Matching thermal expansion of components of turbo-machines

Claim 1

An axial flow compressor for a gas turbine engine comprising: a bladed rotor including a plurality of axially spaced rows of rotor blades; a casing surrounding said bladed rotor; a plurality of axially spaced rows of stator vanes disposed between the rows of rotor blades, said rows of stator vanes having roots supported by said casing; said casing having an inner wall and a radially spaced outer wall at locations surrounding the rows of stator vanes and surrounding at least one row of rotor blades; said inner wall including a first plurality of continuous and unsegmented platform rings with each one of said platform rings extending about and supporting a row of stator vanes and a second plurality of continuous and unsegmented rings disposed between said platform rings and extending about and spaced from each of said rows of rotor blades, said inner wall and said outer wall being spaced from each other by radially extending flanges defining spaces surrounding the roots of the rows of stator vanes and surrounding the rows of rotor blades; a heating insulating medium in each of said spaces; a lining of heating insulating material on a radially inner surface of each of said second plurality of rings at a location of said rows of rotor blades; a rigid mass spaced radially outwardly of and extending around said casing, said mass being relatively cool with respect to said casing and having a lower rate of thermal expansion than a rate of thermal expansion of said casing; and means rigidly connecting said mass to said casing whereby said inner wall of said casing as defined by said first and second plurality of rings are restrained in their expansion and prevented from getting out of round by said rigid mass so that at least said second plurality of rings have a rate of expansion substantially equal to a rate of expansion of said bladed rotor.