U.S. patent number RE31,029 [Application Number 06/212,081] was granted by the patent office on 1982-09-14 for dialyzer cartridge and method for its manufacture.
This patent grant is currently assigned to Dr. Eduard Fresenius Chemisch-pharmazeutische Industrie KG, Apparatebau. Invention is credited to Wilfried Schael.
United States Patent |
RE31,029 |
Schael |
September 14, 1982 |
**Please see images for:
( Certificate of Correction ) ** |
Dialyzer cartridge and method for its manufacture
Abstract
A dialyzer with a housing includes a pair of inflow and outflow
pipes for blood and dialysis solution, and a tubular ring body
formed from a plurality of hollow filaments joined to one another
at their ends and positioned in the housing such that one pair of
the pipes is in communicating relationship with open ends of the
hollow filaments and the other pair of the pipes communicates with
the interstices between adjacent filament forming said tubular ring
body. The invention also provides a dialyzer cartridge and a method
of manufacturing such cartridge.
Inventors: |
Schael; Wilfried (Bad Homburg,
DE) |
Assignee: |
Dr. Eduard Fresenius
Chemisch-pharmazeutische Industrie KG, Apparatebau (Bad
Homburg, DE)
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Family
ID: |
5957190 |
Appl.
No.: |
06/212,081 |
Filed: |
December 1, 1980 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
724935 |
Sep 20, 1976 |
04141836 |
Feb 27, 1979 |
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Foreign Application Priority Data
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Aug 24, 1975 [DE] |
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2542438 |
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Current U.S.
Class: |
210/321.81;
210/456 |
Current CPC
Class: |
B01D
63/021 (20130101); B01D 63/02 (20130101) |
Current International
Class: |
B01D
63/02 (20060101); B01D 031/00 () |
Field of
Search: |
;210/321.1,321.2,321.3,321.4,321.5,433.1,456,646 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1566589 |
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Oct 1970 |
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DE |
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2300312 |
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Jul 1973 |
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DE |
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2231421 |
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Dec 1974 |
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FR |
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Primary Examiner: Adee; John
Attorney, Agent or Firm: Fasse; W. G. Kane, Jr.; D. H.
Claims
What is claimed is:
1. A dialyser comprising housing means having a longitudinal axis
and a central plane of symmetry extending perpendicularly to said
longitudinal axis, said housing means including first and second
housing members each of which has a substantially
mirror-symmetrical shape relative to the respective other housing
member and relative to said plane of symmetry, each housing member
having an open end portion facing said plane of symmetry and means
for connecting the open end portions of the two housing members to
each other, each housing member further comprising a port section
opposite said open end portion, each port section comprising first
central port means arranged substantially concentrically relative
to said longitudinal axis and a central cavity smoothly merging
into said central port means and open opposite the respective first
port means, each port section further comprising second port means
located radially outwardly of said first, central port means and a
ring cavity surrounding said central cavity and smoothly merging
into the respective second port means, said ring cavity also being
open toward said open end portion of the respective housing member,
dialyser cartridge means in said housing means, said dialyser
cartridge means comprising hollow tubular core means with a wall
therein dividing said hollow tubular core means into two cavities
extending coaxially relative to said longitudinal axis and
substantually in register with the respective one of said central
cavities in the corresponding port section, hollow filaments wound
on said hollow, tubular core means, said hollow filaments having
open ends, means bonding said open ends of said filaments to each
other so as to close the spaces between the filaments adjacent the
open ends and to form a ring body of filaments directly around said
hollow tubular core means, said ring body of filaments having
interstices between adjacent filaments intermediate said bonding
means, radially extending holes in said hollow, tubular core means
to provide for a smooth flow communication between said first port
means through said central cavities, through said radially
extending holes, and through said interstices between adjacent
filaments, said open ends of said filament ring body extending
substantially in register with the respective one of said ring
cavities to provide for a further smooth flow communication between
said second port means through said ring cavities and
longitudinally through said hollow filaments.
2. The dialyser of claim 1, further comprising jacket means
surrounding said filaments on said tubular core means.
3. The dialyser of claim 1, wherein said hollow filaments are
directly wound on said hollow, tubular core to form winding
sections having a curved shape and extending in planes slanting at
an angle relative to said longitudinal central axis, said angle
being such that said open ends of said filaments face the
respective ring cavity (FIG. 2).
4. The dialyser of claim 1, wherein said hollow filaments are
directly wound on said hollow tubular core to form winding sections
having a substantially rectangular shape initially having axially
and radially extending portions, the latter having been cut off so
that said open ends of said filaments face the respective ring
cavity, (FIG. 3).
