Continental Disc’sZAP (insert assembly pictured here) and KBA reverse-acting rupturediscs utilize knife blades to open the rupture discs as reversaloccurs. The rupture discs are differential-pressure relief devices thatprovide instantaneous full opening for protecting equipment, vessels,and systems from overpressure conditions. Designed fornonfragmentation, ZAP and KBA rupture discs respond in milliseconds tooverpressure situations, allowing them to be used in a variety ofapplications. The rupture discs have the media pressure acting on theconvex side of the rupture disc, placing it in compression. When theburst pressure rating of the rupture disc is reached, the compressionloading on the rupture disc causes it to reverse, snapping it throughits neutral position and through the knife blades resulting in a fullopening.