🔍 Key Concepts

• Labyrinth packing purpose and construction in steam turbines • How rotational movement of packing rings would be stopped mechanically • Difference between forces that hold in place vs forces that stop rotation

💭 Think About

• Think about which option describes a positive mechanical lock that physically prevents turning, not just holding something against a surface. • Which forces listed (weight, steam pressure, spring tension, a key/slot) are directional and reliable for stopping circular motion? • In a high‑speed turbine, what kind of device is usually used to prevent a circular part from spinning with the shaft or steam flow?

✅ Before You Answer

• Identify which choice provides a direct mechanical connection between the packing ring and the stationary diaphragm. • Eliminate any options that mainly provide sealing pressure rather than anti‑rotation. • Ask: which method would still prevent rotation if steam pressure changes or the turbine is in a different orientation (e.g., not relying on weight)?