Rupture disk

1. A rupture disk for relieving pressure between the interior of a box and the exterior of the box, the box having an outlet opening, comprising:

a) a first layer that provides a gasket which abuts the box, the gasket having a central opening which aligns with the box opening;

b) a second layer in the form of a reverse buckling disk having a disk flange, a domed portion and a weakened score on the dome that defines a disk burst pressure, the second layer having concave and convex sides;

c) a third layer that is an outlet ring that sandwiches the second layer in between the first and the third layer layers, the outlet ring having a central opening surrounded by an edge;

d) a plurality of regularly spaced apart and circumferentially extending teeth on the third layer extending from said edge inwardly a distance, each tooth having a circumferentially extending edge;

e) a plurality of recesses, one recess in between each pair of said teeth;

f) the combination of teeth and recesses extending completely around said third layer central opening;

g) a plurality of tabs on the first and third layers, said tabs including circumferentially spaced apart tabs on each of said first and third layers, each tab having a tab opening, said tabs generally aligning so that a fastener can be passed through the tab openings of the first layer and the third layer;

h) fasteners that affix the first and third layers to the box;

i) wherein the second layer is generally circular and surrounded by the fasteners; and

j) wherein circumferentially extending edge of each tooth is positioned on the concave side of the second layer and next to the score.

2. The rupture disk of claim 1 wherein the second layer is of a metallic material.

3. The rupture disk of claim 1 wherein the score tracks a generally circular path.

4. The rupture disk of claim 1 wherein the fasteners do not pass through the second layer.

5. The rupture disk of claim 1 wherein the second layer has a diameter of between about 2 and 6 inches.

6. The rupture disk of claim 1 wherein the first and third layers each have the same number of tab openings.

7. The rupture disk of claim 1 wherein the second layer is metallic.

8. The rupture disk of claim 7 wherein the second layer is stainless steel.

9. The rupture disk of claim 1 wherein the third layer is metallic.

10. The rupture disk of claim 9 wherein the third layer is stainless steel.

11. The rupture disk of claim 1 further comprising a battery box and the first, second and third layers are mounted to said battery box.

12. A rupture disk for relieving pressure between the interior of a battery box and the exterior of the battery box, the box having an outlet opening, comprising:

a) a first layer that provides a gasket which abuts the battery box, the gasket having a central opening which aligns with the battery box opening;

b) a second layer in the form of a reverse buckling disk having a disk flange, a domed portion and one or more scores on the domed portion that define a disk burst pressure, the second layer having concave and convex sides;

c) a third layer that is an outlet ring that sandwiches the second layer in between the first and the third layer layers, the outlet ring having a central opening surrounded by an edge;

d) a plurality of teeth on the third layer, each tooth extending from said edge inwardly a distance, each tooth having an innermost tooth edge that is positioned adjacent said score and that extends circumferentially along a part of the score;

e) a plurality of recesses, one recess in between each pair of teeth;

f) the combination of teeth and recesses surrounding said third layer central opening;

g) a plurality of tabs on the first layer, said tabs including circumferentially spaced apart tabs, each tab having a tab opening;

h) a plurality of tabs on the third layer, said tabs including circumferentially spaced apart tabs, each tab having a tab opening;

i) fasteners that affix the first and third layers to the box, the fasteners being arranged generally in a circle to provide a fastener circle;

j) wherein the second layer domed portion is positioned inside of the fastener circle, surrounded by the fasteners; and

k) wherein the teeth are positioned on the concave side of the second layer.

13. The rupture disk of claim 12 wherein the first layer is of a foam material.

14. The rupture disk of claim 12 wherein the first layer is of a neoprene material.

15. The rupture disk of claim 12 wherein the second layer is metallic.

16. The rupture disk of claim 12 wherein the second layer has one or more scores that define at least in part the weakened portions.

17. The rupture disk of claim 12 wherein the fasteners do not pass through the second layer.

18. The rupture disk of claim 12 wherein the second layer has a diameter of between about 2 and 6 inches.

19. The rupture disk of claim 12 wherein the first and third layer each have the same number of tab openings.

20. A rupture disk for relieving pressure between the interior of a battery box and the exterior of the battery box, the box having an outlet opening, comprising:

a) a first layer that provides a gasket which abuts the battery box, the gasket having a central opening which aligns with the battery box opening;

b) a second layer in the form of a reverse buckling disk having a disk flange, a domed portion and a weakened score on the dome that defines a disk burst pressure, the second layer having concave and convex sides, with the height of the dome from the disk flange adjustable but accurately controlled;

c) a third layer that is an outlet ring that sandwiches the second layer in between the first and the third layer layers, the outlet ring having a central opening surrounded by an edge;

d) a plurality of teeth on the third layer, each said tooth extending from said edge inwardly a distance, each tooth having a circumferentially extending edge;

e) a recess between each pair of teeth;

f) a plurality of tabs on the first and third layers, said tabs including circumferentially spaced apart tabs on each of said first and third layers, each tab having a tab opening, said tabs generally aligning so that a fastener can be passed through the tab openings of the first layer and the second layer;

g) the third layer is attached to the second layer which is a metal membrane by means of spot welds around the disk flange and the first layer attached to the metal disk by means of an adhesive thus forming a rupture disk assembly;

h) wherein the second layer is generally circular and surrounded by the fasteners;

i) wherein circumferentially extending edge of each tooth is positioned on the concave side of the second layer and next to the score;

j) fasteners that pass through the tab openings of the first and third layers and affix the rupture disk assembly to the box and

k) wherein the combination of teeth and recesses extend three hundred sixty degrees around said third layer outlet ring cental opening.