Note: Descriptions are shown in the official language in which they were submitted.
1059924
DIALYZER PLATE CARTRIDGE
This invention relates to a structure for facilitat-
ing the process of dialysis in artificial kidney systems and
the like.
In artificial kidney systems, blood is withdrawn
from a patient and applied to a dialyzer through which dialysate
solution is circulated and then, by the process of dialysis,
chemical wastes, electrolytes and water in the bload pass
into the dialysate solution (and in some cases vice versa)
through t~in walls of a membrane structure, such as hollow
fibres, carrying the blood. The dialysate solution containing
the wastes and water is drawn from the dialyzer and disposed
of and the blood is returned to the patient. This process
of transporting wastes and water from the blood is referred
to as hemodialysis.
Dialyzers or dialyzer cartridges of the hollow
fibre type typically include a bundle of hollow fibres potted
at either end in rubber or other suitable material for holding
the fibres. The cross section of the bundle and the potting
material is circular to enable insertion of the bundle into
a cylindrically-shaped container. Blood is then introduced into
one end of the container
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to flow through the fibres to the other end and
dialysate solution is introduced near the central
portion of the container to flow about the exterior
surfaces of the fibres and then out again. With
this configuration, the cross-sectional area of the
potting material is rather large and, since the
material is supported only around its periphery,
pressures caused by the dialysate solution and the
blood may cause the material to deform, fracture,
and leak. This configuration may also present
fabrication problems, from a quality control stand-
point, because of the large cross-sectional area of
the potting material and the difficulty of depositing
potting material around the ends of the fibres.
Finally, the cylindrically-shaped dialyæer cartridge
` containex can accommodate only one fibre bundle size thus
necessitating a change in both the container and the
fibre bundle when a dialyzer cartridge having a
different dialyzing effective area is desired.
A specific illustrative embodiment of the
invention includes a gasket member defining a hollow,
~irst and second cross members extending between
interior side ~alls of the gasket member to divide the
hollow into first, second and third portions and
membrane elements extending across the second portion
1~)599Z4
of the holl~w from the first portion to the third portion
for carrying fluid therebetween. One fluid may be introduced
into the first portion of the hollow for transport through
the membrane elements to the third portion, and another fluid
may be introduced into the second portion of the hollow to
circulate about the membrane means and thereby facilitate
the dialysis process.
In accordance with the invention, there is provided a
.,,
dialyzer cartridge comprising a gasket member defining a
hollow, first and second cross members affixed in and extend-
ing between the side walls of the gasket member to divide the
hollow into first, second and third portions, membrane means
for carrying fluid, said membrane means extending across the
second portion of the hollow between the cross me~bers to
` provide a passageway for carrying fluid between the first and
third portions of the hollow, sealing means for sealing the
first and third portions from the second portion, means for
introducing a first fluid into the first portion so that the
first fluid is carried by the membrane means to the third
portion, and means for introducing a second fluid into the
second portion to flow about the exterior surface of the
membrane means, said dialyzer cartridge further comprising
divider means dividing the first portion of the hollow into
first and second sections, means for introducing said first
fluid into the first section, said first fluid being carried
from the first section by the membrane means to the third
portion of the hollow and then being carried by the membrane
means to the second section, and means for receiving said
second fluid from the second section.
~05992~
The gasket member and cross members may be constructed
of resilient material such as silicone rubber, polymethyl-
- methacrylate or the like.
m e gasket member and cross members may define a
, substantially planar profile and sealing means may comprise
a pair of plates for securing the gasket member therebetween.
Such dialyzer cartridge may further comprise means for urging
the two plates together to compress the gasket member there-
between. In this construction at least one of the plates may
have an aperture therein through which fluid may be introduced
into the first portion of the hollow, at least one of the
v plates may have an aperture therein through which fluid may
be received from the third portion of the hollow, at least
one of the plates may have an aperture therein through which
fluid may be introduced into the second portion of the hollow,
and at least one of
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10599Z4
the plates may have an aperture therein through which
fluid may be received from the second portion.
