TUBULAR FIBER MEMBRANE FOR MATERIAL EXCHANGE AND METHOD OF MAKING SAME

Abstract

The invention relates to a method for producing a device for material exchange between two mediums, in which at least one mat of semipermeable hollow fibres (3) is wound onto a winding core (2), which has at least one core opening (2a) in its outer surface for a first in- or out-flowing medium, and the winding core (2) is arranged in an axially extending housing (1) having at least one housing opening (1a) for the first in- or out-flowing medium and the axial end regions of the housing (1) are sealed by an adhesive (4) arranged around the hollow fibres (3), wherein at least one chamber region (5) surrounding the hollow fibres (3) is formed via the adhesion between the axial end regions (1b, 1c) of the housing (1) and between the winding core (2) and the housing (1), through which chamber region the first medium can flow via the core opening (2a) and the housing opening (1a), wherein the axial distance between the core opening (2a) and the housing opening (1a) is adjusted to a desired value of multiple possible values via the axial shifting of the winding core (2) relative to the hollow fibre winding (3) arranged around the winding core (2) and relative to the housing (1), and the hollow fibres (3) are adhered to the side of the housing (1) near to the housing opening (1a) in a region between the axial end surface of the housing and the housing opening (1a), and the hollow fibres (3) are adhered to the side of the housing (1) near to the core opening (2a) in a region between the axial end surface of the housing and the core opening (2a). The invention also relates to a number of multiple devices for material exchange between two mediums, wherein all devices comprise at least identical housings (1) and winding cores (2) that are identical at least in regions.

Claims

1. A method of making an apparatus for exchanging substances between two media, the method comprising the steps of: winding at least one mat of semipermeable fiber tubes on a winding core whose outer surface has at least one core opening for a first or outflowing medium, flowing a first medium into or out of a port of an axially extending housing surrounding the winding core, forming with the sealing adhesive between the axial ends of the housing and between the winding core and the housing a chamber containing at least one of the fiber tubes and through which the first medium can flow between the core opening and the port, flowing a second medium through the fiber tubes in their extension between the axial ends of the housing, axial displacing the winding core relative to the fiber tube winding around the winding core and relative to the housing to adjust an axial spacing between the core opening and the port to a desired value from several possible values, and sealing an end of the housing close to the port the fiber tubes are sealed with adhesive in an area between the axial the end face of the housing and the port, and sealing the fiber tubes at an end of the housing close to the core opening in an area between the axial end face of the housing and the core opening axially up to the core opening.

2. The method according to claim 1, wherein there is at least one further winding core in the winding core with a core opening for the medium flowing in or out and whose wound fiber tubes thus extend between two winding cores with the axial displacement of at least the outer winding core also of the at least one further winding core, setting the axial spacing between the core openings the nested winding cores to a desired value is set from several possible values.

3. The method according to claim 1, wherein the winding core has an axial length that is greater than an axial length of the housing and after the shift to adjust the axial position of the core opening that projects at least at one end past an axial end face of the housing, the method further comprising the step of, after sealing cutting off the excess area near the end face and an axial housing end cap, the projecting part extending past and being connected to the axial end of the housing connected, and/or fitting an axial housing end cap with a hole over the projecting part and sealing same with the axial end of the housing.

4. The method according to claim 1, further comprising the steps of: closing the axial ends of the housing by identical axial housing end caps.

5. The method according to claim 4, wherein the identical housing end caps each have a hole, one of the end caps with its the hole being fitted over a projecting part of the winding core and the hole in the other end cap being plugged with a closure element.

6. The method according to claim 1, comprising the step of: using a set of identical housings and a set of identical winding cores for creating different displacements of the winding cores and thus several different set positions of the core openings for adjusting mass transfer between two media across mass transfer surfaces of different sizes.

7. An apparatus for exchanging substances between two media produced according to claim 1.

8. A set of several apparatuses each according to claim 1 for mass transfer between two media, wherein all the apparatuses at least have identical housings and at least partially identical winding cores, the core openings of the winding cores lying in different axial positions and in connection with different amounts of adhesive, the apparatuses of this set of different sizes having effective mass transfer surfaces.

