US3168289A

US3168289A - Disc for centrifuge

Info

Publication number: US3168289A
Application number: US217888A
Authority: US
Inventors: George S Voses
Original assignee: CORNELL MACHINE CO
Current assignee: CORNELL MACHINE CO
Priority date: 1962-08-20
Filing date: 1962-08-20
Publication date: 1965-02-02
Anticipated expiration: 1982-02-02

Description

Feb. 2, 1965 G. s. VOSES 3,168,289

DISC FOR CENTRIFUGE Filed Aug. 20, 1962 2 Sheets-Sheet 1 INVENTOR 650205 5' W528 L ATTORNEYS Feb. 2, 1965 G. s. VOSES 3,168,289

v DISC FOR CENTRIFUGE Filed Aug. 20, 1962 2 Sheets-Sheet 2 i Z '-//d INVENTOR 56006:: S. Vases ATTOR NEYS United States Patent ()fifice 3,lh8,289 Patented Feb. 2, 1965 3,168,289 DISC FOR CENTREFUGE George S. Voses, Flushing, N.Y., assignor, by mesne assignments, to The Cornell Machine (Zonrpany, Springfield, NJL, a corporation of New Jersey Filed Aug. 20, 1962, Ser. No. 217,888 3 Claims. (Cl. 259-3) This invention relates to an improved centrifugal disc and in particular relates to an improved centrifuge disc shaped for improved control of the homogenization of materials such as liquid suspensions impelled upon the spinning disc.

In accordance with a well-known type of centrifuge, a

relatively flat disc is spun at selected speeds with material to be homogenized being impelled upon the center of the disc. The disc is shaped so as to form a film of material over the surface of the disc and extending to the outer periphery thereof, where the material is delivered to an outlet tube or other collection means. During the flow of the material in film form over the surface of the disc, the particles are abraded and sheared as the result of friction thereof against the surface of the disc, and as the result of attrition of one particle against the other, with resulting homogenization of the particles in the material.

This invention makes use of the principle that the friction exerted upon the particles of the material depends upon the speed of movement thereof and the angle of the disc surface over which they move.

An important object of the invention is to provide a centrifugal disc of the above-described type which can be of reduced size and of greater efliciency in forming the film and in homogenizing the particles. It is particularly advantageous to be able to reduce either the diameter and mass of the disc, or the speed of rotation thereof, or both, depending upon the desired conditions of operation of the centrifuge. This results in a centrifuge which is more economical to produce and more eificient in operation. Furthermore, in many instances, with a smaller device and lower speed of operation, it is possible to achieve degrees of homogenization previously requiring very large, high speed devices.

In accordance with a preferred embodiment of the invention, the centrifugal disc has a flat center portion mounted on a hub for rotation at selected speed about an axis, the disc being transverse to said axis. The material to be homogenized can be impelled upon the front face of said center portion of the disc.

In accordance with the invention, the centrifugal disc further comprises an annular intermediate portion or film-forming portion connecting with the periphery of the center portion and extending forwardly outwardly therefrom at a shallow acute angle to the transverse. The disc further comprises an annular outer portion connecting with the outer periphery of the intermediate portion and extending forwardly outwardly therefrom at a relatively large acute angle to the transverse. The center and intermediate portions of the disc are adapted to form a film of liquid material applied to the front of the center portion by rotation of the disc at its selected speed and to sustain this film to the outer periphery of the outer portion or principal homogenization portion of the disc.

The angle of the intermediate portion of the disc is such that the component of centrifugal force on the liquid along the surface of the intermediate portion is much greater than the component of centrifugal force on the liquid normal to the surface of the intermediate portion. As a result, there is only a small amount of friction and resulting breakdown of particles in the liquid along the intermediate portion of the disc.

On the other hand, the angle of the outer portion is preferably such that the component of centrifugal force on the liquid normal to the surface of the outer portion is greater than the component of centrifugal force on the liquid along the surface of the outer portion. This will result in production of high friction and high resulting breakdown by abrasion or attrition of particles in the liquid at the outer portion of the disc.

