U.S. patent number 3,877,634 [Application Number 05/364,150] was granted by the patent office on 1975-04-15 for cell washing centrifuge apparatus and system.
This patent grant is currently assigned to E. I. du Pont de Nemours and Company. Invention is credited to Josef Blum, Vernon C. Rohde.
United States Patent |
3,877,634 |
Rohde , et al. |
April 15, 1975 |
Cell washing centrifuge apparatus and system
Abstract
Apparatus and system for treating biological materials by
alternate centrifugation and decanting steps. Predetermined equal
quantities of treatment or washing liquid are automatically
introduced simultaneously into each of a plurality of rotating
swinging centrifuge tubes by means of a distributor that rotates
with the centrifuge. After centrifugation, the centrifuge tubes
descend to a restricted vertical or near vertical position in which
location decantation takes place while the centrifuge rotates at a
slower decanting speed. Thereafter, the cycles of centrifugation
and decantation are repeated automatically. Means are also provided
for preventing contamination of wash liquids during transmission
thereof to the distributor.
Inventors: |
Rohde; Vernon C. (Newtown,
CT), Blum; Josef (Norwalk, CT) |
Assignee: |
E. I. du Pont de Nemours and
Company (Wilmington, DE)
|
Family
ID: |
23433245 |
Appl.
No.: |
05/364,150 |
Filed: |
May 25, 1973 |
Current U.S.
Class: |
494/1; 494/17;
494/29; 494/11; 494/20 |
Current CPC
Class: |
B04B
5/0421 (20130101); B04B 11/06 (20130101); C12M
47/12 (20130101); B04B 13/00 (20130101) |
Current International
Class: |
B04B
5/04 (20060101); B04B 5/00 (20060101); B04B
13/00 (20060101); B04b 015/02 () |
Field of
Search: |
;233/1D,14R,14A,17,23R,24,25,26,27 ;23/259 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Krizmanich; George H.
Claims
We claim:
1. A system for treating biological materials and the like,
comprising: a swinging tube centrifuge having a rotor, a plurality
of swinging tube holders mounted on said rotor for holding
centrifuge tubes, and a variable speed drive for said rotor; a
distributor mounted on and rotating with said centrifuge, said
distributor having a plurality of spaced, radially extending
nozzles equal in number to said tube holders, said nozzles being
aligned with but unconnected to said tube holders, said tube
holders being pivotally mounted on said rotor so that the mouth of
the centrifuge tubes held by said swinging tube holders is brought
into close proximity with said nozzles when said rotor is in high
speed rotation; a source of treatment fluid; tube means connected
between said source and said distributor for transmitting said
fluid to said distributor; and pulsing pump means operating upon an
exterior portion of said tube means for urging said fluid from said
source to said distributor.
2. The system according to claim 1, and further comprising valve
control means between said source and said pump for adjusting and
controlling the flow of said fluid between said source and said
distributor.
3. The system according to claim 1 wherein said pump means
comprises a peristaltic pump.
4. The system according to claim 1 wherein said distributor is
removably mounted on said centrifuge and wherein said system
further comprises cooperating indexing means on said distributor
and on said centrifuge for locating said nozzles opposite
respective tubes.
5. The system according to claim 4 wherein said nozzles are arrayed
outwardly and downwardly at an angle and wherein said tubes in the
centrifuging position are at an angle for receiving fluid directly
from said nozzles.
6. The system according to claim 1 wherein said drive is a
two-speed drive for said centrifuge, said tubes assuming an
outwardly extended array in the high speed mode of said drive, said
tubes assuming a vertical decanting position in the low speed mode
of said drive and said nozzles projecting fluid into respective
tubes only when the latter are in the centrifuging mode.
7. The system according to claim 6 and further comprising an
annular trough surrounding said centrifuge, said trough receiving
liquid materials from said tubes when the latter are in the
vertical decanting mode.
8. The system according to claim 1 wherein said drive is a
two-speed drive and said tubes are maintained in a vertical or near
vertical position for decanting liquids from said tubes at low
speed drive.
9. The system according to claim 8 wherein said pump means is
operative only when said tubes are in the centrifuging mode to
cause equal amounts of fluid to be projected by centrifugal force
through said nozzles into respective tubes.
10. The system according to claim 9 and further comprising
electrical circuitry for operating said two-speed drive and said
pump means, and timing means in said electrical circuitry for
determining the sequence and timing of filling the tubes with
treatment fluid, and operating said drive at centrifuging and
decanting speeds.
