INFUSION FILTER, AND INFUSION SET WITH INFUSION FILTER

Abstract

An infusion filter and an infusion set that includes the infusion filter and an infusion line. The infusion filter has a housing defining a flow path between a housing inlet, couplable to a portion of the infusion line, and a housing outlet. A hydrophilic filter membrane is arranged in the flow path. The housing has, upstream of the filter membrane, an elbow for a first deflection of a flow along the flow path transversely to the main flow direction, and a baffle surface for a second deflection of the flow back into the main flow direction, ensuring that flow impinges on the filter membrane exclusively at the upstream membrane side. The infusion line has a first end portion with a connector for a container with an infusion solution, and a second end portion with a connector for a patient port or a further infusion line.

Claims

1. An infusion filter for at least one medical infusion line, the infusion filter comprising: a housing defining a flow path between a housing inlet and a housing outlet, the housing inlet being couplable to a first portion of the at least one infusion line, and the housing outlet being coupleable to a second portion of the at least one infusion line; and a filter membrane that is hydrophilic and arranged in the flow path, the filter membrane being aligned parallel to a main flow direction predetermined by the at least one infusion line and placed in the housing in such a way that the filter membrane divides the housing into an upstream housing portion and a downstream housing portion, the housing comprising, upstream of the filter membrane, a first flow-guiding element that forms a first elbow for a first deflection of a flow along the flow path in a direction transverse to the main flow direction, and a second flow-guiding element forming a baffle surface oriented obliquely to the main flow direction for a second deflection of the flow back into the main flow direction, so as to ensure the flow against the filter membrane exclusively at an upstream membrane side of the filter membrane.

2. The infusion filter according to claim 1, wherein the housing has a third flow-guiding element downstream of the filter membrane that forms a second elbow that deflects the flow flowing substantially vertically through the filter membrane into the main flow direction.

3. The infusion filter according to claim 1, wherein: the housing inlet has a first receiving region for receiving the first portion of the at least one infusion line, the housing outlet has a second receiving region for receiving the second portion of the at least one infusion line, and the first and second receiving regions are adapted to dimensions of the at least one infusion line in such a way that, m-thein a coupled state, inner diameters of the at least one infusion line end flush with surfaces of the receiving regions.

4. The infusion filter according to claim 1, further comprising a vent filter that is air-permeable and arranged in the housing, the vent filter being connected to an outer housing side via an opening formed in the housing.

5. The infusion filter according to claim 1, wherein the housing comprises: a support structure for receiving or mounting the filter membrane, the support structure having a crosspiece that is closed and follows a geometry of the filter membrane; and support elements arranged within the crosspiece.

6. The infusion filter according to claim 5, wherein: the support elements are configured as ribs and knobs, the ribs are arranged in the main flow direction aligned downstream of the filter membrane directly following filter membrane, and the knobs are placed downstream of the ribs with respect to the main flow direction.

7. The infusion filter according to claim 1, wherein the filter membrane has a bubble pressure between 0.2 and 0.45 bar and/or an area intended for flow below 2.0 cm.sup.2.

8. The infusion filter according to claim 1, wherein the filter membrane is constructed from one of: a plurality of parallel tubes, a block with gaps, lamellae, or an open porous material, a felt or a foam.

9. An infusion set comprising: the infusion filter according to claim 1; and an infusion line, the infusion line comprising a first end portion comprising a first connector for a container with an infusion solution, the infusion line further comprising a second end portion comprising a second connector for a patient port or a further infusion line.

10. The infusion set according to claim 9, wherein the infusion filter is arranged in a flow direction of the infusion solution from the first end portion to the second end portion directly upstream of the second end portion.

11. The infusion set according to claim 9, wherein the infusion filter is directly integrated in the second connector.

12. The infusion filter according to claim 1, wherein the first deflection of the flow is perpendicular to the main flow direction.

13. The infusion filter according to claim 4, wherein the vent filter is arranged in an upstream housing portion of the housing.

14. The infusion filter according to claim 4, wherein the crosspiece is circular.

15. The infusion filter according to claim 6, wherein the knobs are transversely offset to the ribs with respect to the main flow direction.

