NON-RETURN VALVE, DRIP CHAMBER, PORT FOR NEEDLE-FREE METERING OF A LIQUID, BACK-FLOW BARRIER, INFUSION OR TRANSFUSION SYSTEM AND METHOD FOR PRODUCING A NON-RETURN VALVE

Abstract

A check valve includes a pot-shaped valve body. The valve body has a lateral wall, a bottom wall, and an opening opposite the bottom wall. The valve body includes an elastic material. The elastic material is cut along a cut. The elastic material includes a material processed by liquid injection molding.

Claims

1. A check valve comprising a valve body that is pot-shaped, wherein the valve body has a lateral wall, a bottom wall, and an opening opposite the bottom wall; wherein the valve body comprises an elastic material; wherein the elastic material is cut along a cut; and wherein the elastic material comprises a material processed by liquid injection molding using liquid silicone rubber.

2. (canceled)

3. The check valve according to claim 1, wherein the material processed by liquid injection molding has a self-healing rate of at most 50%.

4. The check valve according to claim 1, wherein the elastic material comprises an additive.

5. The check valve according to claim 4, wherein the additive comprises a functional filler which increases a roughness of a cut surface of the cut as compared to a material processed by liquid injection molding without this filler.

6. The check valve according to claim 1, wherein the lateral wall and the bottom wall are formed as one piece, and/or wherein the cut is arranged in the lateral wall.

7. The check valve according to claim 1, wherein a protrusion and/or a groove is provided on the outer surface of the lateral wall, and/or wherein a protrusion and/or a groove is provided on the inner surface of the lateral wall.

8. The check valve according to claim 1, wherein the inner surface of the lateral wall tapers in the direction towards the bottom wall.

9. The check valve according to claim 1, wherein the cut has cut surfaces which have a roughness of at least Ra=0.15 μm.

10.-13. (canceled)

14. A method of manufacturing the check valve according to claim 1, wherein the method comprises the following steps: (A) providing the elastic material; (B) liquid injection molding the elastic material to form the valve body; and (C) cutting the elastic material along the cut.

15. The method according to claim 14, wherein an additive is added to the elastic material before step (A) and/or between step (A) and step (B) and/or during step (C).

16. The check valve according to claim 4, wherein the additive is a filler.

17. The check valve according to claim 16, wherein the filler comprises a mineral substance and/or wherein the filler comprises particles.

18. The check valve according to claim 16, wherein the filler comprises a silicate.

19. The check valve according to claim 18, wherein the filler comprises talcum powder.

20. The check valve according to claim 8, wherein the bottom wall tapers conically.

21. The check valve according to claim 1, wherein a flange surrounding the opening is attached to the lateral wall.

22. The check valve according to claim 21, wherein the lateral wall and the flange are formed as one piece.

23. The check valve according to claim 1, wherein the check valve is incorporated in at least one of the following components of an infusion or transfusion system: a drip chamber, a port for needleless admixture of a fluid, and a backflow preventer for preventing a flow of a fluid in a fluid line in one flow direction.

24. The method according to claim 15, wherein a dosage of the additive, based on a total amount of the additive and the elastic material, is at least 1% by weight.

25. The method according to claim 15, wherein the additive is a filler.

26. The method according to claim 25, wherein the filler comprises a mineral substance and/or wherein the filler comprises particles.

27. The method according to claim 25, wherein the filler comprises a silicate.

28. The method according to claim 25, wherein the filler comprises talcum powder.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0030] FIG. 1 shows an isometric view of the check valve according to a first embodiment of the invention.

[0031] FIG. 2 shows a sectional view of the check valve according to the invention according to the first embodiment.

[0032] FIG. 3 shows a further sectional view of the check valve according to the invention according to the first embodiment.

DETAILED DESCRIPTION

[0033] FIGS. 1 to 3 show various views of the check valve 1 according to the invention. The check valve 1 comprises a pot-shaped valve body 2, i.e. the valve body 2 is in the form of a hollow body closed on one side. The valve body 2 has a lateral wall 3, which forms the skirt of the hollow body, and a bottom wall 4, which forms the closed bottom of the hollow body. On the side opposite the bottom wall 4, the valve body 2 has an opening 5.

