U.S. patent application number 17/023834 was filed with the patent office on 2021-01-07 for sorbent pouch.
The applicant listed for this patent is Medtronic, Inc.. Invention is credited to Martin T. Gerber, Christopher M. Hobot.
Application Number | 20210001307 17/023834 |
Document ID | / |
Family ID | |
Filed Date | 2021-01-07 |
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United States Patent
Application |
20210001307 |
Kind Code |
A1 |
Gerber; Martin T. ; et
al. |
January 7, 2021 |
SORBENT POUCH
Abstract
A sorbent pouch for use in sorbent dialysis. The sorbent pouch
allows for fluid to freely pass into and through the sorbent
materials, while keeping the sorbent materials inside the sorbent
pouch.
Inventors: |
Gerber; Martin T.; (Maple
Grove, MN) ; Hobot; Christopher M.; (Rogers,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Medtronic, Inc. |
Minneapolis |
MN |
US |
|
|
Appl. No.: |
17/023834 |
Filed: |
September 17, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15938009 |
Mar 28, 2018 |
10807068 |
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17023834 |
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14637606 |
Mar 4, 2015 |
10286380 |
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15938009 |
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62016613 |
Jun 24, 2014 |
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Current U.S.
Class: |
1/1 |
International
Class: |
B01J 20/28 20060101
B01J020/28; B01D 15/08 20060101 B01D015/08; A61M 1/16 20060101
A61M001/16 |
Claims
1. A sorbent pouch, comprising: a porous material forming in-part a
sorbent containing a material consisting essentially of alumina,
the porous material retaining at least 98% by weight of the
alumina.
2. The sorbent pouch of claim 1, the porous material allowing
dissolved urease to pass through the porous material.
3. The sorbent pouch of claim 1, the porous material preventing
undissolved urease from passing through the porous material.
4. The sorbent pouch of claim 1, wherein the porous material is
selected from the group consisting of bolting cloth, porous
polymer, porous metal, cotton, ashless filter paper, Dacron, and
polyethylene terephthalate.
5. The sorbent pouch of claim 1, wherein the sorbent pouch has a
shape selected from the group consisting of a circular shape, a
square shape, a triangular shape, a rectangular shape, and a disc
shape.
6. The sorbent pouch of claim 1, wherein the sorbent pouch is
shaped to be adapted into an internal cavity defined by a sorbent
cartridge in which the sorbent pouch is housed.
7. The sorbent pouch of claim 1, wherein the sorbent pouch has a
semi-rigid structure.
8. The sorbent pouch of claim 1, wherein the sorbent pouch has a
rigid structure.
9. The sorbent pouch of claim 1, wherein the sorbent pouch has a
flexible structure.
10. The sorbent pouch of claim 1, further comprising side portions
constructed from a fluid impermeable material.
11. The sorbent pouch of claim 10, further comprising an
elastomeric material disposed on a side portion of the sorbent
pouch.
12. The sorbent pouch of claim 1, wherein the porous material is
impregnated with an antimicrobial substance and/or an
anticoagulant.
13. The sorbent pouch of claim 1, wherein the sorbent pouch further
comprises an o-ring seal member disposed on an outer periphery of
the sorbent pouch.
14. The sorbent pouch of claim 1, wherein the sorbent pouch can be
opened and re-sealed.
15. The sorbent pouch of claim 14, further comprising one or more
engagement members on a top portion and a bottom portion of the
sorbent pouch for sealing the sorbent pouch.
16. The sorbent pouch of claim 14, further comprising a hinge
connecting a top portion and bottom portion of the sorbent pouch
for opening and resealing the sorbent pouch.
17. The sorbent pouch of claim 14, further comprising an interior
or exterior ring around a top portion or bottom portion of the
sorbent pouch.
18. The sorbent pouch of claim 1, the sorbent pouch comprising an
extra layer of the porous material in a center of a bottom of the
sorbent pouch.
19. The sorbent pouch of claim 1, wherein a top portion and bottom
portion of the sorbent pouch are sealed by any one of: heat
sealing, adhesive, or woven fibers.
20. The sorbent pouch of claim 1, further comprising glass beads in
the sorbent pouch.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent
application Ser. No. 15/938,009 filed 28 Mar. 2018, which is a
Continuation of U.S. patent application Ser. No. 14/637,606 filed
Mar. 4, 2015, now U.S. Pat. No. 10,286,380, which claims benefit of
and priority to U.S. Provisional Application No. 62/016,613 filed
Jun. 24, 2014, now expired, and the disclosures of each of the
above-identified applications are hereby incorporated by reference
in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a sorbent pouch wherein the sorbent
pouch contains at least one sorbent material, and the sorbent pouch
is constructed such that fluid freely passes through the sorbent
pouch while the sorbent materials remain inside the sorbent
pouch.
BACKGROUND
[0003] One of the drawbacks of sorbent dialysis systems is high
cost due to expensive sorbent materials. Disposing of cartridges
housing sorbent materials after each use generates waste and also
drives up costs. Known dialysate fluid circulation systems and
apparatuses have separate housings where a first housing has a
sorbent material capable of performing a first function such as
releasing sodium into dialysate fluid flowing through the first
housing, and a second housing having a material capable of
performing another function such as binding sodium ions from
dialysate fluid flowing through the second housing. However, such
systems are not modular and customizable and are usually formed
into a single housing design that limits flexibility and the
possibility of customized use personalized to a particular patient.
Such sorbent systems are one-size-fits-all and operate using
similar amounts of sorbent materials across different treatment
sessions regardless of the unique needs or dialysis parameters for
a particular patient. Moreover, known sorbent systems do not
provide for recharging some or all of the components of a sorbent
cartridge that would allow reuse of specific components and enable
lower long-term costs for operating such systems, nor ease of
manufacturing the separate sorbent housings.
[0004] As such, there is a need for a sorbent cartridge having a
separation of materials within the sorbent cartridge to allow for
isolation of those materials. There is also a need for a sorbent
cartridge providing for isolation of one or more sorbent materials
to allow for cheaper or non-reusable materials to be discarded,
while more expensive and reusable materials are recharged. As such,
there is a need for a sorbent partition such as a sorbent pouch or
a system of sorbent pouches that can allow dialysate to freely move
into and out of the sorbent pouch while keeping the sorbent
material inside. There is a need for a sorbent pouch that keeps the
different sorbent materials separated from each other.
[0005] There is also a need for facilitating ease of packaging and
shipping using a modular interchangeable system to house sorbent
materials. There is a need for providing an option for allowing
sub-vendors to manufacture sorbent housing or separate assembly
line fill production facilities from one another. There is also a
need for providing a customized sorbent system wherein different
layers of sorbent materials can be used together wherein each
sorbent pouch is modular and interchangeable. There is also a need
for reducing final assembly steps required in preparing a dialysis
system for use. To combat counterfeiting, there is a need for
isolating individual vendors from a sorbent manufacturing process
wherein specific sorbent materials used for dialysis can be
pre-filled separately. There is also a need for pre-filling a
component housing sorbent materials at precise quantities to avoid
user error.
SUMMARY OF THE INVENTION
[0006] The first aspect of the invention relates to a sorbent
pouch. In any embodiment of the first aspect of the invention, the
sorbent pouch can comprise a porous material forming in-part a
sorbent pouch containing at least one sorbent material wherein the
porous material can allow fluid to pass through the sorbent
pouch.
[0007] In any embodiment of the first aspect of the invention, the
porous material can allow fluid to pass through the pouch and can
substantially retain the at least one sorbent material in the
sorbent pouch.
