A rupture disc is a safety device that acts as the "fuse" of a pressurized system: it remains leak-tight as long as the pressure stays below a preset value and opens instantly when that pressure is exceeded, releasing the excess energy to prevent explosions or damage to vessels, piping and valves. Unlike pressure relief valves, it has no moving parts, which eliminates the risk of sticking, reduces leakage to zero during normal operation and minimizes maintenance.
Its construction can be solid metal, graphite or fluoropolymer composites; the principle is always the same: a calibrated diaphragm designed to rupture in a controlled way under overpressure or critical vacuum, protecting chemical, pharmaceutical, food and oil and gas facilities.
Full guide: What is a rupture disc: definition, operation and uses