GB470639A - Improvements relating to relay or like control systems - Google Patents

Abstract

470,639. Fluid - pressure servomotorcontrol systems valves. NOBLE, G. S. Jan. 18, 1936, Nos. 1641 and 8910. [Class 135] A fluid-pressure valve comprises two rotatable parts having co-operating ports for simultaneously connecting an output pipe with a pressure source and with a vent, one part being rotated by means determining the required output pressure and the other by means responsive to the output pressure. As shown in Fig. 2, a valve body 7, rotatable by an arm 7A, has an input port 15 for pressure fluid, an output port 16, and a vent port 17, and has rotatably mounted therein, with clearance, a valve spindle 1 provided with a cross port 2 which is in constant register with port 16 and which overlaps the ports 15 and 17. Spindle 1 has an arm adjustably connected to the free end of a resilient metallic bellows 20 to the interior of which the output pressure is communicated through a branch pipe 19. The spindle 1 thus follows-up the movement of the body 7 and a definite pressure corresponding to the position of the body 7 is maintained in the output pipe 18. As shown in Fig. 3, arm 7A of body 7 is connected to the bellows 20, responsive to the output pressure, while arm 13 of spindle 1 is controlled by a metallic bellows 30 provided with a tube 35 depending into a mercury bath 37. The spindle 1 is thus controlled by the atmospheric pressure. The level of the mercury can be lowered below the mouth of the tube, so as to render the device ineffective, by pulling out a plunger 39. Such a device may be applied to maintain the height of an aircraft, the output pressure controlling the elevator. It may also be applied in a submarine, the bellows 30 being exposed to the water. Figs. 4 and 5 show an arrangement wherein a rotatable valve body 44 it controlled by a bellows 56 responsive to the output pressure and is provided with input, output, and vent ports 50, 51 and 52 respectively, an inner disc valve 40 having a co-operating groove 53. As applied to maintaining the direction of movement of an aircraft, the output pressure controlling the rudder, the valve 40 carries a gimbal ring 46 in which is mounted a gyro rotor 47 which is spun by an air jet 48 fed from the groove 53 and the axis of which is substantially horizontal. The first Provisional Specification suggests that the output from a first valve may operate a second valve. It also suggests that the rotatable valve spindle may be ported by having a helical groove or grooves formed thereon, the valve body being fixed and the spindle being movable axially under the control of a diaphragm. It also states that sleeve or slide valves may be used.