Lubrication, Cooling, and Routine Maintenance
Core concepts
Lubrication reduces friction and wear and helps seal the cylinder. Candidates must distinguish cylinder lubrication (steam-cylinder oil, often compounded to resist washing by wet steam) from bearing and crankcase lubrication (mineral or synthetic oils). Superheated steam demands oils with higher thermal stability; wet steam can wash away unsuitable oils. Understand viscosity selection, oil feed rates, and contamination control.
Cooling and heat management: bearings and glands must not overheat; cooling water or air may be used on some components. Routine maintenance includes checking oil levels and condition, replacing filters, inspecting rings and liners, checking gland packing, verifying valve timing, and testing safety devices. Predictive checks include vibration and temperature trending.
Traps in questions
- Using ordinary bearing oil in the steam cylinder; it may wash out or carbonise.
- Over-lubricating, causing deposits and fouling.
- Ignoring oil analysis; water contamination in crankcase oil is common.
- Confusing cooling of bearings with cylinder warming; cylinders are kept warm, not cooled.
Worked example / rule of thumb
Rule of thumb: cylinder oil feed is typically set low, just enough to maintain a film; excessive feed causes carbon deposits and ring sticking. Change crankcase oil on schedule and after any water ingress. Track bearing temperature rise; a sudden rise of more than about 10 degrees Celsius above baseline warrants investigation.