Surface,
preparation on both sides of the flange, to get an
optimal resin adherence.
Cover Installation
Once the cover is stuck, the flange, screws and shunts are definitely protected while the gas is drained to the top.
Imperviousness Checking
The SF6 leak must be located only on the top part, through the vent.
Shell Installation
The shell is placed over the flange. It is not only a formwork but also a protection against outside damages.
Resin Preparation
The polymer used is a polyurethane resin with a minimal temperature of use of +10°C (F50°F).
Resin Injection
This low viscosity resin is poured from the top part of the formwork. Once the level reaches the vent, the filling is stopped and the resin is left to cure (between 4h to 8h).
Vent Plug
When the curing time is over, the resin will be able to contain the pressure stress. Then, the plug is placed.
Imperviousness Checking
The gas detector is used to make sure that there is no more SF6 leak. Once the imperviousness insured, the formwork is filled with resin to get the vent drowned.
Work Completed
Repair weight : about 40 kg for a 420 kV GIS flange
Installation time : about 16 hours.
