GB736012A - Improvements in or relating to jet nozzles for gas-turbine units - Google Patents

Abstract

736,012. Jet-propulsion nozzles. ROLLS-ROYCE, Ltd. June 10, 1953 [June 18, 1952], No. 15409/52. Addition to 640,428. Class 110 (3). A jet nozzle arrangement as claimed in the parent Specification has each of the nozzle portions constructed of sheet metal to have radially spaced walls which are arranged so that the inner wall is free to expand relative to the outer wall. A nozzle portion 15, Fig. 2, through which cooling air is constrained to flow as indicated by arrows 20 by the action of the hot gases passing through the nozzle orifice when the nozzle portions are in the extended position shown, comprises three sheet metal walls 21, 22 and 23. The outer wall 22 and central wall 23 are secured together to form a box-like load-bearing structure and are held in spaced relation by circumferentially extending channel members 28, 29. The lateral edges of the walls 22, 23 are spaced apart by channel members 31, Fig. 10, welded to the walls. The wall 23 has an angle-section member 33 welded to it. To this member 33 is bolted the leading edge flange 34 of the member 21 which is locally stiffened by a metal strip 35. The member 33 also supports a sealing element 18 comprising a pair of axially directed flanges 44, 45 supporting a length of braided metal 46 which cooperates with a flange 48 on the end nozzle fitting 14. The inner wall 21 extends rearwardly from the angle member 33 in spaced relation to the central wall 23 to form a cooling air passage to which air is supplied through spaced apertures 37, 38. The trailing edge of the inner wall 21 has a number of hooked tabs 39, Fig. 13, the fingers 39a of which engage channel sectioned tabs 40 welded to the inner surface of the central wall 23. The hooked tabs 39 are engaged in the looped tabs 40 when the inner wall is brought in position to be secured to the angle member 33. Each lateral edge of the inner wall has an F-sectioned part, formed by welding together two angle strips 42, 43, attached to it. The flange 43a of the F-sectioned part engages one of the flanges of the channel member 31 which joins the walls 22, 23 which thus act as an edge guide for the wall 21. The walls 21, 22, 23 consist of partspherical portions 21a, 22a, 23a and part frustoconical portions 21b, 22b, 23b. Specification 598,183 is referred to.