11. The system for treating biological materials and the like,
comprising a swinging tube centrifuge, a multi-speed motor for
rotating said centrifuge at a predetermined centrifuging speed, and
alternately at a lower decanting speed, a source of treatment
fluid, means for transmitting said fluid to said centrifuge,
pulsing pump means operating on said transmitting means for urging
said fluid from said source to said centrifuge, a pump motor for
said pump, electrical circuit means connected between said
centrifuge motor and said pump motor for causing said centrifuge
motor to operate alternately for the respective centrifuging and
decanting modes of said centrifuge, and for causing said pump motor
to operate to transmit treatment fluid to said centrifuge driving
the centrifuging mode.
12. The system according to claim 11 and further comprising control
means in said electrical circuit for predetermining the timing and
sequence of each of the tube filling, centrifuging and decanting
modes of the system.
13. The system according to claim 12 and further comprising means
in said electrical circuit for causing the system to repeat for a
predetermined number of cycles the successive tube filling,
centrifuging and decanting modes of the apparatus.
14. The system for treating biological materials and the like,
comprising a swinging tube centrifuge, a plurality of swinging
tubes in circular array on said centrifuge, a source of treatment
fluid, a distributor removably mounted on and rotating with said
centrifuge for projecting treatment fluid into respective
centrifuge tubes, said distributor comprising a plurality of spaced
radially extending nozzles equal in number to said swinging tubes,
said nozzles being aligned with but unconnected to said swinging
tubes, means for alternately rotating said centrifuge at a
centrifuging speed and at a lower decanting speed, means for
transmitting a metered quantity of treatment fluid into and through
said distributor and into said centrifuge tubes during the
centrifuge mode of the centrifuge, said centriguge tubes being
pivotally mounted to swing into close proximity with said nozzles
during the centrifuging mode.
15. The system according to claim 14 and further comprising timing
means connected between said rotating means and said fluid
transmitting means to control and selectively predetermine the
operational times of the separate and successive tube filling,
centrifuging, and decanting functions of said system.
16. The system according to claim 14 wherein said fluid
transmitting means comprises a peristaltic pump connected between
said source and said centrifuge.
17. The system according to claim 16 and further comprising a
restrictor valve connected in said fluid transmitting means between
said source and said peristaltic pump.
18. The system according to claim 14 wherein said fluid
transmitting means comprises a closed system between said source
and said distributor.
19. The system according to claim 14 wherein said fluid
transmitting means comprises a flexible tube connected between said
source and said distributor and a peristaltic pump operative upon
the exterior portion of said tube to cause the movement of said
fluid from said source to said distributor.
Description
BACKGROUND OF THE INVENTION
1. Field Of The Invention
The present invention relates to an apparatus and system for
treating and washing biological materials and, more particularly,
to a system including means for centrifuging said materials in a
plurality of swinging centrifuge tubes, a distributor which is
separably connected to and rotates with the centrifuge rotor and
which projects washing fluid into each of said tubes, and a
metering peristaltic pump which transmits a predetermined quantity
of washing fluid to the rotating distributor.
2. Description Of The Prior Art
In Blum et al., U.S. Pat. No. 3,420,437, a cell washing centrifuge
is disclosed in which a swinging tube centrifuge rotor provides for
alternate centrifugation and decantation of materials without
removal of the rotor from the apparatus. In that system, it is
necessary to remove the cover of the apparatus to insert fresh wash
liquid into each of the test tubes before the next procedure of
centrifugation and decantation takes place.
Blum U.S. Pat. No. 3,706,413, discloses automatic means for filling
the centrifuge tubes with wash liquid, including a system for
transmitting said wash fluid by a piston pump to a stationary
distributor spaced apart and independent from the centrifuge rotor.
A second piston pump was provided for producing air stream jets to
purge residues of liquid from the nozzles of the distributor and
project them into the respective centrifuge tubes. In this
apparatus, it was necessary to transmit the wash fluid through a
piston pump which introduced possibilities of contamination of
sterile wash liquids necessary in the treatment process.
Furthermore, indexing means were necessary to locate the centrifuge
tubes precisely opposite the respective stationary distributor
nozzles when the tube filling step took place.
Other prior centrifuging systems are disclosed in the reference
patents cited in U.S. Pat. Nos. 3,420,437 and 3,706,413.
