US 3050239 A
Abstract available in
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Description (OCR text may contain errors)
Aug. 21, 1962 F. e. WILLIAMS, JR
CENTRIFUGE APPARATUS 2 Sheets-Sheet 1 Filed NOV. 20, 1959 FIG.
FRED G WILLIAMS JR INVENTOR.
Aug. 21, 1962 F. G. WILLIAMS, JR
CENTRIFUGE APPARATUS 2 Sheets-Sheet 2 Filed Nov. 20, 1959 FIG. 5
FRED G. WILLIAMS JR.
ATTORNEYS United States Patent 3,050,239 CENTRIFUGE APPARATUS Fred G. Williams, Jr., Redwood City, Calif., assignor to Beckman Instruments, Inc., a corporation of California Filed Nov. 20, 1959, Ser. No. 854,281 4 Claims. (Cl. 233-24) This invention relates generally to a centrifuge apparatus and more particularly to a centrifuge apparatus suitable for microchemical analysis.
In prior art centrifuge apparatus, the liquid to be centrifuged is contained in a tube which, in turn, is supported in a Well formed in a metal rotor or in metal buckets carried by a supporting structure. To provide a structure sufficiently strong to support both liquid and tube, a heavy rotor or heavy buckets and supporting structure are required. The inertia of conventional centrifuge rotors is much greater than that contributed by the liquid column itself. In sedimentation of relatively large particles, such as precipitates and blood cells, the acceleration and deceleration time of a conventional rotor is often as great or greater than the actual time necessary for sedimentation.
It is a general object of the present invention to provide a centrifuge apparatus including a rotor having minimum inertia.
It is another object of the present invention to provide a centrifuge rotor whose diameter is less than the minimum radius at which centrifugation occurs.
It is a further object of the present invention to provide a centrifuge rotor which is adapted to support centrifuge tubes from their open end.
It is a further object of the present invention to pro vide a centrifuge rotor which is economical of materials, simple to manufacture, and represents an extreme of compactness, portability, and simplicity of manipulation.
These and other objects of the invention will become more clearly apparent from the following description when taken in conjunction with the accompanying drawmg.
Referring to the drawing:
FIGURE 1 is an elevational view, partly in section, of a centrifuge apparatus in accordance with the invention;
FIGURE 2 shows a modified rotor for the centrifuge apparatus of FIGURE 1;
FIGURE 3 is an enlarged view of the rotor of FIG- URE 1;
FIGURE 4 is a sectional view taken along the line 44 of FIGURE 3;
FIGURE 5 shows a centrifuge tube suitable for use in the apparatus of the present invention; and
FIGURE 6 shows a plurality of tubes mounted on a support.
The centrifuge apparatus of the present invention includes a housing 11 which houses a drive motor 12 for driving the rotor assembly 13. Controls 14 are provided for controlling the speed of rotation. The motor shaft 16 extends upwardly through a bowl 17 which forms a rotor chamber to receive and support the rotor 18. A set screw 19 is provided for adjusting the position of the rotor on the shaft 16. The bowl 17 is seated on the rim 2'1 carried at the upper end of the housing 11 and a cover 22 is provided to close the top of the bowl. The cover may be lifted until the end 23 is accommodated in the longitudinal slot 24. The cover is then held open to provide access to the rotor chamber.
Referring particularly to FIGURES 3 and 4, the rotor includes a plurality of longitudinal grooves 26 which are provided with slots 27. The longitudinal grooves are spaced so that the rotor is balanced, for example the "ice slots may be equally spaced about the circumference of the rotor. The rotor is locked to the shaft 16 by set screws 28.
Each pair of spaced slots 27 accommodates a tube support 31. Each support is provided with a plurality of tube receiving apertures which receive the tubes 32. The open ends of the tubes 32 are provided with a rim 33 which rides against the support 31. The closed end extends outwardly from the support. The tube 32 may be provided with a stopper or closure 34, FIGURE 5, to prevent loss of sample when the rotor is stationary. The holder with tubes is placed in the accommodating slots 27 and the various tubes are disposed, FIGURE 1 for centrifugation. It is observed that, in general, the maximum diameter of the rotor is only slightly greater than the diameter of the circle including the rims of the tubes. Thus, it is apparent that the inertia of the rotor is at a minimum while affording suflicient support for the tubes.
It is observed that the tubes may be readily mounted in the support 31 and that a complete assembly of the tubes and support may be conveniently placed on the rotor for a centrifugation operation.
The tubes 32 may be made of plastics and can be rotated at speeds which cause stresses in the tubes which are near the limits of their strength. In the event of failure of the light, plastic tube due to the stresses, there is little hazard to personnel.