[0008] In any embodiment of the first aspect of the invention, the
porous material can retain greater than 98% by weight of the
sorbent material in the sorbent pouch. In any embodiment of the
first aspect of the invention, the porous material can allow fluid
to pass through the sorbent pouches but can retain anywhere from at
least 70%, 75%, 80%, 85%, 90%, 92%, 93%, 94%, 95%, 96%, or 97% by
weight of one sorbent material in the sorbent pouch.
[0009] In any embodiment of the first aspect of the invention, the
sorbent pouch can contain a sorbent material selected from
activated carbon, hydrous zirconium oxide, urease, alumina,
zirconium phosphate and ion-exchange resin, or combinations
thereof.
[0010] In any embodiment of the first aspect of the invention, the
sorbent pouch can contain glass beads.
[0011] In any embodiment of the first aspect of the invention, the
sorbent pouch can contain solid urease and the porous material can
allow fluid containing dissolved urease to pass through the sorbent
pouch material so that it can be become immobilized to another
sorbent material, such as alumina.
[0012] In any embodiment of the first aspect of the invention, the
porous material can be selected from any one of bolting cloth,
porous polymer, porous metal, cotton, ashless filter paper, Dacron
and polyethylene terephthalate.
[0013] In any embodiment of the first aspect of the invention, the
sorbent pouch can contain two or more sorbent materials.
[0014] In any embodiment of the first aspect of the invention, the
sorbent pouch can contain two or more sorbent materials mixed
together.
[0015] In any embodiment of the first aspect of the invention, the
sorbent pouch can have any geometric shape. In any embodiment of
the first aspect of the invention, the shape can be selected from
the group consisting of a circular shape, a square shape, a
rectangular shape, a triangular shape, or a disc shape.
[0016] In any embodiment of the first aspect of the invention, the
sorbent pouch can be shaped to be adapted into an internal cavity
defined by a sorbent cartridge in which the sorbent pouch is
housed.
[0017] In any embodiment of the first aspect of the invention, the
sorbent pouch can have a semi-rigid structure.
[0018] In any embodiment of the first aspect of the invention, the
sorbent pouch can have a porous structure.
[0019] In any embodiment of the first aspect of the invention, the
sorbent pouch can have a rigid structure.
[0020] In any embodiment of the first aspect of the invention, the
sorbent pouch can further comprise side portions constructed from a
fluid impermeable material.
[0021] In any embodiment of the first aspect of the invention, the
porous material can be impregnated with an antimicrobial substance
and/or an anticoagulant.
[0022] In any embodiment of the first aspect of the invention, the
sorbent pouch can further comprise an o-ring seal member disposed
on an outer periphery of the pouch.
[0023] In any embodiment of the first aspect of the invention, at
least one portion of the sorbent pouch can comprise a double layer
of the sorbent pouch material.
[0024] In any embodiment of the first aspect of the invention, the
sorbent pouch can be opened and re-sealed.
[0025] In any embodiment of the first aspect of the invention, the
sorbent pouch can further comprise an elastomeric material disposed
on a side portion of the pouch.
[0026] Any of the features disclosed as being part of the first
aspect of the invention can be included in the first aspect of the
invention, either alone or in combination.
[0027] The second aspect of the invention is directed to a sorbent
pouch system. In any embodiment of the second aspect of the
invention, the sorbent pouch system can comprise one or more
sorbent pouches wherein the one or more sorbent pouches can be
formed from a porous material and can contain inside at least one
sorbent material. In any embodiment of the second aspect of the
invention, the one or more sorbent pouches can be capable of being
attached and/or detached from each other. In any embodiment of the
second aspect of the invention, the porous material can allow fluid
to pass through the one or more sorbent pouches but can
substantially retain at least one sorbent material from passing out
of the one or more sorbent pouches.
[0028] In any embodiment of the second aspect of the invention, the
porous material can retain greater than 98% by weight of the
sorbent material.
[0029] In any embodiment of the second aspect of the invention, the
sorbent pouch system can have sorbent material selected from the
group consisting of activated carbon, hydrous zirconium oxide,
zirconium phosphate, ion-exchange resin, alumina, urease, and
combinations thereof.
[0030] In any embodiment of the second aspect of the invention, the
sorbent material can be urease, and the porous material can allow
fluid containing dissolved urease to pass through the pouch.
[0031] In any embodiment of the second aspect of the invention, any
one of the one or more sorbent pouches can contain two or more
sorbent materials.
[0032] In any embodiment of the second aspect of the invention, the
at least one sorbent materials can be mixed together.
[0033] In any embodiment of the second aspect of the invention, the
sorbent pouch can comprise a separator that separates the sorbent
pouch into a top portion and a bottom portion. The separator can
allow liquid to pass through the separator but can prevent any of
the sorbent materials from passing through the separator. In any
embodiment of the second aspect of the invention, the top portion
of the sorbent pouch can contain at least one sorbent material, and
the bottom portion of the sorbent pouch can contain at least one
sorbent material. In any embodiment of the second aspect of the
invention, the at least one sorbent material contained in the
bottom portion of the sorbent pouch can be different from the at
least one sorbent material contained in the top portion of the
sorbent pouch.
[0034] In any embodiment of the second aspect of the invention, the
sorbent pouch can comprise more than one separator.
[0035] In any embodiment of the second aspect of the invention, the
sorbent pouch system can have a sorbent pouch containing alumina
and also a sorbent pouch containing urease, wherein the sorbent
pouch containing urease is constructed of a porous material that
allows fluid to pass through the sorbent pouch and also allows
dissolved urease to pass through the sorbent pouch material to
become bound to an enzyme immobilizing sorbent material.
[0036] In any embodiment of the second aspect of the invention, the
one or more sorbent pouches can each comprise sidewalls having a
thickness different from that of the other sorbent pouches, such
that the one or more sorbent pouches have differing interior
diameters.
[0037] In any embodiment of the second aspect of the invention, the
one or more pouches can be placed in series, such that each pouch
has a sidewall thickness greater than that of the previous pouch in
series.
[0038] In any embodiment of the second aspect of the invention, the
one or more sorbent pouches can each have a differing exterior
diameter from the other pouches.
[0039] In any embodiment of the second aspect of the invention, the
one or more pouches can be placed in series, such that each pouch
has an exterior diameter smaller than that of the previous pouch in
series.
[0040] In any embodiment of the second aspect of the invention, the
one or more pouches can each contain one or more annular ring,
wherein the one or more annular ring can be constructed from a
fluid impermeable substance. In any embodiment of the second aspect
of the invention, the annular ring can be disposed on the interior
circumference of the sorbent pouch and can extend radially into the
center of the sorbent pouch.
[0041] In any embodiment of the second aspect of the invention, the
annular ring can have a cross-sectional shape selected from the
group comprising circular, rectangular and triangular.
[0042] Any of the features disclosed as being part of the second
aspect of the invention can be included in the second aspect of the
invention, either alone or in combination.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 is a top view of a disc-shaped sorbent pouch.
[0044] FIG. 2 is a top view of a rectangular sorbent pouch.
[0045] FIG. 3 is a perspective view of a rectangular sorbent
pouch.
[0046] FIG. 4a is a side view of a string of disc-shaped sorbent
pouches.
[0047] FIG. 4b is a top view of a string of disc-shaped sorbent
pouches.
[0048] FIG. 4c is a top view of a string of disc-shaped sorbent
pouches showing the detail of the outer edges of the sorbent
pouches.
[0049] FIG. 4d is a perspective view of a string of disc-shaped
sorbent pouches showing the detail of the outer edges of the
sorbent pouches.
[0050] FIG. 5a is a side view of a string of rectangular sorbent
pouches.
[0051] FIG. 5b is a top view of a string of rectangular sorbent
pouches.
[0052] FIG. 5c is a top view of a string of rectangular sorbent
pouches showing the detail of the outer edges of the sorbent
pouches.