SUMMARY OF THE INVENTION
In order to improve upon the apparatus and systems shown in the
prior art, the present invention obviates some of the drawbacks and
disadvantages thereof by providing a distributor releaseably
connected to the rotor of a swinging tube centrifuge, said
distributor rotating with said rotor and projecting wash fluid into
each of said tubes during rotation of the rotor. Furthermore, the
distributor is supplied with metered amounts of wash fluid by means
of a peristaltic pump, or the like, which transmits sterile or
other "biologically clean" fluids without subjecting the latter to
any possible contamination that would otherwise be incurred when
passing such fluids through the interior of a pumping mechanism.
The peristaltic pump produces impulses externally upon a flexible
tube made of vinyl or the like through which the fluid passes
directly from the storage reservoir to the centrifuge
distributor.
Since the distributor rotates with the centrifuge rotor during the
tube filling action, the requirements for indexing means is
obviated and centrifugal force takes care of purging the
distributor nozzles of residual droplets of wash liquid which are
automatically discharged into the respective centrifuge tubes.
According to the improved system and apparatus herein, the cell
washing process takes place automatically through the successive
steps of tube filling, centrifugation and decantation from
beginning to end without contamination or handling of wash fluids
and without the necessity of performing repeated manual operations
to fill and refill the swinging tubes of the centrifuge rotor.
These and other novel features and advantages of the present
invention will be described and defined in the following
specification and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically represents the cell washing system of the
apparatus herein, including a fragmentary portion of the reservoir,
a front elevation of the peristaltic pump, and a side elevation of
the contrifuge and decanting apparatus, part of the latter being
broken away to show a portion of the interior thereof in
elevation;
FIG. 2 is a vertical central section view of the upper portion of
the centrifuge apparatus shown in FIG. 1, some parts being shown in
elevation and some parts in dotted outline;
FIG. 3 is an exploded partial view, in elevation, of a portion of
the apparatus shown in FIG. 2, some parts being omitted and some
parts being shown in section;
FIG. 4 is a top view taken on line 4--4 of FIG. 3, some parts being
omitted and some parts being broken away;
FIG. 5 is a bottom view taken on line 5--5 of FIG. 3, some parts
being broken away;
FIG. 6 is a greatly enlarged top view of the distributor shown in
FIGS. 3 and 5, some parts being broken away and some parts being
shown in dotted outline;
FIG. 7 is a section view taken on line 7--7 of FIG. 6;
FIG. 8 is a somewhat enlarged perspective view of a portion of the
peristaltic pump shown in FIG. 1; and
FIG. 9 is a diagrammatic representation of the control circuit for
the apparatus and system herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, there is shown in FIG. 1 a schematic
representation of the improved cell washing system herein including
an automatic cell washing apparatus, generally designated 11, which
has a base section 12 mounted on suitable feet 13 that rest upon a
laboratory table or the like.
Base 12 contains an electric centrifuge motor 14 and electrical
circuitry operated by a suitable control knob 15. Supported on base
12 is a generally circular, bowl shaped centrifuge container 16 to
which is connected, by means of hinge 17, a circular closure cover
comprising an annular wall 18 and a cover plate 19 integrally
formed therewith. Said cover is releaseably secured in position by
a suitable lock element 20. Located within container 16 and cover
18 is a centrifuge apparatus which will be described in greater
detail hereinafter. Mounted on the central top portion of cover 18
is an angled tubular fixture 21.
The system herein includes a wash water supply reservoir 22
connected by way of flexible tube 23 to fixture 21 on the
centrifuge. Located between reservoir 22 and centrifuge apparatus
11 is a peristaltic pump 24 operated by an electric motor 25. An
intermediate portion of tube 23 extends around a rotatable capstan
26 of peristaltic pump 24 (FIG. 8) whereby the spaced rollers 27 of
said capstan produces successive peristaltic pinches on tube 23 in
order to cause the wash fluid to flow therethrough to the
centrifuge apparatus. A suitable variable restrictor valve 28 may
be incorporated into that portion of tube 23 extending between
reservoir 22 and pump 24 for predetermining or controlling the
quantity of fluid that passes from the reservoir to the
centrifuge.
The centrifuge apparatus for rotating a plurality of swinging test
tubes is similar to that shown in Blum et al. U.S. Pat. No.
3,420,437 (issued Jan. 7, 1969), which discloses detailed
structures for controlling the positioning of the tubes during the
respective centrifuging and decanting operations. It is to be
assumed that such control structures or suitable modifications
thereof are also utilized in the present apparatus.
