Gas cushion (with reverse acting rupture discs)

When using reverse acting rupture discs it must be ensured that there is always a gas cushion between the bursting disc and the medium to be secured. Gases are compressible when pressurised whereby they store a certain energy. This energy is required in order to ensure a perfect opening of the bursting disc. Reverse acting rupture discs are torn open by the impulse generated when the burst membrane turns. The energy of the impulse is taken from the compressed gas. For pure liquid applications this results in the burst membrane being turned (or deformed); however, this does not ensure opening. If the burst membrane of a reverse acting rupture disc turns but does not open the bursting pressure of this (damaged) reverse acting rupture disc will increase significantly. As a consequence, the safety function of the bursting disc device is definitively no longer available. Therefore it must be accurately checked during each single installation whether there is a gas cushion – or not.