Pressure relief valve with floating diaphragm

Abstract

Pressure relief valve of a packaging container, comprising: a main body (2) with an edge region (3) and with a sealing face (4), wherein the edge region (3) is connectable in sealing fashion to a wall (10) of a packaging container (100) and wherein at least one passage opening (51) is formed in the sealing face (4), said passage opening extending through the main body (2), a first diaphragm (6) that is arranged over the passage opening (51) and at least partly covers the sealing face (4), a second diaphragm (7) that at least partly covers the first diaphragm (6), and a fluid (8) that is applied to the sealing face (4) and by means of which fluid the first diaphragm (6) is held on the sealing face (4) in floating fashion.

Claims

1. A pressure relief valve for a packaging container, the pressure relief valve comprising: a main body (2) with an edge region (3) and with a sealing face (4), wherein the edge region (3) is configured to be connected in sealing fashion to a wall (10) of the packaging container (100) and wherein the sealing face (4) surrounds at least one passage opening (51) that extends through the main body (2), a first diaphragm (6) that is arranged over the passage opening (51) and at least partly covers the sealing face (4), a second diaphragm (7) that at least partly covers the first diaphragm (6), and a fluid (8) that is applied to the sealing face (4), wherein the fluid (8) is arranged between the sealing face and the first diaphragm (6), wherein the fluid (8) brings about lateral mobility of the first diaphragm (6) and of the second diaphragm (7) with respect to the sealing face (4) and within the edge region (3), wherein the fluid (8) is arranged, completely in each case, between the first diaphragm (6) and the sealing face (4) and between the first diaphragm (6) and the second diaphragm (7).

2. The pressure relief valve according to claim 1, wherein the first diaphragm (6) has a first external dimension (D1) in a plane parallel to the sealing face (4), wherein the second diaphragm (7) has a second external dimension (D2) in a plane parallel to the sealing face (4) and wherein the first external dimension (D1) is less than or equal to the second external dimension (D2).

3. The pressure relief valve according to claim 2, wherein the first external dimension (D1) and a position of the at least one passage opening (51) on the sealing face (4) are matched to one another in such a way that the first diaphragm (6) completely covers the at least one passage opening (51) in the case of any lateral displacement of the first diaphragm (6) on the sealing face (4).

4. The pressure relief valve according to claim 1, wherein a ratio of a fluid volume of the fluid to an internal volume (V) of the main body (2) is at least 3:100.

5. The pressure relief valve according to claim 1, wherein two passage openings (51, 52) are formed in the main body (2) and wherein the two passage openings (51, 52) are arranged in off-centered and symmetric fashion with respect to a central axis (21) of the main body (2).

6. The pressure relief valve according to claim 1, wherein the first diaphragm (6) and the second diaphragm (7) are each embodied as a circular film disk.

7. The pressure relief valve according to claim 1, wherein the first diaphragm (6) has greater flexibility than the second diaphragm (7).

8. The pressure relief valve according to claim 1, wherein the main body (2) has a round cross-sectional form.

9. The pressure relief valve according to claim 1, wherein the main body (2) is an injection-molded part.

10. The pressure relief valve according to claim 1, wherein a ratio of a fluid volume of the fluid to an internal volume (V) of the main body (2) is at least 5:100.

11. The pressure relief valve according to claim 1, wherein a ratio of a fluid volume of the fluid to an internal volume (V) of the main body (2) is no more than 3:10.

12. The pressure relief valve according to claim 1, wherein the main body (2) is an injection-molded part and is formed from plastics.

13. A packaging container comprising at least one pressure relief valve (1) according to claim 1.

14. The pressure relief valve according to claim 1, wherein the fluid (8) is a liquid.

15. The pressure relief valve according to claim 1, wherein the second diaphragm (7) is formed of plastic.

16. The pressure relief valve according to claim 1, wherein the first diaphragm (6) is held in floating fashion on the sealing face (4) and the second diaphragm (7) is held in floating fashion on the first diaphragm (6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Below, the invention is described on the basis of exemplary embodiments in conjunction with the figures. In the figures, functionally equivalent components are denoted by the same reference sign in each case. Here:

(2) FIG. 1 shows a simplified schematic sectional view of a pressure relief valve according to a first exemplary embodiment of the invention,

(3) FIG. 2 shows a plan view of the pressure relief valve of FIG. 1,

(4) FIG. 3 shows a simplified schematic sectional view of a pressure relief valve according to a second exemplary embodiment of the invention, and

(5) FIG. 4 shows a simplified schematic sectional view of a pressure relief valve according to a third exemplary embodiment of the invention.

