| 摘要 |
<p>An electrohydraulic doser actuator of the kind comprising a differential area piston the axial position of which is variable as a function of metered doses of pressurized fluid which are vented to or from a control chamber by valve means connecting the latter either to a high pressure source or to a low pressure source.</p><p>According to this invention, the valve means include a first on-off valve (32) and a second on-off valve (34) connecting the control chamber (22) to the high pressure source and low pressure source respectively, said valves being normally closed and thus estabilishing a hydraulic lock on the piston (18, 20) to maintain same in its last axial position.</p><p>For use particularly in gas turbine control systems.</p> |
