CH642853A5 - MEDICAL SEPARATION DEVICE, PARTICULARLY FOR ARTIFICIAL KIDNEY, AND METHOD FOR MANUFACTURING SUCH A DEVICE. - Google Patents

Description

The invention relates to improvements made to medical separation devices, in particular for artificial hollow fiber kidneys using the type of hollow fiber bundle described in US Patent No. 3,228,876.

Artificial kidneys using a single bundle of the type described in the aforementioned patent and comprising thousands of semi-permeable hollow fibers, made of cellulose or cellulose acetate, have spread throughout the world after their commercial introduction into the United States by the firm Cordis Dow Corporation, at the end of the 1960s and, since that date, the proportion of use of these kidneys has been continuously increasing.

Several commercial versions of such artificial kidneys, having the general configuration of a tube and shell heat exchanger and similar to that described in US Patent No. 3,228,877, generally include a shell of about 10 to 25 cm in length and 4 to 10 cm in diameter, generally containing more than 5,000 and less than 25,000 independent hollow fibers. The envelope is divided into two blood chambers separated by an intermediate dialysate chamber inside which the hollow semipermeable fibers, in which the blood flows, are continuously bathed, on their outer surface, by a dialysate solution. . The fibers are fixed to each other by a tube plate made of solidified resin and the plates, located at the two ends of the fibers, seal between the blood chambers and the intermediate dialysate chamber. The vast majority of artificial kidneys of this type have a cylindrical dialysate chamber, made in one piece with the extreme blood chambers whose diameter is greater than that of the dialysate chamber, as described in the patents of the United States. America N ° 3228876 and N ° 3228877 above mentioned and as shown more particularly in fig. 4 of United States Patent No. 3882024. The tube sheets are generally formed by centrifugal molding of a synthetic resin to be molded around the fibers while the latter

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They are positioned inside the envelope so that the solidified tube plate occupies the cylindrical cross section of the enlarged part, forming the blood chamber, of the envelope. Such widely used methods of fiber coating or centrifugal molding are described in United States Patent Nos. 3442002 and 3492698. Another usable method is described in United States Patent N ° 3755034.

An advantage inherent in the centrifugal molding of the tube support plate, directly in the envelope of the kidney, is that this plate automatically constitutes a barrier or a separating element between the dialysate and blood chambers. In addition, this separation element at the same time ensures a fluid tightness between the dialysate and blood chambers, and this tightness results from the contact between the inner surface of the wall of the envelope and the outer surface of the edge of the plate. . Ideally, the desired joint results from the adhesion between the chosen molding resin and the envelope when the resin forming the plate solidifies in this envelope. The implementation of this process for industrial production has made it possible to obtain several thousand artificial kidneys functioning satisfactorily. However, care must be taken to choose for the envelope, the tube plate and the hollow fibers of the materials which bind fibers in a compatible manner to each other in the tube plate and which at the same time ensure fluid tightness. , necessary between the envelope and the plate, in the variable temperature and pressure conditions encountered during transport and implementation of the kidneys for the desired function. Significant research has focused on the issues raised by the maintenance of these vital joints. Epoxy-type compositions for tube sheets have been tried and described in US Pat. Nos. 3619459 and 3703962. Suitable fibers, with selective permeability, are described in United States patent N ° 3423491, while polyurethane compositions for tube sheets are described in US Patents Nos. 3362921, 3643805, 3708071 and 3962094.

Despite the aforementioned research efforts, manufacturing difficulties persist due to the precise tolerances required on the peripheral dimensions and on the uniformity of these dimensions of the separate elements in order to ensure and maintain a satisfactory seal, meeting the manufacturing specifications or the actual conditions encountered during medical use. A persistent problem results from the tendency of hollow fibers to expand under certain conditions of use, that is to say when they are wetted internally by blood, that they are surrounded externally by the resin of the plate to tubes and that they are wetted by the dialysate on their outer surfaces, in the immediate vicinity of the inner end of the tube plates. It has been observed that this expansion can be sufficient to cause a rupture of the seal formed between the envelope and the edge of the tube plate. Likewise, a rupture between the envelope and the tube plate may result from an uneven withdrawal of the resin from the plate with respect to the interior surface of the wall of the envelope during solidification, or else a partial rupture. may occur during a test or in use when the fibers are not centered in the tube sheet with respect to the envelope.

