GB598184A - Improvements in or relating to variable jet nozzles for jet propulsion units - Google Patents

Abstract

598,184. Fluid pressure servomotorcontrol systems. LOMBARD, A. A., and GRIMWOOD, M. V.. and SKIPWITH, G., [Representatives of COURLAY, G. K. L.]. March 9,1945, No. 5988. [Class 135] A variable jet nozzle for a jet propulsion unit is adjusted by a hydraulic ram 9 supplied with pressure liquid from a pump 10 under the control of a valve 13, itself controlled by a temperaturesensitive device 16 in the jet pipe, the supply of pressure liquid also being controlled by a follow-up device actuated by the ram to prevent hunting. As shown, a spring-loaded valve piston 14 is actuated by pressure liquid being admitted to or allowed to escape from a chamber at the left-hand end of the piston according to the position of a further spring- loaded piston valve 23 actuated by the temperature-sensitive device. In operation, should the temperature in the jet pipe change to move the valve 23, say, to the right, pressure liquid will act on the piston 14 to move it to the right, thereby admitting pressure liquid, by a conduit 19, to the ram vhilst venting a conduit 20, the consequent movement of the ram adjusting the nozzle by moving a pair of sector-members 6 about a pivot 7, and also,cutting off the supply of liquid to the ram after a certain displacement corresponding to the displacement of the piston 14, by moving a ported sleeve 17 constituting the follow-up device. A temperature change in the opposite sense results in a reduction of the pressure acting on the piston 14, allowing the latter to be moved by its spring to effect movement of the ram in the other direction. In a modification, the temperature-sensitive device acts directly on the piston 14 through a lever. Specification 598,182 is referred to.