US2552889A - Rotor for dispersion machines - Google Patents

Description

y 1951 c. F. EATON ROTOR FOR DISPERSION MACHINES 3 Sheets-Sheet 1 Filed Nov. 22, 1946 May 15, 1951 'c. F. EATON ROTOR FOR DISPERSION MACHINES 3 Sheets-Sheet 2 Filed Nov. 22, 1946 y 1951 c. F. EATON ROTOR FOR DISPERSION MACHINES 3 Sheets-Sheet 3 Filed Nov. 22, 1946 Q will! Patented May 15, 1951 ROTOR FOR DISPERSION MACHINES Charles F. Eaton, Methuen, Mass., assignor to Bennett Incorporated, Cambridge, Mass., a corporation of Massachusetts Application November 22, 1946, Serial No. 711,699

The present invention relates to machines for subdividing into minute particle sizes, and dispersing in a liquid medium, solid matter or liquid substances which are immiscible in the medium. One specific object for which the embodiment of the invention hereinafter described is designed, is to make an emulsion of clay and starch in water to be used for coating paper to receive the imprint of printing plates and type. But it may also be used for homogenizing and emulsifying many other mixtures of liquid vehicles with other liquids, plastics, solids, etc. which are insoluble in the liquid vehicle.

Various machines have been manufactured and used for many years in the past to produce such dispersions and emulsions. It has been my present object to provide improvements over the machines heretofore used by which greater strength and rigidity are obtained; liquids under pressures of greater magnitude than those heretofore employed may be safely contained in the homogenizing chamber of the machine and retained against leakage; the rotating parts may be more firmly supported and vibration when rotated at high speed eliminated; and the frictional heat generated in the operation of the machine may be conducted away by efiicient cooling means. Other objects, related or incidental to the foregoing have been realized by this invention and appear from the detailed description which follows of one specific machine in which the invention is embodied.

In the accompanying drawings,

Fig. 1 is a side elevation, with parts broken away and shown in section, of a machine embodying this invention, but with omission of the driving motor and of that part of the base on which the motor is supported;

Fig. 2 is a horizontal section taken on line 2-2 of Fig. 1 of so much of the machine as appears in Fig. 1; Fig. 3 is a plan view of a driving motor, one of two alternative means for transmitting rotation therefrom to the rotor of the machine, and that part of the base on which the motor is mounted;

Fig. 4 is a cross section of the machine taken on line 4-4 of Figs. 1 and 2;

Fig. 5 is a detail elevation of the dispersing element or rotor of the machine, shown on a larger scale than that of the preceding figures; Fig. 6 is a fragmentary sectional view of the dispersing element taken on line 6-6 of Fig. 5.

Like reference characters designate the same parts wherever they occur in all the figures.

1 Claim. (Cl. 241-4693) The main parts of the machine comprise a base II], a housing or cylinder ll supported by the base, a rotor or dispersing member l2 in the cylinder and. independently supported by the base, and a driving motor [3 also supported by the base.

Describing these parts more in detail, the housing II is composed of a tubular body and two heads or end covers l4 and 15 secured detachably to the opposite ends of the body. These parts are preferably made of brass castings with accurately finished surfaces at their abutting portions and with the interior cylindrical surface of the body accurately finished to an exact diameter. The heads are secured detachably to the ends of the cylinder body by bolts l6 and gaskets may, if desired, be interposed between their abutting surfaces; although it is possible to make the joints liquid tight under pressures amounting to one thousand or more pounds per square inch by accurate formation and fitting of the abutting surfaces. Pipes I1 and I8 for admission of the mixture to be homogenized and eduction of the resulting emulsion are connected to opposite ends of the housing body at the side which is placed uppermost when the machine is set up for operation. A drainage opening is provided in the under side of the housing body and is closed by a plug IS.

The dispersing or mixing element, or rotor, is composed of a tubular section, to which the reference character 12 is applied, (this tubular section being preferably made of stainless steel and seamless), having external helical ribs or flutes 20, a shaft 2| and two disks 22 and 23 which are fitted on and keyed to the shaft and have shouldered circumferential surfaces fitting in and supporting the ends of the tube I 2. Disk 23 abuts against a shoulder 24 on the shaft. It is held firmly against the shoulder, and the other parts of the rotor firmly pressed against one another, by a nut 25 which bears on the outer side of the disk 23 and is threaded on the shaft.

The portion of the rotor constituted by the tubular section l2, disks 22 and 23, and nut 25 is considerably shorter than the internal chamber of the housing and is located in that chamber clear of both ends thereof so as to provide ample space to contain the mixture adjacent to the ports wherein the pipes l1 and I8 are connected. But the outside diameter of the rotor flutes approaches nearly to the value of the inside diameter of the housing, being so related thereto as to provide a minimum clearance.