5. The dialyser of claim 1, wherein said radially extending holes
in said hollow, tubular core means are located near the outer ends
of said hollow, tubular core means away from said wall in said
hollow tubular core means whereby flow of liquid extends
substantially radially adjacent said bonding means into and out of
said interstices and substantially axially through said interstices
intermediate said holes in said hollow tubular core means.
6. The dialyser of claim 5, wherein said wall is located
substantially in said plane of symmetry.
7. The dialyser of claim 1, further comprising shoulder means in
said port sections, said shoulder means contacting said hollow,
tubular core means in a sealing manner. .Iadd. 8. A dialyzer
comprising housing means having a longitudinal axis and a central
plane of symmetry extending perpendicularly to said longitudinal
axis, said housing means including first and second housing members
each of which has a substantially symmetrical shape relative to the
respective other housing member and relative to said plane of
symmetry, each housing member having an open end portion facing
said plane of symmetry and means for connecting the open end
portions of the two housing members, each housing member further
comprising a port section opposite said open end portion, each port
section comprising first central port means arranged substantially
concentrically relative to said longitudinal axis and a central
cavity coupled into said central port means, each port section
further comprising second port means located radially outwardly of
said first, central port means and a ring cavity surrounding said
central cavity and smoothly merging into the respective second port
means, said ring cavity being open toward said open end portion of
the respective housing member, hollow filament means in said
housing means, core means extending coaxially relative to said
longitudinal axis and between the respective central cavities in
the corresponding port sections, said hollow filament means being
held on said core means, said hollow filament means having open
ends, means bonding said open ends of said hollow filaments to one
another so as to close the spaces between the filaments adjacent
the open ends and to form a ring body of filaments around said core
means, said ring body of filaments having interstices between
adjacent filaments intermediate said bonding means, radially
directed passage openings from the central cavities at the ends of
the core means to provide a continuous communication between said
first port means through said central cavities, through said
radially directed passage openings and through said interstices
between adjacent filaments, said core blocking any flow directly
between said central cavities, said open ends of said filament ring
body extending substantially in register with the respective one of
said ring cavities to provide for continuous smooth flow
communication between said second port means through said ring
cavities and longitudinally through said hollow filaments.
.Iaddend..Iadd. 9. The dialyzer of claim 8, wherein said means for
connecting the open end portions of the two housing members
comprise sealing jacket means (19) surrounding said fiber bundle
means. .Iaddend..Iadd. 10. The dialyzer of claim 8, wherein said
first or second housing members comprise flanged enclosure portions
enclosing said dialyzer and abutting against each other in
connecting relationship. .Iaddend..Iadd. 11. A dialyzer comprising
elongated housing means having a longitudinal axis, said housing
means including outer jacket sealing means extending coaxially to
said longitudinal axis, central core means extending coaxially
within the outer jacket sealing means, said outer jacket sealing
means and central core means defining therebetween an annular space
extending along the longitudinal axis of the housing, first and
second housing end members engaging the coaxial outer jacket
sealing means and central core means at each end of the housing
means; hollow filament means comprising hollow filaments positioned
about said central core means and substantially occupying the
annular space between the outer jacket sealing means and the
central core means, said hollow filaments having open ends facing
the respective end member at both ends of said housing means; means
bonding the open ends of said filaments to each other to close
spaces between the filaments at each end of said housing means,
thereby forming substantially a ring body of open ended filaments
around the core means, whereby the open filament ends face the
housing end members; said housing end members defining at each end
of the housing means a ring cavity facing the open filament ends,
said end members comprising peripheral port means smoothly merging
into the ring cavity means for continuous smooth flow communication
of fluid from said peripheral port means through said ring cavity
and into the hollow filaments of the bundle through the open
filament ends; said hollow filament means having interstices
between adjacent filaments extending substantially the entire
length of the filament bundle intermediate the bonding means at
each end; said first and second housing end members further
defining in combination with said central core means, central
cavity means at each end of said housing means, said end members
comprising central port means opening into said central cavity
means; said central core means comprising flow blocking means
intermediate the ends thereof to prevent passage of fluid through
said central core means from one end to the other; said central
core means further comprising opening means distributed around the
periphery of said core means at each end of the core means for
directing fluid from the central cavity radially outwardly into the
interstices between said filaments at one end of the filaments and
for receiving fluid from the interstices at the other end of the
filaments; said outer jacket sealing means and central core means
thereby confining the flow of fluid, received through the central
port means and distributed radially into the interstices of the
filaments, axially along the interstices through substantially the
entire length of the filaments between the bonding means.