Another problem recurring from time to time in industrial centrifugal coating manufacturing, producing a tube plate which contains off-center fibers, is the formation of clots in stagnant areas on the surface of the tube plate exposing the open ends fibers with the mass of blood in the blood chamber. The latter is generally delimited by a cup-shaped element which is applied hermetically against the flat surface of the tube plate by means of a conventional circular ring, for example as shown in FIG. 4 of the aforementioned patent No. 3882024. In the case where the hollow fibers passing through the tube plate are off-center, a stagnation zone is formed in the off-center part or in the curved segment surrounded by the circular ring. In this segment, the surface of the plate to

tubes are full and no open end of fiber is present to receive the blood which, by stagnating in this area during a certain part of the hemodialysis treatment, can form a clot. In addition to constituting an undesirable blood loss for the patient, these clots are difficult to remove or remove by backwashing in preparation for possible reuse of the kidney and, if they are not eliminated, they force to discard the kidney.

The invention relates to a separation device eliminating the problems indicated above and described in claim 1.

The invention also relates to a method of manufacturing a device according to the invention which is characterized by claim 6.

The invention will be described in more detail with reference to the drawings annexed by way of example and in which:

fig. 1 is a perspective view of the device according to the invention; fig. 2 is an elevation of the device shown in FIG. 1; fig. 3 is a partial and schematic view, in exploded perspective, showing the elements of the device of FIG. 1 which include, from right to left, the envelope surrounding the frustoconical tube plate with which it is made in one piece, the organ or the head delimiting the blood chamber, the sliding ring seal and the cap protecting the sterility of the blood flow orifice;

fig. 4 is a partial and schematic view, in exploded perspective, showing members used during the centrifugal molding process, before assembly, these members comprising, from right to left, the envelope which contains a bundle of fibers, combined means for centering and forming the frustoconical tube plate and an end mold;

fig. 5 is a partial section along line 5-5 of FIG. 2; fig. 6 is a partial section, on an enlarged scale, showing the sealing members shown in the lower part of FIG. 5;

fig. 7 is a partial longitudinal section, on an enlarged scale, showing a detail of the organ or of the head delimiting the blood chamber and shown diagrammatically in FIG. 3;

fig. 8 is a partial longitudinal section of the end mold shown schematically in FIG. 4;

fig. 9 is a partial longitudinal section, on an enlarged scale, of the combined centering and frustoconical molding element shown diagrammatically in FIG. 4 and oriented, relative to the end mold of FIG. 8, so that it can be placed inside the latter before centrifugation molding;

fig. 10 is a partial longitudinal section, on an enlarged scale, of the cap of the blood flow orifice shown in FIG. 5; the flg. 11 is a view along line 11-11 of FIG. 10;

fig. 12 is a partial longitudinal section, on an enlarged scale, of a detail of the wall of the cap shown in FIG. 5;

fig. 13 is a partial elevation of the cap shown in FIG. 5, showing tamper-proof access windows, and FIG. 14 is a partial section along line 14-14 of FIG. 13, showing members that can be deformed in order to facilitate assembly.

