Component Related Documentation

Direct-acting directional control valves may be actuated by manual, pilot (pneumatic or hydraulic) or solenoid operators. Direct acting indicates that some method of force is applied directly to the spool, causing the spool to shift. Typically, the spools of 2-position directional control valves are spring-offset, meaning that when the operator is not shifting the spool, the return spring located on the opposite end of the spool will return the spool to the spring-offset (de-actuated or de-energized) position.

Safety Related Notes

Before working on this machine, perform lockout-tagout procedures per the rules of your plant. Determine the sources of energy on this machine – electrical, pneumatic and hydraulic – and release or vent sources of stored energy – electrical capacitors, air receivers, and hydraulic accumulators. Shut off sources of power – electrical, pneumatic and hydraulic. Safely block mechanical sources of energy such as loaded springs and loaded machine members, or safely position the machine members so they are unloaded and springs are not under tension. Beware of hot hydraulic fluid and hot surfaces which can cause burns. Never “crack a hydraulic or pneumatic fitting” to check for the presence of stored energy. Hydraulic fluid injection injuries, as well as injection injuries from many other fluids, are extremely serious and must be treated immediately by medical personnel familiar with this type of injury. Loss of body parts or death may result from improperly treated fluid injection injuries! Never use your hands to feel for a hydraulic leak! Review the schematics and think before proceeding to work on the machine to ensure you have made the machine safe to work on.