US3184221A - Homogenizing apparatus - Google Patents

Description

May 18, 1965 H. w. MOULD, JR 3,184,221

HOMOGENIZING APPARATUS Filed Jan. 23, 1962 FIG. I

I a k 2 FIG. 4

IN V EN TOR.

HARRY w. MOULD, JR.

ATTORNEY United States Patent Office 3,184,221 Patented May 18, 1965 3,184,221 HOMUGENIZING APPARATUS Harry W. Mould, Jr., Butfalo, N.Y., assignor, by mesne assignments, to Liberty National Bank and Trust Company, Buffalo, N.Y., a national banking association Filed Jan. 23, 1962, Ser. No. 168,197 7 Claims. (Cl. 259--7) This invention relates to apparatus for blending and emulsifying or homogenizing fluids such as milk, oil, and the like.

The effectiveness and quality of a homogenization or emulsification process is determined by the extent of reduction of particle size, and the ultimate uniformity of particle sizes as brought about by the process.

The most frequently used homogenizing or emulsiflcation process is an open paddle-tank type operation. However this is a batch type process and normally requires a relatively long period of time for completion. Moreover, because of the relatively extended period of time during which a given patch need be subjected to the agitator, the open paddle tank apparatus, not infrequently subjects the fluid being treated to undesirable temperature rises during the blending operation. Moreover, since the agitator employed in the open paddle tank apparatus tends to create a vortex in the fluid which is being blended, the blending action throughout the tank is uneven; the fluid adjacent the vortex gets much greater action than the fluid remote from the vortex. Furthermore because of the batch nature of the open paddle tank process relatively large and cumbersome equipment is required if any production is to be achieved at all. For these reasons efforts have been made to homogenize or emulsify fluids by continuous flow processes in which the fluid is flowed through a device containing high speed shearing elements which function to agitate and positively reduce the size of particles in the fluid during the passage of the latter through the device.

An object of this invention is to provide an improved continuous-flow homogenizing or emulsifying unit.

' Another object of thi invention is to provide an improved continuous-flow homogenizing or emulsifying unit wherein the incoming fluid is subjected to a blending operation before passage of the fluid to the shearing elements of the unit.

' Another object of the invention is to provide an homogenizing or emulsifying apparatus of the continuous flow type which will be extremely compact. To this end, it is a further object of the invention to provide an homogenizing or emulsifying apparatus of the type described in which the pump for moving the fluid through the apparatus is combined with the shearing mechanism itself. Still another object of the invention is to provide apparatus of the type described in which the shearing mechanism, the pump and the drive motor for the pump are all view of a homogenizing unit made in accordance with one embodiment of this invention;

'FIG. 2 is a fragmentary sectional view on an enlarged scale taken along the line 2-2 of FIG. 1 and looking in the direction of the arrows;

FIG. 3 is a longitudinal sectional view ona reduced scale of a modified form of unit made according to the invention and in which a slotted inner rotor is employed to initially blend the fluid prior to its entry into the shear elements of the unit; and

FIG. 4 is a fragmentary sectional view on an enlarged scale taken along the line 4-4 of FIG. 3 and looking in the direction of the arrows.

Referring now to the drawing by numerals of reference and first to FIGS. 1 and 2, 10 designates the electric drive motor for the unit. Keyed to the armature shaft 11 of this motor is a conical split collet type adaptor or arbor 12. Adaptor 12 has diametrally opposite slots 13 through it which provide two resilient jaws 14. The adaptor supports ashaft 15 which has an enlarged portion 16 at its rear end that has a conical bore which fits over the adaptor. Screws 17, which pass through a flange 18 at the rear of the shaft and which thread into an opposed flange 19 on the adaptor, serve to secure the shaft on the adaptor so that the two rotate together.

Shaft 15 is of reduced diameter forward of its foot portion 16 as denoted at 21. It has a second reduced diameter portion 22 forward of portion 21; and it has a third reduced diameter portion 24 forward of portion 22. It is threaded at its front end 26.