[0034] A flange 6 is attached around the opening 5 on the side opposite the bottom wall 4. The flange 6 serves to fix the check valve 1 in a component, in particular in a component of a medical device. The flange 6 is integrally attached to the lateral wall 3. In alternative embodiments of the invention that are not shown in the drawings, the flange 6 is not formed integrally with the rest of the valve body 2 but as a separate element and connected to the lateral wall 3. In further alternative embodiments of the invention, also not shown in the drawings, the valve body 2 does not comprise a flange 6 and is intended to be fixed in a component by attachment means other than a flange, for example by gluing and/or welding and/or a press connection. Since the flange 6 provides a secure and simple means of fastening the check valve 1, it is preferred that the check valve 1 has a flange 6. With regard to the manufacture as well as the properties and function of the integrally moulded flange 6, the liquid injection moulding process is particularly advantageous. It is possible to realise the flange 6 by means of the liquid injection moulding process without any additional processing step. In the case of a manufacturing process based on material removal, the flange 6 would have to be created in a separate step, e.g. by cutting its shape out of the valve body 2.

[0035] In the orientation of the check valve 1 shown in FIGS. 1 and 2, in which the bottom wall 4 is at the top, the lateral wall 3 is cut through on one side below the inner surface 41 of the bottom wall 4, i.e. it has a cut 7. The material of the lateral wall 3 is bisected along the cut 7.

[0036] FIG. 3 shows a section in the plane A-A, which is indicated in FIG. 2 and which is perpendicular to the longitudinal direction of the check valve 1 from the opening 5 to the bottom wall 4. The cut 7 lies in the plane A-A.

[0037] Accordingly, in the present embodiment, the cut 7 lies in a plane, i.e. the cut surfaces are flat. In alternative embodiments that are not shown in the drawings, the cut 7 does not lie in a plane, i.e. the cut surfaces are not flat, but, for example, curved.

[0038] In the present embodiment, the cut 7 is parallel to the inner surface 41 of the bottom wall 4. In alternative embodiments that are not shown in the drawings, the cut 7 is not parallel to the inner surface 41 of the bottom wall 4, but inclined to the inner surface 41 of the bottom wall. In this case, it is preferred that the cut 7 is arranged in the lateral wall 3 in such a way that it has an inclination to the inner surface 41 of the bottom wall 4 which is at most 10°, more preferably at most 5°, even more preferably at most 2°, and in particular preferably at most 1°.

[0039] In the present embodiment, the cut 7 has a distance from the inner surface 41 of the bottom wall 4 which is approximately 25% of the outer diameter d of the lateral wall 3 in the region of the cut 7. In alternative embodiments that are not shown in the drawings, the cut 7 has a greater or lesser distance from the bottom wall 4.

[0040] The depth t of the cut 7 in the present embodiment is 75% of the outer diameter d of the lateral wall 3 in the plane A-A, i.e. the lateral wall 3 is cut along 75% of the outer diameter and not cut along the remaining 25%. The non-cut area of the lateral wall 3 is shown hatched in FIG. 3. In alternative embodiments that are not shown in the drawings, the cut 7 is deeper or less deep than 75% of the outer diameter d of the lateral wall 3. In this case, it is preferred that the depth t of the cut is at least 50%, more preferably at least 60%, even more preferably at least 70%, and in particular preferably at least 72.5% of the outer diameter d of the lateral wall 3 in the region of the cut 7. Herein, it is further preferred that the depth t of the cut is at most 90%, more preferably at most 85%, even more preferably at most 77.5% of the outer diameter d of the lateral wall 3 in the region of the cut 7. In all cases, the depth t of the cut 7 is to be selected such that the check valve 1 opens reliably at the desired opening pressure but not at lower pressures, in that the lateral wall opens in the region of the slit and allows a fluid to flow through in the direction of passage.

[0041] In the present embodiment, the inner surface 31 of the lateral wall 3 tapers in the direction from the opening to the bottom wall 4. In alternative embodiments that are not shown in the drawings, the inner surface 31 of the lateral wall 3 is circular cylindrical.

[0042] The lateral wall 3 comprises a circumferential protrusion 32 on its outer surface. This bead 32 offers advantages in production processes, for example because it can improve the fastening of the check valve in another component that has a corresponding groove. In addition, the protrusion 32 can improve the seal against that component even if the latter does not have a groove. In alternative embodiments that are not shown in the drawings, the lateral wall 3 has a circumferential groove as an alternative or in addition to this protrusion. The protrusion or groove can also be arranged on the inner surface of the lateral wall 3. The protrusion or groove does not necessarily have to be circumferential, i.e. run along the entire circumference of the lateral wall 3. There may also be several protrusions and/or grooves.