The medical separation device is generally represented at 10 in FIG. 1 to be used in an artificial kidney of the hollow fiber type. It is however obvious that the artificial kidney is only one example of the use of the separation device which also applies to hemofilters, to oxygenators of the blood or to other separators intended to remove impurities from the blood or other bodily fluids, or injectors intended to introduce other fluids or gases into the blood or into other bodily fluids. The device 10 comprises a central chamber 12 with dialysate placed between two spaced-apart chambers 14 with blood connected to the ends of the intermediate chamber (FIG. 5). Each blood chamber 14 terminates in an axial orifice 16 for the flow of blood, covered with a cap generally represented at 18 or 20. The dialysate chamber 12 has conventional inlet and outlet orifices 22 and 24 of the dialysate and it surrounds a bundle 26 of hollow and semipermeable fibers, axially oriented and of the type described in the aforementioned US Patent No. 3228876. The

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bundle 26 of fibers comprises several thousand, for example 3000 to 30,000 fibers, and preferably 5,000 to 25,000 separate fibers, which can be of any type currently well known, including cellulose fibers produced by deacetylation of cellulose acetate , as described in United States Patent No. 3,546,209, or else by the cuprammonium process. As a variant, the fibers can be made of cellulose acetate or any other cellulose ester, or else of polyesters or polyamides. It is also possible to use other fibers with selective permeability, for example those described in the patents of the United States of America Nos 3423491 and 3532527 cited above. The fibers are fine and have the dimension of capillaries, their internal diameter generally being between 150 and 300 (tm and the thickness of their wall being between 20 and 50 (im. The fibers 27 of the bundle 26 pass through two tube plates spaced apart 28. The plates 28, as shown in Fig. 5, differ significantly from those used hitherto in commercial hollow fiber kidneys and they constitute one of the main elements of the device 10 according to the invention. The tubes tubes typical of the prior art are molded by centrifugation, then cut transversely to form a disc-shaped member closing one of the outer ends of the envelope and having a flat face which uncovers the open ends fibers coated in the solidified resin. The flat face of the tube plates constitutes the interior surface of a blood chamber having substantially the shape of a cup and formed by placing lace of a ring around the central part of the face in order to expose the open ends of the fibers, a cup-shaped collector then being applied under pressure and sealingly against the ring. The important difference between these prior art tube plates and the tube plate 28 lies in the presence of a frustoconical part 30 made in one piece with a part 32 in the form of a disc, of conventional type. This conical part 30 projects axially towards the outside of the disc 32 and terminates in a flat face 34 which uncovers the fibers 27 extending over the entire extent of this surface, up to the peripheral edge of the frustoconical part 30 (fig. 3). The fibers 27 are oriented roughly parallel to each other or in a helix inside the dialysate chamber 12 and they deviate slightly outwards in the slightly flared parts 36, 38 connecting the chamber 12 to the extreme chambers 40 and 42 with blood. The fibers 27 being held circumferentially during the cylindrical molding of the tube plates, they follow approximately the taper of the part 30 so that the profile, or the external configuration, of the bundle 26 of fibers appearing on the face 34 is circular, as shown on fig. 3 and 6.

The frustoconical part 30, and in particular its flared outer surface, is used in conjunction with a collector or a head 44 delimiting the blood chamber to form or delimit a cavity 14 intended to contain blood, in a manner described in more detail below. below, after the description of the process for producing the tube plates 28.

Figs. 4 and 5 allow a better understanding of the process for producing the tube plates 28 of the device. The bundle 26 of fibers is initially formed on a conventional belt reel by the implementation of known operations such as those described in US Patent No. 3,755,034, and the separate fibers 27, thus formed, are assembled in several annular layers 45, arranged in a helix and held tightly by means of bands 46 which may consist of ribbons of nylon or polypropylene, in an extreme flat part of small diameter, which is also representative of the two ends of the bundle ( fig. 4).

The envelope of the device 10 is formed separately by the implementation of conventional molding techniques, in any one of a number of resins the medical use of which is approved, for example transparent polystyrene, impact polystyrene , polypropylene, polyacrylates, etc. The manufacture of this envelope does not fall within the scope of the invention. Although the casing or jacket of the device 10 and the extreme chambers

enlarged 40 and 42 to blood are shown as having a circular cross section, it is obvious that other shapes can also be used, and suitable shapes include lenticular, elliptical or otherwise curvilinear sections, making it possible to surround or house various tube plate configurations, for example those shown in figs. 3 and 6-10 of U.S. Patent No. 4,138,460.

