methods of mixing are combined in an eflicient and advantageous manner in this single apparatus. To recapitulate, turbulent flow mixing is obtained within the internal portion of the rotating shaft 2, by virtue of the confined flow channel and the continuous rotatlonof the shaft itself. Jet or orifice mixing is obtained by means of the continuous flow through all of the plurality of sets of orifices l3 and 14 that spray against the dished baflle plates 1'5 and I 6, each bafiie being concave to their respective set of orifices. The impinging jet streams in turn tend to diffuse and mix upon the surface of each of the bafiles and form a continuous sheet-like film of fluid which is centrifuged outwardly and away from the outer periphery of each of the bafiie plates, by virtue of the continuous flow and the continuous rotation of the baffles with the hollow shaft 2. In still another step, there is a cross flow mixing, resulting from the sprayed streams from the peripheries of bafiles l5 and 16. The plurality of propellerlike blades I1 effect still further mixing and turbulence by virtue of their continuous rotating motion throughout spaced portions of the housing.

In still another step, an homogenizing cone, such as I8, may be combined with the mixing section of the unit to exert a shearing action'on the fluid stream and effect a desired homogenizing or emulsification of immiscible fluid streams.

The power requirements for the motor or other driving means attached to the rotating shaft 2 will of course vary in accordance with the type of fluid streams which are being introduced into the mixer, however, it may be pointed out that the improved construction and arrangement is such that the power requirements are substantially low as compared with a mixer which has blades or paddles acting directly within a retained body of liquid. In other words, the present paddles act on sprayed streams or raining droplets of liquid resulting from the cross stream contact.

I claim as my invention:

A fluid mixing apparatus comprising a vertically positioned cylindrical housing, a hollow shaft rotatably mounted in and extending axially through said housing, means for introducing fluids to said shaft, means for rotating the shaft, a plurality of pairs of dish-shaped bailles of approximately equal diameters mounted on said shaft in opposition to each other and having their peripheries vertically spaced a substantial distance apart, whereby fluid films discharging from the peripheries of the respective baffles cross each other within the housing, a set of orifices in said shaft a short distance below the upper baffle of each of said pairs and inclined upwardly toward the last-named bafile, a second set of orifices in said shaft a short distance above the lower baflie of each of said pairs and inclined downwardly toward said lower baffle, a radially extending mixing blade on said shaft between adjacent pairs of the bafiies, and means for removing mixed fluids from said housing.

WILLIAM R. KINNAIRD.

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

UNITED STATES PATENTS Number Name Date 1,340,464 Schaub May 18, 1920 1,720,573 Roberts July 9, 1929 1,965,905 Parker July 10, 1934 2,068,136 Hulbert Jan. 19, 1937 2,273,835 Cornell Feb. 24, 1942 2,341,538 Fash Feb. 15, 1944

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