GB903518A - Improvements in or relating to the regulation of liquid flow - Google Patents

Abstract

903,518. Fluid-pressure servomotor-control systems. SOC. NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. July 26, 1960 [July 28, 1959; June 22, 1960; July 8, 1960], No. 26033/60. Class 135. [Also in Group XXVI] A device controlling the flow of a fluid, such as the flow of fuel to a gas turbine, comprises a piston regulator 4, Fig. 3, controlling the flow of fluid from a pump 1 through slots 3. The piston regulator 4 is subjected on one end face to the pressure in chamber 10 on the downstream side of the slots and on its other face to the pressure in chamber 5 which is suppled by the pump through a restriction 7 and the leakage from which is controlled by a regulating valve comprising a ball 9 slidable in a bore 30. The ball 9 contacts a three-dimensional cam 19 which is rotated in response to a variable characteristic, such as compressor outlet pressure, and is movable axially by manual operation. As shown, the regulating valve may be mounted on an arm 38 pivoted at 39 and provided with the necessary fluid-flow passages. The arm 38 carries an adjustable member 37 bearing against an adjustable plate 35 mounted on a rod attached to the piston regulator 4. In operation, as the position of the cam 19 is varied, the ball varies the leakage from the chamber 5 and the piston regulator assumes a new position and in so doing restores the position of the valve relative to the cam surface. A further valve (not shown), is provided for maintaining a constant pressure drop across the slots 3. Adjustment of the plate 35 varies the initial setting of the piston regulator while adjustment of the member 37 varies the movement of the piston regulator for any specific movement of the cam. In a modification without the adjustments provided by plate 35 and member 37, the regulating valve is positioned on the end of the rod attached to the piston regulator. In a further modification in which the valve meters fuel for post combustion, the ball 9, Fig. 7, of the regulating valve is controlled by a lever in response to a variable characteristic, such as compressor delivery compressor, while an extension 50 of the rod carrying the regulating valve is spring-loaded into contact with a cam 19 formed between the piston regulator 4 and a second piston member 4<SP>1</SP>, the cam providing the follow-up as above when the piston regulator moves in response to variations in the characteristic. The cam may be a three dimensional cam, as shown, in which case rotation of the cam by the lever 70 provides a manual adjustment or if manual control is not required, the cam is formed by a surface of revolution. A piston 14 forms the valve providing a constant pressure drop across the slots 3, this piston being loaded to move to the left by a spring 16 and the pressure in the chamber 10 and loaded to the right by the pressure upstream of the slots through line 15.