The first operation of the process for producing the tube plate 28 consists in introducing or inserting the bundle 26 into the elongated envelope shown in FIG. 1 so that the bands or collars 46 extend substantially the same distance to the outer ends of the envelope. With the bundle 26 in place, a combined element for centering and shaping the frustoconical tube plate, generally represented at 48 in FIGS. 4 and 9, is moved axially above the strip 46 and along the fibers 27, this element 48 being oriented as shown in FIG. 4 and moved a sufficient distance to position or fit the outer axial ends 49 of centering fingers 50 in juxtaposition with the end and inner surface 53 of the strip 46. Each centering finger 50 has a part 52 which projects axially towards the exterior and which is connected to a portion 54 projecting radially inward, and each finger has a width or extends over a circumferential arc sufficient to cover several fibers 27 and bear against these fibers under a pressure or radial force of compression exerted elastically. The combined element 48 is made, for example of polyethylene, polypropylene or the like, so as to have a chosen thickness which gives the fingers 50 sufficient bending resistance to maintain the external circular profile formed by all of the external surfaces. fibers forming the outer annular layer 45 of fibers, at the plane of the rear surface 53 of the strip 46, for the entire duration of the molding by centrifugation. This profile is maintained so as to be identical to the inner circular profile formed by the inner ends 49 of the fingers 50 which together surround the peripheral surface of the beam 26 in the plane of the inner surface 53. The reason or the necessity of the use of the fingers 50 will be indicated in detail below with the description of the centrifugation molding operation. It can however be noted as of now that the element 48 is an element to be discarded after use, used during the molding by centrifugation. After the ends of the fibers have been exposed by cross section of this element and the fibers, said element is discarded.

The combined element 48 also comprises a conical part 56 which projects radially outwards and which projects axially inwards from the junction 57 with the axial internal ends of the parts 52 of the fingers 50. The axial length of the conical part 56 determines the length of the truncated cone which can be molded against this part and, consequently, the length of the frustoconical part 30 of the tube plate 28. This length can be modified as required for the different dimensions of the device to be achieve. Although the length is not critical, it must be chosen so that it is possible to reduce the diameter of the rim or of the disc-shaped part 32 of the plate 28 to the diameter of the flat surface of the frustoconical part 30, at an angle between 8 and 32 °, and preferably between 15 and 25 ° relative to a diametral plane passing vertically through the envelope of the device 10 when the latter is oriented vertically. The element 48 has a rim 58 which begins at the internal axial end of the conical part 56 and which leaves radially outwards to join, by its external lip, a skirt formed by two parts 60 and 62 and extending more axially inward. The skirt 60, 62 has an inside diameter roughly equal to the diameter of the outer end surface 64 of the envelope (fig. 5).

The final assembly of the combined element 48 on the bundle 26 of fibers, in preparation for centrifugal molding, ends with the positioning of the skirt 60, 62 around the outer outer surface 64 of the envelope to delimit thus the frustoconical cavity desired around the fibers 27.

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The combined element 48 being in place as described above, the centrifugal molding assembly is completed by the placement of an end mold 66 around the element 48 so that an interior conical surface 68 of the mold 66 is applied in contact with the outer surface of the conical wall 56 of the element 48 while the rim 58 bears against a support rim 59 of the end mold 66. In this position, the centering fingers 50 and the strip 46 which projects axially are placed in the space delimited inside the axial external end part 70 of the end mold 66. The molding device is then positioned in a conventional type centrifugation molding apparatus, for example the apparatus described in United States patent No. 3442002 and the resin selected to be molded, preferably a polyurethane resin of the type described in the United States patent United States of America No. 3962094, is suitably preheated and introduced simultaneously into the two orifices 22 and 24 of passage while the apparatus is rotated. The centrifugal force resulting from this rotation causes the resin to be molded in the cavity delimited by the interior surface of the wall 64, towards the exterior outside the orifice 24, and by the conical cavity extending axially towards the exterior of this orifice. and delimited by the conical inner wall 56 of the element 48, as described above. The resin to be molded penetrates into the space between the fibers 27, wets the outer surface of these fibers and, during the continuation of the rotation, solidifies the axial inner end of the disc 32 and the frustoconical extension 30 of the plate 28 to tubes thus obtained.

