| 摘要 |
A control valve (36, 37, 39, 40) for controlling the flow of fluid to a fluid-operated actuator, in an open condition in use, allows the flow of fluid from a fluid source to the actuator and, in a closed condition, prevents the flow of fluid from the fluid source to the actuator. There is a vent (V) for fluid supplied to the actuator, which vent is closed in the condition of the valve and is open in the closed condition of the valve. The valve is provided with energy storage means (38) which, in use of the valve, stores energy from the fluid source and, in the event of a failure of the supply of fluid to the valve if the valve is in the open condition, uses such stored energy to cause the vent to be open.
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