16. The infusion filter according to claim 7, wherein the filter membrane has a bubble pressure between 0.2 and 0.45 bar and/or an area intended for flow below 1.7 cm.sup.2.

17. The infusion filter according to claim 8, wherein the filter membrane is constructed from a membrane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The disclosure is explained in more detail below with reference to preferred configuration examples with the aid of Figures.

[0032] FIG. 1 shows a perspective view of an infusion filter according to a preferred configuration example;

[0033] FIG. 2 shows an exploded view of the infusion filter according to the preferred configuration example;

[0034] FIG. 3 shows a perspective view of a lower housing part of the infusion filter according to the preferred configuration example;

[0035] FIG. 4 shows a longitudinal sectional view of the lower housing part of the infusion filter according to the preferred configuration example;

[0036] FIG. 5 shows a perspective view of a housing lid of the infusion filter according to the preferred configuration example;

[0037] FIG. 6 shows a bottom view of the housing lid of the infusion filter according to the preferred configuration example;

[0038] FIGS. 7a and 7b show schematic diagrams of the mode of action of a hydrophilic filter membrane of the infusion filter according to the preferred configuration example;

[0039] FIG. 8 shows a longitudinal sectional view of the infusion filter connected to an infusion line according to the preferred configuration example; and

[0040] FIG. 9 shows a perspective view of an infusion set with the infusion filter according to the preferred configuration example.

DETAILED DESCRIPTION

[0041] FIG. 1 shows a perspective view and FIG. 2 an exploded view of an infusion filter/air separator 1 according to a preferred configuration example for an infusion set 2 described in more detail below, i.e. the infusion filter 1 is arranged to be connected to an infusion line 3 carrying an infusion solution or to be interposed in the infusion line 3.

[0042] As shown in FIG. 1, the infusion filter 1 has a housing 4 with a lower housing part 5 and a housing lid 6 that is connected in a form-fitted and/or force-fitted manner to the lower housing part 5.

[0043] Inside the housing 4, i.e. in the region of a cavity 7 (hollow space) formed between the lower housing part 5 and the housing lid 6, a hydrophilic (fluid) filter membrane 8 and a vent filter 9 are arranged, as shown in FIG. 2. As described in more detail below, the filter membrane 8 acts as an air barrier and the vent filter 9 allows air that collects in the region of the cavity 7 to be transported to an outer side of the housing 4. The filter membrane 8 thus divides the housing 4 into an upstream housing portion 4a and a downstream housing portion 4b.

[0044] FIG. 3 shows a perspective view of the lower housing part 5 of the infusion filter 1 according to the preferred configuration example. The lower housing part 5 has a main body 10 which, in a top view, is configured in the form of an escutcheon, i.e., the main body 10 has a symmetrical polygonal shape with a wide first portion 10a and a tapering second portion 10b. Furthermore, the lower housing part 5 has a beam body 11 disposed on an underside of the main body 10 and extending in the longitudinal direction beyond the first and second portions 10a, 10b of the main body 10. In other words, the lower housing part 5 has the main body 10 and the beam body 11, the beam body 11 being longer than the main body 10 in its extension direction and narrower than the main body 10 transversely to its extension direction.

[0045] Furthermore, as shown in FIG. 4, the beam body 11 has an opening on each of its two front surfaces, each of which is in fluid communication with the cavity 7 formed between the lower housing part 5 and the housing lid 6. Accordingly, the beam body 11 forms a housing inlet 12 and a housing outlet 13, wherein the housing inlet 12 is formed on the side of the second portion 10b with respect to the main body 10 and the housing outlet 13 is formed on the side of the first portion 10a.