[0053] FIG. 6 is a perspective view of a sorbent cartridge
comprising a stacked assembly of sorbent pouches containing
activated carbon, hydrous zirconium oxide, urease, alumina, and
zirconium phosphate.
[0054] FIG. 7a is a perspective view of a sorbent pouch having the
ability to open and reclose via a hinge and a latch member.
[0055] FIG. 7b is a perspective view of a sorbent pouch in an open
state.
[0056] FIG. 8a is a perspective view of a sorbent pouch having an
internal sealing ring.
[0057] FIG. 8b is a perspective view of a sorbent pouch having an
external sealing ring.
[0058] FIG. 9 is a perspective view of a sorbent pouch with an
internal separator.
[0059] FIG. 10 is a perspective view of a sorbent pouch with an
o-ring seal member.
[0060] FIG. 11 is a perspective view of a sorbent pouch with an
elastomeric material on the side walls.
[0061] FIG. 12 is a perspective view of a sorbent pouch and
cartridge with a key function to ensure correct alignment.
[0062] FIG. 13 is a perspective view of a sorbent pouch with a
double layer of material in the center to control flow through the
sorbent pouch.
[0063] FIG. 14 shows an exemplary sorbent cartridge containing
activated carbon, hydrous zirconium oxide, urease, alumina, and
zirconium phosphate.
[0064] FIG. 15 shows an exploded cross-sectional view of a sorbent
cartridge having stacked sorbent pouches, with each sorbent pouch
in series having a thicker sidewall, and therefore smaller interior
diameter, than that of the previous sorbent pouch in series.
[0065] FIG. 16 shows an exploded perspective view of a sorbent
cartridge having stacked sorbent pouches, with each sorbent pouch
in series having a thicker sidewall, and therefore smaller interior
diameter, than that of the previous sorbent pouch
[0066] FIG. 17 shows an exploded cross-sectional view of a sorbent
cartridge having stacked sorbent pouches, with each sorbent pouch
in series having a smaller exterior diameter than that of the
previous sorbent pouch.
[0067] FIG. 18 shows a cross-sectional perspective view of a
sorbent pouch having an annular ring disposed on the interior
circumference of the sorbent pouch.
DETAILED DESCRIPTION OF THE INVENTION
[0068] Unless defined otherwise, all technical and scientific terms
used herein generally have the same meaning as commonly understood
by one of ordinary skill in the relevant art.
[0069] The articles "a" and "an" are used herein to refer to one or
to more than one (i.e., to at least one) of the grammatical object
of the article. By way of example, "an element" means one element
or more than one element.
[0070] An "adhesive" is any substance known in the art for use in
affixing one surface to another surface, or to seal two surfaces
together.
[0071] An "annular ring" is a ring having a substantially circular
shape. The cross-section of the ring may be rectangular,
triangular, round, or any other known shape. The ring may be
constructed of any rigid or semi-rigid material, and may be adhered
to the inner surface of a sorbent pouch by any means known in the
art. An annular ring may also be an "o-ring."
[0072] The term "cartridge" refers to any container designed to
contain a powder, fluid, or gas made for ready connection to a
device or mechanism. The container can have one or more
compartments. Instead of compartments, the container can also be
comprised of a system of two or more modules connected together to
form the cartridge wherein the two or more modules once formed can
be connected to a device or mechanism.
[0073] A "circular shape" describes a sorbent pouch constructed in
a generally round shape having the form of a circle. This term is
not intended to limit the shape of the sorbent pouch to any
particular size or dimensions, and may encompass oval or oblong
configurations as well.
[0074] The term "comprising" includes, but is not limited to,
whatever follows the word "comprising." Thus, use of the term
indicates that the listed elements are required or mandatory but
that other elements are optional and may or may not be present.
[0075] The term "consisting of" includes and is limited to whatever
follows the phrase "consisting of" Thus, the phrase indicates that
the limited elements are required or mandatory and that no other
elements may be present. The term "consisting essentially of"
includes whatever follows the term "consisting essentially of" and
additional elements, structures, acts or features that do not
affect the basic operation of the apparatus, structure or method
described.
[0076] The term "detachable" or "detached" relates to any component
of the present invention that can be separated from a system,
module, cartridge or any component of the invention. "Detachable"
can also refer to a component that can be taken out of a larger
system with minimal time or effort. In certain instances, the
components can be detached with minimal time or effort, but in
other instances can require additional effort. The detached
component can be optionally reattached to the system, module,
cartridge or other component. A detachable module can often be part
of a reusable module.
[0077] "Dialysate" is the fluid that passes through the dialyzer on
the side of the dialysis membrane that is opposite to the fluid
(e.g. blood) that is being dialyzed.
[0078] "Dialysis" is a type of filtration, or a process of
selective diffusion through a membrane. Dialysis removes solutes of
a specific range of molecular weights via diffusion through a
membrane from a fluid to be dialyzed into a dialysate. During
dialysis, a fluid to be dialyzed is passed over a filter membrane,
while dialysate is passed over the other side of that membrane.
Dissolved solutes are transported across the filter membrane by
diffusion between the fluids. The dialysate is used to remove
solutes from the fluid to be dialyzed. The dialysate can also
provide enrichment to the other fluid.
[0079] A "disc-like shape" describes a sorbent pouch forming a
flat, circular shape, as in a compressed cylinder. This definition
is not intended to limit the dimensions or radius of the sorbent
pouch, and may therefore encompass discs having an oval shape, and
discs of any radial width or thickness.
[0080] A "double layer of material" describes a second layer of
material of the same or smaller area than the primary layer of
material, disposed on the surface of the primary layer of material
forming a surface of a sorbent pouch. The material used to form the
double layer can be the same or different from the material forming
the primary layer. Any rigid or flexible porous material known in
the art is contemplated.
[0081] An "elastomer" or "elastomeric material" is a material
comprising a polymer having high elasticity, such that the material
may be easily stretched and shaped to be adapted to an internal
cavity defined by a sorbent cartridge.
[0082] "Engagement members" allow compartments to cooperatively
engage. In certain embodiments, these engagement members may be
clasps or latches. In one embodiment, an engagement member allows
for coupling of a top portion and a bottom portion of a sorbent
pouch that can be opened and resealed.
[0083] "Flow" refers to the movement of a fluid or gas.
[0084] A "fluid" is a liquid substance optionally having a
combination of gas and liquid phases in the fluid. Notably, a
liquid, as used herein, can therefore also have a mixture of gas
and liquid phases of matter.
[0085] The term "fluid communication" refers to the ability of
fluid or gas to move from one component or compartment to another
within a system or the state of being connected, such that fluid or
gas can move by pressure differences from one portion that is
connected to another portion.
[0086] A "fluid impermeable material" is any material through which
fluid cannot pass.
[0087] The term "fluidly connectable" refers to the ability of
providing for the passage of fluid or gas from one point to another
point. The two points can be within or between any one or more of
compartments, modules, systems, components, pouches and rechargers,
all of any type.
[0088] A "geometric shape" refers any geometric shape in Euclidean
and other geometries such as a rectangle, disc, triangle, or
polygon inter alia. In reference to a sorbent pouch as described in
the invention, the geometric shape can refer to one or more side of
the sorbent pouch wherein a rectangular sorbent pouch can be
generally constructed to have a rectangular shape at least on one
side to form a porous sealed bag.
[0089] The term "immobilized urease" refers to urease that has been
adsorbed onto a solid material, such as alumina.
[0090] The term "immobilizing sorbent material" refers to the
process of a sorbent material being placed onto another material,
such that the sorbent material is held in place by some force. The
force may be provided by absorption, adsorption, adhesion, or any
other method for the chemical to be held in place.