Extending through and rotating freely through a suitable aperture
31 in the bottom of container 16 is a drive shaft 32 connected to
and rotated by electric motor 14 is base section 12. See FIGS. 2
and 4.
Mounted on shaft 32 and rotatable therewith is a circular
centrifuge bowl 33. Secured to the central interior portion of said
bowl, and rotating therewith, is a circular base element 34.
Extending through and upwardly from base 34 and located axially
relative to drive shaft 32 is a spindle 36 which is rotatably
driven by shaft 32. Removably mounted over and rotated by spindle
36 is a tubular hub 37 to the upper end of which is axially
connected horizontal carrier plate 38 extending outwardly from said
hub. Arrayed in a circle coaxially with hub 37 near the outer
portion of plate 38 is a plurality of evenly spaced apart slots 39,
each of which is pivotally engaged by the curved hinge 41 of a
skeleton tube carrier, generally designated 42, integrally formed
with said hinge. Each tube carrier 42 comprises an elongated spine
having one or more spaced apart integrally formed circular tube
bands or rings 43. The bottom portion of tube carrier 42 terminates
in an outwardly curved supported flange 44. Each swinging tube
carrier accommodates an elongated centrifuge tube 46.
When the centrifuge is at rest or in the decanting position, tube
carriers 42 and tubes 46 are positioned in a vertical or near
vertical position. When the apparatus is in the centrifuging
condition, tube carriers 42 and tubes 46 swing outwardly, as shown
in FIG. 2, where they are retained at the angled position by virtue
of the outward ends of flanges 44 bearing by centrifugal action
against the inner wall of bowl 33. It is understood that the
various suitable mechanisms for releaseably locking the tube
carriers 42 in the decanting position, as disclosed in U.S. Pat.
No. 3,420,437, or mechanisms similar thereto, will be utilized in
the apparatus described herein.
Secured to the upper interior end of tubular hub 37 is a stub 47,
the upper end of which terminates in a knob 48 extending upwardly
above carrier plate 38. Knob 48 has upper and lower inwardly
beveled annular surfaces 49 and 51, respectively, the function of
which will be described hereinafter.
An annular collector trough 56, located within annular closure wall
18, has an integrally formed annular flange 57 which is secured to
a peripheral portion of the bottom surface of cover plate 19. See
FIG. 2. The bottom of collector 56 has an integrally formed,
inwardly extending annular shelf 58, the inner circular edge of
which is located in a position where decanting liquids are received
from centrifuge tubes 46 when the latter are rotated in the
vertical or near vertical position. In one location of shelf 58, at
a juncture with the vertical portion of collector trough 56, there
is a drain outlet 59 to which is connected one end of flexible
drain tube 61 which extends through a suitable aperture in annular
wall 18. The other end of tube 61 (not shown) is located in a
suitable place for collecting or disposinng of the decanted
materials.
Secured to the inner central top portion of cover plate 19 is the
central base portion 62 of a downwardly and outwardly extending
annular baffle 63. The vertical portion of tubular fixture 21 is
secured to cover plate 19 by means of a circular shield 64 which
closes the central apertures in cover plate 19 and in base portion
62, respectively. The lower end of fixture 21 has an integrally
formed port element nozzle 66 which extends a short distance below
the inner surface of base portion 62 into the interior of the
centrifuge apparatus.
The distributor, generally designated 70, comprises an assembly of
two releaseably connected elements, namely, a circular nozzle
holder 71 and a closure cover 72, secured to the nozzle holder by
means of spaced screws 73. See FIGS. 2, 4, 5, 6 and 7. The bottom
portion of nozzle holder 71 has a central circular recess 74
bounded on two sides by elongated arcuate niches 75 spaced
180.degree. apart. Located in circular array on the peripheral
bottom portion of cover 72 are integrally formed, downwardly
extending spaced legs 76 that define a plurality of alignment
recesses, the function of which will be described hereinafter.
Secured fast by means of a screw 77 on the inner end of recess 74
is the base of a spring element 78 having integrally formed,
downwardly extending, inwardly biased bowed spring wings 79. When
distributor 70 is assembled into the apparatus, it is pressed
downwardly over knob 48 whose beveled surface 49 urges wings 79
apart. Wings 79 then ride over the wide portion of said knob and
engage beveled surface 51 to secure the distributor assembly 70 to
the knob. Niches 75 provide room for the flexing action of wings 79
which are aligned therewith. Carrier plate 38 has a plurality of
sockets 81 in spaced circular array which accommodate
correspondingly arrayed downwardly descending pins 82 mounted in
the bottom surface of nozzle holder 71 in order to cause said
distributor to rotate in unison with the centrifuge.
