GB654259A - Improvements in liquid-fuel supply systems - Google Patents

Abstract

654,259. Gas turbine plant. DOWTY EQUIPMENT, Ltd. Nov. 13, 1947, No. 30234. [Class 110(iii)] [Also in Groups XI and XXIX] In a liquid fuel supply system for an. aircraft internal combustion turbine power unit as described in Specification 654,244, the circulating pump is utilized when thrust boost is required in order to supply burners for reheating the exhaust gases while the main combustion chamber burners receive fuel from the other pump. Fig. 1 shows the system with the parts. in the positions occupied during reheating. During normal engine running the supply pump 13 feeds from a tank 14 through a throttle 15, conduits 23, 40 and a changeover valve 17, to the inlet conduit 34 of the circulating pump 12. The conduit 23 also leads to a solenoid valve 19 which is de-energized during normal engine running so that the valve element is moved: by a spring to close the end of the conduit 23 and to place a conduit 24 in com-- munication with a conduit 39 connected with the low pressure zone of the tank 14. A relay valve 18 is thereby moved by a spring 25 to place conduits 26, 27 in communication with the conduit 39 so that the pressure above the valve 17 is low and the valve rises to connect the conduits 34, 40. In this position of the valve 17, the pump, 12 circulates fuel through a conduit 31, change-over valve 17, the swirl chamberof the main burners 11, the return line 29, the change-over valve 17, and the conduit 34. When the lever 20 of the throttle 15 is moved through the side step 21 to the full line position shown a switch closes to energize the solenoid valve 19 to move the valve element into the position shown. Fuel then passes from the supply pump 13 through the throttle 15, conduit 23, valve chamber 22 and conduit 24 to shift the element of the relay valve 18 against the spring 25, thereby connecting the conduits 26, 27 and moving the change-over valve 17 to its lower position. Fuel from the supply pump 13 also passes via the upper .end of the valve 17 through the conduit 28 to supply the main burners 11, the return line 29 being closed at the valve 17. The circulating pump 12 supplies the re-heating burners 16 through conduit 31, changeover valve 17, and conduit 32, the fuel returning through lines 35 and 34, the line 35 including a restrictor 36 and a non-return valve 37. The pump 12 is supplied with fuel from the tank 14 through conduits 33, change-over valve 17 and conduit 34. In a modified construction the re-heating spill burners are replaced by .direct injection burners and the restrictor 36 and non-return valve 37 are replaced by an altitude control. The circulating system for the main burners; may alternatively, be modified so that the. circulating pump is capable of emergency operation as a supply pump as described in Specification 654,265, and in such a system the supply pump may feed the re-heating burners whilst the circulating pump feeds the main burners. According to the Provisional Specification an auxiliary pump may be utilized to supplement the capacity of the circulating pump when the latter is required to feed the re-heating burners. The altitude control comprises an aneroid release valve 44, Fig. 3, associated with a pressure regulating byepass valve 45., Fuel is supplied to the burners 41 through conduit 42, valve 45 and conduit 46 and a proportion is returned through a conduit 43. in an amount regulated by the opening of the valve 45 as determined by the setting of the valve 44.