US3288360A

US3288360A - Liquid centrifuge core

Info

Publication number: US3288360A
Application number: US375681A
Authority: US
Inventors: Edwin F Babelay; Hubert P Barringer
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-06-16
Filing date: 1964-06-16
Publication date: 1966-11-29
Anticipated expiration: 1983-11-29

Description

1966 E. F. BABELAY ETAL 3,288,360

LIQUID CENTRIFUGE CORE Filed June 16, 1964 INVENTORS.

Edwin F. Babe/0y BY Huberf P. Barringer ATTORNEY United States Patent 3,288,360 LIQUID CENTRIFUGE CORE Edwin F. Babelay, Knoxville, and Hubert P. Barringer,

Oak Ridge, Tenn., assignors to the United States of America as represented by the United States Atomic Energy Commission Filed June 16, 1964, Ser. No. 375,681 Claims. (Cl. 233-22) The present invention relates to liquid centrifuges generally and more specifically to an improved core for a liquid centrifuge bowl.

A basic problem encountered in the development of the liquid zonal or density-gradient centrifuge has been to accelerate the liquid gradient to operational speed with a minimum of mixing, and to recover the gradient at the end of the centrifugation with a high resolution in separation between the zones of differing density or dilferent sedimentation coefficients. Another problem has been that of providing rotor stability during high speed operation. Instability at the high speeds of interest not only causes mixing but may also result in the destruction of the centrifuge.

It is accordingly an object of this invention to provide a liquid centrifuge core characterized by a high resolution of the isopycnic and rate zonal separations.

Another object of this invention is to provide a rotor core characterized by high resolution of the zonal separations with a small number of rotor partitions.

Another object is to provide a core having a high critical vibrational frequency.

Other objects of the invention will become apparent from an examination of the following description of the invention and the appended drawings wherein:

FIG. 1 is a vertical sectional view showing an embodiment of the subject improved core design mounted within a liquid centrifuge bowl.

FIG. 2 is a horizontal section of the centrifuge bowl and improved core of FIG. 1.

FIG. 3 is a cross sectional view of the subject improved core design illustrating the movement of a gradient band toward the core withdrawal point.

In accordance with the present invention, an improved core is provided for a liquid centrifuge of the type incorporating a vertically oriented cylindrical bowl which is rotated about its axis. The improved core comprises a right regular prismatic body having a plurality of longitudinally extending flat faces which is centrally disposed in the bowl. Vanes or septa extend outwardly from the prismatic body along planes bisecting each included angle at the periphery of the body. Each of the fiat faces is equally divided by a longitudinally extending groove of varying depth, the groove having its greatest depth at a withdrawal port which communicates with a conduit passage disposed within the prismatic body and communicating with an end face thereof.

To facilitate an understanding of the invention, reference is made to FIGS. 1 and 2 wherein a preferred embodiment of the subject invention is illustrated. A rotor bowl 1 and rotor end caps 2 and 2' define a right-cylindrical cavity in which a core 3 according to the subject invention is disposed. As can be seen most readily in FIG. 2, core 3 comprises a central portion 4 of square crosssection, having equally spaced, integral vanes or septa 5 extending radially from the corners thereof. Withdrawal grooves '6, of varying depth cent-rally spaced on the flat faces 7 of central portion 4, extend axially along the faces to withdrawal ports 8. The grooves 6 have their greatest depth at the withdrawal ports which communicate with a tubular passageway 9 disposed axially within central portion 4 of core 3 and extending to an end face thereof. The core 3 is supported centrally inside bowl 1 by means "ice of stud and recess systems 10 and 11 between core 3 and top and bottom end caps 2 and 2' respectively.

Although the central portion 4 of core 3 has a square cross-section in the preferred embodiment illustrated'in the drawings and described above, other right prismatic cent-r al portions having a greater or less number of flat side faces may be used. In general, however, the central portion which operates satisfactorily with the least number of faces is most desirable as it will be the simplest and easiest core to fabricate. A secondary benefit also results in that with fewer septa a larger percentage of the rotor volume is available to the fluid being centrifuged, thereby enabling the fluid volume and centrifuge capacity to be correspondingly increased.

In a typical operation, an impure virus sample was separated from associated foreign proteins and other undesirable materials contained therein using the hereinbefore described centrifuge system.

Core 3 and a rotor bowl 1, having a 4 inch internal diameter, were assembled and rotated at 5000 r.p.m. While rotating at this speed, a liquid batch having a gradually increasing density was admitted at the inner rotor periphery through tubular passageway 12 which runs through end cap 2. After the density gradient was in the rotor, additional dense fluid (concentrated sucrose), termed the cushion was pumped in through passageway 12 until the light end of the gradient began to flow out the center passageway 9 within core 3 indicating that the rotor was completely full. At that point the sample layer was introduced through the center passageway 9, reversing the direction of fluid flow through the rotor and causing part of the cushion to flow back out through the edge passageway 12. In order to form the sample layer into a thin zone, an overlay of fluid lighter than the sample layer was introduced after the sample. This forced the sample layer out into the rotor chamber clear of the center core. The connection to the rotor edge through passageway 12 was then closed, and the center passageway attached to a reservoir of water to allow a small volume of fluid to flow into the rotor during acceleration to compensate for rotor expansion.