A circular impeller 31 is secured on shaft 15. The impeller 31 is bored and counterbored to receive the shaft 15 including the shoulders 23 and 25 formed on the shaft at the junctures of its first and second reduced diameter portions 21 and 22 and of its second and third reduced diameter portions 22 and 24, respectively. The'impeller seats against shoulder 23. The outer peripheral surface of the impeller is provided with a plurality of peripherally spaced, axially extending, notches 32 that have sidewalls slightly inclined in a direction opposite to the direction of rotation (see arrow 34, PEG. 2) of the impeller. Slots 32 define impeller blades 33 and provide a primary centrifugal pumping effect upon the rotation of shaft 15.

Integral with the impeller 31 and projecting forwardly therefrom is an annular rotor element 35. The outer peripheral surface of this rotor is at approximately the same radial distance from the axis of shaft 15 as are the bottoms of the grooves 32 in impeller 31, that is, it is approximately in line with the bottoms of the grooves 32. The rotor element 35 has a plurality of peripherally spaced, shallow grooves 36 formed on its inner face. These extend axially from the rear end of the rotor for substantially the full length of the rotor. As shown clearly in FIG. 2, they are substantially rectanguler in cross section. Preferably there are thirteen equi-spaced notches 32 in the peripheral surface of impeller 31, and twenty-six equally spaced grooves 36 on the inner peripheral surface of rotor 35. At the rear end of each groove 36 is circular aperture 37 which is drilled radially through the rotor.

Impeller disc 31 and rotor 35 are secured to rotate with shaft 21 by an internally threaded retaining sleeve 41 which is threaded onto the threaded end 26 of shaft 15.

' Sleeve 4-1 has a disc or flange 43 integral therewith which has an outside diameter that is less than the inner diameter of rotor element 35.

Interposed between the disc or flange 43 and the rotor 35, and in very close proximity to both is a coaxial annular stator 50. Stator 50 has an axial length slightly greater than the axial length of rotor 35 and extends into'an annular recess 51 in the inner face of impeller 31. In its outer peripheral surface stator 50 has a plurality of peripherally spaced axially-extending, shallow grooves 52 which are essentially rectangular in cross section (FIG. 2) and which confront and are approximately coextensive with the grooves'36 in rotor 35. The number of grooves 52 is preferably one more or one lessthan the number of grooves 36. At the front end of each of the grooves 52 there is a circular aperture 53 drilled through the stator. Each groove 52-on the exterior of the stator 50 is thus placed in communication with the interior of the stator.

a particle is subjected during its" passa 60 will be inversely proportional to trolled by positioning a :valv'e; c oc outlet end 74 of thehousing; t 7

a rate of dowof fluid throughlhousing 60 is decreased, thus I increasing the number ofv shearing ,actionsjtofwhich-a particle will be submitted during; its passage through'the housing Conversley,xas.the valveop'eningisin '6 ed The stator 50 is integral with a cover plate 55. This cover. plate is secured by a plurality of threaded studs 7 56 and wing nuts 57 to the (front end of a cup-shaped housing60.

The housing 60 contains impeller 31, rotor 35, stator 50, and disc 43, which aredisposed coaxially. It rearend wall 62 has a central openingthrough' which the, shaft 1 5 extends into the housing; and'it has an integral collar portion 63 by which the housing is centered in a circular opening provided in the (front wall 64 of a supporting member 65. Housing 60 is secured to the front Wall of supporting member 65 .by the threaded studs 66 and winged nuts 67'. Supporting 'member 65 .is bolted or otherwise secured to the front (face of the housing motor to be supported thereby." I 1 .7 V