It has been observed in the prior art, during the centrifugal molding of tube plates during operations such as those described in the aforementioned patents Nos 3444002 and 3492698, in particular when using a centrifugal device rotating the device in a horizontal plane, that, when the resin penetrates between the fibers and fills the cavity, it tends to float the outer outer strip 46 towards a position allowing this strip to move away from the axis of the rotating device . This has the undesirable result of a bending of the fibers 27 or a migration of the latter, with the whole of the bundle, towards an off-center position. When the molding resin solidifies, the fibers 27 remain fixed in the off-center position and, after the tube plate obtained has been cut transversely to reveal the open ends of the fibers 27 on the extreme flat and external surface, the fibers are located in an off-center position. The rotation of the device in a vertical plane, although giving better results than those obtained with a horizontal rotation, does not solve this problem. This off-center position of the fibers in the flat surface of the tube plate raises the risk of clots forming during use and possible re-use, and its elimination has long been desired. According to the invention, the centrifugal molding, in the vertical plane or in the horizontal plane, carried out with very diverse resins comprising thermosetting resins and thermoplastic resins, makes it possible to obtain a tube plate such that the fibers are centered by relative to the longitudinal axis of the envelope as long as centering members or other equivalent members are present around the bundle of fibers during centrifugation molding. The improvement obtained in the precision of the uniformity of the distribution of the fibers and in the precision of the axial centering of the fibers, by the implementation of the method of the invention, is particularly advantageous in the case of the frustoconical tube plate thus produced.

The centering members 50 and the pressure exerted by the surfaces

49 on the outer layers of fibers ensure that the fibers 27 substantially follow the taper or the outer surface of the frustoconical part 30 of the tube plate 28. This orientation of the fibers results from the gathering and bonding of all the fibers to the inside of the profile defined by the peripheral edges 49 of all the fingers

50 at the level of the planar inner surface 53, in particular as a result of the cross section of the bundle 26 of fibers internally with respect to the planar surface 53 and towards the planar surface 34 (FIG. 4). The preferred position of the cross section is along or near a transverse plane located at the junction 57 of the end, located axially outward, of the conical part 56 and the inner axial ends of the parts 52 of the fingers 50. When the cut is made along this plane, the fibers 27 have uniformly spaced open ends which extend wholly or almost wholly up to the junction 72 of the peripheral edge of the surface of the conical wall with the outer and flat end face 34 of the frustoconical tube plate 28.

When the cross section is completed, the device 10 thus obtained comprises spaced-apart tube plates 28, situated at the two ends of the elongated envelope and each having the combination of a discoid shape and a frustoconical shape. The tube plates 28 normally make fluid-tight joints between the outer surface of their edge and the inner surface, as indicated in 74 for the outer outer wall 64, due to the adhesion produced between the materials used for the manufacture of the casing and the tube plates 28.

The improved device 10, not removable, double sealing, comprising the new tube plates 28, and the embodiment of the double sealing will now be described in particular with reference to FIGS. 5 to 9.

The member or collector 44 delimiting a blood chamber is shown in the assembly position with the tube plate 28 in FIG. 5 and on an enlarged scale in FIG. 6. This collector 44 has the form of a stepped funnel and comprises a tubular orifice 16 for the flow of blood which, as shown in FIG. 7, has a smooth outer connecting surface which can be slightly conical if desired. A first conical part 78, produced in one piece with the orifice 16 for the flow of blood, extends axially inwards and radially outwards from this orifice. The angle formed between the wall of the conical part 78 and the vertical axis of the envelope, when the manifold is assembled as shown in FIG. 5 and that the envelope is oriented vertically, is not critical. This angle can vary between 30 and 90 °, and it is preferably between 50 and 80 °. The first conical part 78 joins, by its inner end, a second conical part 80 which extends axially inwards and radially outwards from the part 78 so as to form an angle between 8 and 32 ° with a vertical plane passing through the axis of the manifold 44 and of the envelope when the latter is oriented vertically. The angle chosen for the part 80 and that of the taper of the frustoconical outer surface 30 must be equal, or else must not differ by more than 1 °.

