Assembly for the closure of the end of a flattened tube

Assembly is disclosed for clamping and sealing the end of a flattened tube. The assembly includes a groove for receiving an end of a flattened tube, and a clamping member including a beaded portion for clamping and sealing the end of a flattened tube when the clamping member is in a clamping position within the groove and the end of the flattened tube is properly disposed in said groove. The groove has a first groove surface and a second surface disposed at an oblique angle relative to said first surface, the second surface including a clamping portion, and the clamping member including a locking portion adapted to mate with said clamping portion of the second surface of the groove when the clamping member is in the clamping position within the groove, whereby the beaded portion is held in its sealing position relative to the end of the flattened tube disposed within the groove.

BACKGROUND OF THE INVENTION 
The present invention relates to an apparatus for clamping a flattened tube 
in a diffusion device. More particularly, the present invention relates to 
an apparatus for sealing a semi-permeable membrane in a dialysis device. 
A number of apparatuses for closing tubular membranes are known. For 
example, U.S. Pat. No. Re 27,510 discloses a device in which the ends of a 
tubular membrane are folded around a highly elastic terminal tube 9 and 
pulled together under strong friction so as to be leak-proof. The patentee 
thus employs a conical bore 8 of a confining rim 10 in the outer casing 13 
as best shown in FIG. 4 of the patent. 
U.S. Pat. No. 3,712,474 teaches another such device which includes 
connector units 52 and 54 as best shown by FIG. 6 of the patent. In each 
unit, patentee includes a substantially resilient body portion 60 in a 
relatively less flexible cup element 62. By closely conforming the 
internal cup dimension to that of the body and by forming the body of a 
substantially resilient material, a snug fit is provided. Moreover, at 
least one O-ring 72 supported by the body insures a better fluid tight 
seal and prevents a possibility that the membrane will pull loose. Similar 
teachings are contained in U.S. Pat. Nos. 3,709,367 and 3,743,098. 
U.S. Pat. No. 3,880,760 discloses yet another such device which includes a 
core cover section 2 adapted to mate with a core base section 1 with the 
ends of the tubular membrane therebetween. A similar structure is employed 
at the other end of the tubular membrane as shown by FIG. 2 of the patent. 
The core cover and core base sections are provided with seals 5 and 6 to 
seal the membrane tube 9 with the open end 7 of the blood inlet conduit 
within the membrane tube. 
In a similar vein is U.S. Pat. No. 3,962,095 which discloses blood inlet 
and outlet means 26 for connection with arterial and veinous lines 
attached to a casing 22. The cover plates 28 are secured to the casing by 
means of screws 30. The cover plate 28 and the casing 22 carry seals 32 to 
seal the free ends of the membrane tube 12 with the blood inlet and blood 
outlet means 26. 
U.S. Pat. No. 4,059,530 discloses blood inlet and outlet ports in a 
dialyzer membrane tube 3 comprising a connector 30 connected to a header 
32 through a hole in the membrane. The header 32 is thus located 
internally in the tubular membrane. A locking disc 33 locks the membrane 
tube 3 against one wall of the header 32. The header is provided with 
internal chambers 35 communicating with the interior of the tubular 
membrane 3. The end of the tube is shown squeezed between connector 30 and 
a wall opposite the connector. 
Other similar devices are shown in U.S. Pat. No. 3,963,621, British Pat. 
No. 1,417,446 and British Pat. No. 1,433,512. U.S. Pat. No. 3,963,621 
merely states that a tube 18 communicates conventionally with the end 20 
of a membrane 16. FIG. 3 of British Pat. No. 1,433,512 shows a membrane 
tube 2 pleated around a rigid connecting plug 38. Medical plaster 41 is 
applied around the membrane tube and the tube is secured by means of two 
knotted cords 42 and 43 in the annular grooves 39 and 40. British Pat. No. 
