US2153537A - Homogenizing apparatus - Google Patents

Description

April 1939- s. B. HEATH ET Al. 5

HOMQGENLZING APPARATUS Filed Dec. 2, 1936 2 Sheets-Sheet 1 INVENTORS v .Sfie/aon 5. Aka/A farzs/ l7. M'nqer ATTORNEYS WJW April 11, 1939. .s. B. HEATH ET AL HOMOGENIZING APPARATUS Filed Dec. 2, 1936 2 Sheets-Sheet 2 INVENTORS ti m .p...wN R R mf m M A sh Patented Apr. 11, 1939 UNITED STATES HOMOGENIZIN G APPARATUS SheldonfB. Heath and Forest R. Minger, Midland, Mich, assignors to The Dow Chemical 7 Company, Midland, Mich., a-corporation of Michigan Application December 2, 1936, Serial No. 113,843

2 Claims.

The invention relates to apparatus for dispersing and emulsifying solid or liquid materials suspended in a liquid medium which is a non-solvent for the suspended material, whereby to form a homogeneous highly dispersed emiilsion of the suspended particles in the medium. Various forms of apparatus intended for the aforesaid purpose are commonly known as colloid mills or homogenizers.

More particularly, the invention relates to the general type of colloid mills or homogenizers in which a rotating member, called the rotor, revolves at high speed within an enclosing casing, called the stator. In apparatus of the type just mentioned a grinding, shearing and mixing ac tion is exerted upon the material which is fed into the space between the working faces of the rotor and stator. A substantial pressure is imposed upon the fluid material within the casing, and in the various types of apparatus heretofore used it has been a serious problem to prevent leakage of fluid from the casing outward around the rotor shaft. The usual expedients have been tried by providing packing glands and the like to seal the space between the shaft and easing, but it has been found extremely difiicult to keep such packing glands tight for any great length of time around a shaft operating at the high speeds employed. Furthermore, leakage of material into the packing gland around the shaft often causes rapid wear, scouring or scoring of the shaft, which in turn progressively increases the diiiiculty of maintaining the gland tight and gives rise to the necessity for frequent repairs and replacement. It is an object 'of the invention to provide an apparatus in which the use of packing glands can be dispensed with, thereby avoiding all of the mechanical difficulties which their maintenance entails in other forms of homogenizing apparatus. Another object is to provide an apparatus having a high capacity or rate of output in proportion to size.

pear as the descriptionproceeds. The invention, then, consists in the novel and improved apparatus illustrated in the annexed drawings and hereinafter fully described.

In said annexed drawings:-' v

Fig. 1 is a cross-sectional View of the apparatus or mill.

Fig. 2 is a detail View of the rotor and adjacent working face of the stator as shown in Fig. 1.

Figs. 3 and 3a are detail views of a side member of the stator casing.

Figs. 4 and 4a are detail views of a sealing plate of the apparatus.

Fig. '5 is an end view of the apparatus.

Referring to Fig. l of the drawings, a cylindrical rotor l is mounted on a shaft 2 which is sup ported by bearings 3, 3,'the peripheral face of rotor I being relativeiy narrow as compared with Other objects and advantages will ap-' its diameter. The rotor is enclosed in closely spaced non-contacting relation by a casing which is composed of two side plates 4,! and a ringshaped stator 5 between them. Stator 5 is concentric with rotor l, and a small clearance space separates the cooperating faces of the two. Shaft 2 passes through central openings 8, 6, one in each side plate 4, openings 6 being somewhat larger in diameter than the shaft, leaving an annular space between the shaft and casing. Against each side plate 4 is bolted a sealing plate 1, the two plates being spaced apart by means of suitable lugs or bosses on the faces thereof so as to form a discharge chamber 8 on either side of the casing, the side walls of chambers 8 being formed by plates 4 and 1, respectively. Chambers 8 are closed at the top and sides but open at the bottom, as shown, and communicate with the interior of the casing through openings 6. To the outer face of sealing.plates I are attached bearing housings 9, 9 to support bearings 3, housings 9 also being spaced away from plates 1 to provide drip chambers l0 therebetween. Floor supports H, II for the apparatus are attached to housings 9.

The shape and contour of side plates 4 is shown in detail in Figs. 3 and 3a. Plates 4 consist in a flat circular disc having on the outer side an arcuate boss I 2 -axiallydisposed with reference to the central shaft opening 6, and at the bottom afiat extension or lip IS. The upper arcuate end of boss I2 has suificient width to provide a bearingsurface against which sealing plate 1 is bolted, but at its lower, open end is tapered in width, serving simply as a spacer. The inside edge of the wide, arcuate section of boss 12 is provided with a depressed shoulder M. The inner face of plates 4 is fiat except for a depressed shoulder l5 near the outer edge, which coincides with a corresponding raised shoulder on stator 5.

Figs, 4 and 4a show similarly details of sealing plates 1. These correspond in shape and dimensions with the boss outline of side plates 4, and have a central shaft opening l6. 0n the inner face of plates 1, around the outer edge, is an arcuate boss I! corresponding to. the similar boss on plates 4, the respective bosses l2 and. I1 registering when plates 4 and l are bolted together. On the outer face of plates 1 is a circular row of lugs l8 and ill to serve as bearing surfaces against which housing 9 is bolted, the lugs also spacing the housing 9 away from plate I to form the drip chamber i0.

