US3219266A - Annulated rotor - Google Patents

Description

1965 J. WAG MAN 3,219,266

ANNULATED ROTOR Original Filed Feb. 26, 1960 ack Magma/1 BY aw y. f? v United States Patent 3,219,266 ANNULATED ROTOR Jack Wagman, Frederick, Md., assignor to the United States of America as represented by the Secretary of the Army Filed Dec. 4, 1963, Ser. No. 328,134

3 Claims. (Cl. 23328) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a new and improved rotor for a centrifuge. In the past when it was desired to separate particulate matter from a solid suspension in a liquid, it was necessary to pour the material into centrifuge tubes, insert the tubes into a holder in the centrifuge rotor, accelerate the rotor to the desired speed, wait until there is a separation, decelerate the rotor, remove the tubes from the rotor, without disturbing the well defined layers, a task which is rather hard to accomplish, and finally separate the two components being careful not to mix the two phases. Another inherent disadvantage of this method is that the two phases are in contact with each other during the entire operation.

The present rotor allows a complete physical separation, almost instantaneously, and not just a separation into two layers, thereby eliminating the danger of the two phases being remixed.

This rotor can also separate intermediate reaction products. These products exist for only a short time because their continued contact with the other constituents causes the reaction to go to completion thereby destroying the intermediates. Since this rotor can physically sepa rate these phases from contact with each other almost instantaneously, these intermediate products can be separated and collected before they are destroyed by further reactions. This apparatus can separate two or more immiscible liquids, or suspended solids from a liquid.

Because this rotor can make actual physical separations, it can be used as an analytical tool to study the kinetics of enzyme reactions, and to study rates of adsorption or penetration of ions into bacterial cells or other living material. Many other analytical uses of similar nature can be devised using this new rotor. This rotor can be easily adapted for use on any standard centrifuge.

The drawing shows a section of a side elevational view of this rotor.

The rotor is coupled to the drive unit of the centrifuge in the standard fashion by means of pins 12 which are contained in recess 14. Bowl 16 is found in the upper center portion of the rotor. The bowl is open at the top and is bounded by conical side wall 17 and bottom wall 18. The bottom portion of side wall 17 does not join directly with bottom wall 18 but there is a recess 19 which extends under side wall 17 for some distance. Within side wall 17 there are a number of channels 20 spaced from each other. These channels are in communication with recess 19 and preferably extend upwardly at approximately 60 from the horizontal. The angle of the channels is not critical and may be anywhere between 0 and 90. The upper or outer ends of channels 20 open at 21 into annular recess 22. A projection wall 24 extends inwardly and above the lower annular recess or indentation and provides a partition between the annular indentation 22 and the upper annular indentation 26. These annular indentations may be made of a size and shape to accommodate the particular needs.

In operation the rotor is spinning within the centrifuge, for example at 10,000 r.p.m. A liquid with suspended solids, for example, is introduced at a suitable rate into 3,219,266 Patented Nov. 23, 1965 the bottom of the bowl where it is immediately thrown to the outer limits of the bowl, that is to the recess 19. The suspension is forced up the channels and thereby instantly acquires the same speed of rotation as that of the rotor. After passing through the channels 20, the suspension enters the lower annular indentation. As the latter becomes filled with suspension the heavier solids are crowded into its outer portion and clear supernatant fluid is formed at the inner surface of the liquid layer closer to the axis of rotation. Further introduction of suspension results in a flow of clear supernatant fluid over projection wall 24 and into upper annular indentation 26. After the required amount of clear supernatant fluid collects in the upper annular indentation 26, the rotor is decelerated. With the rotor at rest, cleared supernatant fluid can be drawn off with a pipette or syringe from the upper annular indentation 26, and if desired the packed solid can be scraped from the lower annular indentation.