1,417,446 merely discloses that the core 1 includes an opening in which a 
sleeve 31 fits so that the blood tube 12 can be connected to the membrane 
tube 2. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, an assembly has now been prepared 
including a groove for receiving an end of a flattened tube and a clamping 
member including a beaded portion for clamping and sealing the end of a 
flattened tube when said clamping member is in a clamping position within 
said groove and the end of the flattened tube is properly disposed in said 
groove, said groove comprising a first groove surface and a second groove 
surface disposed at an oblique angle relative to said first groove 
surface, said second groove surface including a clamping portion, and said 
clamping member including a locking portion adapted to mate with said 
clamping portion of said second groove surface when said clamping member 
is in its said clamping position within said groove whereby said beaded 
portion is held in its sealing position relative to the end of a flattened 
tube properly disposed within said groove. The first and second groove 
surfaces are preferably planar. 
In a preferred embodiment of the present invention, the clamping member is 
in the form of a clamping strip including a clamping rail fitting into the 
groove, said clamping rail having a first clamping surface including the 
beaded portion on its face and a second clamping surface, said beaded 
portion on said first clamping surface cooperating with the first groove 
surface and the second clamping surface cooperating with the second groove 
surface so as to hold said end of said flattened tube in a fluid tight 
seal between the first groove surface and the beaded portion on said first 
clamping surface. Such an apparatus has been found to be advantageous 
because of its simple design and very secure sealing of the end of a tube. 
In another preferred embodiment of the present invention, the groove is 
defined in the wall of a cylindrical core or bobbin around which the tube 
is helically wound. The groove is preferably arranged axially on the 
surface of the bobbin. The end of the tube is disposed in the groove and 
the clamping member is arranged so that the outer surface of the clamping 
member coincides with the outer surface of the bobbin to complete a 
cylindrical shape. The clamping member can be manufactured separately and 
thus be detachable from the bobbin. Such an arrangement is advantageous 
because it provides simple design and secure sealing, while allowing good 
flow conditions inside the tube due to the smooth cylindrical surface 
formed by the clamping member and bobbin. 
In another preferred embodiment, the outer surface of the above-mentioned 
clamping strip defines a plurality of peripherally extending surfaces 
which are separated by grooves. Also, the second clamping surface of the 
clamping strip pereferably defines a series of substantially radially 
extending protuberances separated by grooves. Such a design allows the 
clamping strip to be bendable and also allows the use of less material in 
preparing the clamping strip. Thus, such a design insures that the beaded 
portion can be reliably pressed against the flattened tube along the whole 
of its opening. 
In yet another preferred embodiment of the present invention, the clamping 
portion on the second groove surface consists of a bead along the upper 
end of the second groove surface. The bead preferably extends inwardly 
into said groove. Such a bead in combination with the obliquely positioned 
second surface of the groove allows a pressure on the beaded portion on 
the first clamping surface of the clamping member which can be adapted so 
as to achieve an effective compressing and sealing of the tube against the 
first groove surface. 
In still another preferred embodiment of the present invention, the 
above-mentioned bead along the upper end of the second groove surface is 
arranged to cooperate with a chamber or recess in the outer surface of the 
clamping member at the transition between said outer surface and the 
clamping rail. The cooperation of the bead and the recess and the 
construction as a whole of the clamping assembly allows the end of a 
flattened tube to be brought into position in the groove and pressed 
together without substantial stretching or displacement of the material of 
the tube, which stretching or displacement may otherwise cause breakage or 
leakage in the tube. 
The assembly of the present invention may be used in any suitable dialysis 
arrangement or a so-called artificial kidney of the type disclosed in U.S. 
Application No. 902,353 filed May 3, 1978, the disclosure of which is 
incorporated herein by reference. While the assembly of the present 
invention is intended primarily to be used in connection with dialysis, it 
will, however, be clear to those skilled in this art that the assembly may 
be used for many other diffusion and/or filtration processes such as use 
in oxygenators. Thus, the term "fluid" herein is intended to cover gases 
as well as liquids.