In an alternative constructio~ side walls of the
gasket member may have a first opening through which fluid
may be introduced into the first portion of the hollow, a
second opening through which fluid may be received from
the third portion of the hollow, a third opening through
which fluid may be introduced into the second portion of
the hollow, and a fourth opening through which fluid may
be received from the second portion of the hollow.
The membrane means employed in the dialyzer cartridge
of the invention may include a plurality of hollow fibres,
the ends of which are embedded in respective cross members
to extend from the first portion to the third portion of
the hollow for carrying fluid therebetween.
One embodiment of the dialyzer cartridge of the
invention further comprises divider means dividing the
first portion of the hollow into first and second
sections, means for introducing fluid into the first
section, said fluid flowing from the first section through
the membrane means to the third portion of the hollow and
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then through the membrane means to the second section, and
means for receiving fluid from the second section.
Further constructional aspects and details of a
dialyzer cartridge construction in accordance with the in-
vention will become appaxent with reference to the accompanying
drawings in which:
Fig. 1 is an exploded, perspective view of a dialyzer
cartridge made in accordance with the present invention;
Fig. 2 is a top view of the gasket member and the
membrane structure of the dialyzer cartridge of Fig. 1 and
Fig. 3 is a top view of an alternative embodiment
of the gasket member and membrane structure.
The dialyzer cartridge of Fig. 1 will be described
assuming that the cartridge is to be used for hemodialysis.
As will be apparent, however, the cartridge could be used
for various types of dialysis. As shown in Fig. 1, the
cartridge includes a generally rectangularly-shaped gasket
member 2 circumscribing and defining a hollow area there-
within. The gasket 2 is constructed of a material such
as silicone rubber of polymethylmethacrylate. A pair of
cross members 4 and 6, advantageously constructed of the
same material as the gasket 2, extend between parallel
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1059924
interior side walls of the gasket 2 to divide the hollow
area defined by the gasket into three portions or sub-
sections 8, lO and 12. The cross members 4 and 6 may
be molded integral with the gasket 2 or may be fabricated
separately and then affixed in the gasket 2 by a suitable
adhesive. The gasket 2 and cross members 4 and 6 define
a generally planar profile having a substantially uniform
thickness.
A plurality of membrane elements in the form of
hollow fibres 14 extend between the cross members 4 and
6 across the central hollow portion 10. The ends of the
fibres are embedded in and carried by respective ones
of the cross members 4 and 6 to hold the fibres in place.
The terminations of the fibres extend through corresponding
cross members into the two end hollow portions 8 and 12.
A portion of the terminations of the fibres 14 which extend
into the hollow portion 8 are shown at 16 of Fig 1. The
hollow fibres 14 may be constructed of cellulose or other
semipermeable membrane.
Embedding the fibres in the cross members may be
accomplished in a variety of ways. For example, a few
of the fibres may be positioned in a form or mold and
, .
` 105~924
s
un-solidified room temperature vulcanizing silicone rubber
applied thereto. When the applied silico~e rubber cures or
solidifies, more fibres may be laid in place and more
unsolidified silicone rubber applied to the fibres. m is
' process can be repeated until the desired number of fibres
are secured in the silicone rubber cross members. If
desired, the fibres and silicone rubber may be cut at either
end thereof to neatly "square off" the fibre terminations.
The structure for supporting and containing the gasket
2 and fibres 14 includes a pair of generally flat plates 20
and 22. The plates 20 and 22 are respectively placed above
and below the gasket 2 and then secured together by bolts 24,
inserted through holes in the plates 20 and 22 and through
the hollow portions 8 and 12, and by nuts 26 screwed onto the
bolts. The plates 20 and 22 are urged together by tightening
the nuts on the bolts to thereby compress the gasket 2 and
cross members 4 and 6 to thereby seal each of the hollow
portions 8, 10 and 12 from the others. m at is, the plate 20
is urged against the upper surfaces of the gasket 2 and
cross members 4 and 6, and the plate 22 is urged against the
bottom surfaces thereof to thus form the necessary seals.