[0046] As mentioned above, according to the preferred configuration example, the infusion filter 1 is arranged to be fluidically connected to the infusion line 3. That is, the housing inlet 12 can be connected to an upstream portion of the infusion line 3, whereas the housing outlet 13 can be coupled to a downstream portion of the infusion line 3. For this purpose, the upstream portion and the downstream portion are pushed into the housing inlet 12 and the housing outlet 13, respectively. For easier handling during inlaying/insertion of the infusion line 3, the housing inlet 12 and the housing outlet 13 each have an insertion structure 14 configured as a chamfer/inclination. A respective receiving region 15 for the respective portions of the infusion line 3 adjoins this insertion structure 14 in the insertion direction. At the end region of the receiving regions 15 facing away from the insertion structure 14, a respective circumferential step 16 is formed as a stop for the portions of the infusion line 3. As shown in FIG. 7, a height of the step 16 corresponds substantially to a wall thickness of the infusion line 3, i.e. the receiving regions 15 are adapted to the infusion line 3 in such a way that no steps/shoulders are formed when the infusion line 3 is inserted, thus preventing possible turbulences that could lead to the formation of air bubbles by avoiding shoulders/steps along the flow path. In other words, dimensions of receiving regions 15 of housing inlet 12 and of the housing outlet 13 are adapted to dimensions of infusion line 3 such that there are no shoulders or gaps between infusion line 3 and receiving region 15. In yet other words, the receiving regions 15 of the housing inlet 12 and the housing outlet 13 are adapted to the dimensions of the infusion line 3 in such a way that in the inserted state, i.e. when the infusion line 3 has been inserted into the infusion filter 1, the inner diameters of the infusion line 3 are flush with the surface of the steps 16. This prevents residual air bubbles from settling here.

[0047] Adjacent to step 16, i.e. on the side of housing inlet 12 and housing outlet 13, is a deflection region/elbow 17, via which the flow of the infusion solution is deflected by approximately 90?. As shown in FIG. 4, the deflection regions 17 are rounded or have the shape of a quartered sphere, one open cut surface of which is oriented toward the housing inlet 12 and the housing outlet 13, respectively, and the other open cut surface of which is arranged to form a right angle to the one open cut surface. In yet other words, the deflection in the housing 4 is spherical, so that the flow can be deflected without creating turbulences or dead water areas.

[0048] As can be seen in FIG. 4, the infusion filter 1 according to the preferred configuration example is configured in such a way that the elements described above, i.e. the insertion structure 14, the receiving region 15, the step 16 and the deflection region 17, are the same for the housing inlet 12 and the housing outlet 13. That is, the housing inlet 12 is substantially symmetrical to the housing outlet 13 with respect to a center plane of the infusion filter 1.

[0049] On the side of the housing inlet 12, an inlet opening 18 opening towards the cavity 7 adjoins the deflection region 17, whereas on the side of the housing outlet 13, an outlet opening 19 opening towards the cavity 7 is formed. In a top view of the lower housing part 5, both the inlet opening 18 and the outlet opening 19 are in the form of a half ellipse, with the radii of the half ellipses being aligned with each other.

[0050] As can be seen in FIG. 3, a mounting portion 20 with a projecting mounting pin 21 is formed on a side of the inlet opening 18 facing away from the outlet opening 19. On a side of the inlet opening 18 facing the outlet opening 19, a circular crosspiece 22 is arranged, within which the outlet opening 19 as well as ribs 23 aligned in the extension direction of the beam body 11 and individual knobs 24 are formed. As described in more detail below, the crosspiece 22, ribs 23 and knobs 24 serve as a support structure for the filter membrane 8 received in the lower housing part 5. This support structure for the filter membrane 8 can prevent possible turbulences and residual air bubbles during priming of the infusion filter 1.

[0051] In a rim region of the main body 10, a further crosspiece 25 is formed which follows the shape of the main body 10 in the region of the second portion 10b and is semicircular in the region of the first portion 10a. In other words, in the region of the second portion 10b, the crosspiece 25 is offset inward from the edge of the main body 10 in such a way that a step of constant width results. In the region of the first portion 10a, the crosspiece 25 describes a semi-circular shape so as to expose shoulder regions 26 of the main body 10 which, as will be described in more detail below, serve for receiving the housing lid 6.