[0091] The term "impregnated" describes any process known to a
person of ordinary skill in the art by which a material may be
caused to absorb or be saturated with a substance. In one
embodiment, the material forming a sorbent pouch may be impregnated
with an anticoagulant, such that the surface of the sorbent pouch
absorbs the anticoagulant. "Infusate" is a solution of one or more
salts for the adjustment of the composition of a dialysate.
[0092] The term "in-part" describes a portion up to and including
one hundred percent. For example, a component formed in-part by a
material means that the material forms at least some portion of the
component, and that the material may form up to the entire
component.
[0093] An "o-ring seal member" is a mechanical gasket having a ring
shape; it is a loop of elastomer or other suitable material known
in the art with a round cross-section, designed to be seated in a
groove and compressed during assembly between two or more parts,
creating a seal at the interface. In one embodiment, an o-ring seal
member may be used to seal the interface between a sorbent pouch
and a sorbent cartridge such that fluid is directed through, rather
than around, the sorbent pouch.
[0094] A "porous material" may describe any suitable porous
material known in the art from which a sorbent pouch may be
constructed. For example, the porous material can include, but is
not limited to, bolting cloth, porous polymer, porous metal,
cotton, ashless filter paper, Dacron and polyethylene
terephthalate. The porous material chosen for individual sorbent
pouches may be selected based upon specific porosity in view of the
sorbent material to be contained within the sorbent pouch.
[0095] A "porous structure" describes a sorbent pouch being formed
of a porous material, wherein the sorbent pouch can be manipulated
to fit an internal cavity defined by a sorbent cartridge.
[0096] A "pouch" is any in-part porous container, having any shape
and being made of any material as described below, containing at
least one sorbent material and allowing fluid to pass through the
pouch. For example, a pouch may have a disc-like shape, having
rigid side walls and porous, flexible upper and lower surfaces,
such that fluid is allowed to flow through the lower and upper
surfaces of the pouch, but does not pass through the side walls of
the pouch. Alternatively, the pouch may be rectangular or
triangular in shape. The pouch may be made entirely of flexible
porous material, or may be formed of entirely rigid, partially
porous material. The pouch may be formed in dimensions correlating
directly to the cartridge into which the pouch is inserted, such
that the edges of the pouch are flush with the interior surface of
the cartridge. Alternatively, the pouch may be formed of a flexible
material with dimensions slightly larger than those of the interior
of the cartridge, such that a seal is formed between the pouch and
the interior surface of the cartridge. In another embodiment, the
pouch may be formed in dimensions smaller than that of the interior
of the cartridge, such that the pouch may be simply placed in the
cartridge. A pouch may be formed of bolting cloth, porous polymer,
porous metal, cotton, ashless filter paper, Dacron, polyethylene
terephthalate, or any other flexible or rigid, permeable or
semi-permeable material.
[0097] A "rigid structure" describes a sorbent pouch being formed
of inflexible material such that the sorbent pouch cannot be
manipulated and reshaped to be adapted to an internal cavity
defined by a sorbent cartridge, but instead maintains its
shape.
[0098] A "semi-rigid structure" describes a sorbent pouch having a
combination of rigid and flexible surfaces. For example, a sorbent
pouch having a disc-like shape may have a rigid outer
circumference, with flexible top and bottom surfaces. Other
combinations are also available.
[0099] A "sensor" is a component capable of determining the states
of one or more variables in a system. In one embodiment, a sensor
may be capable of sensing the presence and/or concentration of at
least one compound in the fluid flowing through at least one
sorbent pouch, using any means known in the art.
[0100] A "separator" is a layer of flexible or rigid material
positioned within a sorbent pouch that divides the sorbent pouch
into top and bottom portions, such that sorbent materials housed in
the top and bottom portions, respectively, do not come in contact
with each other. The separator is formed of a porous material such
that spent dialysate or other fluid may flow between the top and
bottom portions of the sorbent pouch through the separator, but
such that the sorbent materials housed in the top and bottom
portions of the sorbent pouch cannot pass through the separator.
Any given pouch may contain one or more separator.
[0101] "Sorbent cartridge" refers to a cartridge that can contain
one or more sorbent materials. The cartridge can be connected to a
dialysis flow path. The sorbent materials in the sorbent cartridge
are used for removing specific solutes from solution, such as urea.
The sorbent cartridge can have a single compartmental design
wherein all sorbent materials necessary for performing dialysis are
contained within the single compartment. Alternatively, the sorbent
cartridge can have a modular design wherein the sorbent materials
are dispersed across at least two different modules, which can be
connected to form a unitary body. Once the at least two modules are
connected together, the connected modules can be referred to as a
sorbent cartridge, which can be fitted to a device or mechanism. It
will be understood that when a single module contains all the
sorbent materials necessary for performing dialysis, the single
module can be referred to as a sorbent cartridge.
[0102] "Sorbent materials" are materials capable of removing
specific solutes from solution, such as urea or urea
byproducts.
[0103] The term "sorbent pouch" refers to a structure that contains
at least one sorbent material, and is constructed from a material
that can allow fluid to freely pass through the sorbent pouch while
substantially retaining the sorbent material inside.
[0104] "Spent dialysate" is a dialysate contacted with blood
through a dialysis membrane and contains one or more impurity, or
waste species, or waste substance, such as urea.
[0105] A "square" or "rectangular" shape describes a sorbent pouch
having four edges and four angles. This description is not intended
to limit the size and dimensions of the sorbent pouch, and may
therefore encompass sorbent pouches having corners with angles
greater than or less than ninety degrees, and with edges of
differing lengths with respect to each other.
[0106] The term "substantially" is used in conjunction with a term
to describe a particular characteristic. For example, as used in
the phrase "substantially retains the at least one sorbent material
in the sorbent pouches," the term describes the ability to retain a
sorbent material or particles characterized by an average pore
diameter such that a significant amount of the material or
particles are retained within the sorbent pouch.
[0107] A "triangular shape" describes a sorbent pouch having three
edges and three corners, wherein the edges and corners may vary in
length and degree individually and with respect to each other.
Sorbent Pouches
[0108] The present invention utilizes separate sorbent pouches that
contain individual portions of sorbent material, or multiple layers
of sorbent material. The sorbent pouches are designed such that
spent dialysate or water may pass through the pouch and into the
sorbent material or materials within, and the spent dialysate or
water may then pass out of the sorbent pouch, while the sorbent
materials remain inside the sorbent pouch.
[0109] The sorbent pouches of the invention can be constructed in
any shape. For convenience, they are often drawn as circular or
disc shaped. However, any of the described embodiments of the
invention can be made in any shape, including triangular,
rectangular, etc.
[0110] For example, FIG. 1 depicts a disc-shaped sorbent pouch 61
containing sorbent material 62, whereas FIG. 2 shows a rectangular
sorbent pouch 41 containing sorbent material 42. The sorbent
pouches may be constructed of any known material, including bolting
cloth, porous polymer, porous metal, cotton, ashless filter paper,
nylon, Dacron, and polyethylene terephthalate as described herein,
and each may be constructed in any shape.
[0111] In one embodiment, the sorbent pouches of the invention can
be configured as shown in FIG. 2. The sorbent pouch 41 can be
constructed of a material that can allow fluid to pass through the
sorbent pouch 41, but will not allow the sorbent material 42
contained within the sorbent pouch 41 to pass out of the sorbent
pouch 41. The sorbent material 42 can be placed loosely within the
sorbent pouch 41, allowing the sorbent material 42 to move within
the sorbent pouch 41, but not to travel out of the sorbent pouch
41. The sorbent pouch 41 can be made in any size or shape. In some
embodiments, as shown in FIGS. 2 and 3, the sorbent pouch can be
roughly rectangular shaped. In another embodiment, as shown in FIG.
