Page 248 - Valve Selection Handbook

Rupture Discs 235

The cross-scored rupture disc has the advantage over the reverse-buck-
ling disc shown in Figure 6-14 by functioning without the assistance of
knife blades. The advantages and disadvantages of both types of reverse-
buckling discs are otherwise identical.

Reverse-buckling disc with partial circumferential score line. Figure
6-17 through Figure 6-19 show three types of reverse-buckling discs with
a partial circumferential score line around the rim of the disc. When
buckling occurs, the discs shear open along the score line and fold
around a pivot.
In the case of the rupture disc shown in Figure 6-19, the score is perfo-
rated to permit the achievement of an extremely low burst pressure. The
perforations are sealed with an O-ring that becomes energized as soon
the fluid pressure is applied.
These rupture discs offer all the advantages of cross-scored rupture
discs. In addition, the discs may be employed in liquid-full systems.

Figure 6-17. Reverse-Buckling Disc with Partial Circumferential Score Line. [Courtesy of
Continental Disc Corporation.)