Steam Turbine Gland Sealing—Startup Phase: Temperature Is The Keyto Sealing

During the startup of a steam turbine, the front steam seal acts as a "protective suit" for the rotor, and the steam supply temperature is the key to activating this protection. If the temperature is too low, steam will condense within the seal cavity; the resulting water droplets can impact the rotor surface, causing microscopic scratches. Conversely, if the temperature is too high, the sealing strips may overheat and deform, thereby losing their sealing elasticity.

The ideal condition is to maintain the steam supply temperature at 20–30°C above the rotor surface temperature. This temperature differential ensures that the steam does not condense while simultaneously preventing damage caused by thermal stress. Much like warming up an engine before driving in winter, the steam turbine requires this "warm-up" process to ensure a safe and secure startup.