Impeller Refurbishment and Coating at Thermal Power Plant

Posted On : Wednesday, November 22nd, 2023 in News

A thermal power plant in Gujarat, India, required refurbishment and corrosion protection for four vertical turbine pump impellers. The pumps, which were made of super duplex steel and had no prior protective coating, had been in operation in sea-water for approximately 12 to 15 years.

The impellers had developed cracks and mechanical damage over time, which significantly impacted their performance. To address these issues, the client approached our partners in India, Kirloskar Corrocoat Private Ltd (KCPL). KCPL were to provide a comprehensive solution; repairing and rebuilding the blades, as opposed to replacing with new impellers.

Pump Impeller - before - damaged vane

                 Damaged impeller before repair work                                           Damage/crack on impeller blade


Along with sister company Kirloskar Brother Limited; a global leader in pump systems, KCPL were able to offer a turnkey solution to repair the damage to the impeller vanes, using both cold and hot refurbishment methods, followed by DP (dye penetration) and UT (ultra-sonic testing).  Polyglass VEHA was then applied, with an overcoat of Fluiglide.

Pump Impeller - weld repair - DP dye penetration

                 Mechanical repair of  impeller blade                                              Dye Penetration Test


Polyglass VEHA is a cold cured glass flake vinyl ester acrylic co-polymer, which was selected as its properties make it ideal for immersion environments, where superior resistance to chemical attack is required.

Whereas Fluiglide; a cold cured, highly modified chemically resistant, two-pack resin system filled with stabilising enforcement to reduce cold flow characteristics, was used to reduce friction and increase energy efficiency.

Following the mechanical refurbishment and coating work as per ISO 21940, the team carried out dynamic balancing of the impeller.  They also successfully resolved the problem of uneven clearances between the impeller and liner, further optimising the pump’s performance and efficiency.

KCPL’s specialist pump refurbishment and coating technology provided an effective and efficient solution for the client, ensuring extended lifespan and improved performance, and significant time and cost savings. The cost to refurbish each impeller was just 30% of the original price of the impeller, not to mention the short lead time to repair, as opposed to the delivery timescales for new impellers.

Pump Impeller - repaired and protected

Impeller following refurbishment and protection

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