The gland seal unloading line connects to which turbine stage?

The gland seal unloading line connects to which turbine stage?

• A. LP turbine
• B. HP turbine
• C. Main turbine
• D. Low pressure generator

Answer: (A)

Gland seal steam is used to purge and seal the turbine shaft, and the unloading line carries any excess seal steam away so it doesn’t build up pressure in the seal area. This excess is best dumped into the low-pressure portion of the turbine, where the pressure and temperature are relatively low and the steam can mix with the exhaust flow without creating backpressure on the high-pressure stages. That’s why the line is connected to the low-pressure turbine stage. The high-pressure stage would see too much pressure, a general term like “main turbine” isn’t specific to a stage, and a generator isn’t a turbine stage.

Gland seal steam is used to purge and seal the turbine shaft, and the unloading line carries any excess seal steam away so it doesn’t build up pressure in the seal area. This excess is best dumped into the low-pressure portion of the turbine, where the pressure and temperature are relatively low and the steam can mix with the exhaust flow without creating backpressure on the high-pressure stages. That’s why the line is connected to the low-pressure turbine stage. The high-pressure stage would see too much pressure, a general term like “main turbine” isn’t specific to a stage, and a generator isn’t a turbine stage.