The cover'plate 55 has a collar portion '68'integral therewith and projecting forwardly therefrom." Its bore 69 provides an inlet through which the fluid that is to be homogenized or-em-ulsified can enter the housing. ,It is externally threaded, as denoted at 70, for coupling it to piping through which the fluid is delivered to the homogenizing unit. ,Upon the rotation oi -impeller 31, the fluid is drawrithrough apertures 53 in stator'50, and forced down the thin axially extending annularpassagew75'bea tween grooves 52 and 36, out of the apertures37 in rotor into thelannularrsp-ace 7-2 between theouter surface of rotor 35 "3.I1d theconfronting inside face. of'the side wall of the housing 60,-into grooves 3-2 of impeller 31, and finally out of the housing 60 through'a port or'duct. 73 in the annular sidewall .ofthe housingand the bore of an externally threadedcollar 74 which is integral with the housing 60. As the fluid passes down the annular passage 75 the rotating edges of the grooves 36 cooperate with the stationary edges of the grooves 52 on theouter .5 peripheral sun-face of stator 50 .to, positively; shear the particles carried in the fluid-which is being pumped: ,Inf addition to this positive shearing causedby cooperating. edges of the grooves 36 and 52,;the particles in the liquid passing between the rotor 35 andstator' 50 are also subjected to an implosion phenomenon-resulting frorn the cavitation effect produced when the rotor "is operated at; a.

' high speed relative to the stator. The high speedcreates an energy level of ultrasonic sound waves measurable in" kilocyclesper second. A suitable sound energy levelforr frequency for a particular type of particle, i.e., a frequency a a at which the dispersion or reduction of'particle sizes is-at an optimum, may be achieved byvarying the rotor speed, and/or, the number'of grooves'disposed about the confrontingj peripheral surfaces of the rotorand statonres spectively. As a'general. rule this energy level-has been I found to rbe' most eifective when held within the range of 2.2 to 27.6 kilocycles per second. 1 1

By forcing the particlesin the fluid; to travel through the space 75 from-oneend thereto to the other, "all or the particles are exposed .to the shearing edges ofgrooves 36 .and 52' essentially at, all times during their passage 1. axially through thepumphousingr'j The'time duringrwhich' a .respective particle is subjected to a positive shan'n'gifl rate of; fluid wthr-oughthe: unit. Moreovr, a ertures .53, j and to alesser extent apertures '37,"tend to causeareduc tion in particle size as;a'resu1t of compressive-forces, exerted upon the particlesas they are forced through these respective aperture-s1 i 1 Since" as a "general; rule 'thezjiiiotor 1Q is eoperated'at a constant speed, the number of shearingactionstoi yvhich? gefthrough housingi i 7 ate ,of'flow of fluid through-thehousing-The fluidflow ate is redily con i lik a the tling' the valve the70 Theinclified rem: slots thereby passing arespective particle throughthe housing more rapidly so that it is subjected to a lesser number of shearing actions during its passage therethrough.

Fnom FIG. 1 it will be noted that the annular flange 43 prevents theinco-ming-fluid fromby-passing the apertures 53 in stator50 and flowing directly from the open rear end *of: the latter through -the adjacent apertures 37 in rotor 35. Moreover, apertures 53 are aligned in a circular path opposite the ends of grooves 36 remote'from impeller 31, while the apertures 37 are aligned with the terminal ends of grooves 52 remote from cover plate 55. The fluid is thus forced to flow axially through annular passage as it passes through pump housing 60;

'I1he housing 60 is readily removablefor.cleaning, re-

. pairing, or for the replacement thereof by a similar hous- J posed between the disc and the shoulder 82 formed at the juncture of part 16 of the shaft and the first. reduced diameter portion 21 thereof. V

'In order to remove the-homogenizingunitzfrorn the motor; ,10-the screws17 areau'nthreaded. The .bore' 83 in endwall 64 of supporting member 65 has a diameter great-enough. forthe enlarged .end of shaft 15 to pass freely therethrough. 7 At diametrically opposite sides, supporting member 65; has openings-85 therein which permit access toscrews -17 and'nuts 67.