The respective angles and diameters of the intermediate and outer portions of the disc, together with the selected speed of rotation, are such as to insure delivery of the liquid film to the outer periphery of the disc with most of the desired homogenization of the liquid occurring over the surface of the outer portion.

The advantage of this shape of the disc is that most of the breakdown of the particles occurs in the region of the disc at which they have achieved the necessary high speed for effective breakdown. The intermediate portion of the disc is present to assure the effective formation of the film and achievement of the desired high speed thereof, with partial homogenizations. With the relative separation of the film forming and homogenization functions of the disc into the respective intermediate and outer portions or zones thereof, it is possible to achieve the desired homogenization of the particles at a relatively favorable combination of speed of rotation and diameter of the disc, as compared to centrifugal discs previously known.

Other objects and advantages of the invention will become apparent from the following description, in conjunction with the annexed drawing, in which preferred embodiments of the invention are disclosed.

In the drawing,

FIG. 1 is a perspective view of a centrifuge in accordance with the invention.

FIG. 2 is a transverse section on line 22 of FIG. 3.

FIG. 3 is a longitudinal section of the centrifuge.

Upon reference to the drawing in detail, it will be noted that certain details of the device as a whole are not shown since the overall device is substantially conventional, with the main improvement being in the centrifugal disc.

FIGS. 1 and 2 show a casing 10 adapted to be supported upon the floor, such casing 10 being omitted in FIG. 3. Casing 10 contains the drive motor and associated parts, vacuum pump, etc., all of these being conventional. An auxiliary casing 11 is shown as mounted on the front of casing 10. This casing 11 is generally cylindrical, with its axis extending longitudinally. In this embodiment, but without limitation thereto, the axis of casing 11 is shown as extending horizontally. Since the details of casing 11 are conventional, they are not described in detail. It is sufiicient to state that the rear end of casing 11 is secured by flange 12 and clamps 13 to casing 10 by any suitable means. Casing 11 has a tubular peripheral wall 11a which is closed at the front by annular plate 14 removably secured thereto by clamping means 15. A sight glass 16 is secured over the center opening of plate 14. A tube 17 is connected to the top of casing 11 an dis connected through line 18 and pump P or other suitable device (both shown diagrammatically) to the atmosphere so as to exhaust air from casing 11 to maintain a selected vacuum, as measured by vacuum gauge 19 or other suitable device.

Horizontal shaft 20 extends longitudinally through the rear plate 21 of casing 11 and into the rear thereof. Shaft 29 is coaxial with the peripheral wall 11a of casing 11. Shaft 20 extends rearwardly of casing 11 into the interior of casing 10 where it is connected to the drive means (not shown) so that shaft 20 may be rotated at selected speed. Optionally, but without limitation thereto,

' portion or zone32 and outer or principal homogenization portion or zone 33. Disc also comprises a protective return portion 34 connecting with the outer periphery of portion 33.

The center portion 31 of disc 30 is circular, fiat, and of approximately the same diameter as mounting disc 22.

, Said center portion 31 extends transversely to the longitudinal axis of shaft 20, and the plane of disc 31 is indicated diagrammatically by the broken line 31a.

The intermediate portion 32 of disc 30 connects with the outer periphery of center portion 31 and extends forwardly outwardly therefrom at a shallow acute angle to the transverse. This is the angle 32a between portion 32 and plane 31a.

The annular outer portion 33 connects with the outer periphery of intermediate portion 32 and extends forwardly therefrom at a relatively large acute angle 33a to the transverse. For convenience, the angle 33a of portion 33 is shown relative to a plane 31b which is parallel to plane 31a and which is taken at the junction 32b between

disc portions

33 and 32. Angle 33a. preferably exceeds 45 degrees. The outer periphery 36a of disc 30 is located slightly inwardly radially of the tubular peripheral wall 11a of casing 11. The disc portion 33 isoptionally curved slightly inwardly just before the peripheral point 30a so as to accommodate the discharge tube. The return portion 34 extends inwardly outwardly from periphery 30a at an angle 34a to the transverse reference plane 310 shown diagrammatically at the periphery 30a. The front and inner edge 34b of return'portion 34 defines a central opening and is locatedapproxirnately halfway between the endsof casing 11, this position being not critical and being selected so as to accommodate the intake and discharge tubes. a

For intake of liquid, a radial tube 40 is extended through wall 11a by any suitable fitting means41 and ,over the rear of tube 42, as best shown in FIG. 3. The

material to be homogenized may be fed into tube 40 by any suitable means (not shown), under any desired pressure velocity conditions, in the direction of arrow 44. The material is discharged or impelled from tube 42 onto ,disc center portion 31.. Any conventional delivery means can be provided.