[0043] In the present embodiment, apart from the cut 7, the check valve 1 has a rotationally symmetrical design. This is not necessary for the function of the check valve 1, such that other shapes are also possible. However, a rotationally symmetrical shape is in many cases advantageous from a manufacturing point of view and/or better adapted to the spatial conditions of the component in which the check valve 1 is to be installed than, for example, a shape with an elliptical cross-section.

[0044] In the present embodiment, the valve body 2 consists of an elastic material. In alternative embodiments, the valve body is not entirely made of an elastic material but comprises further components made of a different material in addition to the elastic material. For example, a flange 6 made of a non-elastic material may be connected to the rest of the valve body made of an elastic material.

[0045] In any case, the valve body 2 comprises an elastic material which has been processed by liquid injection moulding. By means of the invention, it is thus possible to manufacture a check valve 1 with appropriate properties and to use the advantages of liquid injection moulding, in particular an economically advantageous process control and/or simple automation and/or unproblematic compliance with the required manufacturing tolerances.

[0046] In liquid injection moulding, a liquid polymer material is used which is usually produced from various components by mixing. The different components may be, for example, a base and a catalyst-containing component. When these components are mixed with each other, a polymerisation reaction and/or a cross-linking reaction starts. Initially, the mixture is liquid and can be processed by liquid injection moulding. For this, the mixture is dosed into the moulds. The material cures in the mould and is ejected from the mould when the curing process is sufficiently complete. Due to the liquid processing, liquid injection moulding is less complex in terms of equipment than, for example, HCR pressing, where high pressures and high temperatures have to be applied. In addition, processing by means of HCR pressing is slow.

[0047] In preferred embodiments of the invention, the material processed by liquid injection moulding is a silicone, in particular a silicone rubber. In other words, a liquid silicone rubber (“LSR” for short) is used for liquid injection moulding. The elastic material of the check valve 1 is then a cured and/or cross-linked liquid silicone rubber. This designation does not mean that the cured and/or cross-linked material is still liquid, but that it has been processed in liquid form and therefore has the corresponding properties.

[0048] In alternative embodiments, the material processed by liquid injection moulding is a polyolefin. In this case, cross-linkable polyolefin plastisols (also referred to as “PO plastisols”) are used for liquid injection moulding.

[0049] It is preferred that the elastic material has a low self-healing rate, in particular a low self-healing rate when energy is introduced into the material, for example in the form of heat or other radiation, for example high-energy radiation (gamma radiation, etc.) introduced for sterilisation purposes.

[0050] Herein, the self-healing rate of an elastic material is defined as the proportion (in percent) of a number of test specimens provided with a slit, whose slit surfaces have reduced in size to a maximum of 10% after a test duration due to partial closure of the slit. At least ten flat test specimens with a thickness of 2 mm serve as test specimens. The cut runs in the direction of the thickness of the test specimen. The length of the cut is 5 mm. The test duration is 14 days. During the test period, the test specimens are exposed to a temperature of 50° C.

[0051] In particularly preferred embodiments of the invention, the selected liquid silicone rubber is a liquid silicone rubber with advantageous chemical and physical properties, in particular a liquid silicone rubber that leads to an elastic material with a low self-healing rate and/or has a low content of volatile substances and/or meets the requirements of the authorities responsible for the approval of medical devices.

[0052] It is further preferred to add an additive to the material to be processed by liquid injection moulding before or during processing by liquid injection moulding to further improve the properties of the elastic material. The additive may be added to any of the components of the liquid injection mouldable material, or it may be added to the liquid injection mouldable material as an additional component. For example, a suitable additive may be added to reduce the self-healing rate.

[0053] Preferably, the additive is added in a dosage of at least 1 wt % and/or at most 20 wt %. The weight percentages (wt %) result from the mass of the additive in relation to the sum of the mass of the material to be processed by liquid injection moulding and the mass of the additive. A dosage of at least 2% by weight and at most 20% by weight is more preferred, and most preferably at least 2% by weight and at most 10% by weight. This makes it possible, for example, to achieve an advantageously low self-healing rate with simultaneously advantageous elastic properties.

