SF6 Flange Leakage

Flange Leakage at OVIT Albertirsa Transformer Station

Challenge

Because of environmental impact, aluminium flange was damaged by corrosion, SF6 (sulphur-hexafluorite) gas leakage appeared. The pressure inside was 4.5 bars.

Application

Complete flange was sandblasted to a SSPC-SP5 white metal finish to remove all corrosion. All possible leakage area was then sealed with 1-min epoxy and a rubber belt was applied on top. Devcon SF was put on the flange and bolts. Sabloons mounted around were filled with Flexane 80 L as a weather proof outside layer.

Result

In order to effectively seal the gas holder without the requirement for opening it up and replacing the internal flange seals all work was completed on the outside of the unit.

Initial leakage was stopped with the use of the rapid curing epoxy and this was then backed up with a series of additional coats to make this a permanent fix. The final polyurethane coating provided a weather proof seal from the outside elements but also an effective extra seal in the event of the Plastic Steel 5 minute Epoxy fracturing due to stresses in the metal.

Each stage of the process was a rapid cure so the overall repair could be effected within one day. This saves unnecessary downtime, as transformers can often be in remote locations and are essential to supply electricity to areas. This is especially important in situations where they are stand-alone and not a network of transformers on one site.


Applied Products

ITW Engineered Polymers