A: modified form-of ,the inventiod'isi illustrated in FIGS.:3 and 4. It is recommended when itais desirable, to

have a'preliminaryfmixing of the fluid before shearing The modified device isidenticalg, Ito thatsho'wnin 'FIGS. '1 and 2 with the exception that the particles thereof.

the retaining sleeve 41'and its integral disc 43 are repla'cedgby an inner rotorf-designated generally at Sin'cewwith the exceptioni'of rotor-140, the elements employed in the modificationshown in" FIGS.'3 and 4 are identical to the elements .employedjin the embodiment illustrated inflFIGS. land 2; only portions of the pump housing are illustratedin- FIG- 3 Identical parts are identified by identical reference numerals in all the figores.

The rotor '14 0,jv vhich is cupshaped has an annular wall-'141fand is closed at. one end-by an axially bored 7 end Wall: 142, which hasan internally 'threadedhub por 1 {clon extending torwardlytherefrom. Rotor 140falso has; an annular fiangeor collar .146' extending axially rearwardly' fromitsrlpottom 142; The annular wall 141 of"the :rotor' 140; hasan outside diameter slightly less thangthe-insidediameter of stator- 50, and an axial length slightly less 'than the axial length of rotor '35.. Rotor 140 is "disposed concentrically within ,stator50 with its open 7 end facing cover platei55.: Its 'hub portion 145 is threaded onto shaft15 so that-collar' 146on' the rotor 140"ab1'1ts'the impeller 31 to seat a 7 g p, v of the ishafL-f action is thus maintained at a maximum-for al grven flow thepimpeller: against the shoulder 23 The annular wallportion of rotor has a plurality' of peripherally spaced, axially extending slots 147 intermediate'the" ends thereof. .Slots 147 extend subs'tanv tially the full lengthiof the"annularwall portion' of the 1 rotor-.1 The sidesofze'ach slot extendfparallel to one an otheri and lie in planes ofiset from; the axis ofi the rotor. They are preferably dis pos'edrto be inclined in a direction opposite to the direction (arrow.150'in'FIG.4) of rotation or the rotor. Preferably therotor has a different number (for'f instance," twenty-four) 'of slots from those in stator 50 and rotor 35;.

.lWith this second embodiment of the iii vention, hipon entering thethous1ngj60'through cover plate55, fluid first passes through-"thet slots "1470f theyrotor 140 before assing;throngh' apertures 53in stat'or 50. It thenflows through the" axially extendingfann'ulargpassage: 75 .and

out apertures 37' inrotor' 35' toethe oiitletjsideof the pump;

7' tend notonlyt'o cp l stantly blend or mix the fluid, but also impart a slight centrifugal pumping effect to the fluid thereby more readily to urge the fluid and the particles therein through the circular apertures 53 in the stator 50. The opertion which takes place in this second described unit is thus essentially a two stage operation, the first being a mixing stage when the fluid is exposed to rotor 140; and the second a particle shearing stage when the fluid passes down passage 75 between the closely adjacent, confronting, grooved faces of the stator 50 and of the rotor 35. As in the case of the annular flange 43 in the embodiment illus trated in FIGS. 1 and 2, the transversely disposed end wall or bottom 142 of the rotor 140 prevents incoming fluid from bypassing the apertures 53 in stator 50.

By restricting the flow of fluid so that it must pass from a point adjacent the inlet end of the unit (as defined by the circular path of apertures 53), axially through the particle shearing area, as defined by the annular space 75 between the stator and outer rotor, before being permitted to pass out of the pump housing, it will be apparent that applicant has provided a novel homogenizing or emulsifying unit in which the most efficient use is made of the shearing elements contained in the unit. In addition, by incorporating centrifugal pumping means along with the blending and shearing means in the unit housing, applicant has provided a continuous flow homogenizing or emulsifying unit which tends to eliminate undesirable temperature rises in the fluid during the processing thereof by the unit, and wherein the rate of flow of fluid through the unit is readily controlled by means of a valve at the outlet end of the unit rather than by altering the speed of rotation of the pumping element itself.