The material treated upon disk fitl is taken off at periphery 30a by means of discharge tube 45. The main portion of discharge tube 45 extends radially, by means of any suitable fitting 46, through wall liaof casing 11, forwardly'of disc .30. Outwardly of wall 11, tube .45 isoptionally bent forwardly longitudinally at 45a, and connected to any suitable receptacle (not shown), with the material which has been treated passing th'rough the discharge tube in the direction of arrow 47. 'Tube 45 extends inwardly of edge 34b, and is there bent rearwardly asshown at 45d, with the free end 452 of the tube being located'adjacentthe periphery 30a. As a result, as ma terial'reaches the periphery 30a it passes into the mouth or end 45e and then is gently directed away from the circumferential through the curved tube portion 45d and ultimately through all of the sections of the tube 45.

Disc 30 may be spun or otherwise formed from any suitable metal, such as carbon steel or stainless steel. As stated above, the portion 31 is fiat. The portion 32 may optionally be frusto conical, and optionally may be part spherical. However, in view of the shallow or small angle 32a, the portion 32 has such a large radius of curvature'as to approach the flat for practical purposes. The portion 33 may also optionally be generally frusto conical, although with rounded peripheral portions. The return portion 34 may also be generally frusto conical.

The disc 30 is rotated at selected speed, so that the material impelled upon center portion 31 is formed by the center portion 31 and intermediate portion 32 into a film which is sustained to the periphery 30a of intermediate portion 33. The film may form on intermediate POI? tion 33 radially outwardly of its junction with center portion 32. The angle 32:: of intermediate portion 32 is such that the component of centrifugal force on the material along the surface of intermediate portion 32. is much greater than the component of centrifugal force on the liquid normal to the surface of intermediate portion 32. The result is to minimize friction and resulting breakdown of particles of the material along the surface 32. This is advantageous in that the centrifugal speed of particles along the surface 32 is ordinarily not sufiicient to provide the liquid along the surface of outer portion 33. The

result is to produce a very high amount of friction upon the particles along surface 33, with high resulting breakdown of particles in the liquid. This is advantageous in that the surface 33 is oriented so as to produce high friction of the particles when they are traveling at a speed such as to insure a high degree of abrasion and attrition and resulting breakdownv of the, particles. This makes possible maximum favorable design. factors of the disc .asa whole. The respective angles and diameters of intermediate and outer.

portions

32 and 33 relative to the selected speed of rotation of'the disc are such as to insure ,delivery of the liquid film to the outer periphery 30a of disc 39 with. the principal portion of the desired homogenization of the liquid occurring over the surface of outer portion 33.

While a preferred embodiment of the invention has been disclosed, and various possible changes, omissions and additions have been disclosed, it will be apparent that various other changes, omissions and additions may be made in the invention without departing from the scope and spirit thereof.

What is claimed is:

1. In a centrifuge of the type described, a centrifugal disc forope'ration at selected speed comprising a flat center portion for rotation at said selected speed'about an axis, said disc being transverse to said axis, an vannular intermediate portion connecting with the outer periph- -ery of ''said center portion and extending forwardly angle tothe transverse, said center and intermediate portions being adapted to form a film of liquid, material impelled upon the front of. said center portion by rotation j of said disc at said' selected speed and to sustain said film to the outer periphery of said outer portion, the angle of said intermediate portion "being such that the component of centrifugal force on the liquid along the surface of said intermediate portion is much greater than the component of centrifugal force on the liquid normal to the surface of said intermediate portion so as to minimize friction and resulting abrasion and attrition of particles in said liquid, the angle of said outer portion being such that the component of centrifugal force on the liquid normal to the surface of said outer portion is greater than the component of centrifugal force on the liquid along the surface of said outer portion so as to produce high friction and high resulting abrasion and attrition of particles in said liquid, the respective angles and diameters of said intermediate and outer portions r-lative to said selected speed being such as to ensure delivery of said liquid film to the outer periphery of said disc with the major portion of the desired homogenization of the liquid occurring over the surface of said outer portion, and means for taking material from said disc positioned to receive said material beyond the outer periphery of said outer portion.