The speed of the rotor was then increased to 40,000 r.p.m. for a period sufficient for the particulate matter in the virus sample to sediment in the gradient provided by the liquid batch previously inserted into the rotor.

The rotor speed was then reduced to 5000 r.p.m. and the sediment components of the virus sample removed from the bowl through inner passageway 9 by admitting a dense sucrose solution to the rotor edge through passageway 12, thereby driving the lower density zones into withdrawal grooves 6, ports 8 and passageway 9.

The entire gradient, as it was recovered, was passed through an ultraviolet absorption monitoring system, and into fraction collector tubes.

FIG. 3 illustrates schematically the withdrawal of a single zone or band 13 of particulate matter as it is brought increasingly close to the core '3 as shown in quadrants I through IV. Note that the flat faces 7 have the effect of increasing the width of the band as it approaches the withdrawal groove and acts to funnel the band into the withdrawal groove. This effect is due to the fact that a flat surface cuts across the density gradient which increases radially in a rotating centrifuge. The flat faces 7 are placed so that the withdrawal grooves 6 are located at the innermost radial position of the faces and therefore at the point of least pressure and lowest density. The band being collected advances along the flat faces 7 from the higher pressure region where they join with the septa 5, to the withdrawal grooves 6 which are at the lowest pressure, radially-innermost point along each wall. The withdrawal grooves 6 are varied in depth to a maximum depth at withdrawal ports 8 so as to con- J tinue the path of decreasing pressure and density inwardly to passageway 9.

ORNLr-3415, available from the OFrice' of Technical Services, Washington, D.C., describes an intermediate speed B-II zonal rotor in which the subject core may be used. This report was issued in connection with the Joint National Institutes of Health-Atomic Energy Conn mission Zonal Centrifuge Development Program.

The above description of one form of the invention was offered for illustrative purposes only, and should not be interpreted in a limiting sense. It is intended that the invention be limited only 'by the claims appended hereto.

What is claimed is:

1. A core for insertion into a cylindrical centrifuge bowl comprising:

(a) an elongated right prismatic body having at least three fiat side faces,

('b) radially extending fins affixed to said prismatic body along the lines of intersection of said side faces,

(c) a longitudinally extending inclined groove disposed centrally in each of said side faces, and

(d) fluid conducting rneans communicating with the deepest point of each of said grooves.

2. A core for insertion into a cylindrical centrifuge bowl comprising:

(a) an elongated right prismatic body having at least three flat side faces, each face defining first and second angles between it and respective adjacent faces,

(b) radially extending fins bisecting each of said angles at each intersection of two faces,

() an axially-extending passageway through said elongated prismatic body,

((1) radially-extending ports each leading from said axial passageway to a point below a respective face midway between adjacent fins, and

(e) an inclined groove disposed centrally in each face and extending longitudinally in opposite directions from said port, said ports communicating with the deepest point in each of said grooves.

3. A core for insertion into a cylindrical centrifuge bowl comprising:

(a) an elongated regular right prismatic body having at least three side faces,

(b) radially extending fins integrally affixed to said prismatic body along the lines of intersection of said side faces,

(c) an axially extending passageway disposed centrally within said prismatic body,

((1) a longitudinally extending inclined groove disposed centrally in each of said side faces, and

(e) radially-extending ports leading from said axial passageway to the deepest point of each of said inclined grooves.

4. A core for insertion into a cylindrical centrifuge bowl comprising:

(a) an elongated right prismatic body having four side faces,

(b) radially extending fins integrally afiixed to said prismatic body along the intersections of said side faces, said fins coinciding with planes passing diagonally through said prismatic body,

(0) an axially extending passageway disposed centrally within said prismatic body,

(d) a longitudinally extending inclined groove disposed centrally in each of said faces, and

5. A core for insertion into a cylindrical centrifuge bowl comprising:

(a) an elongated right prismatic body having a square cross section,

(b) radially extending fins equal in length to said prismatic body integrally affixed to the corners of said body,

((1) a longitudinally extending groove of increasing depth disposed centrally in each side face of said prismatic body, and p (e) radially-extending ports leading from said axial passageway to the deepest point of each of said grooves.

References Cited by the Examiner UNITED STATES PATENTS 2,563,550 8/1951 Quist 233-21 3,168,474 2/1965 Stallman et al 233-33 3,195,809 7/1965 Pickels et a1. 233-21 M. CARY NELSON, Primary Examiner.

HENRY T. KLINKSIEK, Atssistant Examiner.

Claims

1. A CORE FOR INSERTION INTO A CYLINDRICAL CENTRIFUGE BOWL COMPRISING: (A) AN ELONGATED RIGHT PRISMATIC BODY HAVING AT LEAST THREE FLAT SIDE FACES, (B) RADIALLY EXTENDING FINS AFFIXED TO SAID PRISMATIC BODY ALONG THE LINES OF INTERSECTION OF SAID SIDE FACES, (C) A LONGITUDINALLY EXTENDING INCLINED GROOVE DISPOSED CENTRALLY IN EACH OF SAID SIDE FACES, AND (D) FLUID CONDUCTING MEANS COMMUNICATING WITH THE DEEPEST POINT OF EACH OF SAID GROOVES.