While the invention has been described in connection with two specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pert-ains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, What I claim is:

l. Homogenizing apparatus comprising a housing having a chamber therein, rotary means in said chamber for pumping fluid therethrough from an inlet adjacent one end of said chamber to an outlet adjacent the opposite end thereof, at least two tubular elements nested in spaced, coaxial relation one within the other in said chamber and defining therebetween an annular passage extending axially of said chamber, the confronting peripheral surfaces of said tubular elements having peripherally spaced, axially extending grooves therein, the grooves in one of said surfaces being essentially coextensive with the grooves in the other of said surfaces, the inner tubular element having a plurality of peripherally spaced apertures therethrough adjacent one end only thereof, and the outer tubular element having a plurality of peripherally spaced apertures therethrough adjacent the opposite end only thereof, each of the apertures in said inner element communicating with one of the grooves in said inner element, and each of the apertures in said outer element communicating with one of the grooves in said outer element, means in said chamber operative to guide incoming fluid through the apertures in said inner element, so that the fluid will flow axially along said annular passage and out of the apertures in said outer element, and one of said tubular elements being operatively connected to said pumping means to rotate therewith relative to the other of said elements, whereby the edges of the grooves in said inner and said outer elements, respectively, cooperate to shear therebetween the fluid carried through said passage.

2. Homogenizing apparatus comprising a casing having a chamber therein, said casing having an inlet and an outlet for admitting fluid to and from said chamber, respectively, homogenizing means in said chamber including a first annular element extending between said inlet and said outlet, a second annular element extending between said inlet and said outlet, and disposed in confronting, radially spaced coaxial relation about said first annular element, particle shearing means disposed on the outer peripheral surface of said first annular element and the inner peripheral surface of said second annular element, respectively, said first annular element having at one end only thereof a plurality of radially extending apertures which are disposed adjacent said inlet, and said second annular element having a plurality of radially-extending apertures which are disposed at the end thereof only which is distal from said one end of said first annular element and which is adjacent said outlet, guide means in said chamber operative to direct incoming fluid into the apertures of said first annular element, whereby during its passage through said casing said fluid is caused to pass successively through the apertures in said first annular element axially along the space between said particle shearing means on said first and second annular elements, respectively, and htrough the apertures in said second annular element to said outlet.

3. Apparatus as defined in claim 2 wherein said particle shearing means comprise a plurality of peripherally spaced, axially extending grooves in the outer peripheral surface of said first annular element and in the inner peripheral surface of said second annular element, respectively, each of the grooves on said first annular element communicating at one end thereof with one of the apertures in said first annular element, and each of the grooves in said sec- 0nd annular element communicating at one end thereof with one of the apertures in said second annular element.

4. Apparatus as defined in claim 2 wherein said guide means includes a rotary deflecting member positioned coaxially in said first annular element intermediate the ends thereof and having a plane surface extending transversely to the axis of said first annular element and having a diameter slightly less than the internal diameter of said first annular element, and means for mounting said second annular element and said guide means in said chamber for rotation relative to said first annular element.

5. Apparatus as defined in claim 4 wherein the plane surface of said rotary deflecting means is positioned adjacent the end of said first annular element which is remote from said inlet, said rotary deflecting means has an annular wall integral with and extending forwardly from said plane surface toward said inlet coaxially of said first annular element, and said annular wall has a plurality of peripherally spaced, axially extending slots therein operative upon rotation of said deflecting means to subject the incoming fluid to a blending operation before passage of said fluid radially outwardly through the apertures in said first annular element.