DETAILED DESCRIPTION 
The present invention may be described in greater detail with reference to 
the figures shown in the preferred embodiments of the present invention, 
in which like numerals refer to like portions thereof. 
Referring specifically to FIG. 1, a flattened tube 1 is wound around a core 
or bobbin 2 together with a supporting net 3. The inner end of the tube 1 
is secured in a groove 4 by a clamping strip 5. A fluid tight seal of the 
end of tube 1 is achieved along the line 6 by a clamping bead 7 on a leg 
or rail 5' of the clamping strip 5. A feed duct 16 supplies a liquid for 
the interior of the tube 1. The introduction of this liquid into the tube 
may occur in any suitable manner, for example, by the apparatus shown in 
U.S. Patent Application No. 902,353 filed May 3, 1978, the disclosure of 
which is incorporated herein by reference. 
Referring to FIg. 1a, the operation of the apparatus of the present 
invention is shown, but for sake of clarity, the flattened tube has been 
left out. The groove 4 consists of a first groove surface 8 which in the 
embodiment shown has been given a plane shape and a second groove surface 
9 which is in an oblique position in relation to the first groove surface 
8. The clamping leg or rail 5' of the clamping strip 5 consists of a first 
clamping surface 10 provided with a clamping bead 7 and of a second 
clamping surface 12 which is intended to cooperate with the oblique groove 
surface 9. The oblique groove surface 9 terminates at the top of the 
groove in a clamping bead 13 which is adapted so as to cooperate with a 
recess 14 in the clamping strip 5 at the transition between the peripheral 
surface 15 of the clamping strip and the second clamping surface 12. By 
the construction shown, a pressure is directed substantially 
perpendicularly to the tube along the line 6 on the groove surface 8. 
Referring to FIG. 2, a construction of an apparatus in accordance with the 
present invention is shown which in principle is the same as that shown in 
the embodiment in FIG. 1 with regard to the actual sealing of the tube 1. 
Accordingly, corresponding parts have been given the same reference 
designation but with the addition of the letter a. Thus, the tube 1a is 
sealed by means of a clamping strip 5a along the line 6a by a clamping 
bead 7a on the clamping leg or rail 5a'. Thus, in this embodiment of the 
invention, the clamping leg or rail 5a' is fitted into a groove 4a 
arranged in a coupling strip 2a which coupling strip corresponds to the 
drum or bobbin 2 in FIG. 1. For a more detailed discussion of the 
structure of a suitable coupling strip, reference is made to U.S. Patent 
Application No. 902,353 filed May 3, 1978. The groove 4a is formed by a 
first groove surface 8a and a second groove surface 9a arranged in an 
oblique position in relation to the first groove surface 8a. The clamping 
bead 7a on the first clamping surface 10a cooperates with the first groove 
surface 8a and the clamping surface 12a cooperates with the groove surface 
9a so as to seal the tube between said clamping bead 7a and said groove 
surface 8a. The clamping bead or rail 5a is held securely in position by a 
clamping bead 13a on the upper portion of the second groove surface 9a and 
a recess 14a in the clamping strip 5a at the transition between the 
peripheral surface 15a of the clamping strip and the clamping surface 12a. 
Thus, liquid can be withdrawn from the space inside the tube via a duct 
16a connected to the tube 1 at the opening 17 in a manner described, for 
example, in U.S. Patent Application No. 902,353 filed May 3, 1978 
mentioned above. Other types of connections known in the art may, of 
course, also be used. 
It will be understood that the embodiments described above are merely 
exemplary and that persons skilled in the art may make many variations and 
modifications without departing from the spirit and scope of the 
invention. For example, the form and shape of the individual parts 
included in the apparatus of the present invention may be varied 
considerably without thereby exceeding the scope of the invention. All 
such modifications and variations are intended to be included within the 
scope of the invention as defined by the appended claims.