Component Related Documentation

A variable displacement, pressure compensated pump is designed to respond to the flow demands occurring in a hydraulic system based on system pressure. Advantages of a pressure compensated circuit over a system powered by a fixed displacement pump are reduced input energy consumption and reduced heat generation. Typically, pressure compensated pumps are used with closed center systems (systems in which the directional control valves have closed P-ports). When the directional control valve spools are centered (in the closed position), the pump flow will deadhead (be blocked by the closed directional control valve pressure ports) and system pressure will increase (pressure being defined as “resistance to flow”).

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.