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Hydropower Case Study – Giving New Life to an Old Radial Seal

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Hydropower Case Study – Giving New Life to an Old Radial Seal

THE CHALLENGE – Reduce Shaft Seal Leakage AND Extend Seal Face Wear Life

A large Canadian hydro utility wanted to extend the wear life of a 1250mm (49″) diameter shaft seal that required frequent replacement of the seal segment faces, and suffered from high leakage rates resulting in cooling water supply challenges for other units. This 134MW vertical propeller turbine serves a vital function in this large power station that is responsible for providing baseload power for the grid, so minimizing unit downtime is a top priority for operations staff.

Typical of many older hydro power stations in Canada, the drawings were dated, there was some uncertainty about the spring parameters, and measurements of the existing segments were required to ensure a precise fit of the new Thordon SXL elastomer seal faces. The Thordon and Millstream team was up to the challenge, and developed a direct retrofit solution to be installed inside of the existing seal housing.

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Existing Seal Housing

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Old Carbon Segment

THE SOLUTION – Retrofit with Thordon SXL

Thordon proposed to upgrade the existing seal assembly with modified center spacer plate, new SXL seal segments, new backing plates and garter springs, and an upgraded water filtration system. The Thordon SXL elastomer seal segments were installed at site in the existing seal housing in early 2022 and have been performing very well to date, with a noticeable reduction in seal leakage and no sign of accelerated face wear that was common with the previous carbon-graphite seal faces.

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New Thordon SXL Seal Faces

Limestone GS Existing Cross Section

Original Seal Assembly Markup

Do you have challenges with your bearings, shaft seals, or water filtration systems and need a creative, cost-effective solution? Allow Millstream Engineering’s team of specialists to lead your group to a successful, economical solution. Contact us today.