1, the sorbent pouch 61 can be disc-shaped. In any embodiment, the
sorbent pouch can be shaped to be adapted into an internal cavity
defined by a sorbent cartridge. In this way, the sorbent pouch may
fit in the space, such that there may be void space, but such that
the sorbent pouch generally fits the space. For example, a sorbent
cartridge having a cylindrical internal cavity can accommodate a
circular or disc-shaped sorbent pouch, while a sorbent cartridge
having a conical internal cavity could accommodate a triangular
sorbent pouch, and a sorbent cartridge having a square or
rectangular internal cavity could accommodate a square or
rectangular sorbent pouch.
[0112] FIG. 3 shows a rectangular sorbent pouch embodiment in which
the sorbent material is contained in a raised inner portion of the
sorbent pouch 51, while the outer perimeter of the sorbent pouch,
having a serrated edge 52, is sealed by any means known in the art,
including heat or pressure stamping, sewing, or adhesive sealing.
The outer serrated edge 52 of the sorbent pouch may be permanently
sealed, or may alternatively be resealable, such that the sorbent
pouch may be opened and reclosed. For example, the serrated edge 52
may be sealed with a resealable adhesive, hook and loop fasteners
(not shown), or with interlocking ridges (not shown) that may be
separated and reclosed by the user. Optionally, a latch member (not
shown) may be included on the serrated edge 52 of the sorbent pouch
to provide additional strength in sealing the sorbent pouch. In
some embodiments, the outer edge may simply be a folded edge. In
use, compression from the other materials within a sorbent
cartridge can keep the folded edge sealed and the sorbent materials
inside the sorbent pouch. Alternatively, the sorbent pouch may be
sealed with drawstrings that when tightened create a seal.
[0113] In some embodiments, the sorbent pouches can be formed from
a material that is flexible. In general, the material is porous and
allows fluid to pass through the sorbent pouches such that
substantially all of the sorbent material or particles are retained
by the material. Sorbent materials are generally formed from a
solid substance that adsorbs and/or absorbs other substances. In
other embodiments, the material forming the sorbent pouches can
allow fluid to pass through the sorbent pouches but substantially
retain the sorbent material in the sorbent pouch. In yet other
embodiments, the material forming the sorbent pouches can allow
fluid to pass through the sorbent pouches but retain at least 98%
by weight of one sorbent material in the sorbent pouch. In still
yet other embodiments, the material forming the sorbent pouches can
allow fluid to pass through the sorbent pouches but can retain
anywhere from at least 70%, 75%, 80%, 85%, 90%, 92%, 93%, 94%, 95%,
96%, or 97% by weight of one sorbent material in the sorbent
pouch.
[0114] In some embodiments, the pore size of one or more of the
sorbent pouches may be large enough so that the sorbent material
can leave the sorbent pouch. For example, a sorbent pouch
containing solid urease may be made with a pore size at a
sufficient porosity to allow dissolved urease, or in certain
embodiments, undissolved urease, to travel through the sorbent
pouch material. The urease in such embodiments can be dissolved by
a fluid as it passes through the sorbent pouch during priming of
the sorbent cartridge prior to dialysis whereupon the urease can
exit the sorbent pouch. The urease in solution can then contact a
sorbent pouch containing immobilized alumina, where the urease will
become bound to the alumina in the alumina sorbent pouch.
Alternatively, the sorbent cartridge can contain a sorbent pouch
containing alumina, and a solution of urease can be injected into
the flow path before the sorbent cartridge. The urease solution can
enter the sorbent pouch containing alumina, where the urease will
become bound to the alumina in the alumina sorbent pouch. However,
in other embodiments, it may be desirable to retain the dissolved
urease in the sorbent pouch and as such the sorbent pouch is
constructed from a material that substantially retains the urease
within the sorbent pouch. In any embodiment, the sorbent assembly
can comprise two or more sorbent pouches stacked in series.
[0115] The size of the sorbent pouches can vary in the invention.
Because different amounts of each sorbent material may be required
for a dialysis session, the sorbent pouches of the present
invention may be in multiple sizes. In any sorbent pouch, glass
beads can be incorporated into the sorbent material to facilitate
flow.
[0116] The sorbent pouches may be constructed of a flexible or
rigid material. The flexible material can be selected from any
non-toxic material suitable for the intended use in a dialysis
wherein the material can allow fluid to pass through the material
yet substantially retain the sorbent material in the sorbent pouch.
The flexible material can be selected from materials that have the
appropriate porosity, strength and durability. When the material is
selected for use with urease, alumina may also be provided in the
sorbent pouch. Because the alumina will adsorb the urease, and keep
the urease from flowing out of the sorbent pouch, the flexible
material need only substantially retain the alumina.
[0117] In some embodiments, the sorbent pouches may be constructed
out of both a flexible and a rigid material. For example, the top
and bottom of the sorbent pouch may be constructed from a flexible
material having a particular porosity to allow fluid flow, while
the sides of the sorbent pouch may be constructed from a rigid
material to define a particular shape such as a disc. In one
embodiment, the sorbent pouches can be constructed of a material
such as a porous polymer. The polymer may be made porous by
creating small holes or pores in an otherwise solid polymer
material. The polymer may be constructed from polyethylene
terephthalate, high density polyethylene, low density polyethylene,
polyvinyl chloride, polypropylene, polystyrene, or any other
polymer known in the art.
[0118] In embodiments where the sorbent pouch is made of fabric,
the weave of the fabric can have a specified porosity suitable for
use with the sorbent material described herein for the intended use
of dialysis. The pores of the sorbent pouch material must be large
enough to allow the spent dialysate to freely travel into and out
of the sorbent pouch, while at the same time must be small enough
to keep the particles of the sorbent material inside the sorbent
pouch. For this reason, sorbent pouches with different pore or mesh
sizes can be utilized for different material layers. In another
embodiment, the sorbent pouch may be made out of a natural fiber,
such as cotton. In still other embodiments, the sorbent pouch may
be constructed from ashless filter paper. The sorbent pouches may
also be constructed out of a synthetic material such as Dacron, or
polyethylene terephthalate.
[0119] In any embodiment, multiple sorbent pouches may be connected
as a string of sorbent pouches, as shown in FIGS. 4a, 4b, 4c, 4d,
5a, 5b and 5c. For example, as shown in FIGS. 4a, 4b and 4c, the
individual sorbent pouches 301-305 may be permanently or separably
connected directly, or may be connected at their outer edges
306-310 by any means known in the art, including by perforations in
the material forming the outer edges 306-310. The individual
sorbent pouches 301-305 comprising the string of sorbent pouches
may be composed of the same material; may be composed of different
materials such that each sorbent pouch in the string of sorbent
pouches is composed of a different material; or may be composed of
different materials such that some sorbent pouches in the string of
sorbent pouches are composed of the same material, while others are
composed of different materials, and are arranged in a random or
repeating pattern. The materials of which the individual sorbent
pouches are composed may be selected with particularity to the
sorbent material housed inside the sorbent pouch. For example,
sorbent pouches containing activated carbon may require a larger
mesh to prevent the larger particles from escaping the sorbent
pouch. By contrast, sorbent pouches containing hydrous zirconium
oxide may require a smaller mesh to prevent the smaller particles
from escaping the sorbent pouch. Any combination of sorbent pouch
materials and mesh sizes among the string of sorbent pouches, and
any number of individual sorbent pouches making up the string of
sorbent pouches, is envisioned. Additionally, the interior portion
of the sorbent pouches containing the sorbent material 301-305,
though shown in FIG. 4c as circular, may be constructed in any
shape, including but not limited to, rectangular, as shown in FIG.
5c, wherein both the interior portion of the sorbent pouches
containing the sorbent material 291-295 and the outer edges of the
sorbent pouches 296-300 are shown having a rectangular shape.