The rotor shaft 2| is substantially longer than the housing and extends at both ends through the covers or heads l4 and [5. Both heads are constructed as stuffing boxes, having bore enlargements in which packing rings 26 and glands 2'! are contained. The glands have flanges 23 through which studs 29 pass from the adjacent heads and on which pressure is exerted by nuts 30, threaded on the, studs, to compress the packing 26 tightly around the shaft.

These packing glands are designed as part of a cooling system fo dissipation of heat generated by friction. They are designed to extend deeply into the stuffing box bore of the associated cylinder head and to overlie a long length of the shaft. Each is internally recessed to provide a chamber 31 surrounding the shaft. Induction and eduction pipes 32 and 33 are connected with the flange 28 on each gland'and through ports therein with the chamber 3|. The pipes 32 may be connected with any available source of cold or cool water and, when the machine is in operation, water is caused to flow constantly through these pipes and the chambers. Part of the heat generated in the housing, and most of that caused by friction of the shaft in the packing, is conducted to the water in the chambers 3| and thereby dissi ted.

Boththe cylinder or housing and the rotor are supported by the base 18 independently of each other. Four cradles 34, 35, 36 and iii are formed as .partsof the base, and separable yokes 38, 3t, 40 and 4| are associated with them. The yokes and cradles collectively enclose cylindrical spaces, all in axial alinement. The housing is formed with external grooves 42 and 43 (Fig. 2) spaced conformably to the middle pair of cradles and 36 and the diameter of which is equal to the di: ameter of the spaces encompassed by these cradles and their associated yokes, with only enough clearance to permit assembling and gripping by the cradles and yokes.

The outer cradles 34 and 31, with thei associated yokes, support ball or roller bearings 44 and 45, in which the shaft 2! is mounted and by which the entire weight of the rotor is supported and its tubular part I2 is centered in the housing. As the cradles and yokes are made with the utmost accuracy of internal radius and axial alinement, the housing and shaft, when mounted in the cradles and yokes, are accurately alined and centered. The shaft is massive and rigid so that its deflection by gravity in the length between the bearings 44 and 45, when in horizontal position, is inappreciable and is less than the clearances provided for it in the cylinder heads l4 and I5. This arrangement limits the bearing contact between the housing and rotor to only that contact which is made by the packings 28.

The mode of mounting the shaft hearings in the cradlesof the base involves useful featuresl Considering the bearing 45, its inner race is confined against a shoulde 46 of the shaft by a nut 41, and its outer race is fitted to the inner circumference of a massive ring 48, called a cartridge, the outer circumference of which is fitted to the cradle 31 and yoke 4|. Cap disks 49 and 50 are secured to opposite end faces of the cartridge 48 by bolts, as shown in Fig. 2, and have ribs 51 and 52 on their inner faces which bear against the opposite end faces of the outer race. Collars 53 and 54 are secured by set screws on the shaft 2| in positions to embrace hub flanges on the disks 49 and 50, respectively, to exclude foreign matter from the bearing.

The bearing 44 is similarly associated with a ring or cartridge 55 and disks 5B and 5 5, but its inner race is not mounted directly on the shaft. Instead it is mounted and secured on a sleeve 53 having an internally tapered bore which fits a tapered zone 59 of the shaft and is secured thereon by an end plate 69 and screws ti. The end plate overlaps the end of sleeve es and the screws pass through the plate into threaded engagement with the shaft. A cover 52 is secured to the disk 56 across the central opening thereof in which the end plate to is contained.

For elimination of vibration, the rotor is accurately balanced or poised before being assembled with the housing. Poising is accomplished by removing bits of the material of the tube i2 thereof between the flutes at the heavier side. I have found it possible in this way to ob tain practically perfect balance. When thus balanced, the roto is preferably chromium plated to obtain ample assurance against corrosion and electrolytic action.

The base is provided with upright walls 63, 63 between the cradles 34 and 35, and similar walls 64, 64 between the cradles 36 and 3?. These walls and the cradles provide catch basins for the cooling water which issues from the interior chambers of the packing glands. The water collected therein is allowed to drain off through openings in the base. Alternatively, the eduction pipes 33 can be connected with a drain pipe. Dowels 65, one of which is shown in Fig. 1, and typifies them all are mounted in the several cradles to engage the housing body and bearing cartridges, respectively, and prevent their rota tion. The yokes which cooperate with the cradles are not relied on to prevent rotation by frictionally gripping the encircled bodies. 'Rather, they are made with an accurate fit sufiicient to hold the confinedbodies in place without appreciable side play, but not necessarily with gripping action. Endwise displacement of the housing is prevented by the dowels and the side Walls of grooves 42 and 43; and the rotor is restrained from end play by the disks 49, 50, and 5?. These disks are made with outside diameters large enough to overlap the boundaries of the spaces in which the cartridges 48 and 55 are contained; and they are spaced apart by the cartridges in measure such that they embrace the adjacent cradles and yokes closely.

