GB790280A - Gas turbine engines having a multiple-stage turbine - Google Patents

Abstract

790,280. Gas turbine engines. KLOMPAS, N., and PURVIS, J. T. Feb. 28, 1956 [Feb. 28, 1955], No. 6185/56. Class 110 (3). In a gas turbine engine having a multi-stage turbine with a row of stator blades between two rotor stages, a shroud and casing assembly encircles the first stage rotor, a shroud ring encircles the second stage rotor and an outer casing ring encircles the inter-stage stator blades. The stator blades form part of an assembly comprising shroud ring segments disposed circumferentially end-to-end, each segment carrying a group of stator blades, whereby the stator shroud ring assembly may be installed in sections after assembly of the two rotor stages. The turbine shown comprises two rotor discs 14, 15 coupled together by bolts 16, and the first stage rotor blades 17 are surrounded by a shroud ring 31 and casing 32. The inter-stage stator blade assembly is built up of segments each comprising a segment 19 of the outer stator shroud ring, a segment 20 of the inner shroud ring and a number of inter-stage stator blades 18 mounted therebetween. Each stator blade segment may be inserted into position by a radial movement. A segment 33 of the second stage rotor blade shroud ring is secured to each stator blade segment and an outer casing 35 is moved axially over the assembly of stator vane segments and second stage rotor blade shroud segments and is secured to the casing 32 surrounding the first stage rotor. An exhaust casing 37, 38 is secured to the casing 35. Each segment 19 of the outer stator shroud ring comprises two walls 19a, 19b, the wall 19b being formed with openings to receive the outer ends of the stator vanes 18, and the wall 19a being formed with flanges 22, 23 and with strengthening ribs 27. The flange 22 is formed with an axially-directed flange 24 having a notch which engages a dowel pin 43 so as to locate the segment circumferentially. The flange 24 is clamped by the casing 35. The flange 23 of the wall segment 19a is also formed with axially-extending flanges 25, 26, the flange 26 being received in a groove in the edge of the second stage rotor blade shroud segment 33 and the two parts secured together by dowel pins 34. The flange 25 is received in a groove formed by a flange 35c on the inner surface of the casing 35. A groove at the downstream edge of the rotor blade shroud segment 33 is engaged by another flange on the casing 35. Each segment of the inner stator shroud ring 20 has secured thereto a ribbed member 28 and a channel member 29, labyrinth seal members 30 being secured to the radially inner surface of the channel member so as to co-operate with the rotor disc spacing ring 30a.