Before the final assembly of the manifold, the conical part 80 may have an angle which differs from that of the conical surface 30 but, during assembly, the corresponding surfaces, applied one against the other, take the same angle and a joint 81 extending over an elongated surface is formed. This seal provides a suitable nesting at the junction 72, which prevents crushing of the fragile fibers 27 located in the immediate vicinity of the inner surface 80, while at the same time preventing the formation of a space that can retain blood between the sealing surfaces. As shown in fig. 5, the elongated surface 81 of sealing has a length equal to approximately half the length of the second conical part 80 of the manifold 44, but it is obvious that the length of the sealing contact may vary, this length varying normally depending on the position of the cross section made after centrifugation molding.

The second conical part 80 of the manifold 44 ends, at its inner end, with a radial flange 82 which terminates in a skirt 84 extending axially inwards. The outer surface of the skirt 84 widens slightly at an angle of 2 to 10 °, and preferably equal to about 5 °, relative to an axial plane oriented vertically when the manifold and the envelope are themselves oriented vertically. The inner surface of the skirt 84 has a bead or a circumferential rib 86 projecting inward.

When the manifold 44 is mounted so as to cover the tube plate 28 and the casing, a second seal or safety seal is produced. The outer outer wall of the envelope comprises, at

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its outer surface, an axially elongated portion 64, ending in a conical portion 88. This conical portion 88 extends axially inwardly relative to the outer outer surface 90 of the envelope and widens radially and slightly the surface 90, for example by forming an angle of between approximately 5 and 15 ° with a vertical axial plane when the envelope is oriented vertically. The rib 86 is moved axially by force along the conical part 88 when the manifold 44 is moved towards its assembly position, as shown in FIGS. 5 and 6, and it is compressed enough against this surface to form an airtight seal, even when the pressure inside the dialysate chamber 12 reaches its extreme negative value or drops to a value of approximately —95 kPa. This airtight seal prevents the introduction of air in the event of a failure of the seal formed between the disc 32 and a point on the inner surface of the wall of the envelope near the outer end of this last, this point being indicated in 74.

As shown in fig. 3, the completion of the assembly of the casing, the tube plate 28 and the manifold 44 further requires the installation of a sliding ring 92 on the manifold 44 and on the outer outer wall portion 64 of the envelope, to the position shown in fig. 5 and 6. The sliding ring 92 is a ring which has an inner extreme opening 94 delimited by an axially elongated surface 96. The sliding ring 92 has, at its outer end, an opening 97 which is substantially smaller than the opening 94 and near which inwardly protrudes a disengaged lip 98 intended to engage elastically with a cap 18 of preserving sterility and locking this cap in place in case it is used, which is optional. A second cleared lip 100, larger than the previous one and formed between the lip 98 and the surface 96, is intended to apply a certain pressure on the radial flange 82 of the manifold 44 to move the latter axially inwards when the sliding ring 92 is moved to its final assembly position, as shown. The sliding ring 92 also exerts, respectively on the skirt 84 and on the rib 86, a radial pressure and a compressive force sufficient to deform or flatten the rib 86 against the conical surface 88.