Nozzle holder 71 has a plurality of radially extending spaced
channels 83 oriented downwardly and outwardly from the top center
of said holder. Located in the outer portion of channels 83 are
respective tubular nozzles 84, the outer ends of which extend
outwardly and in radial array toward corresponding centrifuge tubes
46. Access to the inner ends of channels 83 is provided by a
central aperture 85 in cover 72 into and through which wash fluid
is transmitted from nozzle 66.
The outer end of each nozzle 84 may be cut at an angle relative to
the axis thereof so that fluid emerging therefrom may be prevented
from spraying upwardly. The wash fluid being delivered to the well
formed by aperture 85 and the top apex dome 86 of holder 71 is
caused by the rotation of holder 71 at centrifugal speed to expel
said fluid in jet streams through nozzles 84 into the respective
centrifuge tubes 46. By suitable equidistant spacing of channels 83
in relation to the symmetrically shaped conical dome 86, the
distribution of substantially equal amounts of fluid into tubes 46
is ensured.
By virtue of the engagement of pins 82 with corresponding apertures
81 in carrier plate 38, nozzles 84 are always properly aligned with
respective tubes 46.
The electrical schematic drawing of FIG. 9 represents on embodiment
of typical control system for operating the automatic cell washing
apparatus herein. The centrifuge motor to which shaft 32 is
connected is operated by its timer, controlled by knob 15. The
peristaltic pump motor 25 is controlled by its separate timer
operated by a second knob, not shown. Both control knobs are
mounted on the sloping front panel of base section 12. After the
biological specimens have been inserted into each of the centrifuge
tubes 46, the centrifuge motor 14 is started to cause rotation of
carrier plate 38 whereby tubes 46 swing outwardly to the angled
centrifuging position as shown in FIG. 2. The centrifuge timer is
adjusted to determine the duration of centrifugation.
When tubes 46 have reached the angled centrifuging position, a
signal in the electrical control system actuates a solenoid
selector switch to cause operation of peristaltic pump 24 by pump
motor 25 whereupon a predetermined quantity of fluid is transmitted
from reservoir 22 through tube 23 into the well of distributor 70
whence the wash liquid is projected centrifugally through nozzles
84 into respective tubes 46 in a quantity predetermined by the
timer connected to the pump motor and, additionally, by the
adjustment of restrictor valve 28. The setting on the pump motor
timer may be determined and calibrated so that the operator can set
the on time of the pump motor for a requisite period for filling
the centrifuge tubes 46 with the proper amount of wash liquid.
After wash liquid has been introduced into the spinning centrifuge
tubes 46, centrifugation is continued for the necessary time as may
be empirically determined by experimentation and the like, the
timing of this function being set by the timer connected to
centrifuge motor 14.
After centrifugation is completed, the centrifuge timer
automatically stops the rotation of the centrifuge to permit test
tubes 46 to descend to their suspended position where they are all
automatically secured in a vertical or near vertical decanting
position as shown by the dotted outlines in FIG. 2, and retained
there by means described, for example, in U.S. Pat. No. 3,420,437,
or by any other suitable means. Thereafter, the timer again
activates the centrifuge motor 14 to cause rotation of test tubes
46 in the vertical or near vertical position at a slower speed for
a predetermined period whereby decantation of the supernatant fluid
takes place from said tubes onto shelf 58 whence said fluid
descends by gravity through drain outlet 59 and drain tube 61 to a
suitable reservoir or sink. The foregoing steps define a single
cell-washing cycle.
It is to be understood that when the centrifuge tubes are described
and claimed herein as being in the vertical decanting mode, the
word "vertical" is intended to include the concept of "near
vertical" since in various embodiments of the apparatus it may be
desirable, when the apparatus is in the decanting mode, to have the
tubes positioned in slightly outwardly or inwardly inclined
positions relative to the true vertical as distinguished from the
widely angled position of said tubes in the contrifuging mode.
These alternative possibilities are disclosed in Blum et al., U.S.
Pat. No. 3,420,437.