2. In a centrifuge of the type described, a centrifugal disc for operation at selected speed comprising a center portion for rotation at said selected speed about an axis, said disc being transverse to said axis, an annular intermediate portion connecting with the outer periphery of said center portion and extending forwardly outwardly therefrom at a shallow acute angle to the transverse, and an annular outer portion connecting with the outer periphery of said intermediate portion and extending forwardly outwardly therefrom at a large acute angle to the transverse, said center and intermediate portions being adapted to form a film of liquid material impelled upon the front of said center portion by rotation of said disc at said selected speed and to sustain said film to the outer periphery of said outer portion, the angle of said intermediate portion being such that the component of centrifugal force on the liquid along the surface of said intermediate portion is much greater than the component of centrifugal force on the liquid normal to the surface of said intermediate portion so as to minimize friction and resulting abrasion and attrition of particles in said liquid, the angle of said outer portion being such that the component of centrifugal force on the liquid normal to the surface of said outer portion is greater than the component of centrifugal force on the liquid along the surface of said outer portion so as to produce high friction and high resulting abrasion and attrition of particles in said liquid, the respective angles and diameters of said intermediate and outer portions relative to said selected speed being such as to ensure delivery of said liquid film to the outer periphery of said disc with the major portion of the desired homogenization of the liquid occurring over the surface of said outer portion, and means for taking material from said disc positioned to receive said material beyond the outer periphery of said outer portion.

3. Centrifugal disc in accordance with claim 2, the angle to the transverse of said outer portions being greater than degrees.

References Cited in the file of this patent UNITED STATES PATENTS 825,732 Janson July 10, 1906 1,363,572 Dalzell Dec. 28, 1920 2,318,293 Cornell May 4, 1943 2,612,356 Borck Sept. 30, 1952 2,673,075 Borck Mar. 23, 1954 2,785,765 Cornell Mar. 19, 1957 2,952,448 Cornell Sept. 13, 1960

Claims

1. IN A CENTRIFUGE OF THE TYPE DESCRIBED, A CENTRIFUGAL DISC FOR OPERATION AT SELECTED SPEED COMPRISING A FLAT CENTER PORTION FOR ROTATION AT SAID SELECTED SPEED ABOUT AN AXIS, SAID DISC BEARING TRANSVERSE TO SAID AXIS, AN ANNULAR INTERMEDIATE PORTION CONNECTING WITH THE OUTER PERIPHERY OF SAID CENTER PORTION AND EXTENDING FORWARDLY OUTWARDLY THEREFROM AT A SHALLOW ACUTE ANGLE TO THE TRANSVERSE, AND AN ANNULAR OUTER PORTION CONNECTING WITH THE OUTER PERIPHERY OF SAID INTERMEDIATE PORTION AND EXTENDING FORWARDLY OUTWARDLY THEREFROM AT A LARGE ACUTE ANGLE TO THE TRANSVERSE, SAID CENTER AND INTERMEDIATE PORTIONS BEING ADAPTED TO FORM A FILM OF LIQUID MATERIAL IMPELLED UPON THE FRONT OF SAID CENTER PORTION BY ROTATION OF SAID DISC AT SAID SELECTED SPEED AND TO SUSTAIN SAID FILM TO THE OUTER PERIPHERY OF SAID OUTER PORTION, THE ANGLE OF SAID INTERMEDIATE PORTION BEING SUCH THAT THE COMPONENT OF CENTRIFUGAL FORCE ON THE LIQUID ALONG THE SURFACE OF SAID INTERMEDIATE PORTION IS MUCH GREATER THAN THE COMPONENT