Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a device for the
diffusion of substances between two fluids via semipermeable
membranes, which are arranged in a stack separated by spacer
plates, which on their surfaces are provided with ducts con-
nected to the inlets and outlets for at least one of the said
fluids, these spacer plates being arranged in the folds of one
or more membranes folded in zigzag.
The device in accordance with the invention is in-
tended in the first place to be used for the purification of
blood, that is to say as a so-called artificial kidney. How-
ever, it will be clear to those skilled in the art, that the
apparatus in accordance with the invention can also be used for
many other purposes. It may be used for example for the oxygen-
ation of blood. Alternatively, the device in accordance with
the invention may be used for the transfer of substances from
one gas to another. The term fluid, as used in the following
description, means therefore gas as well as liquid.
Apparatuses of the above-mentioned type are known in
themselves and are described in detail for example in the
German "Offenlegungsschrift" 25 23 803 and American Patent
Specification No 3,585,131. It may be said, therefore, that
these documents constitute part of the background art. For
further illustration of the same, reference is made to Swedish
Patent Nos. 218 441, 301 029, 325 370, 314 167, 342 144,
355 293, 365 119, 393 534 and 407 900, all of which show appar-
atUsses comprising a stack of spacer plates with membranes pre-
ferably arranged in pairs between them which, however cannot
be said to be folded in zigzag. Such folding is disclosed
instead, for example, in the American Patent Specification
Nos.4 116 841, 3 979 295, 3 862 031, 3 788 482 and 3 780 870.
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According to the present invention there is provided
a device for diffusion of substances` between first and second
fluid5 through ~ semi-pex~eable ~embrane, said device compris-
i.n~ a stack of longitudinally extending spacer plates including
S i'irst and second ends ~nd fixst and second longitudinally ex-
t:ending sides, said spacer plates alternating between the folds
of a folded semi-permeable ~embrane, first fluid feed means
for feeding said f;irst fluid to one ~ide of said folded semi-
permeable membrane at said fixst end of said spacer plates,
first fluid withdrawal means-for withdrawing saLd first fluid
from said one side of said f~lded semi-permeable membrane at
said second end ~f said spacer plates, second fluid feed means
for feeding said second fluid to the other side of said folded
semi-pexmea~le membrane, second ~luid withdrawal means for with-
drawing said second fluid from said other side of said folded
semi-pexmeable membrane, channel means extending longitudinally
across the face of said spacer plates, said spacer plates in-
cluding transverse duct means extending transversely across
substantially the entire face of said spacer plates, said trans-
verse duct means being in fluid communication both with said
first and second longitudinally extending sides of said spacer
plates and being substantially continuous across the length
thereof whereby no direct fluid communication isprovided be-
tween said transverse duct means and the opposite side of said
spacer plates through said spacer plates, and fluid connect-
ing means extending between said transverse duct means at a
location displaced from said first longitudinally extending
sides of said spacer plates and said channel means for providing
fluid communication therebetween.
The stacks of plates and membrane portions between
them are prefer~bly given an elon~ated shape with the said la-
texal edges bein~ axxanged in longitudinal direction of the
pack. The tr~nsYer$e ducts ~ay extend transvexsely over the
spacer plates~ opening onto both the Q~posite lateral edges.
This makes it possible, fox example, for two transverse ducts
arranged straight opposite one another to be utilized for the
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supply of one mediuml whllst a5pace between them and separated
from them by two membrane layers can be utilized for the supply
of ~he other fluid.
The me~brane material is preferably arranged folded
with its fQlding edges parallel and substantially coinciding
with the later~l edges of the plates. The lateral edges may
then assist in the folding.
The plates are preferably arranged so that they are
inserted ~nto the membrane material from one side only, that
is to say into every other fold. One of the said fluids can
then be supplied from this side, whilst the other fluid can be
introduced from the opposite side, that is to say into the
folds which do not contain any spacer plates. Alternatively,
another type of spacer plates may be inserted into the last-
named folds.
