Which safety feature relieves overpressure in a low-pressure centrifugal refrigeration system?

• A. Check valve
• B. Pressure relief valve
• C. Isolation valve
• D. Rupture disk

Answer: (D)

Relief from overpressure in a low‑pressure centrifugal refrigeration system is provided by a rupture disk. This device is designed to burst at a precise pressure, creating an immediate vent path for the refrigerant and vapor to escape before the vessel or piping can fail. It offers rapid, reliable protection because it has no moving parts to stick or fail to open, which is crucial in dynamic refrigeration scenarios. After it ruptures, it cannot reseal and must be replaced, and the system checked for the cause of the pressure spike.

The other devices don’t provide the same one-time, fast relief. A check valve only stops backflow and doesn’t relieve overpressure. An isolation valve merely blocks flow. A pressure relief valve can vent and reseal, but in some low‑pressure applications a one-time rupture disk is preferred for its instant response and simplicity.