The double seal assembly as described above is transformed into a device with permanent assembly and which cannot be dismantled in any suitable manner, for example by heat-sealing the collector on the envelope and by optional heat-sealing the ring 92 on the collector and / or on the envelope, or by gluing, or preferably by ultrasonic welding. The sliding ring 92 is designed to be welded by ultrasound directly to the wall 64 of the envelope, in the following manner. The inner surface 96 has a slight taper oriented radially outward and axially inward, from a point slightly spaced inwardly of the lip 98, the angle of this taper being understood, for example, between about 3 and 10 °. The surface 96 also has several tabs or parts to be welded 102, projecting inwards and circumferentially spaced. The thickness of these legs 102, measured in the radial dimension, and their circumferential width increase axially inward. The upper surface or surface of the legs 102 located axially inwards is parallel to the longitudinal axis of the ring 92 and of the device 100 when the latter is assembled. The diameter of the upper surface of the legs 102 is slightly less than the outside diameter of the wall 64 of the envelope and it is chosen so that an interlocking under light pressure occurs between the legs 102 and the wall 64 when the ring slide 92 is moved to its final assembly position shown in FIG. 6. Ultrasonic welding of the legs 102 to the wall 64 of the envelope is carried out while the sliding ring is maintained under sufficient pressure, exerted axially inward, to ensure the final junction of all the parts which then form a single block.

The device 10 can optionally include a tamper-evident cap 18 of sterility shown in detail in FIGS. 10 to 14. Briefly described, the cap 18 is a removable member intended to cover the outer end of each of the blood flow orifices on which it is mounted by elastic engagement. This cap 18 also has a sinuous circuit. Its removal requires the destruction of folding windows, so that this removal is visible, which guarantees sterility until the cap is removed voluntarily, in the clinic, before use.

The cap 18 has a frustoconical shape which extends and which joins in a regular manner the external curvature of the sliding ring 92, this ring interlocking internally and tightly around the external surface of the orifice 16 for the flow of blood. Bodies delimiting a sinuous circuit and projecting axially inwards (FIGS. 10 and 11) include a wall 104 in the form of a cup, receiving the cap and having several grooves 106 which establish, between the outside atmosphere and the inside of device 10, a communication circuit passing through the blood flow orifices while simultaneously ensuring bacterial sterility by several bends 107 at 180 °.

The cap 18 comprises members that are flexible or that can be deformed under the application of pressure (FIGS. 13 and 14) which include parts 110, circumferentially spaced, of the external wall 108 of the cap, these parts extending over a angle between 25 and 50 ° from the periphery of the wall 108 and being delimited and weakened by slots 112, as shown. The slots 112 extend axially towards the outside of one end 110 over a short distance and are spaced circumferentially in order to define the edges 114 of the deformable parts 110.

In the preferred embodiment of the cap, two opposite parts 110 are used and each comprise a flange or an elastic interlocking part 116 which projects radially outwards and which extends only between the slots 112, this part being interrupted on the remaining part of the inner end wall 118 connecting the opposite parts 110. The outside diameter of the wall 118 is approximately equal to the inside diameter of the flange 98 of the sliding ring 92 and, consequently, the cap 18 can be easily assembled in the ring 92 by a slight radial deflection towards the inside of the wall portion 110, this deflection being sufficient to allow the flange 116 to engage elastically and to protrude inward the flange 98 under which it is placed when the bending pressure is released.

The cap 18 has tamper-evident windows 120 (FIG. 13) spaced 180 ° apart and formed in the upper upper part of the wall 108, as shown. The windows 120 include two panels 122 and 124 arranged side by side and separated from each other by an axial slot 126 and from the wall 108 of the cap by slots 128,130,132 and 134, axially spaced. The panels 122 and 124 are preferably thinner than the wall 108 and they are made of a material which can be easily stretched and broken, for example a low density polyethylene. The panels are therefore weak enough to easily stretch or tear or break and to allow easy access of the thumb and forefinger to grasp, via the slot 126, the upper wall 136 and, by exerting axial traction, to separate the cap 18 from the sliding ring 92.