.Iaddend..Iadd. 12. The dialyzer of claim 11, wherein said outer
jacket sealing means comprises elongated cylindrical wall means and
wherein said central core means comprises coaxial cylindrical core
means. .Iaddend..Iadd. 13. The dialyzer of claim 11, wherein said
central core means comprises a tubular core and wherein said
separating means for sealing the tubular core means to prevent
passage of fluid through the core comprises wall means across the
tubular core intermediate said opening means at each end of core
means. .Iaddend. .Iadd. 14. A dialyzer comprising housing means
(10, 11), a first set of ports including inflow port means (14) for
blood in said housing means and outflow port means (15) for blood
in said housing means, a second set of ports including dialysis
liquid inflow port means (12) in said housing means and dialysis
outflow port means (13) in said housing means, tubular core means
(4) in said housing means to provide an annular space between said
housing means and said core means (4), hollow filament means (3,
18) having open filament ends, sealing and bonding means (29, 30)
operatively bonding the hollow filament means (3, 18) to one
another adjacent said open ends, said hollow filament means
occupying said annular space, first flow communication means in
said housing means (16, 17) for providing flow communication into
and out of said open filament ends and the respective one of said
port sets arranged at each end of said hollow filament means,
interstices extending between said hollow filament means
substantially all along said hollow filament means between said
bonding means (29, 30), second flow communication means (9) in said
core means (4) for providing flow communication between said
interstices and said second set of ports, said second flow
communication means consisting of first and second passage openings
(9) extending radially outwardly through said core means (4) and
located only substantially directly adjacent to each of said
bonding means (29, 30), and separation means (6) in said core means
(4) for closing off said first passage openings (9) from said
second passage openings (9) except through said interstices whereby
a liquid flowing from said inflow port means to said outflow port
means of said second set of ports is forced to flow through said
interstices substantially along the entire effective length of said
filament means between said first and second passage openings, for
optimally using the available interface surface formed by said
hollow filament means. .Iaddend..Iadd. 15. The dialyzer of claim
14, further comprising jacket means (19) surrounding said hollow
filament means and said core means in said housing means. .Iaddend.
Description
BACKGROUND OF THE INVENTION
The invention relates to a dialyser, in particular for
haemodialysis, which comprises a housing with inflow and outflow
pipes for blood and dialysis solution and open hollow filaments
arranged in the housing and joined to one another at their ends, as
well as to a dialyser cartridge, as well as a method for the
manufacture of such a dialyser.
Haemodialysis requires a membrane of large surface area, some 1-1.5
m.sup.2 in size and 10-20 .mu.m thick, of a material capable of
acting as a dialytic permeable membrane, for example, cellulose
acetate, polyacrylonitrile and similar materials are capable to act
as separating layer between the blood and the suitably composed
dialysis solution. The membrane is relatively easily permeable for
water and low molecular weight constituents of the blood, including
also substances contained in urine. High molecular weight and
corpuscular constituents are however almost completely
retained.
Under the term dialysers for haemodialysis can be recognised spool
or coil dialysers, plate dialysers and also capillary or hollow
filament dialysers, in which the membrane is formed from a large
number (e.g. 10,000) of hollow filaments having a diameter of about
150 .mu.m. In the hitherto usual arrangement the hollow filaments
are collected into a loose bundle of parallel filaments and
arranged in a cylindrical housing. The ends of the bundle of hollow
filaments are sealed off and packed against the housing. The inflow
and outflow of the blood stream is effected by connecting pieces
screwed onto the ends of the housing. The dialysis solution flows,
in countercurrent, along the outside of the capillaries or hollow
filaments, inflow and outflow occurring via lateral connections in
the vicinity of the ends of the housing.
In designing a hollow filament dialyser great efforts are made to
achieve as great an effectiveness as possible, i.e. a flow
distribution as uniform as possible is necessary in order to fully
utilize the membrane surface. High flow velocities are also
desirable since this reduces the diffusion resistance in the blood
and dialysis solution. Furthermore, the blood filling volume should
be as small as possible and the blood flow resistance should be
low. A hollow filament dialyser in principle provides the necessary
prerequisites in order to meet these requirements.
OBJECTS OF THE INVENTION
In view of the above, it is the aim of the invention to achieve the
following objects, singly or in combination:
to provide a dialyser of the afore-mentioned type which optimally
meets the above requirements and which furthermore can be
manufactured in an advantageous manner;
to provide a dialyser in which the hollow filaments are in the form
of a ring with the inflow and outflow of the medium flowing in the
interstices from the middle thereof;
to provide a dialyser cartridge that is replaceable within a
housing, having inflow and outflow pipes associated therewith
especially for blood dialysis; and
to provide a method for manufacturing of a dialyser cartridge
and/or housing.