DETAILED DESCRIPTION

(6) FIG. 1 shows a simplified schematic sectional view of a pressure relief valve 1 according to a first exemplary embodiment of the invention. The pressure relief valve 1 is connected to a wall 10 of a closed packaging container 100, with only a small section of this wall 10 being illustrated. Here, the pressure relief valve 1 is fastened to a side 11 of the wall 10 facing an interior I of the packaging container 100.

(7) The packaging container 100 can be used to package filling materials, such as foodstuff of very different types. By way of example, such a packaging container 100 is suitable as an aroma protective packaging for coffee. What the pressure relief valve 1 according to the invention achieves is that the gases from the interior I of the packaging container 100 can escape to the surroundings U while, in the reverse direction, an ingress of air into the interior I of the packaging container 100 is prevented by the pressure relief valve 1. Such sealing of the packaging container 100 while simultaneously providing the option of equalizing positive pressure is particularly advantageously possible by way of the pressure relief valve 1.

(8) In order to allow gases to escape into the surroundings U from the interior I of the packaging container 100, two holes 12, 13 are formed in the wall 10 of the packaging container 100 in this case, said holes each extending through the wall 10.

(9) The pressure relief valve 1 comprises a main body 2, a first diaphragm 6 and a second diaphragm 7. Here, the main body 2 has a pot-shaped embodiment that is substantially concentric with a central axis 21.

(10) The main body 2 has a disk-shaped sealing region 20, which is adjoined by a ring-shaped edge region 3. At an end lying opposite the sealing region 20, the edge region 3 is connected to the wall 10 of the packaging container 100. The connection between edge region 3 and wall 10 is an ultrasonic bond. Consequently, an interior volume V of the main body 2 is enclosed by the main body 2 and wall 10 of the packaging container 100.

(11) A surface of the sealing region 20 facing the interior volume V forms a sealing face 4 of the pressure relief valve 1. Here, the sealing face 4 is a planar face. Two passage openings 51, 52 are formed in the sealing face 4, said passage openings each extending through the sealing region 20 of the main body 2. Here, the two passage openings 51, 52 are embodied in off-centered and symmetric fashion with respect to the central axis 21 of the main body 2, as is also evident from FIG. 2.

(12) The first diaphragm 6 is arranged on the main body 2 in such a way that said diaphragm partly covers the sealing face 4. Here, the first diaphragm 6 is arranged over the two passage openings 51, 52 and covers the latter. The second diaphragm 7 is arranged in such a way that it covers the first diaphragm 6.

(13) Further, a fluid 8, a silicone oil in this case, is applied to the sealing face 4. The fluid 8 is also arranged between the first diaphragm 6 and the second diaphragm 7. By means of the fluid 8, the first diaphragm 6 and the second diaphragm 7 are held in floating fashion on the sealing face 4 in order to bring about the sealing effect of the pressure relief valve 1. As a result of the capillary effect, the fluid 8 is uniformly distributed between the first diaphragm 6 and the second diaphragm 7. Here, as a result of adhesion between the sealing face 4 and first diaphragm 6, the fluid 8 ensures that the first diaphragm 6 is held on the sealing face 4 by means of an adhesive force and the sealing is brought about thereby, i.e., an ingress of air from the surroundings U into the interior I of the packaging container 100 is prevented.

(14) Moreover, the fluid 8 brings about a floating arrangement of the two diaphragms 6, 7 on the sealing face 4. That is to say, the first diaphragm 6 and the second diaphragm 7 are arranged on the sealing face 4 in a manner movable in relation to the central axis 21 in the lateral direction A. Consequently, the two diaphragms 6, 7 form a movable sealing arrangement together with the fluid 8, said sealing arrangement facilitating a quick and reliable response when changing between opening and closing of the pressure relief valve 1.

(15) If positive pressure arises in the interior I of the packaging container 100 on account of outgassing of packaged products, gas can be vented to the outside, to the surroundings U, through the pressure relief valve 1. To this end, a gas channel forms in the pressure relief valve 1, said gas channel extending through the fluid 8 from one or both of the passage openings, and, at its edge, the first diaphragm 6 slightly lifts from the sealing face 4 in the process. Gas can be vented to the surroundings U through this gas channel and through the holes 12, 13, as a result of which pressure equalization is brought about.

(16) As soon as the pressure has been sufficiently equalized, the gas channel is closed again by the fluid 8 and the first diaphragm 6 is pulled back in the direction of the sealing face 4 by the adhesive force of the fluid 8 such that the pressure relief valve 1 is sealed again. The second diaphragm 7 additionally supports this resealing process. In particular, the second diaphragm 7 causes a certain amount of pretension, which promotes a return of the first diaphragm 6 back into its initial position. Moreover, the capillary effect in this case causes the fluid 8 to be distributed uniformly around the first diaphragm 6, i.e., further promotes the first diaphragm 6 deforming back into its initial form.

