U.S. patent number 3,819,111 [Application Number 05/349,402] was granted by the patent office on 1974-06-25 for centrifuge rotor cover.
This patent grant is currently assigned to Ivan Sorvall, Inc.. Invention is credited to Charles Paulsen, William A. Romanauskas.
United States Patent |
3,819,111 |
Romanauskas , et
al. |
June 25, 1974 |
CENTRIFUGE ROTOR COVER
Abstract
There is disclosed a cover for a centrifuge rotor which is
affixed thereto by being screwed onto the hub of the rotor. The
cover is constructed in a manner to provide a depending skirt which
seats against an upstanding rim of a rotor of a centrifuge. This
cover is constructed to seat tighter under the centrifugal forces
encountered whereby a portion of the skirt is urged outwardly and
down against the seat on the rim. The cover is also designed to
have an annular well for collecting small quantities of overflow
fluid. The cover is also consructed with a means to preliminarily
provide communication between the outside and inside the rotor of
the centrifuge in order to establish equilibrium therebetween prior
to removal of the cover.
Inventors: |
Romanauskas; William A.
(Southbury, CT), Paulsen; Charles (Newtown, CT) |
Assignee: |
Ivan Sorvall, Inc. (Norwalk,
CT)
|
Family
ID: |
23372251 |
Appl.
No.: |
05/349,402 |
Filed: |
April 9, 1973 |
Current U.S.
Class: |
494/16;
494/38 |
Current CPC
Class: |
B04B
5/0414 (20130101); B04B 7/02 (20130101); B04B
2007/025 (20130101) |
Current International
Class: |
B04B
5/04 (20060101); B04B 7/00 (20060101); B04B
5/00 (20060101); B04B 7/02 (20060101); B04b
001/00 () |
Field of
Search: |
;233/1R,3,4,8,27,28,32,44 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Krizmanich; George H.
Attorney, Agent or Firm: Schellin; Eric P. Hoffman; Martin
P.
Claims
What is claimed is:
1. A cover for a centrifuge rotor comprising a substantially disc
means, said disc means having a downwardly depending skirt
substantially along the periphery thereof, said disc means having a
centrally positioned circular aperture, a cylindrical core means,
said core means having a first portion adapted and constructed to
fit slidably relatively snugly within said circular aperture, said
core means having a second portion above said first portion which
has a diameter less than the diameter of said first portion thereby
forming a shoulder on said core means, an outer shell means, said
outer shell means having a bore adapted and constructed to slidably
encompass said second portion of said core means, the disc means
having an upper radially extending flat surface portion radiating
directly from said aperture and a concomitantly lower upwardly
inclined radially extending surface whereby the disc decreases in
thickness, the said upper flat surface terminating in an upwardly
radially extending portion having an increasing thickness, the said
upwardly radially extending portion substantially terminating with
said skirt, the said skirt having a downwardly facing shoulder
along the outer periphery thereof, said skirt beginning at said
shoulder having an inwardly inclined terminal portion adapted to
rest against an annular seat on a centrifugal rotor, the outer
shell having a thickness sufficient to bridge the said first
portion and the said upper flat surface, said core means having
means at the bottom portion thereof for screwing said cover onto
cooperating means on a rotor of a centrifuge, said core means and
said outer shell means having joint handle means at their
respective upper portions thereof.
2. The cover for a centrifuge according to claim 1 wherein an
annular washer means is positioned between the said outer shell
bridging the said first portion and the said upper flat
surface.
3. The cover for a centrifuge according to claim 1 wherein the
means for screwing the cover to the rotor of a centrifuge includes
an internally threaded recess at the bottom of said core means
adapted to be threaded onto a threaded male portion of a rotor.
4. The cover for centrifuge according to claim 1 wherein the said
handle means radially extends through said core means and said
outer shell means.
5. The cover for a centrifuge according to claim 1 wherein the
first portion of said core means has an outwardly radially
extending flange and said aperture has a lower wider diameter
portion adapted and constructed to engage said flange whereby the
said core means is restrained from parting from said disc
means.
6. The cover for a centrifuge according to claim 5 wherein an
annular washer means is positioned between the said outer shell
bridging the said first portion and the said upper flat
surface.
7. The cover for a centrifuge according to claim 6 wherein the
means for screwing the cover to the rotor of a centrifuge includes
an internally threaded recess at the bottom of said core means
adapted to be threaded onto a threaded male portion of a rotor.
