Abstract: An axial flow compressor with an inner casing and an outer casing. The inner casing has bleed apertures. The outer casing is provided with loading devices which are positioned adjacent to the bleed apertures such that the loading devices apply loads on the inner casing in the vicinity of the bleed apertures. Components of the loads applied by the loading devices are arranged to oppose and preferably balance any loads applied on the inner casing due to the bleed apertures' releasing the pressure differential across the inner casing. The loading devices comprise cylinders secured to the inner casing and pistons secured to the outer casing to form chambers. The chambers are supplied with fluid at a predetermined pressure. The loading devices oppose undesirable local reductions in clearance between static shrouds and the rotor blades.

Abstract: The casings of gas turbine engines are subject to loadings which distort the casing and adversely affect the running clearance between rotating and static components contained within the casings. The invention provides an engine having inner and outer housings the inner housing containing one of the engine compressors. The inner casing is mounted on a load transmitting and isolating structure which allows thrust and torque to be transmitted to the outer casing, but isolates the inner casing from distortions of the outer casing. The load transmitting and isolating structure includes a torque reaction and mounting means at the upstream end of the inner casing, a mounting means and a thrust reacting means mounted between the ends of the inner casing. The mounting means are adjacent the bearings of the rotor shaft of the compressor and are not affected to any appreciable extent by outer casing distortion.