The example of separation of solid and liquid given above can be aided additionally by use of an inert liquid of an intermediate density. For example, bacteria which has the density of 1.08 can be separated from water having a density of 1.00. In this case it is advantageous to use a water-immiscible liquid such as dibutyl phthalate having an intermediate density of 1.046 in order to attain a clear cut physical separation. This operation is accomplished in the following manner: the dibutyl phthalate is introduced into the spinning rotor so that the lower annular indentation is partially filled; the mixture of water and bacteria is introduced into the rotating rotor at a suitable rate; the bacteria being heavier than the dibutyl phthalate replaces it in the outer portion of the lower indentation, and the water being lighter than the phthalate is pushed by the continued introduction of the mixture toward the end of the projection wall and around it into the upper indentation; the dibutyl phthalate remains in between the water layer and the bacterial layer. Thus it can be seen that by using an interposing liquid, two significant advantages can be obtained: (1) it reduces the volume of mixture required to recover the desired amount of supernatant liquid, and (2) it aids in the complete physical separation between the solid sediment and the supernatant liquidin other words, it acts as a barrier to contact between the water and bacteria.

An example of how this rotor can be used as an analytical device will now be explained. It is often desirable to know the kinetics of ion penetration into living cells, that is the rate of penetration and the extent of the penetration of the ions into the cell. This can be easily determined using my rotor. For example, a water suspension of bacteria and a salt solution, for example MgSO, in H O, are simultaneously introduced into a mixing chamber at predetermined rates. After rapid and thorough mixing, the flow of mixture is directed into the rotating rotor, whereupon there is a rapid separation of the salt solution and the cells, the salt solution being recoverable from the upper annulus and the cells from the lower indentation. The salt solution is analyzed for anion or cation concentration and is compared with the starting salt solution concentration, taking into consideration the dilution with the water from the cell water suspension. The mixing time may be determined accurately by employing interacting materials with known rates of reaction in a control test using the same flow rates. The rates and extent of penetration can therefore be easily determined from the data obtained. The kinetics of enzyme-substrate reactions can be determined similarly.

A centrifuge with this new improved rotor obviously could easily be modified to provide means for a continuous withdrawal of materials from the lower and upper annuli.

Many other applications besides those mentioned herein can be devised in the employment of this new rotor. I claim:

1. A centrifugal separating device comprising a rotor, said rotor comprising;

fluid separating bowl means having entry means so that fluid may be introduced thereinto, the fluid separating means comprising,

a bottom in the bowl, distributor means consisting of at least one fluid passage means extending from the bottom of the bowl at one end and discharging into a first annular recess in the bowl at its other end, the annular recess being radially outward of the bottom, the annular recess receiving a mixture of heavy and light components from the channels and separating said mixture with the heavy component being outermost, the first annular recess having an annular wall extending radially inwardly over the lip of which the light component spills, and a second annular recess on the other side of light component as it spills over the annular wall and.

to retain the light component therein as rotation of the rotor ceases.

3. Apparatus as set forth in claim 1, the fluid passage means extending axially and radially from the bottom.

References Cited by the Examiner UNITED STATES PATENTS 585,936 7/1897 Linders 23328 2,472,475 6/1949 Hamilton 233-27 X 2,840,303 6/1958 Stuart 233-28 M. CARY NELSON, Primary Examiner.

HENRY T. KLINKSIEK, Examiner.

Claims (1)

1. A CENTRIFUGAL SEPARATING DEVICE COMPRISING A ROTOR, SAID ROTOR COMPRISING; FLUID SEPARATING BOWL MEANS HAVING ENTRY MEANS SO THAT FLUID MAY BE INTRODUCED THEREINTO, THE FLUID SEPARATING MEANS COMPRISING, A BOTTOM IN THE BOWL, DISTRIBUTOR MEANS CONSISTING OF AT LEAST ONE FLUID PASSAGE MEANS EXTENDING FROM THE BOTTOM OF THE BOWL AT ONE END AND DISCHARGING INTO A FIRST ANNULAR RECESS IN THE BOWL AT ITS OTHER END, THE ANNULAR RECESS BEING RADIALLY OUTWARD OF THE BOTTOM, THE ANNULAR RECESS RECEIVING A MIXTURE OF HEAVY AND LIGHT COMPONENTS FROM THE CHANNELS AND SEPARATING SAID MIXTURE WITH THE HEAVY COMPONENT BEING OUTERMOST,

Images