8. The cover for a centrifuge according to claim 7 wherein the said
handle means radially extends through said core means and said
outer shell means.
Description
BACKGROUND OF THE INVENTION
During the last few years chemical laboratory procedures,
especially with regard to clinical chemistry, have demanded that
centrifuges be capable of rotating at ever greater speeds. As a
result, an ultra-centrifuge has been developed which employs a
rotor normally used at revolutions per minute in an excess of
60,000. Of course, such rotors are carefully constructed to provide
accurate balance and good strength integrity so that the rotor does
not fly apart under the terrific centrifugal forces built up as it
is rotated. The centrifuge tubes employed in such ultracentrifuges
are capped and sealed after the liquid contents are added to the
tubes. In many cases it is necessary to insure a sealed environment
within the rotary even though the tubes themselves have been
sealed. The tubes are sealed at ambient atmospheric pressure as is
the rotor itself by means of a centrifuge rotor cover. However, the
rotor is operated in a vacuum.
Under the terrific forces created, the caps may not seal as well as
desired and some of the liquid contents therein may gradually creep
out of the tube. To retain the liquid that may be spilled from the
tubes during centrifugation a rotor must have a cover. As the tubes
may contain liquids which are radioactive or which possess
dangerous biological materials, it will be apparent that serious
problems could follow if there would be leakage beyond the confines
of the rotor. As the rotor is in a vacuum chamber, the vacuum pump
would remove any spilled materials from the chamber and expell at
least some of such materials into the laboratory atmosphere. A well
working cover that performs its task even though being subjected to
considerable centrifugal forces and hydrostatic forces from
accumulated tube leakage is the subject matter of the present
invention.
SUMMARY OF THE INVENTION
The cover of the present invention has an overall disc-like
configuration. A downwardly depending skirt is designed to have a
portion thereof seat itself internally with respect to an upwardly
extending peripheral rim on the rotor. The cover has a concentric
aperture. A core is slidably positioned in the aperture. The core
has a portion of sufficient diameter whereby it fits relatively
snugly within the aperture. The core has a recessed shoulder
approximately flush with the upper surface of the cover directly
associated therewith. The core has an upwardly extending portion
about which is positioned a hollow outer shell. The shell is
designed so that a downwardly facing surface bridges the shoulder
of the core and a portion of the surface of the cover. The outer
shell and core near the upper portion thereof are held together by
a common acting handle. The other end of the core possesses means
whereby it is screwed to the hub of the rotor. As the cover is
screwed to the hub, the outer shell and core which has an O-ring
move slightly relative to the cover whereby a sealing action occurs
as the O-ring is squeezed between the core and inside the aperture
of the cover. This sealing action occurs at the end of the
operation to tighten the cover. Conversely, when the cover is to be
removed the core and outer shell by first being loosened makes it
possible to establish gas pressure equilibrium between the
atmosphere and the space in the rotor.
Of considerable importance to the instant invention is the fact
that the cover has a relatively thinned portion intermediate the
aperture and the outer periphery of the cover. As the centrifugal
forces exert themselves, the skirt will tend to be thrust radially
outwardly and downwardly to seat itself more securely against the
rim which is more resistant to enlargement.
Additionally, the skirt is provided with an annular well internally
with respect to the skirt whereby most of the liquid which may
escape from the centrifuge tubes and creeps upwardly will be
captured by the well and the subsequent hydrostatic pressure will
be self contained minimizing any tendency to lift the lid.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a rotor of an ultracentrifuge with
the cover of the present invention attached thereto.
FIG. 2 is a cross section taken along line 2--2 of FIG. 1 with the
cover not yet completely secured.
FIG. 3 is a similar view as in FIG. 2 with the cover completely
secured.
FIG. 4 is a close-up cross-sectional view to provide a detail view
of the manner of seating the cover of the present invention with
respect to an upstanding annular rim of the rotor of the
centrifuge.
DETAILED DESCRIPTION OF THE INVENTION
Beginning with FIG. 1 the cover shown, generally, by reference
numeral 10, depicts the cover of the present invention. It will be
noted that the cover is secured to a rotor 11 of a centrifuge. The
rotor is of the ultra-high speed type usually machined from a
single metal block with fixed recesses designed to accept specially
constructed centrifuge tubes. These tubes are utilized in a sealed
tightly capped condition. More details with respect to the
centrifuge rotor can be gleaned from FIGS. 2 and 3. The recesses 12
for the centrifuge tubes can be seen.