The bowl 17 is provided to prevent scattering of materials should there be a breakage. Greater fields can be developed using plastic tubes than are available in so-called high speed centrifuges. With metal tubes, the performance of ultra centrifuges can be approached with the apparatus of the present invention while providing short acceleration and deceleration times. The tubes can be easily separated from the support; they are inexpensive and may be disposed after use.
The sample tubes 32 may have an internal diameter such that if they are maintained in a horizontal position, the liquid to be operated upon will not flow outwardly from the open end because of surface tension. However, as previously described, if the tubes are of greater diameter, the stoppers 34 are provided for sealing the ends until centrifugation takes place.
In certain applications, it may be desirable to support the tubes vertically until the apparatus begins to gain speed, at which time the tubes are disposed horizontally. Such a rotor may be of the type shown in FIGURE 2. That is, the rotor is cup-shaped and adapted to be accommodated on and suitably secured to the driving shaft 16. For example, a set screw 41 may be employed to secure the rotor to the shaft. The rotor is slotted at equally spaced points and is adapted to receive the tube 32. The slots extend from the horizontal portion of the rotor upwardly and have a portion which is vertical. Thus, when the rotor is standing still, the tube hangs vertically as shown in dotted outline at 42, while after the centrifuge begins to rotate, the tube will achieve a horizontal position as shown at 43.
Thus, it is seen that there is provided a centrifuge rotor which has a diameter exclusive of the centrifuge tubes which is near the minimum radius at which centrifugation in the liquid column occurs. The tubes are provided with rims which serve to support the tubes from a supporting member, for example, a support plate or from a rotor including holes or slots. The rotor has an external diameter only slightly greater than the diameter of a circle including the open end of the tubes.
1. A centrifuge rotor assembly for supporting centrifuge tubes including, a rotor member adapted to rotate about its axis and having formed therein a plurality of symmetrically disposed elongated rectilinear undercut slots in its outer peripheral surface with their longitudinal axes substantially parallel to the axis of the rotor, each of said slots having an axially facing open end, and a plurality of elongated tube supports each having at least one aperture therethrough to receive a centrifuge tube and support the same by its normally open end, said tube supports being removably positioned substantially entirely within said undercut slots through the open ends thereof with said apertures extending generally radially to support said tubes to extend radially outwardly from the rotor member.
2. A centrifuge assembly comprising elongated separation tubes each having an open end and a closed end, said tubes including a laterally extending rim at the normally open end, a rotor member adapted to rotate about its axis and having formed therein a plurality of symmetrically disposed elongated rectilinear undercut slots in its outer peripheral surface with their longitudinal axes substantially parallel to the axis of the rotor, each of said slots having an axially facing open upper end, a plurality of tube supports each having at least one aperture therethrough to receive one of said tubes and support the same from its rim, said tube supports being inser-table into said undercut slots from the upper end thereof to support the same from the rotor member whereby to support tubes to extend radially outwardly from the rotor member.
3. A centrifuge assembly comprising a housing, a centrifuge bowl carried by said housing, a drive motor disposed said housing and having a drive shaft extending into said bowl, a rotor member adapted to rotate about its axis having at least one elongated rectilinear undercut slot in its outer peripheral surface and with its longitudinal axis substantially parallel to the rotor member disposed in said bowl and carried by said drive shaft, said slot having an axially facing open upper end, at least one elongated tube having an open end and a closed end, said tube including a laterally extending rim at its open end, a tube support having at least one aperture, therethrough to receive said tube and support the same solely from the rim, said tube support being insertable within said undercut slot through the upper ends to support the tube to extend radially outwardly from the motor.
4. Apparatus as in claim 1 wherein said tube supports are each provided with a plurality of spaced apertures for supporting a plurality of tubes from said rotor member, whereby the tubes are longitudinally spaced along said rotor member.
References'Cited in the file of this patent UNITED STATES PATENTS 330,779 Frederiksen et a1. Nov. 17, 1885 330,780 Frederiksen et a1 Nov. 17, 1885 486,390 Berg Nov. 15, 1892 998,529 Ketcham July 18, 1911 1,839,944 Barthels Jan. 5, 1932 2,110,308 Nelson Mar. 8, 1938 2,560,988 Ruda July 17, 1951 2,604,261 Silverstolpe July 22, 1952 2,720,711 Gray et a1 Oct. 18, 1955 2,817,970 Whitby Dec. 31, 1957 I 2,854,189 Garrett Sept. 30, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,050,239 August 21, 1962 Fred G. Williams Jr.
Column 4, line 11 for "motor" read rotor Signed and sealed this 5th day of February 1963.
ERNEST W SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents