The spool of a directional control valve is shifted to a different position by the_______.

• A. Fluid
• B. Operator
• C. Conductor
• D. Cylinder

Answer: (B)

Spool movement is caused by the actuation device controlled by the operator. When you move a lever, press a button, or energize a solenoid, the actuator pushes or pulls the spool from its neutral position to another position. Fluid pressure then flows according to the new spool arrangement, but it doesn’t automatically shift the spool by itself. The cylinder is the component being driven by the valve, not what moves the spool, and “conductor” isn’t a term used for valve actuation. So the device that actually shifts the spool is the operator (the manual or automatic actuator).