[0052] FIGS. 5 and 6 show views of the housing lid 6 of the infusion filter 1 according to the preferred configuration example. The housing lid 6 has, similar to the main body 10 of the lower housing part 5, an escutcheon shape with a first, wide portion 6a and a second, tapered portion 6b. In the region of the first portion 6a, a continuous opening in the form of an elongated hole (vent opening) 27 is formed in the center. As can be seen in FIG. 6, on an inner side of the housing lid 6, which faces the cavity 7 in the assembled state of the infusion filter 1, a circular crosspiece 28 is formed around the elongated hole 27 and serves for receiving the vent filter 9, as will be described in more detail below. In shoulder regions 29 of the first portion 6a of the housing lid 6, mounting pins 30 are arranged in each case, which cooperate with shoulder regions 26 of the main body 10 during assembly of the infusion filter 1 according to the preferred configuration example.

[0053] In a rim region of the housing lid 6, a first crosspiece 31 of triangular cross-section is formed, which substantially follows the shape of the crosspiece 25 of the main body 10 and rests on it or is pressed/pushed against it during assembly of the infusion filter 1, thus forming a seal. In other words, the crosspiece 25 of the main body 10 and the crosspiece 31 of the housing lid 6 seal the lower housing part 5 and the housing lid 6 against each other.

[0054] Within the first crosspiece 31, a circumferential second crosspiece 32 following the shape of the first crosspiece 31 is formed. In the region of the second portion 6b, i.e. at the tapered end portion of the housing lid 6, a mounting region 33 with a mounting opening 34 in the form of a blind hole is arranged so that the mounting pin 21 engages in the mounting opening 34 when the infusion filter 1 is mounted according to the preferred configuration example. Both in the lower housing part 5 and in the housing lid 6, the mounting region 20 or 33 between inlet opening 18 and crosspiece 25 is completely filled with plastic, i.e. formed from solid material. This prevents the formation of a dead water area.

[0055] On a side of the mounting region 33 facing the elongated hole 27, a ramp/chamfer/inclination 35 is formed, which, as will be described in more detail below, ensures a controlled, turbulence-free redirection of the flow through the infusion filter 1, i.e. the inclination 35 in the housing lid 6 helps to direct the flow accordingly and guide it towards the filter membrane 8 without turbulences. In the infusion filter 1 according to the preferred configuration example, the angle of inclination 35 is approximately 15?. However, the inclination 35 can of course also assume a different angle. In particular, the angle of inclination 35 is adapted to the distance between the crosspiece 25 and the inlet opening 18.

[0056] The housing lid 6 can be equipped with one or more vent grooves (venting grooves) on the outside. The vent grooves prevent the vent opening 27 from closing (e.g. by fixing the air separator 1 to the patient or by the patient's position). The vent grooves lead from the vent opening 27 to the outer edges of the housing lid 6. To prevent pressure points on the skin, the housing lid 6 can be configured without raised ribs or other raised regions.

[0057] FIGS. 7a and 7b schematically illustrate the operating principle of the filter membrane 8. In the preferred configuration example, the filter membrane 8 is constructed as a set of hydrophilic capillaries, which can be regarded as a plurality of parallel tubes 36 packed together. Now, when a liquid flows through the filter membrane 8, it flows through the parallel tubes 36 (arrows A in FIG. 7a). As mentioned above, as a liquid, the infusion solution flows in the infusion set 2 due to gravity. I.e. the weight of the liquid provides the pressure required for flow.

[0058] If no more liquid flows, for example because no more infusion solution is present and/or a patient has been administered a full dose of infusion solution, the flow through the capillaries comes to a standstill and a liquid level remains at an upper end of the capillaries, i.e. the filter membrane 8 remains substantially completely wetted or in contact with the infusion solution. Due to capillary forces, as shown in FIG. 7b, a concave meniscus or concave bulge is formed at the respective upper end portions of the individual capillaries at the liquid surface. That is, when the flow of liquid upstream of the filter membrane 8 stops, the liquid adheres tightly between the capillaries, forming a barrier to air. In other words, when the flow of the infusion solution upstream of the filter membrane 8 stops, the filter membrane 8 prevents air from entering the downstream portion of the infusion line 3. Depending on the diameter of the tubes 36 or resp. of the capillaries, the adhesive force between the liquid and the surface of the tubes 36, and the surface tension (surface energy) of the liquid, the capillary forces are large enough to counteract the weight force of the liquid downstream and to prevent the liquid from flowing into the downstream portion of infusion line 3 or out of the infusion filter 1. I.e. the filter membrane 8 represents an air barrier via capillary flow stop.

