| 摘要 |
<p>A hydraulic control valve assembly (10) is described comprising a cut-off valve (18), a control valve (16) and means for connection to at least a supply line (20), a hydraulic apparatus line (24) and a return line (22). The assembly is constructed and arranged such that the cut-off valve is bistable and controls flow of pressurised fluid from the supply line to the control valve, permitting it when primed and preventing it when closed, and the control valve controls the pressure of fluid supplied to the hydraulic apparatus line. In addition means are provided to initiate priming of the cut-off valve, complete the priming of the cut-off valve provided the supply line pressure is above a first predetermined pressure, and maintain the priming of the cut-off valve provided the supply line pressure remains above a second predetermined pressure. <IMAGE></p> |
