Patent GB-723342-A (GB)
Title: Improvements in or relating to air-intakes, more particularly for aircraft
Inventor: BELL JOHN ERNEST
IPC: F02C7/055
Filed: 1953-03-04
Abstract: 723,342. Door operating appliances. BRISTOL AEROPLANE CO., Ltd. March 4, 1953 [March 12, 1952], No. 6474/52. Class 65 (1). [Also in Groups XXVI and XXVIII] The annular intake of 10 a gas turbine engine has a number of screens 16 journalled on pivots 26 the axes of which lie in a plane normal to the axis of the intake. The screens may be swung forwardly from the operative position shown in full lines in Fig. 2 through an opening in the wall 17 into the retracted position shown dotted. The screens 16 carry metal sheets 35, 36 so arranged that they close the part of the opening in the wall 17 adjacent the hinge axes in the operative and retracted positions of the screen. The remainder of the opening is closed by pivoted doors 41. Each door carries an operating lever 43. The operating levers of one set of alternate doors are connected by links 46 to an actuating ring 47 and the levers of the other set of alternate doors are connected by links 48 to an actuating ring 49. The rings 47 and 49 are operated by a hydraulic jack 55, Fig. 3. and the screens 16 are operated by jacks 78. The piston rod 70 of the jack 55, Fig. 3, is connected to the arms 65, 66 of a pair of bell crank levers 57, 58 the other arms of which are connected to the rings 47, 49 respectively. The operation of the jacks 55, 78 is controlled by an actuator valve 80 and operating cylinder 81 so that the doors 41 are first opened, then the screens 16 are moved to the operative position or retracted and finally the doors 41 are closed. In the position shown Fig. 3, the valve 80 is set for movement of the screens 16 from a'retracted to an operative position. The screens may be retracted by moving the plug 83 through 180 degrees. As shown pressure oil from a pump 93 passes through pipe 95, passages 96, 97 and 98 and pipe 100 to a servo-cylinder 87 on the side of the piston 92 remote from the member 89 and thereby moves the member 89 to the left. Pressure oil is also supplied through passages 96, 97 and 99 and pipe 101 to a compartment 85 and thence through a shaft 90 to a port 102 in member 89. On movement of the member 89 the port 102 communicates first with a pipe 103 which supplies oil to the jack 55 to open all the doors 41, then with a pipe 104 which supplies oil to the jacks 78 which moves the screens to their operative position and finally to a pipe 105 which supplies oil to the jack 55 to close the doors 41. When the doors are opened the return oil from the jack 55 passes through pipe 107, passage 108, hollow shaft 91, compartment 88, pipe 109, passages 110, 111 and 112 and pipe 113 to the suction of the pump 93. The return oil from the jacks 78 when the screens are moved to the extended position, passes through pipes 114, 115 to passage 108 whence it returns to the pump as described above. When the doors are re-closed the oil is returned to the pump through pipes 103, 116 and passage 108, whence it returns to the pump as described above. The return oil from the servo-cylinder 87 passes to the pump through the pipes 117, passages 118, 111 and 112 and the pipes 113. The rate of delivery of the pump 93, the inlet area to pipes 103, 104, 105 and outlet area of pipes 107, 115, 116 is such that each movement of the jacks is completed before the ports 102, 108 are moved out of communication with the pipes 103, 104, 105 and 107, 115 and 116 respectively. On completion of the movements, the member 89 is displaced to the left with the ports 102, 108 beyond the pipes 105, 116. Rotation of the plug 83 causes pressure oil to be supplied to servo-cylinder 87 to the right of the piston 92 and move the member 89 to the right and changes the connections between the pump 93 and operating cylinder 81 so that the doors 41 are first opened, then the screens 16 are retracted and finally the doors 41 are closed. A suitable opening for the discharge of solid bodies caught on the screens 16 may be provided in the outer wall 31 of the shroud 12. This opening preferably has a door which may be opened and closed in sequence with the other operations, e.g. as a final stage of the retraction operation.