[0059] In the preferred configuration example, the filter membrane 8 has a bubble pressure between 0.2 and 0.45 bar and an area below 2.0 cm.sup.2, in particular below 1.7 cm.sup.2. The infusion set 2 with the infusion filter 1 according to the preferred configuration example thus has a flow rate above 120 ml/min, preferably 140 ml/min, at a pressure difference of 0.1 bar.

[0060] The plate-shaped vent filter 9 is made of a conventional, air-permeable filter material and, as can be seen in FIG. 8, is accommodated in the housing lid 6. One front surface of the vent filter 9 is oriented towards the cavity 7 and another front surface lies against the inside of the housing lid 6. In the housing lid 6, as mentioned above, the elongated hole 27 is formed, via which the inner housing side is connected to the outer housing side. As can be seen in FIG. 1, the vent filter 9 is accommodated in the housing lid 6 in such a way that the vent filter 9 completely covers the elongated hole 27. Thus, air which collects in the cavity 7, as described in more detail below, can flow through the vent filter 9 and the elongated hole 27 to the outer housing side. I.e. the vent filter 9 and the elongated hole 27 serve to vent the infusion filter 1.

[0061] In FIG. 8, the infusion filter 1 according to the preferred configuration example is shown in the assembled state with the infusion line 3 inserted. When the infusion solution flows into the infusion filter 1 via the infusion line 3 and the housing inlet 12, it first enters the infusion filter 1 at the interface, i.e. the step 16 which is flush with the inner diameter of the infusion line, and is deflected in the deflection region 17 towards the cavity 7, where it flows into the cavity 7 through the inlet opening 18. The inclination 35 on the housing lid 6 ensures turbulence-free deflection and thus optimum flow to/wetting of the filter membrane 8. As long as infusion solution is present, it flows over the filter membrane 8, i.e. through the tubes 36, and is guided to the outlet opening 19 with the aid of the ribs 23 and knobs 24. The infusion solution flows through the outlet opening 19 to the deflection region 17, which deflects the flow so that the infusion solution is guided via the step 16 into the downstream portion of the infusion line 3 without detachment. This means that there are no steps/shoulders along the entire flow path where residual air bubbles can adhere. In addition, all deflections are configured as ramps/inclinations or as radii, so that no dead water areas are formed and thus no turbulences and consequently no air bubbles are created in the infusion filter 1 according to the preferred configuration example.

[0062] When the flow of the infusion solution stops, the filter membrane 8 remains completely wetted, as described above, and thus forms the air barrier. Residual air in the flow sections upstream of the filter membrane 8 collects in the cavity 7 and can flow out via the vent filter 9 and the elongated hole 27.

[0063] FIG. 9 shows the infusion set 2 with the infusion line 3 and the built-in infusion filter 1 according to the preferred configuration example. A connector 37 for a container for receiving/storing the infusion solution is arranged upstream of the infusion filter 1. Connected to the connector 37 is a drip chamber 38, which is a first device for air separation, and a hose clamp 39 for regulating the flow. Downstream of the infusion filter 1, another (patient) connector 40 is arranged, which can be fluidically connected to an injection site of a patient or another infusion line. In other words, the infusion solution flows from the container via the connector 37 into the infusion line 3, through the drip chamber 38, the hose clamp 39, the infusion filter 1 and the connector 40. The turbulence-free flow through the infusion filter 1 described above makes it possible to arrange the infusion filter 1 in the vicinity of the (patient) connector 40. The arrangement of the infusion filter 1 can be installed at any position in the infusion line 3, depending on the therapy required. It is also possible for the infusion filter 1 to be directly integrated in the connector 40.

[0064] In the preferred configuration example described above, the filter membrane 9 is constructed from the set of parallel tubes 11. Alternatively, however, a filter membrane 9 can also be made from a block which has fine gaps running through it in the direction of flow. When the flow stops, the liquid can adhere between these gaps and thus form the air barrier. It is also conceivable that the filter membrane 9 has a plurality of lamellae or is made of an open porous material such as felt or foam.