Operation, Startup, and Shutdown Procedures
Core concepts
Safe operation requires a disciplined sequence. Before startup: inspect the engine, confirm lubrication, check valve gear, drain condensate from steam lines and cylinders, and verify safety devices. Warm-through (slow warming) prevents thermal shock and uneven expansion. Open drains to remove condensate before admitting steam; water in the cylinder can cause hydraulic lock and catastrophic damage.
Startup sequence: confirm auxiliaries running, open cylinder drains, admit steam slowly, turn the engine over on barring or by hand if possible, then bring to speed gradually and close drains once condensate clears. Monitor bearing temperatures, gland leakage, and unusual noise. Shutdown: reduce load, close steam supply, open drains, allow controlled cooling, and apply barring to prevent shaft bowing on large machines. Record readings.
Traps in questions
- Admitting steam before draining condensate (hydraulic lock risk).
- Skipping warm-through and causing thermal shock.
- Closing drains too early, trapping condensate.
- Failing to bar the engine during cooling, leading to shaft distortion.
- Assuming fast startup is efficient; it risks damage.
Worked example / rule of thumb
Rule of thumb: warm-through rate should keep metal temperature rise gradual, typically a few degrees per minute; follow manufacturer limits. During startup, keep drains open until steam at the drain is dry. After shutdown, bar the engine periodically during cooling to maintain straightness. Always verify the low-water and overspeed protections before admitting steam.