GB869546A - A hydraulic system for controlling a regulator member in a fluid flowline - Google Patents

Abstract

869,546. Fluid-pressure servomotor control systems. SOC. ALSACIENNE DE CONSTRUCTIONS MECANIQUES. Dec. 18, 1957 [Dec.26, 1956], No. 39375/57. Class 135. An hydraulic system for controlling a regulator member disposed in a fluid flow line comprises a first cylinder having an actuating piston therein connected to said regulator member, a second cylinder having a movable partition therein, a liquidfilled conduit interconnecting said first cylinder and said second cylinder for transmitting liquid pressure between one side of said partition and one face of said actuating piston, a source of liquid under pressure, means responsive to a variable factor such as liquid pressure or an engine speed effective to move said partition from neutral position in one or the other of two opposite directions, and valve means operable upon movement of said partition from said neutral position to connect said conduit either with said source or with the exhaust to thereby provide an additional operating pressure difference to operate the actuating piston and so cause additional movement of the actuating- piston over that which would be caused without this additional pressure difference. In the first example, Fig. 1, a spring-loaded piston 1 is subject to the pressure of a gas in a container 2 supplied from a pipe 3. Integral with the piston 1 is a differential piston 8 in a cylinder 9 connected by a conduit 11 to a cylinder 10 containing a piston 20 connected by a link 22 to a damper 23 in the pipe 3. A pressure supply is connected by pipes 15, 24 to both cylinders 9, 10. Upon movement of the piston 8 the pipe 24 is either connected to the conduit 11 via ports 13 and bore 12 or to an exhaust conduit 18 via ports 13, 19. The liquid in the conduit 11 acts as a fluid link between the pistons 8 and 20. In the second example, Fig. 2, the system is used to control a motor admission valve 25 in accordance with the speed of the motor 27. The conduit 48 provides the fluid link between the pistons 32 and 72. A speed governor 28 controls a valve member 30 to admit liquid under pressure to or exhaust it from a chamber 45. The resulting movement of the piston 32 actuates the double valve member 57 to connect the conduit 48 to a supply line 42 or to the exhaust line 21.