Method and apparatus for labyrinth seal packing rings

摘要

The present disclosure relates to a seal assembly for a turbomachine that includes at least one arcuate plate, a biasing member, and a packing ring. In addition, the seal assembly includes a plurality of arcuate teeth disposed intermediate to the packing ring and the rotor. The plurality of arcuate teeth includes at least one subset of arcuate teeth. The clearance of at least one of the arcuate teeth is different from the clearances of the rest of the arcuate teeth. The clearances of the arcuate teeth of the at least one subset do not progressively increase going from an upstream to a downstream side of the turbomachinery.

主权项

1. A seal assembly for a turbomachine, the turbomachine comprising a stationary housing and a rotor rotating about an axis, the seal assembly comprising:
at least one arcuate plate coupled to an interior surface of the stationary housing and positioned in a radial plane; a packing ring disposed intermediate to the rotor and the plate, wherein the packing ring is positioned to move along the plate in a radial direction; a biasing member disposed intermediate to the arcuate plate and the packing ring and coupled to both; and a plurality of arcuate teeth disposed on the packing ring, wherein clearances are formed between respective tips of the plurality of arcuate teeth and the rotor, wherein a respective clearance of a tip of at least one of the arcuate teeth is different from respective clearances of tips of at least some others of the arcuate teeth from the plurality of arcuate teeth, wherein the clearances of the tips of the plurality of arcuate teeth do not progressively increase going from an upstream side of the turbomachinery to a downstream side of the turbomachinery, wherein the clearances of the plurality of arcuate teeth create a passive feedback in the hydrostatic forces generated by pressure profiles that vary across the seal assembly as the clearances of the plurality of arcuate teeth varies to enable an equilibrium clearance to be maintained between the arcuate teeth and the rotor during operation of the turbomachinery.