US Patent 7211170 Twist-N-Lock wafer area pressure ring and assembly

Wafer area pressure rings used to confine plasma in plasma processing chambers which are manufactured with bores therein such that replacement of the pressure rings during routine or repair maintenance is significantly eased. The bores allows the pressure rings to be installed by simply aligning the bores under hanging adapters which are connected to the ceiling of the chamber, lifting the rings such that the hanging adapters enter the ring, turning or twisting the entire apparatus a miniscule amount, and then lowering the ring apparatus on the hanging apparatus, thereby locking the rings in place.