After the predetermined decantation cycle takes place, as
controlled by the centrifuge motor timer, the tube restraining
mechanism (not shown) on the centrifuge automatically releases the
holders 42 of tubes 46, after which the centrifuge motor is started
again in the centrifugation mode to cause said tubes to assume the
angled centrifuging position as shown in FIG. 2. At that time, the
pump motor 25 becomes automatically activated to cause peristaltic
pump 24 to draw fresh saline solution from reservoir 22 and
transmit it through tube 23 and fixture 21 into the well formed by
the aperture 85. During this fill cycle, the centrifuge rotor
rotates at approximately 1,200 rpm, while centrifugal force propels
the saline solution through nozzles 84 into the respective
centrifuge tubes 46. By virtue of the geometry of the distributor
and the rotor, nozzles 84 project slightly into the upper open ends
of tubes 46 which are spinning and are maintained at an angle of
approximately 42.degree. from the vertical, in one embodiment of
the apparatus. From the time the saline solution enters the
distributor to the time it impinges upon the previously centrfigued
residuum or button in each tube 46 and is accelerated by increasing
centrifugal force, the velocity of the fluid being projected into
the respective tubes 46 resuspends the residual materials therein
and accomplishes the washing action that is intended by the
apparatus.
After the predetermined metered quantity of saline solution has
been centrifugally projected in the centrifuge tubes 46, pump motor
25 is stopped by its respective timer after which further
centrifugation is continued by centrifuge motor 14 until the
requisite predetermined time has elapsed in accordance with the
setting of the centrifuge motor timer. Thereafter, the tube
filling, cell washing centrifugation, and decanting cycles may be
repeated as required by clinical or experimental considerations. A
suitable wash cycle selector may be included in the control circuit
for the apparatus herein in order to permit the operator thereof to
select the number of complete tube filling, centrifuging, and
decantation cycles to be performed.
The cell washing apparatus disclosed herein provides a virtually
closed system from the saline reservoir 22 to the drain aperture 59
whereby possible contamination and erroneous results are minimized
or eliminated. By providing the unitary tube 23 which transmits
saline from reservoir 22 to the aperture well 85 in distributor 70,
the integrity of that solution is preserved, contrary to the
necessity in other types of apparatus to pass through the interior
of pump cylinders and the like. Tube 23 encircles rotating capstan
26 and the pumping action is impressed upon the exterior of tube 23
by an array of three or more spaced rollers 27 that peristaltically
pinch said tube to cause the movement of fluid therein.
The requisite amount of solution to be transmitted to centrifuge
tubes 46 is empirically determined before the apparatus performs
actual operating experiments, and this is accomplished by adjusting
the flow control or restrictor valve 28 to calibrate the delivery
volume of peristaltic pump 24. Flow control valve 28 is "in line"
in tube 23 and it may be adjusted to accommodate the operation of
the apparatus to the type of material of which tube 23 is made and
to its internal diameter which determines its flow capacity.
Should any contamination occur in the sale wash solution in
reservoir 22 or in tube 23, all that is necessary is to replace or
re-sterilize said tube and reservoir 22, and distributor 70.
By virtue of the fact that distributor nozzles 84 are rotating at
high speed during the transmission of washing fluid into centrifuge
tubes 46, centrifugal force will automatically purge said tubes of
any residual wash liquid so that no auxiliary purge devices and
equipment are required to clear said tubes of the wash liquid.
Since the distributor is attached to and rotates with the
centrifuge rotor, there is no problem of causing the rotor to come
to rest in any one of several discrete locations for alignment of
the centrifuge tubes with stationary jet nozzles as was required in
some prior art devices. Furthermore, there is no requirement in the
present apparatus to provide any high pressure delivery of wash
fluid as is requisite in a stationary fluid-filling apparatus
since, in the present apparatus, centrifugal force causes the wash
fluid delivered from nozzles 84 to be projected with sufficient
pressure into tubes 46 to cause the materials therein to be
resuspended.
It will be noted that when the centrifuge tubes 46 are in the
angled centrifuging position as illustrated in solid lines in FIG.
2, the top portions of said tubes are located within respective
recesses between legs 76 whereby accidental skewing of said tubes
on their respective hinges 41 is prevented, thus ensuring that
liquids from nozzles 84 will be directed into the respective
centrifuge tubes.
Furthermore, in order to ensure a liquid-tight seal between holder
71 and closure cover 72, there may be provided a resilient 0-ring
87 therebetween, made of a suitable material such as nylon, Teflon,
rubber, or the like.
Although the present invention has been described with reference to
particular embodiments and examples, it will be apparent to those
skilled in the art that variations and modifications can be
substituted therefor without departing from the principles and true
spirit of the invention. The Abstract given above is for the
convenience of technical searchers and is not to be used for
interpreting the scope of the invention or claims.
* * * * *