GB742657A - Improvements in or relating to hot-gas-conveying ducting - Google Patents

Abstract

742,657. Generating combustion products under pressure. ROLLS-ROYCE, Ltd. Jan. 7, 1954 [Jan. 16, 1953], No. 1410/53. Class 51 (1). [Also in Group XXVIII] Ducting for conveying hot gases comprises a tubular inner duct and an outer duct, the two ducts being spaced apart and connected by means comprising a first connector piece which is secured to the inner duct at a first location axially of the duct and is capable of movement with respect to the inner duct in a plane normal to the duct axis at a second location axially of the duct. A second connector piece is secured to the first connector piece at the second location and is also secured to the outer duct and is adapted to permit relative axial displacement of the first connector piece and the outer duct. The invention is shown applied in the case of combustion equipment of. a gas turbine engine comprising a plurality of tubular flame tubes disposed within an outer casing. The annular air casing comprises inner and outer walls 15, 16, the inner wall being protected by a series of flame shields 17. An expansion chamber 18 is connected at the upstream end of the air casing and a snout member 33 is connected thereto, the snout member providing a seating 32 for the ring 31 secured to the section 23 which, together with the sections 24, 25, 26 constitutes a flame tube. A flare member 38 is secured to the section 23 and carries a swirl device 40. A peg 36 engages a socket 37 in the ring 31 to locate the flame tube at its upstream end. The downstream end of the flame tube section 26 is in the form of a segment of a circular annulus and a metal strip 41a, 41b, 41c is secured around the periphery thereof at the downstream end diverging from the flame tube wall in an upstream direction. Secured to the upstream end' of the strip 41 is an angle section member 42a, 42b, 42c. The parts 41a, 41b, 42a, 42b are circumferentially disposed, while the parts 41c, 42c are radially disposed. Secured to the outer angle part 42b is a number (say five) straps 44 which extend in a generally circumferential direction but are slightly inclined thereto. The downstream ends of the straps 44 are secured to a flange 45a of a channel member 45, the other flange 45b of which is secured to the structure comprising the outer wall 16 of the combustion equipment and the outer casing 21 of the turbine nozzle box. The inner angle part 42a has an angle member 49 secured thereto which co-operates with a shield section 17 to restrict air flowing into the nozzle box structure. The radially-disposed angle parts 42c are formed with channel-section extensions 51 which have strips 52 secured thereto so as to give a desired clearance between adjacent flame tubes. An angle member 50 is secured to the outer angle part 42b to restrict the air flowing between the straps 44 to the turbine nozzle structure. The nozzle duct 53 is connected to the angle part 55 which is secured to the outer structure by means of circumferentially-extending straps 54 connected at one end to the part 55 and at the other to the nozzle duct.