What device on a turbine ensures a seal-tight system and cannot re-close itself?

The ruptured disc is specifically designed to serve as a safeguard in high-pressure systems, ensuring that when the predetermined pressure is exceeded, it will rupture to relieve that pressure. This mechanism works as a one-time use device that creates a seal-tight system under normal operating conditions. Once it has ruptured, the device cannot re-close itself, which is critical for maintaining safety and preventing pressure buildup.

In contrast, check valves are designed to allow flow in one direction and automatically close if reverse flow occurs, making them capable of re-closing. Relief valves also work to relieve pressure but are designed to reset automatically after the pressure returns to normal, allowing them to re-close as well. Flow meters measure the flow rate of liquids or gases and do not serve a sealing purpose in a turbine system. Thus, the ruptured disc is unique among the listed options in its functionality as a non-reusable device that provides a tight seal before being activated.