Reducing Maintenance with Water Lubricated Turbine Guide Bearings

Design Principles & Case Studies

Greg Auger, P. EngDr.-Ing Guojun Ren, P. Eng

Thordon Bearings Inc.• Designer and manufacturer of water lubricated turbine

guide bearings, self lubricated bearings, and shaft seals • State-of-the-art polymer production & machining facilities

in Canada, with global presence in over 100 countries• In-house research, design, and testing of water

lubricated hydrodynamic fluid film bearings (thrust and radial designs)

Visit us at Booth #137

A Brief History of Water Lubrication• 1840’s - Wood bearings with water lubrication originally

used for ship propeller shafts • 1900’s – Many early vertical & horizontal turbines built in

used wood block or “stave” style guide bearings• 1920’s - The use of natural rubber in water lubricated

bearings becomes more common • 1930’s – Rubber bearings widely used in Russian turbines • Advancements in materials have significantly extended

life and durability of modern water lubricated bearings • Growing interest in the use of water lubrication for turbine

guide bearings for the many benefits, including compliance with increasing environmental regulation

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Implementing a Water Lubricated Bearing – Design Considerations

1. Load capacity, stiffness & damping characteristics2. Bearing running clearance3. Water quality (abrasive content, filtration level)4. Bearing material selection5. Bearing load and Length/Diameter (L/D) ratio6. Water flow & pressure, heat removal7. Vacuum below bearing, restrictor rings8. Bearing construction & fitting methods9. Shaft sealing considerations

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Case Study #1 – Francis TurbineCentral Hidroelectrica de Prada

• End User: Spain• Manufacturer: Neyrpic, 1958• Type: Vertical, Francis• Head: 300m (984 ft)• Speed: 600rpm • Maximum output: 36 MW • Shaft diameter: 500mm (19.7”)• Oil bearing replaced with water

lubricated bearing in 20155

Case Study #1 – Francis Turbine

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Design Review- 2 design configurations considered for water flow - Measurements taken of pressure below existing shaft seal- Oil bearing to be removed entirely

Case Study #1 – Francis Turbine

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Implemented Solution- New shaft seal installed on top of

bearing (easier access)- New water supply system provides

lubrication & cooling - Zero risk of oil/water contamination

Shaft protected against corrosion with stainless steel weld overlay

- Thordon SXL elastomer bearing in new split stainless steel housing

Case Study #1 – Francis Turbine

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Case Study #2 – KaplanCentrale di Fabbriche

• End User: Italy• Manufacturer: RIVA, 1955• Type: Vertical, Kaplan• Head: 30m (98 ft)• Speed: 430rpm • Maximum output: 15 MW • Shaft diameter: 400mm (15.7”)• Oil bearing replaced with water

lubricated bearing in 20169

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Design Review- On-going problems with seal

leakage- Small space means seal is

difficult to access for repairs- Seal water leakage can over-top

oil basin, contaminates oil- Contaminated oil can lead to

wiped bearing- Oil bearing will be removed

completely

Case Study #2 – Kaplan Turbine

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Case Study #2 – Kaplan Turbine

Implemented Solution- New shaft seal installed on top of

bearing (easier access)- Seal leakage is reduced- Zero risk of oil/water contamination- Shaft protected against corrosion with

split bolted stainless steel sleeve and HVOF coating

- Thordon SXL bearing easily replaced or inspected using tapered keyset

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Case Study #2 – Kaplan Turbine

Case Study #2 – Kapan Turbine

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How to Approach a Bearing Conversion1. Feasibility Review Identify refurbishments planned in next 1 – 5 years? Any problems with turbine guide bearing and/or shaft seals? Is there any regulatory concern with use of existing oil bearings?

2. Collect Data & Rough Scoping Gather drawings, unit technical data, sealed water pressure, etc. Work with partner(s) to determine rough concept design

3. Prepare Specifications, Gather Quotes, Initiate Work Seek bids from interested suppliers, finalize contract details,

award contract4. Implement Solution Remove old components, install new components, verify

clearances, test water system, commission & re-start unit

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Greg Auger, P. Eng. - Hydro Business Unit Managergrega@thordonbearings.com

+1 (705) 955-0235 mobile

Thanks to supporting workshops for photos & background!

www.pedrotec.com www.echelanthor.com

www.jobsonitalia.com www.milsatrillo.com

Thank You!