ELECTROHYDRAULIC VALVE

1,144,553. Valves. GEB. BUHLER. 10 March, 1966 [11 March, 1965; 18 Jan., 1966], No. 10576/66. Heading F2V. [Also in Division G1] An electromagnetically actuated valve comprises an annular or E-shaped magnetizable core 31 enclosing a coil 2 and provided with an inlet 3, the flow through which is controlled by a non-magnetizable valve member 46 carried by a magnetizable armature 37. The armature is supported at the centre of a diaphragm 47, the latter being located at its periphery between non-magnetizable annular members 41, 42. Non-magnetizable pins 38, 381 define an air gap 6. In the absence of any fluid or magnetic forces, the valve member 46 seats against the end of passage 45. In use, progressive energization of the coil 2 increases the back-pressure at inlet 3. Ring 41 carries an outlet 15. In Fig. 2, not shown, the diaphragm is omitted and the armature is supported by spring (17) into contact with a non-magnetizable pad (52) having grooves (53). In Fig. 3, not shown, non- magnetizable screws (137) in the armature abut the core to define the air gap and the valve member is carried by a screw (147) threaded into the armature. The valve member or the seat may be adjusted for calibration purposes. In an application (Fig. 4) the valve (71) is located downstream of a relief valve (66) and is variably energized to control pressure in line (65). In a modification, the pressure drop across valve (66) is compensated by a valve (81) downstream of valve (71) and responding to the pressures downstream of the latter and downstream of restriction (85) in main line (86). In Fig. 6, the valve is energized by a pulse generator (see Division G1) to control an hydraulic ram applying cyclic tensile or compressive loads to a testpiece via a piston. In Fig. 7, the valve loads a pressure regulator.