[0120] One non-limiting embodiment of the invention is shown in
FIG. 6. The sorbent cartridge 201 can comprise multiple sorbent
pouches 202-205, including a sorbent pouch containing activated
carbon 202, a sorbent pouch containing hydrous zirconium oxide 203,
a sorbent pouch containing alumina/urease 204, and a sorbent pouch
containing zirconium phosphate 205. In other embodiments, alumina
can be contained in one sorbent pouch and urease in another sorbent
pouch (not shown). Spent dialysate can enter through the bottom
surface 207 of the sorbent cartridge 201, and flow through each of
the sorbent pouches 202-205 sequentially, and then flow out of the
sorbent cartridge 201 through the top surface 206 of the sorbent
cartridge 201. In this way, the spent dialysate can come into
contact with each sorbent material layer, while each sorbent
material layer is kept separate from each of the other layers. One
skilled in the art will understand that the sorbent pouches may be
arranged in alternate orders and still be within the scope of the
invention. For example, the first sorbent pouch 202 may contain
activated carbon, the second sorbent pouch 203 may contain
alumina/urease, the third sorbent pouch 204 may contain hydrous
zirconium oxide, and the fourth sorbent pouch 205 may contain
zirconium phosphate. In another embodiment, the first sorbent pouch
202 may contain activated carbon, the second sorbent pouch 203 may
contain alumina/urease, the third sorbent pouch 204 may contain
zirconium phosphate and the fourth sorbent pouch 205 may contain
hydrous zirconium oxide. The precise order of the sorbent pouches
within the sorbent cartridge is not critical to the invention, so
long as the sorbent pouch containing zirconium phosphate is located
downstream of the sorbent pouch containing alumina/urease. In some
embodiments, a sorbent pouch can contain multiple sorbent
materials, either arranged in layers or alternatively intermixed
within the sorbent pouch. Additionally, any number of sorbent
pouches arranged sequentially in the sorbent cartridge is
envisioned.
[0121] One non-limiting exemplary sorbent cartridge is shown in
FIG. 14. Spent dialysate or fluid can flow from the bottom of the
sorbent cartridge 1 to the top of the cartridge. The first sorbent
material the spent dialysate or fluid contacts can be activated
carbon 2. Activated carbon 2 will remove nonionic toxins from the
fluid by adsorption. Creatinine, glucose, uric acid,
.quadrature.2-microglobulin and other non-ionic toxins, except
urea, can be adsorbed onto the activated carbon 2, removing those
toxins from the fluid. Other non-ionic toxins will also be removed
by the activated carbon 2. The dialysate or fluid then continues
through the sorbent cartridge 1 to the hydrous zirconium oxide
layer 3. The hydrous zirconium oxide layer 3 can remove phosphate
and fluoride anions, exchanging them for acetate anions. The fluid
can continue to move through the sorbent cartridge 1 into the
alumina/urease layer 4. Urease can catalyze the reaction of urea to
form ammonia and carbon dioxide. The result of this is the
formation of ammonium carbonate. The phosphate anions present in
the fluid can also be exchanged for hydroxide ions on the alumina.
As the fluid continues through the sorbent cartridge 1, the fluid
reaches alumina layer 5. The alumina layer 5 can remove any
remaining phosphate ions from the fluid and help retain urease
within the sorbent cartridge 1, and in certain configurations this
layer can exchange urea for ammonium and other components. The last
layer through which the fluid travels can be the zirconium
phosphate layer 6. In the zirconium phosphate layer 6, ammonium,
calcium, potassium and magnesium cations can be exchanged for
sodium and hydrogen cations. Ammonium, calcium, potassium and
magnesium ions all preferentially bind to the zirconium phosphate,
releasing the hydrogen and sodium ions originally present in the
zirconium phosphate layer 6. The ratio of sodium to hydrogen ions
released depends on the ratio originally present in the zirconium
phosphate layer 6, and is therefore controllable. The result of the
fluid passing through the sorbent cartridge 1 is that the fluid can
be regenerated to form clean dialysate that can be safely passed
back through a dialyzer to a patient. In any embodiment, potassium,
calcium, and magnesium can be added to the clean dialysate to
replace any ions which were removed by the sorbent cartridge. The
ions can be added and/or controlled via an infusate system that can
be positioned on a section of the fluid flow path after the sorbent
cartridge.
[0122] In some embodiments, the sorbent pouches of the present
invention may be designed so that they can be opened, as shown in
FIG. 7a. Top portion 213 of the sorbent pouch 211 and bottom
portion 214 of the sorbent pouch 211 may be connected by a hinge
216 and a latch member 212. When latch member 212 on the top
portion 213 of sorbent pouch 211 is engaged with flange 215 (shown
in FIG. 7b) on bottom portion 214 of the sorbent pouch 211, the top
portion 213 of the sorbent pouch 211 can be firmly sealed to the
bottom portion 214 of the sorbent pouch 211. When latch member 212
of the sorbent pouch 211 is disengaged from flange 215, top portion
213 can pivot on hinge 216 to separate from bottom portion 214. The
sorbent material (not shown) within the sorbent pouch 211 can then
be removed in order to be discarded or recharged. The sorbent pouch
211 itself may be reused. The sorbent pouch 211 can be closed by
pivoting the top portion 213 of the sorbent pouch 211 so that top
portion 213 and bottom portion 214 meet, and reengaging latch
member 212 on the top portion 213 of the sorbent pouch 211 with
flange 215 on the bottom portion 214 of the sorbent pouch 211. Any
type of connection between the top portion 213 and bottom portion
214 of the sorbent pouch 211 is contemplated by this invention. For
example, the top portion of the sorbent pouch may include multiple
latches (not shown) in the absence of a hinge member, while the
bottom portion of the sorbent pouch can include engagement members.
When the top portion is placed onto the bottom portion and twisted,
the latches can engage the engagement members, creating a
connection that can be resistant to inadvertent opening. In order
for the connection to be broken, the top portion of the sorbent
pouch can be twisted in the opposite direction, allowing the two
portions to separate.
[0123] In other embodiments, the sorbent pouches may be constructed
so that they cannot easily be opened. In such embodiments, the
sorbent pouches can be completely sealed to form a complete
enclosure around the sorbent material. During construction of the
sorbent pouch, once the sorbent material is added, the sorbent
pouch can be sealed by any possible means. The sorbent pouches can
be heat sealed to fuse the edges of the sorbent pouch together.
Alternatively, an adhesive may be used to connect the edges
together. In embodiments where a fiber is used to construct the
sorbent pouches, the edges may be sewn or woven together to create
a sealed sorbent pouch. Any type of chemical or mechanical closure
to form the sorbent pouches is contemplated by this invention.
[0124] In some embodiments, as shown in FIGS. 8a and 8b, the
sorbent pouches may have an interior or exterior ring 225 disposed
inside of or around the sorbent pouch 221, respectively, creating
an additional sealing member to secure the top portion 223 of the
sorbent pouch 221 to the bottom portion 224 of the sorbent pouch
221. The coupled surfaces of the rings may be coated in an adhesive
material, or the rings may be attached by any other known coupling
means. In some embodiments, the rings may be welded. In other
embodiments, the rings may be mechanically attached to the sorbent
pouches such as with rivets, screws or clamps. In another
embodiment, engagement hooks may be placed on the rings, wherein
the engagement hooks can attach to the sorbent pouch in a similar
fashion as described for connecting the top and bottom portions of
the sorbent pouches as shown in FIGS. 7a and 7b.
[0125] In some embodiments, such as that shown in FIG. 9, a single
sorbent pouch can contain multiple sorbent materials. Sorbent pouch
241 can comprise a separator 244 disposed within the sorbent pouch.