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1059924
of course, a variety of arrangements could be used to secure
the plates 20 and 22 together, including various releasable
clamping mechanisms.
When the plates and gasket are secured in place, blood
' from a patient is introduced into the dialyzer cartridge
through a conduit or tube 30 attached to the plate 20 over an
~,.
opening therein. The opening in the plate 20 is positioned
~, over the hollow portion 8 so that blood applied to the tube 30
f,lows into the hollow portion 8. The tube 30 may be attached
to the plate 20 by any suitable means which will enable
conveyance of blood into the hollow portion 8 while preventing
leaking. For example, a raised cylindrical nipple could be
formed in the plate 20 over which the end of the conduit 30
could be positioned and held in place by a suitable clamp.
The blood introduced into the hollow portion 8 flows through
the fibres 14 to the hollow portion 12 and from there the
blood is carried from the dialyzer cartridge by a tube 32
attached to the plate 20 over an opening in the plate. Again,
the opening over which the tube 32 is attached is positioned
over the hollow portion 12. The positioning of the openings
in the plate 20 are shown by dotted circles in Fig. 2.
T
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The dialysate solution is introduced and removed
from the central hollow portion lO in a similar fashion.
Specifically, the dialysate solution is introduced via
tube 34 into one corner of the central hollow portion
10 and the solution flows and circulates about the
fibres and then out tube 36. As the blood flows through
the fibres 14 and the dialysate solution flows around
the fibres, dialysis takes place and chemical wastes,
electolytes and water in the blood pass through the
walls of the fibres into the dialysate solution.
With the structure shown and described, gaskets
of various thicknesses can be accommodated between plates
20 and 22 and thus the membrane or fibre wall area may
be varied simply by substituting gaskets of different
thicknesses having different numbers of fibres. In
addition, the flat profile of the dialyzer cartridge
facilitates ease of packing and shipping. It may be
desirable to ship the gasket in a sterile membrane cover
(to maintain the gasket in a sterilized condition),
which could remain f-itted over the gasket when the gasket
were positioned between the plates (provided appropriate
holes were made in the membrane to allow introduction
and exit of blood and dialysate solution). The cross
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lOS99:24
members 4 and 6 securing the fibres 14 provide a rugged
support for the fibres since the thickness of the cross
members and thus the distance between points of support
of the cross ~,embers by the plates 20 and 22 is relatively
small. That is, there is little chance for deformation
and fracturing of the cross members due to fluid pressures
introduced into the dialyzer cartridge.
Fig. 3 shows an alternative embodiment of a dialyzer
gasket and membrane structure. In this embodiment, two
hollows or sections 40 and 42 are formed in one end of
the gasket 2 with a central hollow portion 10 and an
opposite end hollow portion 12 also formed in the gasket,
as in the ~gs. 1 and 2 embodiment. Hollow fibres 14
extend across the central hollow portion 10 between the
hollow section 40 and hollow portion 12 and between the
portion 12 and hollow section 42. With this configuration,
dialysate solution is introduced into the central hollow
portion 14, through a section of tube 50 extending through
the side wall of the gasket 2, and blood is introduced
into the section 40, through a section of tube 52
extending through the end wall of the gasket, to flow
through fibres 14 to the hollow portion 12 and then
- through fibres 14 to the section 42. This provides a
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~0599Z4
longer membrane pathway for the blood to travel through
the dialysate solution, thereby facilitating greater
exposure for the blood to the dialysis process. Of course,
plates 20 and 22 would be provided with the gasket
configuration of Fig. 3. In this case, no openings in the
plates would be needed since the blood and dialysate
solution is introduced into and removed from the cartridge
through sections of tube extending through the walls of
the gasket.