SUMMARY OF THE INVENTION
In order to solve this problem the invention provides a dialyser in
which the hollow filaments are arranged in the form of a ring and
the inflow and outflow of the medium flowing in the interstices
between the hollow filament pieces takes place from the middle. The
flow conditions are thereby favorably influenced, and in addition
this also provides the possibility of manufacturing the unit
consisting of hollow filaments in a particularly convenient
manner.
A further embodiment of the invention accordingly proposes that the
hollow filaments are wound on the core and that the ends of the
wound hollow filament body are then impregnated with a cast resin
and the end regions are cut off, after solidification, in such a
way that the front surfaces of the individual hollow filament
pieces are open.
In this connection, the hollow filaments can be wound inclined or
parallel to the axis of the core, winding being carried out with
devices known per se.
BRIEF FIGURE DESCRIPTION
In order that the invention may be clearly understood, it will now
be described, by way of example, with reference to the accompanying
drawings, wherein:
FIG. 1 is a sectional view through a dialyser according to the
invention;
FIG. 2 is a perspective view of a hollow filament body with the
hollow filament windings inclined to the core axis; and
FIG. 3 is a perspective view of a hollow filament body with
windings parallel to the core axis.
DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS
Referring now to the drawings dialyser 1 according to the
invention, is illustrated in FIG. 1, and consists of a two-part
housing 2 in which a hollow filament body or cartridge 3 is
located. The hollow filament body consists of a core 4, on which a
body or hollow filament 5 consists of cellulose acetate or
polyacrylonitrile is wound in accordance with FIG. 2 or 3.
The core 4 may be tubular having an outer wall or surface 4a and an
inner wall or surface 4b with at least one radially extending
separating wall 6 there between, as well as several passage
openings 9 distributed on the periphery between the outer wall 4a
and the inner wall 4b, adjacent the two ends 7 and 8 of the core 4.
The wall 6 separates or divides the core 4 into a pair of chambers
6a that are sealed from each other by the separating wall 6. The
two halves or sections 10 and 11 of the housing 2 each have
together with the tubular shaped core 4 an aligned inflow conduit
or pipe 12 and outflow conduit or pipe 13. The pair or set of pipes
12 and 13 may be in axial alignment with each other and having a
terminal end 12a and 13a respectively. Each pipe 12 and 13 may
extend into an enlarged passage 12b and 13b respectively, which are
in alignment with the chambers 6a to provide a proper flow of fluid
therethrough. Each half 10 and 11 further has another pair or set
of pipes consisting of an inflow pipe 14 and outflow pipe 15 which
open out into a guide channel 16 and 17 in the interior of the
halves 10 and 11 of the housing 2. The width of the two channels 16
and 17 preferably corresponds to the layer of hollow filament
pieces 18 arranged in the form of a ring on the core 4. The inflow
pipe 14 has an outer end 14a, and the outflow pipe 15 has an outer
end 15a. The inflow pipe 14 and outflow pipe 15 are provided in
non-aligned relationship with respect to each other to provide the
necessary flow length for the dialysis fluid.
Like the cylindrical core 4, the hollow filament body 3 also has a
circular cross-section. A jacket 19 is arranged on the
circumference of the hollow filament body 3, which not only holds
together the external hollow filament pieces 18 but also serves for
sealing purposes. The jacket 19 may extend the same axial length as
the core 4 and coincide with the ends 7 and 8 thereof. As
illustrated in FIG. 1 the guide channels 16 and 17 each include an
inner edge or wall 16a and 17a that engages the ends 7 and 8
respectively, of the core 4 as well as each end of jacket 19. The
core 4 and jacket 19 may be in co-axial alignment with each
other.
The manufacture of the hollow filament body is carried out in
accordance with FIGS. 2 and 3 in such a way that the hollow
filament 5 is wound on the core 4 with an arbitrary number of
windings 20, 21 and 22, the winding being performed so that the
windings are either inclined or parallel to the longitudinal axis
or plane of the core 4. During the winding procedure the hollow
filament 5 is led back and forth so that after a certain angle of
rotation of the winding device carrying the core 4, the said
filament moves from one edge to the other edge. A compact or a
lightly wound hollow filament body is thus obtained depending on
the angle of inclination.
The ends of the hollow filament body 3 wound in this manner are
then impregnated with a cast resin so that all interstices are
filled and the windings of the hollow filaments 5 are firmly
embedded. In a following operation the outermost end regions of the
hollow filament body 3 impregnated by the cast resin are cut off
along the dotted lines 23 and 24 in FIG. 2, with the result that
hollow filament pieces 18 roughly corresponding to the length of
the core 4 are formed, which are open and freely accessible at
their front faces for a flow of fluid through the hollow filament
pieces 18.