The separator 244 can run through the entire interior space of the
sorbent pouch 241. The separator 244 creates, within the sorbent
pouch 241, a top portion 242 and a bottom portion 243, which are
kept completely separate from each other. One sorbent material may
be placed in the top portion 242 of the sorbent pouch 241, and a
different sorbent material may be placed in the bottom portion 243
of the sorbent pouch 241. This allows two different materials to be
placed within a single sorbent pouch 241, but still remain separate
from one another. In another embodiment, two or more sorbent
materials can be placed in a single sorbent pouch without a
separator (not shown). The sorbent materials may be arranged in
layers within the sorbent pouch, or may be intermixed. The
separator 244 can be constructed from the same material as the
sorbent pouch 241 itself, or may be a different material that still
allows fluid to pass through the separator 244 freely, while
preventing passage of the sorbent material.
[0126] In other embodiments, more than one separator can be used
within a single sorbent pouch. The present invention contemplates
sorbent pouches containing 2, 3, 4 or more separators within a
single sorbent pouch.
[0127] In other embodiments, multiple sorbent materials can be
mixed within a sorbent pouch. Mixing different sorbent materials
together can be accomplished without a loss in efficiency of the
sorbent materials.
[0128] The sorbent pouches of the present invention can have a
mechanism to create a seal between the sorbent pouch and the inner
surface of the sorbent cartridge in which the sorbent pouch is
placed, such that fluid is kept from flowing around the sorbent
pouch and instead is directed into the sorbent pouch. FIG. 10 shows
one non-limiting embodiment of a seal mechanism. A flexible sorbent
pouch 251, such as one made out of a fiber, can be placed inside of
a sorbent cartridge 252. In other embodiments, the sorbent pouch
may be made out of a rigid material, such as a polymer or metal. In
order to avoid a situation in which spent dialysate flows around
the sorbent pouch 251 and therefore does not contact the sorbent
material inside the sorbent pouch 251, the sorbent pouch 251 may be
sealed to the sorbent cartridge 252. O-ring 253 placed on the
circumference of sorbent pouch 251 can form a seal with the sorbent
cartridge 252 so as to prevent spent dialysate from flowing around
the sorbent pouch 251, and instead directing spent dialysate
through the sorbent pouch 251. The sorbent pouch 251 may be filled
so that the circumference of the sorbent pouch 251 is slightly
wider than that of the sorbent cartridge 252. This will ensure that
the sorbent pouch 251 covers the entire inner area of the sorbent
cartridge 252 and that there are no spaces for fluid to pass by
without flowing through the sorbent pouch 251. O-ring 253 can also
serve to ensure that sorbent pouch 251 keeps the intended shape by
providing a semi-rigid border.
[0129] In an alternative embodiment, shown in FIG. 11, an
elastomeric material 263 may be disposed on the edges of the
sorbent pouch 261. When the sorbent pouch 261 is placed in the
sorbent cartridge 262, the elastomeric material 263 functions like
the o-ring described above to create a seal and keep liquid from
flowing around the sorbent pouch 261. The elastomeric material 263
can be made to completely cover the outside edges of the sorbent
pouch 261, or the elastomeric material can be disposed in one or
more thin strips of material. Alternatively, the inside walls of
the sorbent cartridge may be coated in an elastomeric substance,
which will function to form the same seal when a rigid or
semi-rigid sorbent pouch is placed within. In any embodiment, the
sorbent pouches may be constructed to be slightly larger than the
sorbent cartridge. When the user inserts the sorbent pouches into
the sorbent cartridge, the sorbent pouches can be compressed
slightly to fit in the sorbent cartridge. This will ensure that the
sorbent pouches cover the entire area inside the sorbent cartridge
and facilitate the formation of a seal around the edges of the
sorbent pouch.
[0130] In some embodiments, it may be important to ensure that the
sorbent pouches are properly inserted into the sorbent cartridge.
Any method of doing so is contemplated by this invention. One
non-limiting example is shown in FIG. 12. Groove 273 may be created
in the wall of the sorbent cartridge 272. A key 274, or flange, may
be disposed on the side of the sorbent pouch 271. In order for the
sorbent pouch 271 with key 274 to fit within the sorbent cartridge
272, the key 274 must be aligned with groove 273 in the sorbent
cartridge 272 wall. This will ensure that the sorbent pouch 271 is
disposed within the sorbent cartridge 272 with the correct
alignment. In some embodiments, optional ridges 275 may be placed
within groove 273. The ridges 275 can serve to lock the sorbent
pouch 271 in place vertically within the sorbent cartridge 272. The
ridges 275 may be designed so that they are angled on the top
portion of the ridge 275 and flat on the bottom portion of the
ridge 275. Once the key 274 passes a ridge 275 in a downward
direction, the ridge 275 can serve to keep the sorbent pouch 271
from inadvertently moving back upward within the sorbent cartridge
272.
[0131] The ridges 275 may be designed such that the sorbent pouch
271 may be removed upward from the sorbent cartridge 272 only with
the use of force greater than would be expected from inadvertent
moving but not so much force as to prevent intentionally lifting
the sorbent pouch out of the sorbent cartridge 272. This can be
accomplished by using a semi-rigid material as either the key 274,
the ridges 275, or both, such that when enough force is applied the
key 274 or ridges 275 can be bent far enough to allow removal of
the sorbent pouch 271, after which the key 274 or ridges 275 can
return to their original shape. Alternatively, the ridges 275 may
be attached with a spring mechanism that is connected to a button
(not shown), such that when the button is depressed the ridges 275
recede into the interior wall of the sorbent cartridge 272 and
allow easy removal of the sorbent pouch 271 from the sorbent
cartridge 272.
[0132] In other embodiments, the sorbent pouches may be loosely
contained within the sorbent cartridge. The sorbent pouches need
not be made the same size as, or larger than, the sorbent
cartridge. One or more sorbent pouches may be constructed of a
smaller size than the interior circumference of the sorbent
cartridge, and may be simply placed in the sorbent cartridge.
[0133] After construction of the sorbent pouch containing a sorbent
material or materials, the material within the sorbent pouch can be
washed so as to remove any particles smaller than the pore or mesh
size of the sorbent pouch material. This will ensure that all
particles within the sorbent pouch are large enough so that they
cannot inadvertently pass out of the sorbent pouch. Thus, when used
in a sorbent cartridge, the sorbent pouches themselves can act as a
particulate filter, ensuring that no particulate matter of the
sorbent material, or any other particulate matter, can pass
downstream. This may eliminate the need for the use of external
particulate filters.
[0134] In some embodiments, antimicrobial or antibacterial material
may be impregnated into the sorbent pouch. This allows
sterilization of the dialysate as the dialysate flows through the
sorbent cartridge, and can eliminate the need for antimicrobial
filters. In other embodiments, medication such as heparin or other
anticoagulants, or antibiotics may be impregnated into the sorbent
pouch. This can allow administration of these medications to the
patient without the need for adding the drugs to the dialysate.
[0135] In some embodiments flow throughout the sorbent pouch can be
controlled by variations in the sorbent pouch material. Generally,
fluid moving through a conduit will move most quickly through the
center of the conduit, and more slowly towards the edges. To ensure
that fluid travels more evenly throughout the sorbent pouch, the
sorbent pouch can be constructed such that more fluid enters the
sorbent pouch on the outer edges of the sorbent pouch than enters
in the center. One non-limiting example is shown in FIG. 13. A
sorbent pouch 281, such as one made out of a fabric or other
flexible material, can be constructed with an extra layer of fabric
or other flexible material 282 in the center of the bottom face of
the sorbent pouch 281. This extra layer of fabric 282 effectively
reduces the mesh size of the sorbent pouch in that location. With a
smaller mesh size, resistance to flow will be greater in the center
of the sorbent pouch 282, and fluid flow will be more evenly
distributed to the edges of the sorbent pouch 282. In embodiments
where the sorbent pouch is made out of metal or a polymer, the same
effect can be created by making a smaller pore size, or
alternatively less pores, in the center of the sorbent pouch. In
other embodiments, a separator, similar to the one shown in FIG. 9,
can be utilized in the middle of the sorbent pouch. The separator
can be constructed as described above, such as with an extra layer
of fabric near the center, to better control the flow of fluid
throughout the sorbent pouch. Although shown in FIG. 13 as a
centrally positioned rectangular layer, the extra layer of fabric
282 or other material may be positioned anywhere along the outer
surface of the sorbent pouch 281, and may take any shape, such as
circular, rectangular, triangular, etc such that flow dynamics are
altered.
