GB917392A - Improvements in or relating to gas turbine engine fuel systems - Google Patents

Abstract

917,392. Gas turbine plant. ROLLS-ROYCE Ltd. June 25, 1959 [July 15, 1958], No. 22725/58. Class 110 (3). A gas turbine fuel system comprising a fuel supply control including a power control lever, an ambient atmospheric temperature trim control which is manually preset in accordance with that temperature has presettable mechanism whereby the effect on the engine throttle of any adjustment of the ambient atmospheric temperature trim control can be varied to suit the particular requirements of the engine. Fuel is fed to the injectors 32 of a propeller gas turbine engine from a storage tank 36 by a booster pump 37, main fuel pump 38, shut off cock 39 and fuel supply control unit 15. The fuel control unit 15 comprises a throttle actuated by a lever 15a which may be rocked by a pilot's power control lever 12 and also by an ambient atmospheric temperature trim control lever 21, the levers 12, 15a, 21 being interconnected so that, when the lever 21 is set manually, in accordance with the ambient atmospheric temperature, setting of the lever 12 in a given position will adjust lever 15a to give a particular power output. The interconnection between the levers 12, 15a, 21 is in the form of a mechanical linkage which may be as described in Specification 697,014, in which the lever 12 not only adjusts the lever 15a but also the datum-setting lever 14a of the propeller constant speed unit 14. To enable the fuel system to be fitted to engines having different fuel characteristics, means are provided whereby it may be preset. The link 17b is connected to an arm 44 of a bell-crank the other arm of which, 44a, is connected by a link 45 to the throttle lever 45a. An enlargement 46 at the end of the arm 44a has a curved slot 47, Fig. 2, the radial distance of which, from the pivot of the bell-crank, increases from one end of the slot to the other. The slot receives a slide block 48 to which is bolted, through a universal joint, the arm 45. A bolt 53, extending between the walls 54 and having a head 53a by which it may be rotated, engages the block 48 so that rotation of the bolt varies the radial distance of the point of connection between the links 44a, 45 from the axis of the bell-crank and also varies the longitudinal displacement of the link 45 for a given angular movement of the arm 44a. An abutment 59 is provided for the initial setting of the system by means of a spacer 60. After determination of the actual fuel consumption under I.S.A. conditions, the mechanism is adjusted until the mark 57 on the block 48 registers with the appropriate point on the scale 56. A second stop 61 limits movement of the bell-crank. The lever 21 may be used to operate a number of separate controls in sequence as described in Specification 901,888.