A particularly good seal can be achieved if sealing
bead~ are arranged in longitudinal direction of the plates
parallel with their lateral edges and near these edges, whose
object it is tQ press the membrane material placed between
them against the adjoining spacer plate. In the same way
sealing bead~ may be arranged in transverse direction of the
plates between the said transverse ducts and adjoining front
edges, parallel with these edges, in order to press the mem-
brane matexial placed
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between them tightly against the adjoining spacer plate. Thanks to these
sealing beads, the required quantity of sealing material, which other-
wise is injected and used to separate the two fluids from one another,
can be limited.
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A particularly good tightness is obtained if the stack of spacer plates
and membrane material between them is arranged in an outer casing with
inlets and outlets for the respective fluids. The sealing material can
then be cast in between the outer casing and the stack in the form of
strands. Two strands of sealing material can be adapted so as to extend
around the pack in its transverse direction, as reckoned from the front
edges just inside the openings of the respective transverse ducts. At
the same time two other strands may be adapted, so as to extend around
the pack in its longitudinal direction just inside the lateral edges in
longitudinal direction of the spacer plates. For such an arrangement, a
relatively small amount of sealing material is required, as compared with
when it has to be spread out between the casing and the stack of spacer
plates. Injection of sealing material is facilitated, if the said four
strands are cast together to a unit.
The inlets and outlets of the casing for the respective fluids are
arranged appropriately outside all the said strands of sealing material
in connection with the openings of the transverse ducts and in connection
with the space between the doubled membrane material arranged in the
transverse ducts.
In a preferred embodiment of the invention, the casing consists of a
boxlike maln part and a lid. A particularly good tightness can be achieved
if a further strand of sealing material is cast in between the lid and
the boxlike main part.
On either side of the said sealing strands, sealing beads may be provi-
ded in the main part of the casing and/or the lid, in order to seal off
the sealing materiji against the fluids fed into the apparatus. This is
particularly ;mportant, if the device is to be heat-sterilized whilst
filled wi~ ii tc
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in a preferred embodiment ribs are provided between the transverse
ducts and the working surfaces proper of the spacer plates which are
adapted so as to support from the outside the doublèd membrane materia1
between them without fully compressing the same. The distance between
two such opposite ribs on adjoining plates may be increased Tn the trans-
verse direction of the plate in the direction from the blood inlet and
diminished in the direction towards the b100d outlet. In this way the
device is utilized in the best possible manner over the whole of its
width.
BRIEF DESCRIPTION ~F DRAWINGS
In the following the invention will be described in greater detail with
reference to the enclosed drawings which show by way of example a pre-
ferred embodiment of the subject of the invention and also an alternative
embodiment.
Figure 1 represents a perspective view of a complete device in accordance
with the invention in a preferred embodiment.
20 Figure 2 shows the same device seen from above.
Figure 3 shows schematically a first arrangement of a stack of spacer
plates and membrane material between them arranged in a device in accor-
dance with the invention.
Figure 4 shows an alternative arrangement for such a stack.
25 Figure 5 shows a section along line V-V in figure 2.
Figure 6 and 7 show on an enlarged scale the left-hand and the right-hand
parts respectively of figure 5.
; Figure 8 shows on the same enlarged scale a section along the line
VIII-VIII in figure 2.
Figure 9 shows a smaller part of the section along line IX-IX in
figure 2.
Figures 10 and 11 represent a view from underneath and a longltudinal
section of a lid belonging to the outer casing of the device in accor-
dance with the invention.
Figures 12 and 13 show in the same manner the remainder of the casing
that is to say the bottom part seen from above and from the side partly
In section.
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Figures 14 and lS show a spacer plate included in the device seen from
albove and from underneath~
Figure 16 shows an end view of the same spacer plate.
Figure 17 shows a section along line XVII-XVII in figure 15.
figure 18 shows a section along line XVIII-XVIII in figure 14.
figure 19 shows the circular area XIX from figure 15 detached and
enlarged.
figure 20 finally shows a section along line XX-XX in figure 19.
