Patent attributes
This invention provides a segmented annular seal (10) the sealing leakage gaps between relatively movable components 14,16 between high and low pressure regions in a gas turbine engine, for example for sealing an engine shaft 16. The seal comprises an annular array of circumferentially spaced and radially movable arcuate seal segments (12) which extend in a continuous end to end relationship in annular housing (14) and project radially from the housing for effecting a seal against an engine shaft (16), rotor or the like. The segments (12) are located in a channel (22) in the housing (14) sized such that the segments (12) are able to follow radial movements of the shaft (16). In order to reduce an axial loading on the segments (12) that ends to cause them to seize a pressure balance region (30) vented to the upstream pressure region is formed on the downstream side of the segments (12). A second pressure balance region (42) vented to the downstream pressure region may be formed on the upstream side of the segments (12) to relieve a twisting moment acting on the segments.