[0136] In some embodiments, a patterned flow of fluid through the
sorbent cartridge can be created. Occlusions, or blockages, of some
of the pores can result in restricted flow through some portions of
the sorbent pouch. In some embodiments, some of the pores in the
sorbent pouch may be larger or smaller than other pores in the rest
of the sorbent pouch. Flow will be increased through the larger
pores as compared to the smaller pores, allowing control over fluid
flow into and out of the sorbent pouch. Fluid flows through sorbent
materials of varying particle sizes and granular diameters at
various rates and pressures. Fluid flows at a higher rate and at a
lower pressure through granules of larger diameter, while fluid
flows at a slower rate and at a higher pressure through granules of
smaller diameter. Wicking can occur when fluid generally flows in
the direction of areas of least pressure. For example, fluid flow
through a fine particle sorbent material, such as zirconium
phosphate, can result in wicking. In such an instance, the fluid
has a tendency to flow towards an area of lower resistance,
generally near the wall of the container. This can result in the
fluid not flowing through a large portion of the sorbent material,
such that the fluid is not coming into contact with the sorbent
materials. To ensure that fluid flows through the sorbent pouch and
the sorbent materials more evenly, the sorbent pouches of the
present invention can be constructed such that fluid is directed to
flow away from the walls of the sorbent pouch and towards the
interior of the sorbent pouch.
[0137] In some embodiments, flow of fluid through the sorbent
pouches can be controlled by varying the interior diameters of the
sorbent pouches. In FIG. 15, the second sorbent pouch 102 has an
interior wall 105 that is thicker than the interior wall 104 of the
first sorbent pouch 101, such that the interior diameter 109 of the
second sorbent pouch 102 is smaller than the interior diameter 108
of the first sorbent pouch 101. Similarly, the third sorbent pouch
103 has an interior wall 106 that is thicker than the interior wall
105 of the second sorbent pouch 102, such that the interior
diameter 110 of the third sorbent pouch 103 is smaller than the
interior diameter 109 of the second sorbent pouch 102. Each sorbent
pouch can have a wall that is thicker than that of the immediately
preceding sorbent pouch in a direction from the bottom surface 120
of the first sorbent pouch 102 to the top surface 170 of the third
sorbent pouch 103 while maintaining a substantially identical outer
diameter among each sorbent pouch. Any number of sorbent pouches
can be used in any embodiment of this invention. Fluid flowing
through the bottom surface 120 of the first sorbent pouch 101 to
the top surface 130 of first sorbent pouch 101, through the bottom
surface 140 and top surface 150 of the second sorbent pouch 102,
and through the bottom surface 160 to the top surface 170 of the
third sorbent pouch 103, is directed into the interior space of
each pouch sequentially. Because each sorbent pouch has a thicker
wall than the preceding sorbent pouch in series, each sorbent pouch
has a smaller effective area through which fluid can flow than the
preceding sorbent pouch. This gradually decreasing flow area will
result in pushing the fluid moving from one sorbent pouch to
another sorbent pouch along the edges of the sorbent pouches near
the wall of the sorbent cartridge 107 towards the center of the
subsequent sorbent pouch. In one embodiment, the wall of each
sorbent pouch can be between 5-10% thicker than the wall of the
preceding sorbent pouch. In other embodiments, the thickness of the
wall of each sorbent pouch can be between 1-5%, 10-15%, 15-20% or
20-30% thicker than the wall of the preceding sorbent pouch.
[0138] FIG. 16 is an exploded view of FIG. 15. As can be seen,
fluid flowing up through the first sorbent pouch 101 through
sorbent pouches 102 and 103 will be pushed toward the center of
each sorbent pouch by the thickening side walls of each sorbent
pouch in series.
[0139] In an alternative embodiment, each sorbent pouch may be
constructed with a smaller outside diameter than that of the
preceding sorbent pouch. Constructing each sorbent pouch with a
smaller diameter and the same wall thickness as the previous
sorbent pouch will create the same effect as constructing each
sorbent pouch with a progressively thicker wall. In some
embodiments, as shown in FIG. 17, the interior diameter of the
sorbent cartridge 124 can also decrease to accommodate each sorbent
pouch. The first sorbent pouch 121 can have the largest diameter of
all the sorbent pouches and can be placed in the sorbent cartridge
124 where the interior diameter of the sorbent cartridge 124 is the
largest. Second sorbent pouch 122 can have a smaller diameter than
first sorbent pouch 121 and can be placed in the sorbent cartridge
124 where the interior diameter of the sorbent cartridge 124 is
smaller. Third sorbent pouch 123 can have a smaller diameter than
second sorbent pouch 122 and can be placed in the sorbent cartridge
124 where the interior diameter of the sorbent cartridge 124 is
smallest. The wall thickness 125 of each sorbent pouch can be
constant. In any embodiment, more than three sorbent pouches can be
used, and the sorbent cartridge 124 can have more than three
different sized interior diameters. In this embodiment, fluid can
flow up through bottom surface 175 and top surface 180 of first
sorbent pouch 121, through bottom surface 185 and top surface 190
of second sorbent pouch 122, and through bottom surface 195 and top
surface 200 of third sorbent pouch 123 such that the fluid is
passing through a constricting area with each subsequent sorbent
pouch, and accordingly is pushed toward the center of each sorbent
pouch.
[0140] In other embodiments, as shown in FIG. 18, annular rings or
"o-rings" may be used to direct flow of fluid into the center of
the sorbent pouch. A sorbent pouch 111 can have an annular ring 112
placed and adhered by any known means around the interior
circumference of the sorbent pouch 111. The cross-section of the
annular ring 112 can be angled so that the annular ring 112 extends
radially into the interior 113 of the sorbent pouch 111. The angle
of the annular ring 112 can direct fluid entering the bottom 114 of
the sorbent pouch 111 from the area near the edge of the sorbent
pouch 111 into the interior 113 of the sorbent pouch 111 as the
fluid exits through the top surface 115 of the sorbent pouch 111.
In other embodiments, the annular ring can have a curved shape.
Alternatively, the annular ring can have a rectangular shape. In
some embodiments, each sorbent pouch can include multiple annular
rings. For example, a sorbent pouch may have 2, 3, 4, 5, 6, or more
annular rings spaced along the interior circumference of the
sorbent pouch to continuously push fluid into the center of the
sorbent pouch as the fluid passes through the sorbent pouch. The
annular rings may be made out of any substance known in the art. In
some embodiments, the annular rings may be constructed from an
elastomeric material, such as the o-rings described above. In other
embodiments, the annular rings may be constructed from plastic or
some other inert material. In one embodiment, the annular rings may
extend inwardly towards the center of the sorbent pouch at a length
of between 5-10% of the diameter of the sorbent pouch. In other
embodiments, the annular rings may extend between 1-5%, 10-15%,
15-20% or 20-30% of the diameter of the sorbent pouch.
[0141] One skilled in the art will understand that various
combinations and/or modifications and variations can be made in the
sorbent pouches and systems depending on the specific needs for
operation. Moreover, features illustrated as being part of an
aspect of the invention can be included in the aspect of the
invention, either alone or in combination.
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