SITUATION
It was an ordinary day at the lab. The new medium-voltage transformer was close to being signed off, with just a few safety tests to go. That's when it all went wrong: A sudden bang, a barely-felt sensation of something small and fast whistling past, then at almost the same time the sound of smashing and clattering - from the other side of the lab!
When the manufacturer of the gas-insulated switchgear equipment investigated what had happened, they found the rupture disc had fragmented violently during leak-testing, damaging equipment up to 19 feet away. They discovered it was due to two factors:
- The o-ring seal between the disc and the hold down ring had allowed the disc to slip so that it was no longer seated correctly and could not withstand the pressure as intended.
- The hold down ring itself had also deflected over time,reducing the hold down force on the disc
ACTION
- Switch from a circular scored disc to a four-petal PCR disc to prevent fragmentation
- Weld the disk into an insert-and-shell design to prevent movement, slippage and deflection of the disc. Welding also protects the disc from damage when handling it.
RESULT
The welded rupture disc design provides a drop-in solution that eliminates extra components, offers simple installation and provides a secure, leak-tight seal with a non-fragmenting disc. As a result, the manufacturer has improved the safety and performance of their equipment, with:
- A safer design
- Quicker and easier construction and maintenance
- Reduced inventory
- Reduced training needs and complexity for new staff