Description

[0034] FIG. 1 shows an apparatus manufactured according to the invention apparatus for example for exchanging substances between blood and a gas, in particular for oxygenating blood. FIG. 1 shows an axially elongated housing 1 with a port 1a. This port 1a in this embodiment extends radially as a tubular hose-connection fitting from housing 1.

[0035] A winding core 2 is inserted into the housing 1, here in particular coaxial to the housing 1, and has a core opening 2a. This core opening 2a is an annular gap connected to a hose-connection fitting 2b. The winding core 2 is surrounded by a fiber mat formed by a plurality of joined fiber tubes 3, but in this view only a single fiber tube 3 is shown schematically for clarity. This fiber tube 3 also is, for the sake of clarity, enlarged and shown at a slight spacing from the core.

[0036] At axial ends 1b and 1c of the housing 1 the fiber tubes 3 are potted in an adhesive body 4 that also bonds them to the winding core 2 and the housing 1. The ends of the housing are therefore sealed to contain the contents of the chamber 5 from the outside.

[0037] This bonding, which is also called potting in the art, is for example carried out in a centrifuge so that centrifugal forces restrict the adhesive to the axial ends of the housing. The potting or bonding of the fiber tubes 3 takes place in such a centrifuge for the axial ends 1b and 1c accordingly one after the other, with the end being bonded radially outward of the centrifuge axis.

[0038] Manufacture of this type produces an inner chamber 5 that extends axially between the potted ends 1b and 1c and extends radially between the outer surface of the winding core 2 and the inner wall surface of the housing 1. This chamber 5 are therefore contains the semipermeable fiber tubes 3 around which the medium flows. It can be seen here that medium supplied through the hose-connection fitting 2b of the winding core can enter the chamber 5 via the core opening 2a then flows all around all of the fiber tubes of the winding on the outside and after flowing axially through the chamber region 5 exits through the port 1a. The direction of flow is here for example from the chamber opening 2a to the port 1a and can be reversed.

[0039] The axial end of each semipermeable fiber tube 3, namely the ends 3a and 3b, are accessible, and a second medium flows axially through the fiber tubes 3, for example in the application as an oxygenator by a gas. This gas can be pumped via an appropriate connection 6a in one of two axial end caps 6 into and out of the interior fiber tubes 3.

[0040] If necessary, the axial end faces 3a, 3b of the fiber tubes 3 are cleared, if they get clogged by during potting.

[0041] The axial end caps 6 shown here are identical and each have a central hole 6b, which is plugged in the upper cap of the figure, but here is shown in the open state, and that of the lower end cap 6 the winding core 2 is fitted with a tapered hose connection 2b. In this way, identical axial housing end caps 6 are used, with the unused hole 6b of only one of the end caps closed with an unillustrated plug.

[0042] FIG. 1 shows that the axial spacing between the core opening 2a and the port 1a, which axially flow is through and which is defined by the length of the chamber area 5 and by the axial length of the fiber tubes 3, so as to define, as it were, the total immersed surface of the fiber tubes 3 that participates in mass transfer.

[0043] FIG. 2 shows an apparatus according to the invention apparatus that, like the apparatus of FIG. 1, has exactly the same components, i.e. housing, winding core, fiber tubes and end caps.

[0044] Unlike FIG. 1, however, the core is shifted during manufacturing according to the invention, to axially move the core opening 2a, because here before potting the core 2 is shifted axially in FIG. 2, thereby moving the core opening 2a upward further into the interior of the housing 1 in comparison to FIG. 1.

[0045] Moving the core opening 2a further into the housing 1 creates a shorter axial spacing between the core opening 2a and the port 1a and accordingly also a smaller axial length for flow around the winding formed by the fiber tubes 3.

[0046] In the manufacture method according to the invention, the manufacture of the apparatus according to FIG. 2 uses more adhesive 4 to get a greater fill height at the lower axial end 1c of the apparatus. As in FIG. 1, in FIG. 2 the amount of adhesive 4 to be used when sealing the fiber tubes at the lower end 1c of the housing moves the surface 4a of the adhesive axially upward in the housing 1 to raise the core opening 2a without plugging the core opening 2a with adhesive.

[0047] The invention can provide between the surface 4a of the adhesive 4 and the lower edge of the core opening 2a an axial safety spacing, such as 1% to 10% of the spacing between the core opening 2a and the lower end face of the end 1c.