6. Homogenizing apparatus comprising a casing having a chamber therein, an inlet and an outlet in said casing adjacent opposite ends of said chamber, respectively, for flow of fluid into and from said chamber, coaxial annular homogenizing elements nested in spaced, coaxial relation relative to one another in said chamber, particle shearing means on the confronting peripheral surfaces of at least two of said elements, the shearing means on one of said peripheral surfaces being substantially axially coextensive with the shearing means on the confronting surface of the next adjacent element, said spaced, confronting shearing means defining therebetween an annular passage intermediate the inlet and outlet in said casing, each of said two elements having therethrough a plurality of circumferentially spaced radial openings, which are arranged in a circular path adjacent one end only of a respective element, the openings in one of said two elements being positioned adjacent one end of said passage, and the openings onev element, wherebyzthe incomingfluid passes into said one end of said annular passage and axially thereof to the openings in said other ofsaid two elements, and then to theoutlet in said casing,'and means in said chamber for,

rotating said confronting shearing surfaces relative to one another-to shear therebetween the fluid carried through said passage.

ing a fluid inlet at one end thereof and a fiuidoutlet adjacent the other end thereof, a rotary pumping member mounted in said housing adjacent the outlet end thereof, an annular} shearing elementsecured to said pumping ,rnember'to rotatetherewith, a coaxial annular shearing element fixedly secured to saidfhousing", said shearing elements havingfconfronting peripheral surfaces which define a longitudinal passage betweensaid elements, said elements having confronting longitudinal grooves in their confronting peripheral surfacesrwhose edges constitute shearing edges, one of said shearing elernents having adjacent one end only thereof a plurality of circumferentially spacedholes extending radially through it adjacent said entering said housing into said, grooves, and theother of 'said shearing elements having adjacent one end only there? of: afplurality, of circumferentially spaced holes extending radially throughwit adjacent said outlet and communicating with its grooves to conduct fluid from said grooves to said'outlet, and means for rotating said pumping member and the element secured thereto to punip fluid from said inlet through the holes in said one element, along, said 7 V g 10 passage,"out'th holes 'insaid other element and-out said 7. Homogenizing apparatus comprising a housing, havoutlet. g

4 References Citedby-theExaminer V 1 UNITED STATES PATENTS. 12,321,599 6/43 Ho'frnann; 259-7 X 2,4 8,389 4/49 Aue'r 2598 X 2,544,971 3/51 w611s; 241-255 X 2,591,633 4/52' Stephansen 241255 X 2,90's,390"- 10/59 Richetal; 2599 X Y V FOREIGN PATENTS 1 945,089 6/56 Germany. I

' WALTER'A. SCH EEL,Prima1yfExaminer.

CHARLES A. WILLMUTH, Er'qmin'r;

Claims (1)

1. HOMOGENIZING APPARATUS COMPRISING A HOUSING HAVING A CHAMBER THEREIN, ROTARY MEANS IN SAID CHAMBER FOR PUMPING FLUID THERETHROUGH FROM AN INLET ADJACENT ONE END OF SAID CHAMBER TO AN OUTLET ADJACENT THE OPPOSITE END THEREOF; AT LEAST TWO TUBULAR ELEMENTS NESTED IN SPACED COAXIAL RELATION ONE WITHIN THE OTHER IN SAID CHAMBER AND DEFINING THEREBETWEEN AN ANNULAR PASSAGE EXTENDING AXIALLY OF SAID CHAMBER, THE CONFRONTING PERIPHERAL SURFACES OF SAID TUBULAR ELEMENTS HAVING PERIPHERALLY SPACED, AXIALLY EXTENDING GROOVES THEREIN, THE GROOVES IN ONE OF SAID SURFACES BEING ESSENTIALLY COEXTENSIVE WITH THE GOOVES IN THE OTHER OF SAID SURFACES, THE INNER TUBULAR ELEMENT HAVING A PLURALITY OF PERIPHERALLY SPACED APERTURES THERETHROUGH ADJACENT ONE END ONLY THEREOF, AND THE OUTER TUBULAR ELEMENT HAVING A PLURALITY OF PERIPHERALLY SPACED APERTURES THERETHROUGH ADJACENT THE OPPOSITE END ONLY THEREOF, EACH OF THE APERTURES IN THE INNER ELEMENT COMMUNICATING WITH ONE OF THE GROOVES IN SAID INNER ELEMENT, AND EACH OF THE APERTURES IN SAID OUTER ELEMENT COMMUNICATING WITH ONE OF THE GROOVES IN SAID OUTER ELEMENT,

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