Valve, in particular for a device for administering a liquid medicament, and a corresponding device for administering a liquid medicament

Abstract

The invention relates to a valve, in particular for a device for administering a liquid medicament, with a valve body which has an interior for receiving a liquid, wherein the valve body has a liquid inlet and an opposite liquid outlet which both open into the interior, wherein the interior accommodates a large number of micro channels which extend in a connection direction between the liquid inlet and the liquid outlet. A corresponding device for administering a liquid medicament is also described.

Claims

1. A valve for a device for administering a liquid medicine, having a valve body which has an inner space for receiving a liquid, wherein the valve body has a liquid inlet and an opposite liquid outlet, which both open out into the inner space, wherein a plurality of microchannels is arranged in the inner space, said plurality of microchannels extending in a connection direction between the liquid inlet and the liquid outlet, wherein the plurality of microchannels form a grid made of parallel, rod-shaped boundary elements, or of several parallel layers of a grid that are arranged offset in relation to one another, said grid being formed from parallel rod-shaped boundary elements, wherein, in the absence of an applied pressure, the liquid is held stationary within the valve body, and when the applied pressure exceeds a threshold amount, the liquid is transported out of the valve body.

2. The valve according to claim 1, in which each of the plurality of microchannels have a diameter between 1 μm and 200 μm.

3. The valve according to claim 2, in which each of the plurality of microchannels have a diameter between 5 μm and 20 μm.

4. The valve according to claim 1, in which the boundary elements extend perpendicularly to the connection direction between the liquid inlet and the liquid outlet.

5. The valve according to claim 1, in which a length of the boundary elements is between 20% and 80% of a diameter of the inner space perpendicular to the connection direction between the liquid inlet and the liquid outlet, wherein the boundary elements extend starting from an inner side of a side wall bordering the inner space of the valve body toward an opposite side wall, without reaching this, such that a spacing between the boundary elements and the opposite side wall is formed.

6. The valve according to claim 1, in which the boundary elements have a round or a polygonal cross-section.

7. The valve according to claim 6, in which the valve body has parallel side walls, whose inner sides border the inner space, wherein the side walls open out into the liquid inlet or the liquid outlet on opposite ends.

8. The valve according to claim 6, wherein boundary elements have a circular cross-section.

9. The valve according to claim 1, in which the inner space (2), the liquid inlet and the liquid outlet have the same cross-sectional area perpendicular to the connection direction.

10. The valve according to claim 9, in which the valve body has a constant cross-section across its entire length between the liquid inlet and the liquid outlet.

11. The valve according to claim 1, in which the valve body has a round or a polygonal cross-section.

12. The valve according to claim 11, in which the valve body has a circular cross-section.

13. The valve according to claim 1, in which, to increase the adhesion between the boundary elements and a liquid, a surface of the boundary elements has a functional coating.

14. The valve according to claim 13, wherein the functional coating is a hydrophilic coating.

15. The valve according to claim 1, wherein the threshold amount is the maximum Laplace pressure for the valve body.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further details of the invention are explained by means of the figures below. Here are shown:

(2) FIG. 1 a schematic longitudinal cross-section through an embodiment of the valve according to the invention without negative pressure applied;

(3) FIG. 2 a schematic longitudinal cross-section of the valve according to FIG. 1 having a negative pressure P1>0 applied; and

(4) FIG. 3 a schematic longitudinal cross-section of the valve according to FIGS. 1 and 2 with a negative pressure P2>P1 applied.

(5) With the valve depicted in FIG. 1, the valve body 1 is depicted in longitudinal cross-section. The valve body 1 is bordered by opposite parallel side walls 7. The side walls 7 border an inner space 2 with their inner sides 8, in which inner space 2 a liquid 20, for example a medicine, is received. On opposite sides of the valve body 1, a liquid inlet 3 or a liquid outlet 4 is formed. The liquid inlet 3 and the opposite liquid outlet 4 have exactly the same cross-section as the remaining valve body 1, in particular as the inner space 2. A pump having a pump chamber of a device can be attached, for example, to the liquid outlet 4 for administering a liquid medicine.

(6) The valve body 1 can, for example, have a circular cross-section, or a polygonal, for example a rectangular or, in particular, a quadratic one. The boundary elements 6 shown in cross-section in FIG. 1 are rod-shaped grid bars that extend in parallel to one another and perpendicularly to the drawing plane. In each case, two adjacent boundary elements 6 form a microchannel 5 between them, which extends in the connection direction x between the liquid inlet 3 and the liquid outlet 4 and is open to the two inlets 3, 4.

(7) As depicted in FIG. 1, the microchannels are formed from several parallel layers of a grid that are arranged offset in relation to one another, said grid being formed from parallel, rod-shaped boundary elements.

(8) When there is no negative pressure (Po=0) applied to the liquid outlet 4, the liquid 20 forms a substantially planar, free surface, as is shown in FIG. 1, between itself and the gas 30.

(9) Only when a negative pressure (P1>0) is applied to the liquid outlet 4 (see FIG. 2) does the free surface form a concave geometry between the liquid 20 and the gas 30. With growing negative pressure, the radius of the concave boundary surface decreases between the liquid 20 and the gas 30. In FIG. 3, the case in which P2>P1 applies is shown.

(10) The radius of curvature of the free surface is dependent on the so-called Laplace pressure. This pressure increases with a boundary radius that is getting smaller. Thus, when the negative pressure exceeds the maximum Laplace pressure that is valid for the microchannel structure depicted in FIGS. 1 to 3, the liquid is transported out of the valve body 1. The valve according to the invention is thus suitable, in particular, for the use as an outlet valve with a generic device for administering a liquid medicine.

(11) In principle, the Laplace pressure increases proportionally to the surface tension of the liquid. In order to thus adjust the threshold value for the negative pressure in which the liquid is transported out of the valve body 1, with the surface tension given, to a certain value, it can be necessary to correspondingly align the diameter of the microchannels 5, and, with that, the spacing of the boundary elements 6 in relation to one another.

(12) The embodiment shown in FIGS. 1 to 3 can, for example, have an inner space diameter perpendicular to the inner sides 8 of the side walls between roughly 1 μm and 500 μm. Preferably, this diameter is between 10 μm and 100 μm.

(13) The diameter of the microchannels 5, and, with that, the free spacing or the clearance between the boundary elements 6 can lie between 0.5 and 50 μm. Preferably, the free spacing or the clearance between the boundary elements 6 is between 3 and 15 μm.

(14) The valve according to the invention has the advantage in that the required structures can be produced by means of established micro-structuring methods, for example by means of micro-injection moulding or silicon etching methods.

(15) The features of the invention disclosed in the description above, in the drawing and in the claims, can be essential for the realisation of the invention both individually and in any combination.

LIST OF REFERENCE NUMERALS

(16) 1 Valve body 2 Inner space 3 Liquid inlet 4 Liquid outlet 5 Microchannel 6 Boundary element 7 Side wall 8 Inner side x Connection direction between the liquid inlet and the liquid outlet