Standard Single-Stage Turbine Lubrication

Knowledge of the bearing components and oil specifications are also important. Accordingly, D-R offers the following TOPS TIPS for standard single-stage turbine lubrication.

Steam Turbine Oil Rings in Ring Oiled Steam Turbines: 

Turbine bearings that are not fed from a pressurized oil system have Oil Rings located inside a slot in each bearing. This allows the ring to encircle the shaft while dipping into an oil reservoir in the bottom half of the bearing housing. The purpose of the oil ring is to lift and release oil thus lubricating and cooling the journal and thrust bearings. During operation, the rings, which revolve freely on the shaft, dip into the oil reservoir and carry oil up onto the shaft where it is distributed to each main bearing. The thrust bearing, located inside the shell of the steam end main bearing, receives its lubrication oil from this same action.

Dresser-Rand has designed these oil rings for oil feed with a sufficient safety factor to cover the entire range of turbine operation.

Lubricating Oil and Additives:

Major oil companies produce an oil satisfactory for Steam Turbine use. It is advisable to consult with your oil supplier for specific recommendations following the details in the D-R turbine manual. As a minimum, the selected oil should satisfy the following:

• Properly refined mineral oil filtered to 25 micron.
• Maximum metal wetting ability and ability to prevent the formation of rust on metal parts bathed in oil. High stability toward oxidation and corrosion resistance. This may be accomplished by the use of rust and oxidation inhibitors, or as a result of a particular refining process.
• Free from acid or alkali.
• Best possible ability to separate rapidly from water.
• Minimum tendency to oxidize or form sludge when agitated at actual operating temperatures when mixed with air and water.
• Minimum tendency to emulsify or foam when agitated with water and or air.
• High viscosity index. AGMA 2 / SAE 20, ISO VG 68, 284 – 347 SSU (315 Nominal) @ 100F.

D-R does not recommend any additional additives. Oils meeting the above criteria will provide the lubrication and protection needed by single stage steam turbines.

Water and Cooling Bearings:

To achieve the best performance from such components and lubricants, D-R recommends that the oil supply temperature (reservoir) be maintained at 100°F +- 10°F by the provisions for water-cooling incorporated in the turbine design. The exit temperature should be 130°F +- 10°F. The recommended bearing temperature limits to preclude bearing wear are as follows:

Dresser-Rand maintains technical and marketing resources in the field for your use. Their experience spans over 85 years of proprietary expertise on steam turbines and they are more than willing to provide contacts where solutions have been implemented.