GB624402A - Improvements relating to gas-turbine-engines - Google Patents

Abstract

624,402. Gas turbine plant. JANES, R. June 26, 1947, No. 16931. [Class 110(iii)] Hot gas is abstracted from the exhaust duct by a scoop mounted in a wall of the duct to be movable between a retracted position in which a part of the scoop conforms to the contour of the wall or an operative position in which the mouth of the scoop is in the path of the exhaust gas and faces upstream, a duct being provided to connect the scoop in its operative position with the place where the hot gas is required for heating purposes. The purposes referred to are general heating such as gun-compartment heating on aircraft, and/or deicing or ice-prevention on aircraft. The apex 12b of the inner conical wall of the exhaust duct is movable axially towards and away from the inoperative position in which it is continuous with the base portion 12a. When the apex is spaced from the base as shown, hot exhaust gases are picked up by the lip 12c and caused to flow by the annular plate 28 into the space 41, through ducts 42 into an annular manifold 43 from which they are taken for use in de-icing or heating parts of the aircraft or power plant. The apex 12b is mounted for axial movement on tubular extension 26 of a sleeve 25 carried in a bearing 24 which is supported by a frusto-conical wall 23. The other end of the sleeve 25 is attached to a tubular member 29 carrying a member 30 connected to a rack 32. The rack meshes with a pinion 35 carried by a shaft 36 rotated by a reversible motor 40. To minimise the force required to move the apex 12b, a cylinder 46 in which operates a piston 48 attached to the member 30 is mounted inside the wall 23. The space to the righthand side of the piston is connected through ports to the space 41 and the space to the left-hand side to the exhaust channel through the ports 50, 51 and 52. As the diameter of the piston is the same as that of the apex 12b the gaseous force on these two members are balanced. The inner conical wall 12a is carried by two aligned sets of four struts 13, 14. the struts being arranged in the form of a cross. The outer wall 11 and inner wall 12a are provided with strengthening webs 16, 19 which provide seats for bushes 17, 20. Bolts 18 locate the ends of the struts in the bushes 17, the bushes 20 are free to slide on the struts. Other means for moving the apex portion axially may be used, for example, the apex portion may be rotatable in a fixed threaded sleeve and rotated by a power drive or by controllable vanes attached to it. Alternatively, the near end of the sleeve may engage through a pin with a spiral slot in an arm secured to the shaft 36. A modification in which scoops are pivoted on the outer wall is also described. These scoops are provided with valve means to shut off the inlet of the scoops from the exhaust duct when the scoops are moved to the retracted position. According to the Provisional Specification, the apex portion may be moved by means of the piston 48, the piston being made larger than the apex portion and controlled by adjustment of the pressure on the right-hand side of it.