Patent ID: 7964816

Claim:
A current-interrupting chamber for use in a circuit-breaker, said current-interrupting chamber being filled with a dielectric fluid and including: a moving assembly mounted to move axially between a position at the start of a circuit-breaker opening operation and a position at the end of the circuit-breaker opening operation, said moving assembly comprising: a) a first compression chamber whose volume decreases between the position at the start of the circuit-breaker opening operation and a position at the end of compression of the first chamber; b) a first arcing contact that co-operates with a second arcing contact, the first arcing contact and the second arcing contact being mounted to move axially relative to each other, the first arcing contact and the second arcing contact are in contact with each other at the position at the end of compression of the first chamber; and c) a second compression chamber, communicating at a first end with the first compression chamber, the volume of said second compression chamber decreasing between the position at the start of the circuit-breaker opening operation and the position at the end of the circuit-breaker opening operation, said second compression chamber being designed to inject dielectric fluid into the first compression chamber, between a position where the first arcing contact and the second arcing contact are separated and the position at the end of the circuit-breaker opening operation, when the pressure in the first compression chamber is lower than the pressure in the second compression chamber, wherein the position at the end of compression of the first chamber is reached before the position at the end of the circuit-breaker opening operation, and a position at the end of compression of the second chamber is reached after the position at the end of compression of the first chamber.