(17) Furthermore, the first diaphragm 6 and the second diaphragm 7 are each formed as circular film disks, as is also evident from FIG. 2 in particular. Here, FIG. 2 shows a plan view of the pressure relief valve 1 of FIG. 1, with the packaging container not being illustrated. As is evident from FIG. 2, the first diaphragm 6, the second diaphragm 7 and the main body 2 are each formed with a circular cross section and are arranged concentrically with respect to one another in the non-displaced state illustrated here.

(18) A first diameter D1 of the first diaphragm 6 is 5% smaller than a second diameter D2 of the second diaphragm 7. Moreover, the second diameter D2 is 10% smaller than an internal diameter D3 of the edge region 3 of the main body 2. The internal diameter D3 consequently also corresponds to an external diameter of the sealing face 4. As a result of the first diameter D1 that is smaller in comparison with the second diameter D2, the fluid 8 can be distributed uniformly between the first diaphragm 6 and the second diaphragm 7 in particularly simple fashion on account of the capillary effect since the fluid 8 can easily flow around an edge of the first diaphragm 6. Furthermore, the first diaphragm 6 has a first thickness B1, which equals a second thickness B2 of the second diaphragm 7.

(19) For an optimal function of the pressure relief valve 1, the first diameter D1 and the positions of the two passage openings 51, 52 are matched to one another in such a way that the first diaphragm 6 still completely covers both passage openings 51, 52, even in the case of a maximum lateral displacement on the sealing face 4. That is to say, even if the first diaphragm 6 is displaced so far in the lateral direction A that said diaphragm abuts against the edge region 3, each of the passage openings 51, 52 still is completely covered by the first diaphragm 6.

(20) A fluid volume of the fluid 8 has a ratio of 3:100 to the internal volume V of the main body 2. This ensures that a sufficient fluid volume is available in order to finally obtain the adhesion of the first diaphragm 6 on the sealing face 4 and consequently obtain the adhesion for the sealing effect by means of the adhesive force. Moreover, this ratio also ensures that no excess fluid volume is present, which could have a negative effect on a targeted, reliable adhesion of the first diaphragm 6 on the sealing face 4 and of the second diaphragm 7 on the first diaphragm 6.

(21) FIG. 3 shows a simplified schematic sectional view of a pressure relief valve 1 according to a second exemplary embodiment of the invention. Here, the second exemplary embodiment substantially corresponds to the first exemplary embodiment in FIGS. 1 and 2, with the two diaphragms 6′, 7′ having different proportions relative to one another.

(22) In the second exemplary embodiment in FIG. 3, the first diameter D1′ of the first diaphragm 6′ and the second diameter D2′ of the second diaphragm 7′ are identical. Furthermore, the second thickness B2′ of the second diaphragm 7′ in the second exemplary embodiment is four times as large as the first thickness B1′ of the first diaphragm 6′. Expressed differently, a thickness ratio of the first diaphragm 6′ to the second diaphragm 7′ of 1:4 is present. As a result, the second diaphragm 7′ is significantly more rigid than the first diaphragm 6′ and a more stable arrangement of the two diaphragms 6′, 7′ can be achieved. What can be achieved as a result thereof is that the pressure relief valve 1 opens later, i.e., in the case of a higher positive pressure in the interior I in relation to the surroundings U, in comparison with the first exemplary embodiment since a much larger resistance must be overcome before the first diaphragm 6′ lifts off the sealing face 4. Moreover, the pressure relief valve 1 closes even quicker since the second diaphragm 7′ brings about a greater restoration force.

(23) FIG. 4 shows a simplified schematic sectional illustration of a pressure relief valve 1 according to a third exemplary embodiment of the invention. Here, the third exemplary embodiment substantially corresponds to the first exemplary embodiment in FIGS. 1 and 2, with a third diaphragm 9 additionally being provided, said third diaphragm being arranged between the first diaphragm 6 and the second diaphragm 7. The third diaphragm 9 has a third diameter D4, which equals the first diameter D1 of the first diaphragm 6. As a result of the capillary effect, the fluid 8 is uniformly distributed between all three diaphragms 6, 7, 9 and between the first diaphragm 6 and the sealing face 4. Here, the third diaphragm 9 further promotes the mobility of the floating diaphragm arrangement and consequently ensures a further optimized sealing effect of the pressure release valve 1, particularly in view of opening and closing for the purposes of, or following, the equalization of a positive pressure in the interior I of the packaging container 100.