[0054] The additive is preferably a filler. By a “filler” is meant an additive which does not dissolve or does not dissolve to any significant extent in the elastic matrix material.

[0055] More preferably, the additive is a filler which contains or consists of filler particles. In this case, the filler particles dissolve in the elastic matrix material neither during processing by liquid injection moulding nor afterwards and are therefore still present in the check valve (1) according to the invention as particles dispersed or embedded in the matrix material, even after a long storage time. Such a filler may be added to the elastic material, for example, in the form of a powder. The powder is preferably a fine powder, in particular of a size in the micrometre range.

[0056] For example, the filler may be one of the following substances or a mixture of one of the following substances or a mixture of several of the following substances: [0057] glass, e.g. in the form of glass fibres, glass beads and broken glass [0058] mineral fillers, e.g. silicate or calcium carbonate powder [0059] carbon fibres [0060] carbon blacks.

[0061] Herein, it is preferred that the additive comprises a mineral substance, wherein it is further preferred that the mineral substance is a silicate. In particular, the mineral filler may be talcum powder.

[0062] With suitable additives, in particular mineral fillers and among them preferably silicates and particularly preferably talcum, it may be possible to improve the material properties of the material processed by liquid injection moulding. An improvement of the material properties is primarily understood as an increase in the roughness of the cut surfaces of a cut in the material. Rough cut surfaces do not lie flat against each other, i.e. they are spaced apart from each other at least at certain points. This reduces the self-healing tendency.

[0063] An alternative measure to reduce self-healing may be the use of lubricants as process-accompanying auxiliary materials. Lubricants form a lubricating film on the cut surfaces or they prevent the two opposing cut surfaces (“slit edges”) from touching each other directly. To achieve this, either a liquid or particulate lubricant is applied to the cut surfaces when the valve body is slit, or an appropriate oil or grease is already added to the starting material which then “sweats out”, i.e. gradually escapes, over the duration of storage and use. This alternative measure may not only be relatively expensive to implement. The lubricants may also contaminate the production equipment, for example because the lubricants stick to tools. In particular, problems result when escaping lubricant leads to contamination of the equipment as well as tools, operating facilities, packaging materials, etc. during intermediate storage of the check valves and during installation in equipment (e.g. in medical devices). This results in additional effort due to cleaning measures or even in a deterioration of the product quality. Leaking excipients are particularly problematic in the medical field. For example, if these auxiliary substances get into an infusion solution flowing through the check valve, they subsequently enter the bloodstream of a patient.

[0064] Particularly in view of this, it is preferred, instead of this alternative measure, to add a filler, in particular a mineral filler, to the material to be processed by liquid injection moulding before or during processing by liquid injection moulding as described above. In this way, silicone valves according to the invention can be manufactured quickly, cleanly and inexpensively, and at the same time the self-healing tendency is strongly suppressed.

[0065] While components manufactured by liquid injection moulding from elastic materials to which no fillers are added are usually transparent, the addition of fillers often results in opaque liquid injection products. Opacity does not lead to any limitation of the useful properties of the check valve according to the invention.

[0066] The choice of the liquid material from which the elastic material is manufactured by liquid injection moulding and/or the choice of additives added to this material is an important aspect of preferred embodiments, and may lead to particularly favourable material properties. In addition to biocompatibility and compatibility with the materials of the other components of a medical device, particularly favourable aspects include, for example, a hardness of at least 50 Shore A, a particularly low self-healing rate, and the possibility of producing, by cutting the elastic material, a cut 7 with cut surfaces having a sufficient roughness, in particular a roughness of at least Ra=0.15 μm.

[0067] In the method according to the invention for manufacturing a check valve, the step of cutting through the elastic material along a cut is preferably performed in such a way that the cut surfaces have a sufficient roughness, in particular a roughness of at least Ra=0.15 μm. This may be achieved, for example, by a suitable choice of cutting tool and/or cutting speed depending on the respective elastic material.

[0068] The addition of additives, in particular of particle-containing auxiliary materials, may contribute to an advantageous, material-related roughness of the cut surfaces, in particular a roughness of at least Ra=0.15 μm, or ensure that the cut surfaces have such a roughness. According to a non-limiting theory, this is due to the fact that particles occur in the area of the cut which at least partially protrude from the cut surfaces and thus result in an unevenness of the cut surfaces.