GB1050621A - - Google Patents

Abstract

1,050,621. Fluid pressure senovator systems. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Dec.5, 1962 [Dec.6, 1961], No.43716/61. Headings G3H and G3P. A fluid pressure relay for modulating a supply pressure or amplifying a fluid pressure signal comprises a valve member 1, 2, 3, which may be rotatable by supply pressure P s as in Specification 1, 041, 771 to eliminate friction, an input or signal pressure P 1 derived from a mechanical, electrical or hydraulic control signal and applied to the end 2 of the valve member, a biasing pressure Ps/2 applied to an annulus at the end 1 of the valve member, and an output pressure P o taken from the intermediate, reduced portion 3 of the valve member and communicating through a feedback line which may incorporate a resistance R with a reduced end portion 1a of the valve member. Movement of the valve member varies the output pressure by variably throttling the supply pressure P s and an outlet,O. In a modification, which may be used in conjunction with electrohydraulic apparatus as described in Specification 1,041,772, the supply pressure, instead of being controlled by the valve member, is connected to a junction point to which the feedback and output pressure lines and the reduced portion 3 of the valve member are also connected. In a further modification the feedback pressure, which acts on the whole area of the valve portion 1, is taken from a point between two resistances in a line connecting the output pressure with a datum pressure Ps/2. Fig.4 (not shown) illustrates another embodiment in which the variable pressure acting on the end 1 of the valve member is taken from a point 12 between resistance R 1 , R 2 connecting the input pressure P 1 with the output pressure P o . Phase displacement, differentiating and integrating effects can be obtained by use of resistance-capacitance combinations.