BEST MODE OF CARRYING OUT THE iNVENTlON
The device in accordance with the invention shown as an example is inten-
ded first and foremost to be used for dialysis and will be described
therefore in the following with reference to such a treatment.
The device comprises an outer casing, which as a whole is designated
by numeral 10. This casing consists of a boxlike bottom part 9a and an
upper lid 9b. An inlet and an outlet for blood are designated 6 and 7
respectively and numerals 4 and 5 designate an inlet and an outlet res-
pectively for dialysate, if the device is to be used as a dialyser.
Numerals 3a and 3b designate recessed portions, the first of which is
intended to be used for the securing of the device in a dialysis machine,
whilst the other is provided in order to economize material.
The casing 10 shown in figure 1 is intended to contain a stack of spacer
plates and membrane material between them. In figure 3 is shown a pre-
ferred arrangement of such a stack with the spacer plates designated 1
and the membrane material 2. The membrane material 2 is folded, so that
it forms double folds 2a where the blood can enter as indicated by the
arrows B. The dialysate on the other hand can enter from the opposite
side, as indicated by the arrows D. In this way the blood can flow on
one side of the membrane, that is to say inside the double folds 2a,
whilst the dialysate flows in ducts in the plates on the opposite side
of the membrane material.
Figure 4 shows an a~ternative arrangement of the membrane material and
spacer plates. The membrane material is designated here 2', whilst the
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spacer plates are designated la and lb respectively. The spacer plates
1a comprise ducts for the dialysis liquid D, whilst the spacer plates lb
comprise ducts for the blood B.
Figure 2 shows from above the lid 9b belonging to the casing 10 shown
7n figure 1. The figure is intended primarily to illustrate the position
of the sections shown in the figures 5-9. Numerals 11 and 12 designate
the inlet for the injection of a sealing material, for example polyure-
thane. The manner in which the sealing is carried out will be described
in more detail in the following. Numeral 13 designates orientation holes
intended to facilitate the stacking of the apparatus as a whole.
Figure 5 shows a section along line V-V in figure 2. The casing 10, con-
sisting of the component parts 9a and 9b, contains a stack of spacer
plates 1 with membrane material between them. The latter, designated 2,
can be seen more clearly in the enlarged sections in figures 6 and 7.
Numerals 14 and 15 designate strands of sealing material, wh1ch will be
described more fully in the following, with reference primarily to
figures 10 and 12. In connection therewith, a more detatled explanation
wTll also be given of the sealing beads 16. Numeral 4a designates an
extension of the inlet 4 for dialysis liquid and 7a designates a corres-
ponding extension of the blood outlet 7.
In figure 8, which const;tutes a section along line VIII-VIII in figure
2, examples of sealing strands 14 and 15 and sealing beads 16 are shown.
Figure 8 also shows a cross-section through the transverse ducts 18
arranged across the spacer plates 2 near their front edges 17 and
parallel with these. Finally, figure 8 shows further sealing grooves 19,
which will be explained in more detail in the following.
; In figures 10 and 11 is shown the lid 9b, seen from underneath and in
the form of a longitudinal section. In figure 10 is shown the inlet 6
and the outlet 7 for blood and the inlet 4 and the outlet 5 for dialysis
liquid, seen from underneath or from inside the casing 10. The sealing
strands 14 shown in figures 5-8 are formed through ducts 14a, which are
in connection with the injection openings 11, shown tn figure 2. The
ducts 14a continue also in the bottom part 9a. Consequently, the
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strands 14 will extend around the whole stack of spacer plates 1 and
the membrane material 2 between them ;n longitudinal direction as well
as in transverse direction of the stack. In figure 10 are evident also
the holes 13, which facilitate stacking and the injection holes for
the sealing strands 15. Furthermore, sealing beads 16 are evident on
both sides of the ducts 14a. Finally, numeral 22 designates a clamping
flange intended for the securing of the lid.