[0048] It can be clearly recognized by the hatching of the adhesive 4 in FIG. 2 compared to the adhesive 4 in FIG. 1 that the fill height and thus the fill quantity of the adhesive 4 in the embodiment according to FIG. 2 is greater than in FIG. 1.

[0049] In both cases from inside the chamber 5 viewed areas beyond the core opening 2a the adhesive 4 is excluded from the chamber area 5. Consequently both the chamber volume of the chamber 5 in FIG. 2 is smaller than in FIG. 1 as well as the actively active area of the fiber tubes that take part in mass transfer.

[0050] It can be seen here that in FIG. 2 unlike in FIG. 1 the winding core 2 projects axially above the upper end face 1e of the upper end 1b. However, the axial projection above the end face 1e is less here than the inner free axial length of the end cap 6, so that the projecting end of the winding core 2 is completely covered by the end cap 6.

[0051] It can therefore be seen from FIGS. 1 and 2 in comparison that through the simple axial shifting the position of the core opening 2a and changing the amount of adhesive 4 near this core opening 2a allows systems with different volumes and the exchange areas to be made with identical components.

[0052] FIG. 3 shows another embodiment of the method or of the apparatus where the winding core 2 compared to the embodiment in FIGS. 1 and 2 is of significantly increased axial length. This ensures that the core opening 2a in FIG. 3 is shifted clearly closer to the port 1a during before sealing and thus provides even significantly smaller sizes for the internal volume of the chamber 5 or in the case of the active mass transfer surface.

[0053] In FIGS. 3 to 6, the fiber tubes are not shown, but also here surround the respective core, as in FIGS. 1 and 2.

[0054] Here, too, it can be seen in the comparative consideration of FIGS. 3 and 4 that in FIG. 4 the amount of adhesive 4 is greater due to the higher axial position of the core opening 2a than in FIG. 3. In both figures the surface 4a of the facing the interior of the chamber 5 adhesive is raised to the lower edge of the core opening 2a, in particular, however, without the adhesive in the sealing process getting into the core opening 2a. Again, a safety spacing as described at the beginning must be observed.

[0055] Because of the significantly increased axial length of the winding core 2 provided at least the projecting axial upper end 1b of the winding core 2 projecting from the housing 1 can be cut off before a lid 6 is put on, as indicated schematically by the scissors on the dashed line symbolically above the axial end face 1e of the housing 1.

[0056] Alternatively, however, the invention can also provide that, in use of the housing, end caps 6 with holes 6b large enough to cover the area of winding core 2 surround and are sealed thereon, so cutting off is not absolutely necessary so that here FIGS. 3 and 4 also show the axially upper winding core area can projects upward from the end cap 6 through the opening 6b. The invention can provide here that in the hole 6b at the lower end, where this hole is in cross section, it surrounds the narrowed hose connection area 2b of the winding core 2 with an additional sealing element.

[0057] FIG. 5 shows a further variant of the method according to the invention in which two nested cores are used. In this embodiment, the here radially outer winding core 2 has its radial essentially ring-shaped core opening 2a pointing outward and that core, which in the context of the inventive method is shifted axially, defines the length of the chamber area 5. Here, too, the adhesive is 4 is brought up to the lower edge of the core opening 2a, so that essentially the axial length of the outer chamber 5 is defined by the spacing between the opposite and one another assigned surfaces of the adhesive 4 or the axial spacing between the core opening 2a and the port 1a.

[0058] A further core 2′ is provided within the core 2, also surrounded by an unillustrated winding of fiber tubes, this core having a core opening 2′a that is axially spaced from the core opening 2a and that preferably is in this embodiment essentially axially level with the port 1a.

[0059] The winding core 2′ here essentially corresponds to the embodiments of the winding core 2 of FIGS. 1 and 2, apart from the position of the core opening.

[0060] The method according to the invention here proposes, when comparing the embodiments of FIGS. 5 and 6, that during manufacture the axial position of the inner winding core 2′, as in the various embodiments of FIGS. 5 and 6, is unchanged, whereas the axial position of the outer winding core 2 in FIG. 6 with respect to

[0061] FIG. 5 is shifted such that the core opening 2a of the outer core 2 in FIG. 6 is closer to the port 1a than in FIG. 5.