Again, with particular reference to FIGS. 2 and 3, the cover 10
includes a disc means having an annular portion. The annular
portion has a centrally located aperture 14. The annular portion
terminates in a downwardly depending annular skirt 15. It will be
seen that the annular portion has a flat section 16 facing
upwardly. The other or underside 17 is inclined upwardly. As the
two surfaces, i.e., section 16, and underside 17 are not in the
same plane the annular portion will tend to decrease in thickness
and at 18 assumes its thinnest dimension. The flat section 16
terminates at 18 into an upwardly extending radial portion 19.
Portion 19 will be seen to be somewhat thicker than at 18.
The depending skirt 15 has an outwardly facing shoulder 21, as seen
in greater detail in FIG. 4. The shoulder includes a downwardly
facing flat surface 22. The skirt 15 is inclined inwardly to form
portion 23. An outwardly facing peripheral groove 24 is located in
portion 23. The groove 24 is adapted to accommodate O-ring 25. The
O-ring will be seen to be in confrontation with the internal
portion of the rim 26 of the centrifuge rotor 11. More about this
will be stated below.
Within the aperture is cylindrically shaped core 30. The portion 31
constituting a first portion of the core is designed to fit
slidably but rather snugly within the aperture. The outwardly
extending periphery has an annular groove 32 into which is fitted a
suitable O-ring 33. The aperture 14 has a lower wider diameter
portion so that the aperture 14 is somewhat larger at the bottom
than at the top. Near substantially the bottom of the portion 31 of
the core is an outwardly radially extending flange 35. The flange
35 enlarges the lower part of the core to an extent whereby it
cannot be removed upwardly from its position in the aperture.
The core extends upwardly beyond the plane of the upper flat
surface of section 16 to form a second portion. The core has a
shoulder 36 with a flat upwardly facing section approximately in
the same plane as section 16. An outer shell 38 having a bore
encompasses the remainder of the upwardly extending core. It has a
downwardly facing recess 39 adapted to bridge the shoulder 36 and a
portion of section 16. A peripheral downwardly extending flange 53
forms one wall of the recess. The flange is adapted to fit into
annular groove 54 in section 16. An annular washer 40 is positioned
in the recess 39 and the upwardly facing section and section 16.
The washer 40 acts to prevent wear.
The upper part of the outer shell and the core therein are rotated
by a handle 41 which extends radially therefrom. It is positioned
in a bore 42 normal with respect to the axis of the core. The
handle 41 is also in alignment with bores 43 and 44 in the outer
shell 38. The handle is retained in position by a set screw 45.
The portion 31 of the core has an internally threaded recess 47
adapted to receive a suitably threaded male member 48, constituting
the hub of the rotor. In order to secure the cover of the present
invention the core is screwed onto the hub of the rotor. As the
core is tightened the outer shell moves downwardly with the core.
The annular portion 13 is, of course, positioned on the rim of the
rotor at its outer peripheral extremity. The part adjacent the
aperture 14 is between the outer shell and the flange 35 of the
core. From FIG. 2 it will be seen that the core and outer shell are
withdrawn from the annular portion 13 to the extent permitted by
the cooperation of the flange 35 and the widened portion of
aperture 14. With the core and outer shell withdrawn the O-ring 33,
thereby providing a gaseous communication with respect to one side
of the cover to the other. When the cover is screwed onto the rotor
the core and outershell are screwed onto the rotor therewith
carrying the annular portion to a sealing condition.
In unscrewing the cover the opposite relative movement occurs so
that the core and outer shell recedes from its sealing engaging
position to provide pressure or vacuum relief to the space in the
rotor.
Not mentioned before, is the ingenious annular well 50 internally
around the skirt. As this is the furthermost space from the axis of
the cover any liquid escaping from the recesses 12 of the rotor and
finding its way into the internal spaced defined by the cover will
become segregated in this well.
As was stated heretofore the rotor is fabricated of high strength
metal materials. Likewise, the cover of the present invention
should be constructed of similar materials as the cover is
subjected to the same enormous centrifugal forces as the rotor when
the centrifuge is operated.
* * * * *