In figure 12 and 13, the bottom part 9a is shown partly in section seen
from above and from the side. Here too, the groove 14a can be recognized
which gives rise to the sealing strands 14. Corresponding to the holes
13, which facilitate the stacking, we find here a recessed portion 20.
It should be noted that the recessed portion 20 is situated opposite a
bulging portion 21, which is also evident on the lid 9b in figure 10,
but which is not shown in the more schematically drawn figure 1.
On both sides of the grooves 14a, figure 12 also shows the sealing beads
16 indicated in the figures 5-8. These are intended to prevent the
sealing material used from being forced out of the grooves 14a. At the
20 same time, these sealing beads 16 prevent the blood as well as the
dialysis liguid or other liquids supplied from making contact with the
sealing material used. This is particularly important, if the dialyser
is intended to be heat-sterilized when filled with liquid, since other-
wise material might be transferred from the binder into the incoming
25 1 iquids.
The lid 9b is secured to the bottom part 9a with the help of the clampTng
flange 22, which engages underneath a corresponding clamping flange 23
on the bottom part. Numerals 4a, 5a, 6a and 7a in figure 12 designate
extensions of the corresponding inlets and outlets 4, 5, 6 and 7 for
dialysis liquid and blood respectively.
Other details shown in the figures 10-13 should be more or less self-
explanatory to those skilled in the art, or they are of minor importance
in respect of ~he invention and do not. therefore, require detailed
description in the present description.
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The figures 14-20 show a preferred embodiment of the spacer plates 1
included in the device in accordance with the invention. Figure 14
shows a plate seen from underneath, whilst figure 15 shows the same
seen from above and figure 16 is an end view.
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The plate can be patterned in a largely conventional manner, for
e~ample in accordance wtth anyone of the above-mentioned Swedish patents.
However, it is essential in accordance with the invention that the plate
is provided at its ends with the transverse ducts 18, whlch are also
shown in figure 8. These transverse ducts 18 should open onto at lease
one of the lateral edges 24. In the example shown, the transverse ducts
18 run transversely over the plates 1 and thus open onto both lateral
edges 24. The transverse ducts are parallel w;th the front edges of the
plates. As can be seen from figures 17 and 18, the transverse ducts 18
contain ribs 25, which are adapted so as to press adjoining membranes
in a tight manner against adjoining spacer plates. Moreover, the trans-
verse ducts comprise smaller supporting ribs or supporting fins 26, which
are intended simply to support the membranes from the outside. Between
the transverse ducts 18 and the working surfaces proper, slmilar pressure
ribs 27 are present with somewhat lower supporting ribs 28 marked in
black. The supporting ribs 28 become progressively lower, the farther
away they are situated from the blood inlet and the blood outlet respec-
tively, which is indicated by the arrows B in figure 15. As a result,
an even flow of blood is achieved across the whole width of the plate.
; 25 The working surface itself, as can be seen more clearly in figure 19,
consists of zigzag-shaped ridges 29 and 30.
Figure 20 shows that the ridges 30 are somewhat lower compared with the
ridges 29. Numeral 31 designates transverse distributing ducts, which
are intended to facilitate the distribution of the blood and of the
dialysis liquid on passing the supporting points 32 and the cast7ng
points 33.
Numeral 19 designates sealing beads arranged between the transverse
ducts 18 and the front edges 17. Corresponding sealing beads placed
parallel with the longitudinal edges 24 of the plate are designated 34.
They can be seen, for example, also in figure 9. Thanks to the sealing
grooves 19 and 34, the ~uantity of sealing material inJected can be
limited to the strands 14 (fig. 5-8).
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Gn the spacer plates I the holes facilitating stacking are also present,
designated here 13a Other details given in figures 14-20 will readily
ble understood by those skilled in the art and do not therefore require
detailed description.
Naturally, the invention is not limited exclusively to the details des-
cribed above, but may be varied within the scope of the following claims.
For example, the spacer plates may be modified to resemble any of the
spacer plates described in the aforementioned Swedish patents. Alterna-
tively, it is of course possible to conceive completely new patterns.