[0062] This is achieved in that in the case of the procedure as described for the other figures the core 2 with its core opening 2a is pushed further into the housing and then in FIG. 6 more adhesive is used to attach the fiber tubes to the lower axial end 1b of the housing 1 with one another to glue them to the housing and the cores.

[0063] In principle, the inner winding core 2′ can move between two maximum positions, like the outer winding core 2.

[0064] The embodiments of FIGS. 5 and 6 result form two radially nested chamber areas 5 and 5′, the one after the other in the direction of flow from the supplied medium flow through, whereby in these chamber areas 5 and 5′ there are identical or different fiber tubes.

[0065] The flow path here will essentially be such that the medium enters through the inlet hose connection 2′b of the inner winding core 2′ and moves from its core opening 2′a into the inner chamber area 5′, thus into the interior of the core 2, from whose core opening 2a it flows out into the outer chamber area 5 and flows from there to the outlet port 1a.

[0066] By shifting the core opening 2a of the outer core when performing the method according to the invention, bonding is achieved in that the spacing between the core openings 2a and 2′a of outer and inner cores can be set variably, which thus affects the mass transfer surfaces of the fiber tubes in the chambers 5 and 5′ has the same effect.

[0067] FIG. 5 shows that the winding core 2a projects downward past the axial end face 1e of the housing 1, so that according to the invention in which the embodiment of FIG. 5 with the higher volume and the larger exchange surface the core 2 is cut to length in its lower area, whereas in the embodiment of FIG. 6 the same external core 2 with its upper axial end projecting up past the axial end face 1e of the housing 1 has an upper end that can be cut to length, as shown by the schematic cut line.

[0068] The also provided end caps, which are shown in FIGS. 1 to 4 are not shown in FIGS. 5 and 6, but are basically also used to move gas through the fiber tubes. Here too as in the above-described embodiments, the covers either fit with the larger cross-section of the outer winding core or of the inner connection cross-section of the inner winding core can be adjusted.

[0069] All figures make it clear that in spite of the manufacture use of identical components, in particular identical housings and winding cores, apparatuses with different volumes and mass transfer areas can be realized simply by moving the core openings with respect to their axial position and use of different amounts of adhesive 4.

[0070] FIG. 7 is a flow diagram for carrying out the method using steps 1a to 1h of original claim 1.

[0071] In first step 1a, a mat 2 of fiber tubes is wound around a core 2 with an outer surface forming at least one core opening 2a that has a first medium flowing in or out, as shown in FIG. 1.

[0072] In following step 1b, the winding core 2 is fitted into an axially extending housing, in particular a cylindrical housing 1, preferably arranged coaxially, and having at least one port 1a for the inflowing or outflowing medium.

[0073] An axial displacement then takes place in step 1f of the winding core 2 relative the winding core 2 surrounded by the fiber-tube winding 3 and the housing 1, whereby an axial spacing between the core opening 2a and the port 1a is set to a desired value of several possible values. Two setting modes are shown in FIGS. 1 and 2. In these figures the same winding core 2 has different axial positions relative to the housing 1 and to the fiber tubes 3.

[0074] Then in step 1c, the axial ends of the housing 1 are sealed around the fiber tubes 3 with adhesive 4; preference is given to the axial ends 1b, 1c of the housing 1 with adhesive 4 securing the wound fiber tubes 3 with the core 2, one below the other and to the housing 1.

[0075] Therefore, in this step 1c, steps 1g and 1h are executed, namely according to step 1g depositing adhesive fat the opening to the housing 1a at the near side of the housing 1 and the fiber tubes 3 and in an area between the axial end face of the housing and the port 1a and, according to step 1h, putting adhesive the side of the housing 1 near the core opening 2a the fiber tubes 3 in an area between the axial end face of the housing and the core opening 2a, in particular axially up to the core opening 2a. The FIGS. 1 and 2 show the final result of the bond for two different axial positions.

[0076] According to this, in step 1d adhesive is applied between the axial ends 1b, 1c of the housing 1 and between at least the fiber tubes 3 surrounding chamber region 5 formed between the winding core 2 and the housing 1, so that the core opening 2a and the port 1a can pass the first medium, in particular blood.

[0077] Preferably a second medium, in particular a gas, flows through the fiber tubes 3 between the axial ends 1b, 1c of the housing 1.