Abstract
The invention relates to a filter device for the exchange of substances, comprising a pipe section-shaped housing with a center of gravity and with two housing ends, in which housing a hollow fiber bundle consisting of semi-permeable membranes is arranged, comprising, furthermore, an end cap having a first and second opening, wherein the housing and the end cap configure a first sealing surface which connects the housing and the end cap sealingly, and wherein the first sealing surface is spaced apart further from the center of gravity of the housing than the aperture, and wherein a first fluid chamber is formed between the first sealing surface and the first opening of the end cap, via which first fluid chamber the first opening is connected to the first flow chamber, wherein the housing and the one end cap configure a second sealing surface, wherein the first and second sealing surface are not configured by way of a sealant.
Claims
1. A filter device for material exchange comprising a pipe section-shaped housing having a centre of gravity and having two housing ends, in which housing there is arranged a hollow-fibre bundle composed of semi-permeable membranes, the fibre cavities of which hollow-fibre bundle form a first flow space, and the housing interior surrounding the hollow-fibre bundle forms a second flow space, wherein the flow spaces are separated from one another at the housing ends by at least one flow-space seal, wherein the housing is provided with at least one breach at at least one end and the at least one breach is arranged closer to the centre of gravity of the housing than the flow-space seal, comprising furthermore at least one end cap having a first and a second opening, wherein the housing and the at least one end cap form a first sealing area which connects the housing and the end cap in a sealing manner and wherein the first sealing area is at a further distance from the centre of gravity of the housing than the at least one breach, and wherein a first fluid space is formed between the first sealing area and the first opening of the end cap, via which first fluid space the first opening is fluidically connected to the first flow space, wherein the housing and the at least one end cap form a second sealing area which connects the housing and the end cap in a sealing manner and the second sealing area is arranged closer to the centre of gravity of the housing than the flow-space seal and the at least one breach, and wherein a second fluid space is formed between the first and second sealing area and the second opening of the end cap, via which second fluid space the second opening of the end cap is fluidically connected to the second flow space through the at least one breach, wherein the first and second sealing area are not formed by a sealant.
2. The filter device according to claim 1, wherein in both the first and the second sealing area, molecules of the housing are entangled with molecules of the end cap.
3. The filter device according to claim 1, wherein the first sealing area is at a further distance from the centre of gravity of the housing than the at least one breach and the flow-space seal.
4. The filter device according to claim 1, wherein the pipe section-shaped housing and the end cap are formed from the same group of materials.
5. The filter device according to claim 1, wherein the material of the housing and the end cap comprises polypropylene or copolymers of polypropylene or polycarbonate.
6. The filter device according to claim 1, wherein the first sealing area is equal to or larger than the cross-sectional area of the pipe section-shaped housing at the housing end.
7. The filter device according to claim 1, wherein there are two end caps at the opposite ends of the pipe section-shaped housing and the housing is provided with breaches and flow-space seals at both ends and the breaches are in each case arranged closer to the centre of gravity of the housing than the flow-space seals.
8. The filter device according to claim 1, wherein the housing has a multiplicity of breaches at least one end.
9. The filter device according to claim 7, wherein the filter device is a dialyser and in that the first openings of the end caps allow an inflow of blood and an outflow of blood and in that the second openings of the end caps allow an inflow of dialysate and an outflow of dialysate.
10. The filter device according to claim 9, wherein the pipe section-shaped housing does not comprise a dialysate inlet or dialysate outlet.
11. The filter device according to claim 1, wherein the material of the semi-permeable membranes comprises polysulfone, polyvinylpyrrolidone, polymethyl methacrylate, polyamide, polyester, cellulose or polyacrylonitrile.
12. Method A method for producing a filter device according to claim 1, wherein the first and second sealing area are in each case produced by fusing and cooling of the regions of the housing and the end cap that face the sealing areas with formation of a sealing connection and in that entanglement of molecules of the housing with molecules of the end cap is carried out.
