Metal Stitching on a Perpetual Motion Machine

Nore 1 is a hydropower plant in Statkraft’s Nore facilities. The plant was commissioned in 1928 and is nearing one hundred years old. A crack was recently discovered in the crossbeam of the turbine housing of one of the eight generator units. Stryvo Oslo was assigned the task of repairing the damage using a method proven to be both durable and cost-effective.

21. May 2024

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─ Nore 1 is a large power plant, and reactions in the concrete expose mechanical parts to stress. So it’s not unusual for components to crack. Some parts are complex or embedded in concrete. That makes replacement difficult and very expensive. For us, it’s a great relief that alternatives exist, explains Ole Gunnar Haug, maintenance manager at Statkraft.

When Welding Isn’t an Option

Some parts of the facility are made from materials that cannot be welded. As a result, Statkraft has had to find another way to repair cracks. Stryvo has long worked with metal stitching, also known as “lock ‘n’ stitch.” This method involves first drilling holes into the metal at specific intervals. Grooves are then milled, and the parts are fastened using threaded inserts.

─ A crack is not necessarily straight, so this is a task that requires precision and patience. It’s great that there are two of us on this job, because we can support and help each other, explains Frank Kjelgård, foreman at Stryvo Oslo.

High Degree of Precision

Together with Laurentiu Marinescu, Kjelgård has worked at Stryvo for many years and has solid experience with metal stitching. Kjelgård has worked at Nore 1 on several occasions and appreciates the trust Statkraft places in them.

─ We’ve used Stryvo on several occasions. Performing repairs on a power plant with parts that are nearly a century old requires expertise and accuracy. We see that maintenance and repair are significantly more cost-effective than replacing parts with new ones, concludes Haug.