Pressure relief valve for a packaging container
The invention relates to a pressure relief valve, comprising a base body, which is covered by a valve membrane. The base body which is located on the inner face of a packaging container, permits the escape of excess pressure from the packaging container into the atmosphere by means of passages and perforations that are configured in the wall of the packaging material. The inventive pressure relief valve thus responds particularly well. i.e. allowing particularly low opening pressures, by means of the special configuration of its base area.
1. In a pressure relief valve for a packaging container, having a base body equipped with a circumferential edge region that is raised in relation to a base region; the edge region is fastened to the inside of the wall of the packaging container in a sealed fashion; in the region enclosed by the edge region, the packaging container has at least one through opening for gas; the base body has a recess in its base region encompassed by the edge region, on the side oriented toward the wall; at least one through hole leads from the bottom of the recess; and the base region, with the interposition of a sealing fluid layer, is almost entirely covered by a valve membrane, the improvement wherein the base body is embodied as not flat at least in some areas of the base region encompassing the recess so that zones of different distances between the base region and the valve membrane are produced in the surrounding region.
2. The pressure relief valve according to claim 1 , wherein the base region is at least partially curved.
3. The pressure relief valve according to claim 2 , wherein the curvature is embodied as concave.
4. The pressure relief valve according to claim 1 , wherein the base region is provided with raised areas that hold the valve membrane spaced apart from the base region.
5. The pressure relief valve according to claim 1 , wherein the at least one through hole at the bottom of the recess is surrounded by a rim-like raised area.
6. The pressure relief valve according to claim 2 , wherein the at least one through hole at the bottom of the recess is surrounded by a rim-like raised area.
7. The pressure relief valve according to claim 3 , wherein the at least one through hole at the bottom of the recess is surrounded by a rim-like raised area.
8. The pressure relief valve according to claim 4 , wherein the at least one through hole at the bottom of the recess is surrounded by a rim-like raised area.
9. The pressure relief valve according to claim 5 , wherein the raised area extends to a height below the level of the base region in the region immediately surrounding the recess.
10. The pressure relief valve according to claim 1 , wherein the recess is generally in the shape of a figure “8” and the constriction region of the recess does not have any through holes.
11. The pressure relief valve according to claim 2 , wherein the recess is generally in the shape of a figure “8” and the constriction region of the recess does not have any through holes.
12. The pressure relief valve according to claim 3 , wherein the recess is generally in the shape of a figure “8” and the constriction region of the recess does not have any though holes.
13. The pressure relief valve according to claim 4 , wherein the recess is generally in the shape of a figure “8” and the constriction region of the recess does not have any through holes.
14. The pressure relief valve according to claim 5 , wherein the recess is generally in the shape of a figure “8” and the constriction region of the recess does not have any though holes.
15. The pressure relief valve according to claim 1 , wherein the base region is encompassed by a circumferential recess.
16. The pressure relief valve according to claim 2 , wherein the base region is encompassed by a circumferential recess.
17. The pressure relief valve according to claim 3 , wherein the base region is encompassed by a circumferential recess.
18. The pressure relief valve according to claim 5 , wherein the base region is encompassed by a circumferential recess.
19. The pressure relief valve according to claim 15 , wherein the recess extends out to the edge region.
20. The pressure relief valve according to claim 1 , wherein the base body and the valve membrane have a substantially round cross-sectional shape.