Imperforate bowl: centrifugal separators – Including sealing means – For sealing between stationary and moving elements
Reexamination Certificate
2000-12-08
2004-11-30
Sorkin, David (Department: 1723)
Imperforate bowl: centrifugal separators
Including sealing means
For sealing between stationary and moving elements
C494S045000, C494S048000, C092S09800R, C092S104000
Reexamination Certificate
active
06824506
ABSTRACT:
TECHNICAL FIELD
This invention relates to centrifuge systems for the general processing of fluids and, more specifically, the separation of such fluid into its constituents.
BACKGROUND ART
Centrifugal fluid-processing systems have been in existence for some time. A particularly common use for such systems is for the processing and separation of whole blood into red blood cell, white blood cell, plasma, platelet and other constituents or components. Such centrifuge systems are generally categorized as either being continuous-flow devices or discontinuous-flow devices.
In continuous-flow systems, whole fluid is input through a conduit into a spinning rotor where the fluid is separated into its components. A component of interest may be collected and any unwanted components may be removed through a second conduit on a continuous basis while more whole fluid is being input. These systems typically employ a belt-type rotor which has a relatively large diameter but a relatively small (typically 100 ml or less) processing volume. Although continuous-flow systems have an advantage that the total amount of fluid being processed may be relatively small, they have the disadvantage that the diameter of the rotor is large. Therefore, such systems are large and also tend to be complicated to set up and use.
In discontinuous-flow systems, whole fluid is also input through a conduit into a rotor where component separation takes place. These systems usually employ a bowltype rotor having a relatively large (typically 200 ml or more) volume that must be essentially filled with fluid before any of the desired components can be harvested. When the bowl is full, the input of fresh fluid is stopped and the unwanted components are removed through the same conduit. When the rotor has been emptied, new whole fluid is introduced and a second cycle begins. This process continues until a required amount of component has been collected. Thus, removal occurs intermittently in batches rather than on a continuous basis. Discontinuous-flow systems have an advantage that their rotors are relatively small in diameter but have the disadvantage that the total volume of fluid being processed is large.
Centrifuge systems and methods for processing blood and other fluids that are compact and easy to use and that do not have the disadvantages of prior-art discontinuous-flow systems have been previously disclosed in a number of U.S. patents assigned to Transfusion Technologies Corporation. Such systems generally include a disposable set that acts as a centrifuge rotor. In particular, U.S. Pat. No. 6,074,335, entitled “Rotor with Elastic Diaphragm Defining a Liquid Separating Chamber of Varying Volume,” issued on Jun. 13, 2000, as well as its parent, U.S. Pat. No. 5,733,253, issued on Mar. 31, 1998, are hereby incorporated herein by reference. Embodiments of this rotor include an elastic, impermeable wall (elastic diaphragm) which defines at least a portion of a variable-volume fluid processing chamber. Rotor embodiments include a rigid mounting member to which the elastic diaphragm is mounted and which is held onto and spun by a chuck. This rigid mounting member may include a rigid wall which, together with the elastic diaphragm, defines the variable-volume chamber. Both the diaphragm and the rigid wall are referred to as chamber boundaries since each of them define portions of the interior of the variable-volume processing chamber with each having one side which does not come into contact with the biological fluid. In some embodiments, the diaphragm may be located inside other walls on the exterior of the rotor, such as the rigid boundary wall or an exterior shell.
Numerous rotor embodiments are disclosed in U.S. Pat. No. 6,074,335. By way of example, the rigid boundary wall may be large enough to surround the maximum volume that may be taken up by the chamber, or the rigid mounting member may be only large enough to provide a place where the diaphragm may be mounted and where a chuck can hold and spin the rotor. In another rotor embodiment, the rigid boundary wall is a substantially imperforate circular wall which extends to the periphery of the processing chamber, so as to define the top of the processing chamber. The elastic diaphragm is attached to the perimeter of the wall and defines the remainder of the processing chamber. In yet another embodiment, the rigid boundary wall is substantially imperforate but defines one opening near the rotor's axis of rotation permitting a conduit to pass therethrough so as to be in fluid communication with the processing chamber. In alternative embodiments, the rigid boundary wall may have a plurality of openings and, possibly, numerous conduits for controlling the flow into and/or out of the rotor while the rotor is being spun. Some rotors feature a fixed portion that does not rotate during centrifugation. In particular, such a fixed rotor portion may provide a fluid conduit or, perhaps, more than one such conduit, affording fluid communication between an input source of whole fluid, the rotating portion of the rotor, and an output. Rotors having a fixed portion may include a rotary seal. Embodiments of rotary seals are disclosed in both U.S. Pat. Nos. 6,074,335 and 5,904,355, the latter reference hereby incorporated herein by reference.
FIG. 1
is a top plan view of a prior art rotor embodiment, while
FIG. 2
shows a cross-section of the rotor embodiment illustrated in FIG.
1
. Rotor
2
a
has an elastic boundary (i.e., an impermeable diaphragm
31
) sealed to a rigid, imperforate boundary wall
10
by an O-ring
35
or other means. Diaphragm
31
is preferably made of an elastic, stretchable and resilient material, such as latex or silicone rubber. Diaphragm
31
is a simple diaphragm as shown because, as is hereby defined, in its unstretched condition, it exhibits an essentially constant thickness and is essentially planar. It is to be understood that a simple diaphragm
31
may include a non-planar region in the immediate vicinity of its attachment to (or its seal with) wall
10
(i.e. a rim for mounting or other such equivalently functional mounting feature). A perforate interior wall
40
—also referred to as a plate—having holes
39
, is attached under the rigid boundary wall
10
. Preferably, the boundary wall
10
and the interior wall
40
are made out of a rigid thermoplastic. The perforate interior plate
40
is held a short distance away from the imperforate boundary wall
10
by standoffs (not shown), thereby forming a passage
44
.
FIG. 3
is a bottom view of another prior art rotor embodiment illustrated without a diaphragm
31
in place.
FIG. 4
is a cross-section of the rotor of FIG.
3
. The embodiment of
FIGS. 3 and 4
illustrate a different type of fluid outlet control from the previous configuration. This rotor embodiment features grooves
244
, that are preferably radially aligned, formed on the bottom of boundary wall
10
as the outlet control means, instead of tubes or an interior perforate wall/plate
40
. The grooves
244
are defined by vertical channel walls
240
provided by boundary wall
10
; if the vertical channel walls
240
are placed close enough to each other so that diaphragm
31
will not block off grooves
244
under pressurized or static conditions, they can keep channels (the grooves
244
) open from the holes
239
, which connect the processing chamber
30
and the collector assembly
46
, to, if desired, the periphery of the rotor, or to whatever radius (the radius is illustrated generically in
FIGS. 3 and 4
as reference item
245
) it is desired to maintain a channel. The
FIG. 4
rotor has a fixed portion (including the collector assembly
46
) which interfaces with the rotating portion of the rotor at a rotary seal
48
. An internal wall
237
, shown in
FIGS. 3 and 4
as a portion of boundary wall
10
, is necessary to keep the spinning diaphragm
31
from coming into contact with the fixed portion and possibly being abraded leading to premature failure.
Referring now to
FIGS. 5 and 6
(showing a system incorporatin
Headley Thomas D.
Lamphere David G.
Bromberg & Sunstein LLP
Haemonetics Corporation
Sorkin David
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