GB1372772A - Regulating valves - Google Patents

Abstract

1372772 Fluid-pressure servometer systems RIVA CALZONI SpA 16 June 1972 [7 Aug 1971] 28359/72 Heading G3P A flow control valve, which can be incorporated in a hydraulic circuit for controlling the speed of operation of a hydraulic actuator or a motor, comprises an inlet 3, an outlet 13 and disposed there- between, a piston valve 7 which is subjected to the differential existing across a four-plate slide valve defining a rectangular orifice 13a, the differential being transmitted to the piston valve via passageways 12 and 15. The four-plate valve comprises two pairs of aligned and elongated slide plates 18, 19 and 22, 23 whose facing edges are bevelled at 18a, 19a, and 22a, 23a, respectively, the pairs being arranged orthogonally to one another. As shown in Fig.3, each slide plate is subject to the outward bias of a spring, 37-40. Furthermore, one plate of each pair is adjustable manually by a screw 41 and 42. The remaining plate of each pair is adjustable by, for example, a cam member 47 acting through a follower 43, or a pin 44 subject to rectilinear movement in a predetermined temporal pattern. The slide plates defining orifice 13A and the semi-circular slide plate guides 20, 21, (and 24, 25, Fig.4 (not shown)), are biased against a valve wall 26 by a spring member 27.