To insure rigidity of connection between all parts of the rotor, the disks 22 and 23 thereof are coupled to the shaft 2! by keys 66 and 61 and the sleeve element of the rotor is locked at one end to the disk 22 by a key 68. The external flutes of the particular rotor here illustrated are ten in number. They have a finished external diameter of 5.95, a helix angle of 40, and. a lead of 22 The clearance between the flutes and the surrounding walls of the body is from .017 to .018". The allowable clearance is within the limits of these two values. However, different diameters and different clearances may be provided in different machines designed for ac tion with different materials. And for some purposes the ribs may be straight instead of helical. The base has an extension in one end, which does not appear in Figs. 1 and 2 but isshown in plan at Illa in Fig. 3. This extension supports the driving motor I3. A bracket 69 is secured tothe side of the base extension Illa and the mo tor is here shown as supported partly on the bracket with the axis of its drive shaft at one side of and parallel to the rotor shaft 2|. This drive shaft is geared to the shaft 2| by a belt and pulley drive I0, I l, 12.

Alternatively, the motor can be mounted in alinement with the shaft 2|, holes 13 being provided in the base for reception of the motorholding bolts when in that position. Then the drive shaft of the motor is connected with the rotor shaft 2| by a coupling 14, which may be a sleeve keyed to both alined shafts. This provision for placement of the motor in different positions, and substitution of belt pulleys of different diameters, and a coupling sleeve, for one another, enables the dispersion rotor to be driven either at the same speed as the motor armature or at increased or diminished speed.

The organization of the machine herein described causes the axis of the housing and of the rotating dispersion member to be horizontal. I have found this to be a most important improvement.

In the operation of this machine, the mixture to be homogenized is fed into the housing while the rotor is running at high speed. If the material to be dispersed is solid matter, it is first reduced to powdered or fine granular condition by mechanical means before being mingled with the liquid Vehicle. Liquids to be emulsified, however, can be merely stirred into the dispersion medium, more or less thoroughly.

In treating the specific material mentioned at the beginning of this specification, clay and starch for the coating of paper, the rotor is driven at a speed of 3600 revolutions per minute, or approximately that speed, and the mixture of materials is pumped into the housing under a pressure of 900 to 1000 pounds per square inch or more. All of the entering material must pass between the outer circumference of the rotor and the walls of the housing. In passing through, it is subjected to very intense centrifugal force and shearing action, whereby the material to be dispersed is further subdivided into particles of microscopic or colloidal sizes, and thoroughly mingled and dispersed throughout the carrying liquid. The emulsion issuing from the dispersion machine is carried away through pipes to the point of use or to containers in which it may be stored.

The rotor may be turned in the direction which causes propulsive thrust to be applied on the contained liquid toward the casing outlet. But owing to the steep pitch of the helical ribs, the propulsive thrust is not very great. The rotor, however, may be turned in the opposite direction if it is desired to increase and intensify the disruptive effect on the material to be dispersed. When a rotor with ribs arallel to the axis is used, the direction of rotation is utterly immaterial.

What I claim is:

In a dispersion machine, a rotor comprising a shaft, disks mounted on said shaft in keyed engagement therewith and spaced apart lengthwise thereof, a tubular section having external ribs surrounding the shaft coaxially in supported engagement at its opposite ends with said disks and in keyed engagement with one of them, and means holding said disks and tubular section in lengthwise pressure contact with one another and in fixed position lengthwise of the shaft, the rotor being poised and in substantially perfect balance and being chromium plated.

CHARLES F. EATON.

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

UNITED STATES PATENTS Number Name Date 20,282 Mackerley 1- May 18, 1858 812,122 Fassett Feb. 6, 1906 813,320 Neumann Feb. 20, 1906 816,445 Felsberg Mar. 27, 1906 950,972 Walker Mar. 1, 1910 1,035,303 Bausman Aug. 13, 1912 1,511,336 I-Ioey Oct. 14, 1924 1,563,216 Moog Nov. 24, 1925 1,738,288 Eppenbach Dec. 3, 1929 1,775,743 Wiener Sept. 16, 1930 1,776,974 Henderson Sept. 30, 1930 1,777,605 Dimler Oct. 7, 1930 1,851,071 Travis Mar. 29, 1932 1,951,519 Milne Mar. 20, 1934 1,971,314 Lavenstein Aug. 21, 1934 1,980,589 Acree Nov. 13, 1934 2,027,015 Bell Jan. 7, 1936 2,060,408 Wood Nov. 10, 1936 2,068,071 Quehl Jan. 19, 1937 2,111,364 Hopkins Mar. 15, 1938 2,145,177 Hauge Jan. 24, 1939 2,153,537 Heath Apr. 11, 1939 2,212,662 Hennessy Aug. 27, 1940 2,371,681 Durdin Mar. 20, 1945 2,463,631 Knight Mar. 8, 1949 FOREIGN PATENTS Number Country Date 8,652 Great Britain June 16, 1887 31,501 Norway Dec. 20, 1920,

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