As hydraulic systems on construction equipment continue to evolve, the goal of increasing simplicity, reliability and productivity remains the same. Parker Variable Flow Open-Center (VFO) takes a big step towards realizing these objectives.
Typical hydraulic system layoutsThe most common hydraulic systems on mobile equipment are based on two designs: an open-center valve technology with fixed displacement pumps or load-sensing (LS) valve technology with variable or fixed displacement pumps. Both of these arrangements have their benefits. The open-center system, for example, is simple, cost-effective and provides the operator with a less jarring operation.
Variable flow open-centerVFO innovatively employs a variable displacement pump controlled by an open-center type valve. The result: VFO integrates the advantages of the current technologies (simplicity, cost-effectiveness, smooth operation) with the energy efficiency of piston pumps.

The distinct value of the variable flow open-center system can be seen from several perspectives:
Simplicity: There are no compensators and shuttle networks (open-center valve technology).
Reliability: In general, less complexity means more dependability (open-center valve technology).
Productivity: The system optimizes the energy balance of variable-pump technology.
Applicability: It can work with any valve control type without the need for electronics.
Parker is a global leader in motion and control technologies and a pioneer in the variable flow open-center system.
For in-depth details on our VFO, download the white paper. And for additional construction equipment content from Parker, visit www.parker.com/buildingbetterlives.
Article contributed by Germano Franzoni, Ph.D., senior systems engineer, Parker Hannifin, Global Mobile Systems.
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