13. The method according to claim 12, wherein the sealing areas are in each case produced by welding.
14. A hot-plate welding tool configured for carrying out the method according to claim 12.
15. The method of claim 13, wherein the welding is hot-surface welding, laser beam welding, spin welding or ultrasonic welding.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Further details and advantages of the present invention will be more particularly elucidated on the basis of an exemplary embodiment depicted in the drawings. In the figures:
[0040] FIG. 1 shows a schematic depiction of a pipe section-shaped housing
[0041] FIG. 2 shows a schematic depiction of an end cap
[0042] FIG. 3 shows a schematic depiction of a filter device, comprising a pipe section-shaped housing and an end cap
[0043] FIG. 3a shows an enlarged depiction of FIG. 3 in the region of a first sealing area
[0044] FIG. 4 shows a schematic depiction of an arrangement of pipe-shaped housing, end cap and hot-plate welding tool during a heating phase of a hot-plate welding process
[0045] FIG. 5 shows a schematic depiction of a section of a heating element tool or hot-plate welding tool with the corresponding section of the housing, representative of a special embodiment
[0046] FIG. 5b shows a schematic depiction of a section of a heating element tool or hot-plate welding tool with the corresponding end cap section, representative of a specific embodiment
[0047] FIG. 6a shows a schematic depiction of a section of a heating element tool or hot-plate welding tool, representative of a specific embodiment
DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT
[0048] FIG. 1 shows a pipe section-shaped housing 2 of a filter device 1 that comprises a hollow-fibre bundle 3 composed of semi-permeable membranes 4. At the ends, the pipe section-shaped housing 2 comprises a flow-space seal 8, which is depicted here concavely toward the centre of gravity S. The flow-space seal 8 is made of polyurethane; an arrangement of epoxy resin or ceramic sealing material is similarly possible. If the filter device 1 is used for dialysis, polyurethane is preferred. The outer surface of the flow-space seal 8 is configured such that the hollow-fibre membranes 4 are open, and so a first flow space 6 is formed that comprises the interior of the hollow-fibre membranes 4. The second flow space 7 is situated in the housing 2 outside the hollow-fibre membranes 4. FIG. 1 shows furthermore breaches 9 in the housing 2, which are arranged closer to the centre of gravity S of the housing 2 than the flow-space seal 8. If the filter device 1 is a dialyser, dialysate can be supplied to the outer surface of the hollow-fibre membrane 4 or removed therefrom via said breaches 9, and so material exchange can take place between the blood side of the dialyser, represented by the first flow space 6, and the dialysate, represented by the second flow space 7. In another embodiment, it is also possible to guide the blood in the second flow space 7 and the dialysate in the first flow space 6. The housing 2 comprises furthermore a housing projection 2a, which is arranged closer to the centre of gravity S of the housing 2 than the flow-space seal 8 and the breaches 9.
[0049] FIG. 2 shows an end cap 10 having a first opening 11 and a second opening 12. Provided on the outsides of said openings 11 and 12 are threads 18 or devices for connection of fluid lines, which are not shown here.
[0050] FIG. 3 shows the assembly of the end cap 10 with the pipe section-shape housing 2. The two components are designed such that a first 13 and a second 14 sealing area are present. Via the first opening 11, it is possible, then, for fluid to enter the first flow space 6 or to be removed from the opening 11; the first sealing area 13 prevents an undesired transfer of the fluid into the second flow space 7. Via the second opening 12, it is possible, then, for fluid to enter the second flow space 7 or to be removed from the second opening 12; the first 13 and the second 14 sealing area prevent an undesired transfer of the second fluid into the first flow space 6. Shown on the pipe-shaped housing 2 is the projection 2a, which, in this exemplary embodiment, forms the second sealing area 14 together with the end cap 10.
[0051] FIG. 3a shows an enlargement of the region of the first sealing area 13, and what is formed is a first sealing area 13 which is larger than the cross-sectional area of the pipe section-shaped housing 2 at the housing end. What is shaped is a bead 15. In this exemplary embodiment, it was produced by a hot-plate welding method, the joining partners having been joined with such a pressure that enlargement of the first sealing area 13 occurred.
[0052] FIG. 4 shows schematically the joining process in the formation the filter device 1 by joining of the end cap 10 and the pipe-shaped housing section 2, the two joining partners being composed of polypropylene. Other materials are also possible, especially also polycarbonate. FIG. 4 shows the end cap 10, the pipe-shaped housing section 2 and a cross section of a hot-plate welding tool 16. The tool provides a contact area with those areas of the end cap 10 and the housing 2 that must be brought into contact for joining of the work pieces in order to form the first 13 and second 14 sealing area. In what is depicted, there is also depicted a tool heating element 17, which ensures heating of the contact areas of the joining partners above the melting point or the glass transition point of the material. After the heating process, the joining partners can be moved further apart, so that the hot-plate welding tool 16 can be removed. Then, the joining partners are joined such that the first 13 and second 14 sealing area are formed. In this exemplary embodiment, molecules of the end cap 10 are intimately entangled with molecules of the pipe-shaped housing section 2. This gives rise to first 13 and second 14 sealing areas which exhibit particularly high leak-tightness.
