CASE STUDY: DRUM SCREEN HUB REFURBISHMENT

Following an inspection of a Drum Screen Hub at a natural gas power station, it was found to have elongated holes and wear / damage on the internal hub face. The hub rotated drum screens which remove coarse and fine particles, and prevent the clogging of downstream equipment for cooling water intakes at the plant. This enables the large flow 5m³/s of water to remain unhindered and clean.

Drum hub screen before repair and corrosion protection                              Drum hub screen following repair and protection / Polyglass VEF coating

The original equipment manufacturer (OEM), suggested splitting the two hubs off the shaft for repair. They did however note, this could potentially damage the hub further beyond use. Their primary recommendation to mitigate this, was a full replacement for a new unit.

Having worked with us on numerous projects over the past 8 years and trusting Corroserve’s engineering capabilities, the client contacted us to explore the possibility to repair the drum screen hub, as opposed to replacing it for new.

Upon a detailed inspection, Corroserve’s engineers found that the hub had suffered from corrosion due to its seawater service environment, and also deformation of the bolt holes due to wear caused by forces applied during rotation. The hub required a full mechanical refurbishment and application of a protective coating system. Our team provided a full report to the client highlighting the potential risks, and trusting our expertise in the rehabilitation of this type of equipment, was given the go ahead to carry out the work to refurbish and protect the hub from future corrosion.

Polyglass VEF was the Corrocoat coating system chosen for this project.  Polyglass VEF is very durable with excellent flexibility, undercutting resistance and abrasion resistance. The Polyglass VEF system is a glassflake vinyl ester with a proven record offering a superior protection against seawater service.

Drum hub screen before repair and corrosion protection                              Drum hub screen following repair and protection / Polyglass VEF coating

The hub was first blasted for inspection and dimensional checks. One of the potential risks highlighted during initial inspection was that the hub could not be split due to corrosion on the shafts, which needed boring out. As recommended, the shafts were replaced and restored by a sub-contractor, and Corroserve’s team of engineers machined and sleeved the bolt holes to reinstate the required size, before Polyglass VEF was applied.

The client was extremely satisfied with the end result; Corroserve not only fulfilled all the requirements from the OEM in terms of integrity and dimensional compliance, but also allowed the repair of the drum screen hub, avoiding the replacement for a new unit, at just a fraction of the cost.

Debating whether to repair or replace your damaged equipment? Arrange a call back from a member of the team to discuss how we can refurbish and provide long term protection for your damaged