In the case of the hollow filament body 3 shown in FIG. 3, the
hollow filament 5 is wound over the circumference and the front
sides of the core 4 so that the hollow filament pieces 18 lie on
the circumference of the core approximately parallel to the axis
thereof.
During the winding the core 4 is slowly rotated about its
longitudinal axis, which is at right angles to the winding axis.
The angular displacement depends on the relationship between
winding rate and the rotational velocity of the hollow filament
body. The required distance or spacing between the hollow filament
pieces 18 can be achieved by the simultaneous applying or winding
of foil strips 25 and 26, which are wound in the direction of the
circumference as can be seen from FIG. 3.
When the hollow filament body 3 has been impregnated with cast
resin, hardened, and then cut at its edge or end regions, after the
winding procedure, the jacket 19 is applied, following which the
hollow filament body 3 can be inserted into the housing 2
consisting of practically equal sections of halves 10 and 11. After
insertion, the two halves 10 and 11 or the housing are securely
connected to one another in their flange region 27 and 28 in a
conventional manner.
The dialysis solution enters the dialyser through the centrally
arranged inflow pipe 12 in the direction of arrow 32, and first of
all passes into one half, or chamber 6a, of the tube-shaped core 4,
from which it then flows through the passage openings 9 in the
direction of arrows 34, and splits up in the interstices between
the hollow filament pieces 18. After the dialysis solution has
flowed through the hollow filament body 3, it reenters the core 4
through the passage opening 9, in the direction of arrows 36, at
the other end thereof into chamber 6a and then flows directly to
the outflow pipe 13, in the direction of arrow 38.
The blood flows through the dialyser 1 in the opposite direction.
It enters through the inflow pipe 14, in the direction of arrow 40
which opens out into the guide channel 16. From there the blood is
distributed through the hollow filament pieces 18 from which it
flows into the guide channel 17 in the other half 10 of the
housing, which channel 17 collects the blood and passes it to the
outflow pipe 15 in the direction of arrow 42.
FIG. 1 clearly illustrates the sealing function of the jacket 19,
against the walls 16a and 17a which prevents any bypass for the
dialysis solution parallel to the hollow filament pieces 18 and
into the chamber 6a, or passages 12b or 13b.
A further prerequisite for satisfactory operation is that the end
regions 29 and 30 of the hollow filament body 3, which are sealed
with a cast resin, are absolutely tight and impermeable since
otherwise dialysis solution can pass into the two guide channels 16
and 17. The position of the passage openings 9 is chosen so that
they are immediately adjacent to the end regions 29 and 30
impregnated with cast resin. In this manner the spacing between
each hollow filament 18 is sealed preventing the escape from each
end region 29 and 30, and yet permitting the flow of fluid through
the individual filament pieces 18.
The dialysis solution or medium is distributed very rapidly over
the whole cross-section of the circularly arranged hollow filament
pieces 18 by virtue of the feed of dialysis solution from the
centrally arranged core 4 into the interstices between the hollow
filament pieces 18 which are in communicating relationship with
inflow and outflow pipes 12 and 13. The transition zone from a
uniformly "flushed" cross-section to a "non-flushed" cross-section
is very short at the inflow and outflow, which is accompanied by an
increase in the exchange efficiency on account of the better
utilization of the incorporated hollow filament surface. This can
be fully exploited by incorporating a correspondingly smaller
amount of hollow filament material in the dialyser, any increase in
efficiency being relinquished, and in addition the flow resistance
on the blood side can be markedly reduced if the number of hollow
filaments is increased and their length is reduced, the total
surface area remaining the same. This provides one of the
conditions in haemodialysis for driving the blood circulation
outside the body without the use of blood pumps, the natural
arterial-venous pressure drop being utilized. The invention is not
limited to the examples of the embodiments illustrated in the
figures, and indeed alterations can be carried out without
departing from the basic ideas of the invention. Thus, for example,
it is also possible to provide appropriate separating walls instead
of the separating wall 6 immediately adjacent to the passage
openings 9, so that the dialysis solution passes into the interior
of the hollow filament body 3 via the shortest pathway.
Furthermore, it may also be convenient if the manufacturing
procedure described above is altered and the jacket 19 is applied
before the ends of the hollow fiber body are impregnated with cast
resin.
Although the invention has been described with reference to
specific example embodiments, it is to be understood, that it is
intended to cover all modifications and equivalents within the
scope of the appended claims.
* * * * *