Patent ID: 8231340
Filing Date: 2012-07-31
Classification: F01D,F05D,F16J

Abstract:
1. A seal system for use in a rotary machine, the rotary machine having a higher pressure region and a lower pressure region on opposite sides of the seal system during normal operation of the rotary machine, the rotary machine including static structure, the seal system comprising: a rotor including an outer surface with a leaf-contacting surface portion; and a circumferential array of resiliently flexible metal leaves configured and arranged to seal between said static structure of the machine and the rotor, each leaf having a static end and a free end that contacts the rotor when the rotary machine is in use; wherein, to counteract excessive operational wear of the leaves and the leaf-contacting rotor surface portion on a lower pressure side of the seal system due to blow-down forces that are greater on the lower pressure side of the leaf seal than on a higher pressure side, the free ends of the leaves, the leaf-contacting surface portion, or both has a profile such that when the rotor is stationary and there are no pressure differences across the seal system, a gap is formed between the free ends of the leaves and the leaf-contacting surface portion which gradually increases from zero at the higher-pressure side of the seal system to a maximum at the lower-pressure side of the seal system, and during normal operation of the rotary machine, the leaves are free to deflect through the gap distance under the blow-down forces before the leaves contact the rotor leaf-contacting surface portion.