GB833498A - Improvements in reheat control systems for gas turbine engines - Google Patents

Abstract

833,498. Gas-turbine jet-propulsion plant. HOBSON Ltd., H. M. Aug. 27, 1957 [June 7, 1956], No. 17655/56. Class 110 (3). [Also in Group XI] An aircraft gas-turbine jet-propulsion engine in which reheat fuel is ignited by injecting into the main combustion chamber additional fuel, has an accumulator for the reheat ignition fuel comprising a vessel arranged to fill slowly with fuel during periods when the reheat is switched off, a normally ineffective piston movable in the vessel against a spring to deliver fuel to the igniter jet, a valve for controlling the piston and a device sensitive to the reheat fuel pressure to operate the valve and cause the piston to make a delivery stroke. An accumulator cylinder 13, Fig. 1, is connected through a non-return valve 14 and conduit 15 to an igniter jet arranged in the combustion chamber of the engine before the turbine inlet guide vanes. When the pump system is switched on fuel from the booster pump fills the cylinder 13 through the non- return valve 12. When the pilot selects reheat, the pressure of the fuel supplied to the reheat burners acts on the diaphragm 1 which moves to the left and opens a servo-valve 2. This causes the pressure on the left-hand side of the piston 3 to fall. The piston 3 then moves to the left and opens valve 5 and closes valve 6. The fuel pump delivery pressure in the line 8 is then exerted through the valve 5 on the lower side of the piston 9 which travels upwards against the action of the spring 10 and forces the fuel in the cylinder past a non- return valve 14 to the igniter jet. The pressure of this fuel closes the non-return valve 12. When the pilot returns his lever to the non- reheat position, the valve 5 closes and valve 6 opens. The fuel in the chamber 7 is forced by the spring 10 through the passage 11 and non-return valve 12 into the cylinder 13. As soon as the cylinder 13 is filled the valve 12 closes. In a modification, Fig. 2 (not shown), the main fuel pump is connected to the chamber 7 direct and through a conduit containing an orifice with the cylinder 13. This conduit and the conduit connecting the cylinder 13 with the igniter jet are controlled by two interconnected valves arranged so that when one is open the other is closed. These valves are operated direct by the diaphragm 1. Specification 833,493 is referred to.