Rotary regenerative heat exchanger

Claim 1

A rotary regenerative heat exchanger for a gas turbine engine having a compressor and a turbine, the heat exchanger comprising a housing having air inlet and outlet ports for a stream of compressed air discharged by said compressor and exhaust gas inlet and outlet ports for a stream of exhaust gases discharged from said turbine, a disc-shaped matrix mounted for rotation about its longitudinal axis in the housing and having a plurality of heat exchange passages extending therethrough between opposite end faces of the matrix and non-rotatable seals engaging the end faces of the matrix and defining separate flow-paths through the matrix for said streams of compressed air and exhaust gases in counterflow directions, said seal defining the flow-path for said stream of compressed air into the matrix being of substantially ''D''-shape in plan and including an arcuate portion and a bar-like portion bridging the ends of the arcuate portion and thereby completing the ''D''-shape of the seal, the longitudinal edge of the bar-like portion of said seal being inclined inwardly of said seal in the direction towards the sealing face of said seal and engaging a complementarily inclined face of the housing, the air inlet and outlet ports and the gas inlet port communicating directly with said seals and the cooled exhaust gas leaving the matrix passing into the remainder of the interior of the housing which communicates with the gas outlet port, said seals enclosing effective sealing areas to which the respective pressures of said air and gas streams are applied, the resultant algebraic sum of the products of said sealing areas and said air and gas pressures being substantially zero in the axial direction, the heat exchanger also including resilient biasing means by which said seal defining the flow-path into the matrix for said stream of compressed air is biased continuously into light rubbing engagement with the adjacent end face of the matrix, said resilient biasing means also effecting through said seal, defining the flow-path for said stream of compressed air into the matrix, axial movement of the matrix into light rubbing engagement with said seal at the opposite end face of said matrix which is held from axial movement in the matrix housing, the resilient biasing means holding the two portions of said seal defining the flow-path for said stream of compressed air into the matrix in continuous abutment, in use, despite bodily movement of the whole seal in the axial direction of the matrix, whereby as said seal defining the flow-path for said stream of compressed air into the matrix is moved bodily with the matrix in the axial direction thereof under the action of said resilient biasing means, said bar-like portion is maintained in abutment with said arcuate portion by wedging action between the inclined longitudinal edge of said bar-like portion and said complementarily inclined face of the housing.