Housings 9 (Fig. 1) are provided with a flange 20 which fits against lugs I8 and I9 when the apparatus is assembled. Housing 9, sealing plate 1 and side plate 4 are attached together by means of cap bolts or the like, long bolts 2| passing through holes drilled in flange 2|] and lugs l8 and being screwed into holes threaded in boss l2 of rings 24, 25 and 26 are attached to collars fastened to shaft 2 on either side of the stator cas-.

ing, ring 24 hearing against splash plate 23, ring 25 against the inner face of sealing plate I, and ring 26 against the inner face of housing 3. Rings 24, 25 and 26 are not, however, fitted tightly enough against their respective bearing surfaces to develop any material friction when the apparatus is in use. i

An inlet 21 is provided in stator 5 at the top,

threaded for pipe connection 28 to a source of supply for material fed to the apparatus. "In the bottom is a drain 29 for use in cleaning out the apparatus.

The inner surface 30 'of stator 5 forms the fixed working face, while the circumferential face 3| of rotor I forms the moving working face. working faces 3|! and 3! .are preferably serrated by means of transverse groovesor notches, as shown in Fig. 2. A series of holes 32, preferably equally spaced and located equidistantly from the center and near to the periphery of rotor I, is provided as likewise shown in Fig. 2, the purpose of which holes is to equalize the pressure on' the lateral faces of the rotor when in operation.

The assembled apparatus is shown in Fig. 5, which is an end view.

In the operation of the above described apparatus a coarse liquid suspension of the material to be emulsified is introduced through pipe 28 at inlet 2! under sufficient pressure to overcome the centrifugal force exerted by the moving rotor l,

fine particles are'simultaneously mixed and agitated with the liquid medium to form a highly dispersed homogeneous emulsion. Meanwhile the superposed pressure of the liquid feed continually forces the emulsified mixture out of the working space into the lateral clearance space between the rotor and casing, the pressure on the sides of the rotor being equalized through holes 32. The material in the lateral space progresses toward the center of rotation and is ejected through the annular openings between the shaft and casing into the discharge chambers 8, whence it falls through the open bottom of the chambers into a receiver below. Splash plates 23, and spinner rings 24, 25 and 26, prevent the ejected material from traveling along the shaft and creeping into the bearings. Whatever leakage from chamber 8 may occur is effectually removed in drip chamhers l0, which also have the function of preventing leakage of lubricating oil from the bearing into the process material. w

Although pressure is required to force the process material through the apparatus against the centrifugal force of the revolving rotor, such pressure is moderate as compared with the high pressures used in other types of homogenizing apparatus, and normally does not exceed to amass? v pounds per square inch, but for most purposes is much less than that. 1 I g V In our apparatus, as has been seen, the use of packing glands, stuffing boxes, or the like, is entirely avoided, as are all the well knowndifficulties of operating high speed equipment containing such devices. The apparatus operates with continuous feed and discharge, and has a high capacity in proportion to the volume of working space.

486, filed October 7, 1936, we have disclosed, but

not claimed, the herein described apparatus in connection with a. particular process.

Othermodes of applying the principle of our invention may be employed instead of those explained, change beingmade as regards the apparatus herein'disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

We therefore particularly pointout and distinctly claim as our invention:

1. In homogenizing apparatus, the combination of a cylindrical rotor axially mounted on a horizontal shaft, a stator concentrically disposed relative to said rotor and. in closely spaced cooperating relation thereto, the peripheral face of said rotor and the inner face of said stator constituting the working faces thereof, said working faces being serrated by transverse grooves throughout the extent oftheir working areas, side plates laterally juxtaposed in closely spaced relation to said rotor and each having a. central opening of slightlylarger diameter than said shaft, through which openings the shaft passes, said stator and said side plates being assembled to form a casing for said rotor, an inlet in said stator, means to feed incoming material under pressure through said inlet into the working space between the stator and the rotor against the centrifugal pressure of the revolving rotor, discharge chambers for removal of product laterally disposedwith respect to said side plates, said chambers communicating with the interior of the rotor casing through the 'shaft openings in said side plates.

2. In homogenizing apparatus, the combination of a cylindrical rotor axially mounted on a horizontal shaft, a stator concentrically disposed relative to said rotor and in closely spaced cooperating relation thereto, the peripheral face of said rotor juxtaposed in closely spaced relation to said rotor and each having a central opening of slightly larger diameter than said shaft, through which openings the shaft passes, said stator and said side plates being assembled to form a casing for the rotor, an inlet in the stator, means to feed incoming material under pressure through said inlet into the working space between the stator and the rotor against the centrifugal pressure of the revolving rot-or, discharge chambers for removal of product laterally disposed with respect to said side plates, said chambers communicating with the interior of the rotor casing through the shaft openings in the side plates, bearings outside of said discharge chambers to support said shaft, and splash plate means in said chambers to prevent lengthwise travel of discharged material along the shaft to the bearings.

' SHELDON B. HEATH. FOREST R. MINGER.

. 1o In our co-pending application, Serial No. 104,-

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