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3 sheets of drawings

Claims (8)

642,853 2 1. Medical separation device, comprising an envelope which has an elongated central part and opposite external end parts whose sections are greater than the section of the central part and which have inlet and outlet openings respectively, a bundle ( 26) of hollow and semi-permeable fibers in said envelope extending through the orifices and comprising at each of its ends, a tube plate (28) of molding resin joining the fibers to each other, each tube plate comprising a disc-shaped part intended to fit sealingly into the opening of each of the outer end parts of the envelope so that a dia-lysate chamber (12) is delimited between the inner end surfaces of the parts (32) in the form of a disc, each tube plate also comprising a frustoconical part (30) produced in one piece with the part in the form of a disc and extending axially outwards. of the latter to lead to an extreme outer planar surface (34) which uncovers the open ends of the fibers (27), a collector fixed to the tube plate and representing a blood flow orifice, the frustoconical part of the tube plate constituting a surface of a seal between said plate and the collector, a skirt of the collector and the end part of the envelope representing a seal between the collector and the end part of the envelope, characterized in that the surface (81) of the seal is formed by the frustoconical part (30) of the tube plate (28) and a conical part (80) of the manifold (44); in that the seal is constituted by a conical part (88) of the end part (64) of the envelope leaving axially inwards and radially outwards from the end surface (90) of the envelope, and by a radial inner surface of the skirt (84) of the manifold (44) and covering the conical part (88) of the end part (64) of the envelope, as well as a sealing member (86) at the the interior of the skirt (84) pressing on the part (88) to exert a radial force towards the interior and thus form an airtight seal, and in that an axially sliding ring (92) is provided, intended to surround the skirt (84) and to exert pressure inward to ensure sealing. 2. Device according to claim 1, characterized in that the sliding ring (92) has an annular lip disposed in direct contact with a radial flange (82) of the manifold, and a conical part (96) which extends axially towards the interior of the lip and elements (102) supporting the outer surface of the skirt (84) and pressing against this surface in order to compress the sealing member (86) so as to apply it in a sealed manner against the conical part (88). 3. Device according to claims 1 or 2, characterized in that the collector (44) is covered with a cap (18) connected removably to the sliding ring (92). 4. Device according to one of claims 1 to 3, characterized in that the collector (44) has the form of a stepped funnel, with a first conical part (78) connected to a second conical part (80), extended by the skirt (84) and connected with the latter by the transverse rim (82), the diameter increasing from the part (78) to the skirt (84) and the first conical part (78) comprising a passage (16 ) for blood. (( 5. Device according to claim 4, characterized in that the first conical part (78) diverges at an angle of 30 ° to 90 ° from the blood passage (16) and in that the second conical part (80) diverges at an angle of 8 ° to 32 ° from the first conical part (78). 6. A method of manufacturing a device according to claim 1, obtained by simultaneous coating of a bundle of semi-permeable and hollow fibers in each of the opposite ends of a tubular envelope, having adjacent inlet and outlet orifices at its ends, the opposite end parts of the bundle protruding from the respective end part of the envelope, and carrying bands for gathering the fibers, the envelope being placed in a molding assembly having end molds at its two ends opposite, solidifying molding resin being introduced into each of the two orifices while the molding assembly is rotated so that the centrifugal force exerted on the resin forces the latter to penetrate between the fibers in the region between the orifices and the strip, the resin then solidifying around the fibers, thus producing an end conical part in solidified resin, which will be blade perpendicular to the longitudinal axis of the envelope, this process being characterized in that the molding assembly is completed by placing on each end of the bundle (26) in the end molds (66) a combined element (48) in one piece, comprising a fiber centering element (50) and a part (56) forming a conical tube plate, the centering element surrounding the fibers of the bundle in axial alignment with the envelope and being located near the inner end surface (53) of the strip (46), the portion (56) which forms the tube plate having a conical molding surface extending radially outward and starting at the end inside of the centering element (50) from which it extends axially inwards, thus delimiting around the beam a cavity to form the conical part of the tube plate, and in that the end part is cut conical solidified at a location adjacent to the junction between the end inner half of the centering part and the outer end of the conical part. 7. Method according to claim 6, characterized in that the centering element comprises several flexible and elastic fingers (50), arranged circumferentially, projecting from the outer end of the conical molding surface and extending radially towards the inside this surface. 8. Method according to claim 6, characterized in that the solidifiable molding resin is thermosetting.