[0053] Alternatively, the first 13 and second 14 sealing areas can also be provided by spin welding or by laser beam welding. Spin welding is possible and preferred when the first 13 and second 14 sealing area are arranged with rotational symmetry. Ultrasonic welding is similarly possible, and in this case at least one energy director is to be preferably provided on the pipe-shaped housing section 2 and/or on the end cap 10, respectively.
[0054] FIG. 5a represents a further preferred embodiment of the joining process in the formation the filter device 1 by joining of the end cap 10 and the pipe-shaped housing section 2, wherein the pipe-shaped housing section and the hot-plate welding tool 16 are represented in an enlarged partial view. In this embodiment, the contact surface between the housing section 2 to be melted and the hot-plate welding tool 16 is configured such that the contact surface of the housing section 2 contacts the tool at a surface, which in a longitudinal direction of the housing section is formed in an angle different from 0 and 90?. An angle of between 20 and 70? is preferred, between 30 and 60? more preferred, and between 40 and 50? yet more preferred. In the embodiment, the angle is 45?. Such embodiment has the advantage to enable a precise control of the joining position, resulting in a particularly secure and low-waste joining connection. In addition, a weld bead is particularly small in such embodiment, such that possible restrictions in the fluid flow path during the separation process are reduced. In the case of a dialyzer, this in particular pertains to the dialysate side.
[0055] FIG. 5b represents a further preferred embodiment of the joining process in the formation the filter device 1 by joining of the end cap 10 and the pipe-shaped housing section 2, wherein the end cap and the hot-plate welding tool 16 are represented in an enlarged partial view. In this embodiment, the contact surface between the section of the end cap 10 to be melted and the hot-plate welding tool 16 is configured such that the contact surface of the end cap 10 contacts the tool 16 at a surface, which in a longitudinal direction of the (imaginary) filter device touches at an angle different from 0 and 90?. An angle of between 20 and 70? is preferred, between 30 and 60? more preferred, and between 40 and 50? yet more preferred. In the embodiment, the angle is 45?. Such embodiment has the advantage to enable a precise control of the joining position, resulting in a particularly secure and low-waste joining connection. In addition, a weld bead is particularly small in such embodiment, such that possible restrictions in the fluid flow path during the separation process are reduced. In the case of a dialyzer, this in particular pertains to the blood side. The weld bead is thereby formed such that a dead volume in the blood room is as small as possible, or a dead volume is even avoided altogether. A dead volume at the blood side can lead to strong coagulation of blood, which results in successive clogging of the dialyzer.
[0056] A further embodiment is shown in FIG. 6a, which constitutes a further improved modification of the embodiment of FIG. 5a. In this embodiment, the contact surface between the housing section 2 to be melted and the hot-plate welding tool 16 is configured such that the contact surface of the housing section 2 contacts the tool at a surface, which in a longitudinal direction of the housing section is formed in an angle different from 0 and 90?, wherein the surface has a concave curvature. A concave curvature is to be understood such that the curvature protrudes into the welding tool. The radius of the curvature has to be adjusted to the dimensions of the housing. In the case of a filter device having the size of a dialyzer, preferred curvature radii are between 1 mm and 10 mm, in particular between 2 and 8 mm, further in particular between 3 and 6 mm. In the embodiment, the radius is 4.5 mm. A concave curvature simplifies the precise reception of the joining partner even at higher tolerance of the joining partner, resulting in a further increased product safety and quality of the weld. High tolerance occurs in particular if polyolefin, more particularly propylene-based material is used as a housing material. FIG. 6b is applicable to the joining of the end cap 2 accordingly.
LIST OF REFERENCE SIGNS
[0057] 1 Filter device [0058] 2 Pipe section-shaped housing [0059] 2a Housing projection [0060] 3 Hollow-fibre bundle [0061] 4 Semi-permeable membrane [0062] 5 Housing interior [0063] 6 First flow space [0064] 7 Second flow space [0065] 8 Flow-space seal [0066] 9 Breaches [0067] 10 End cap [0068] 11 First opening [0069] 12 Second opening [0070] 13 First sealing area [0071] 14 Second sealing area [0072] 15 Bead [0073] 16 Hot-plate welding tool [0074] 17 Tool heating element [0075] 18 Thread [0076] S Centre of gravity [0077] K Contact surfaces
