Patent GB-617473-A (GB)
Title: Improvements relating to gas-turbine engines
IPC: F01D5/08
Filed: 1946-10-02
Abstract: 617,473. Gas turbines; stuffing-box substitutes. JUDSON, C. A., READ, J. R., and HUNTER, P. E. Oct. 2, 1946, No. 29428. [Classes 110 (iii) and 122 (v)] [Also in Group XXVIII] The rotor of a gas turbine is cooled by air passing through a passageway formed in the rotor, which passageway is supplied with cooling air from a stationary duct located downstream of the turbine rotor assembly and supplied with cooling air by means extending through the turbine exhaust assembly, sealing means being provided between the duct and the rotor to permit relative rotation between them. Cooling air, which may be taken from the compressor of the plant, is supplied from a stationary duct 49, Fig. 2, to a cooling air passageway in the hollow bolt 34 through an intermediate duct 57 which may rotate relatively to both the bolt and duct. The sealing means at the inlet end of the intermediate duct 57 comprises a ring-like plate member 53, bolted to an extension 50 of the duct 49, the rear face of which at the inner radius is formed as a spherical seat which co-operates with a corresponding surface of a carbon sealing ring 54 which is held in contact with the seat by a spring-loaded ring 55. The carbon sealing ring is preferably split diametrically to accommodate wear in use and a spring garter 56 is provided to hold the parts together. The sealing means at the outlet end comprises a spherical surface on the duct 57 which co-operates with internal spherical surfaces of a carbon bearing ring 58 which is held in the head 43 of the bolt 34 bv a washer 60 and a spring plate 59 bolted to the flange 46. The carbon bearing'ring is split in a plane transverse to its axis to permit assembly and to accommodate wear. The greater part of the. relative rotation between the duct 49 and bolt 34 is taken by the inlet sealing means. In a modification, the open end of the duct 49 is provided with a recessed plate to accommodate the ring 55 and associated spring and a further recessed plate is provided to house the sealing ring 54. In another modification, the carbon bearing ring 58 is held in position by means of a circlip between which and the washer 60 is placed a spring washer. The major part of the cooling air flows through the intermediate duct 57 into the hollow bolt member, but a small leak is permitted at the inlet and outlet sealing means to provide cooling air for the near face of the disc 20. The cooling air after passing through the bolt 34 flows into the space between the disc 19 and nut 33, then through radial channels 61 cut in the spigot on the flange 32 to the space between the T-shaped member 35 and disc 19. The cooling air then passes through ports 62 into the labyrinth seal, the ports 62 being positioned to meter the air to both the rear face of disc 19 and the forward face of disc 20. The construction of the rotor is the same as that described and claimed in Specification 617,474. According to the Provisional Specification the discs 19 and 20 may be hollow and the cooling air from the passageway may be used to cool the internal faces of the discs and, if hollow blades are used, the blades themselves.