By means of flow sharing, also known as LUDV, LSC or social LS system, different consumers can be moved proportionally and synchronously to each other even in case of undersupply (pump delivery volume < consumption).
With simple hand lever directional valves without pressure compensator, the oil flows to the consumer with the smallest resistance (pressure). The operator regulates the speeds of the consumers intuitively by means of the slide deflection and slows down the function that is running too fast.
In proportional directional valves with upstream individual pressure compensator (e.g. HPV41), the pressure compensator regulates a constant pressure difference via the slide valve, i.e. the consumer speed, automatically and independently of the pressure. However, if the pump flow rate is not sufficient to supply all required sections with oil, the functions with the highest pressure stop. This makes the machine control unpredictable.
Flow sharing provides a remedy in this case. By installing the individual pressure compensator after the throttle point (slide valve), all sections are internally preloaded to the same pressure level and the functions work at reduced speed in case of undersupply, but still synchronously with each other.
Flow sharing has mostly been used in construction machinery such as excavators, but is now increasingly being used in other applications.
Control types
© Bosch Rexroth
Paul Forrer offers the following valve series with flow sharing:
EDC for various applications up to 310bar, 120 l/min at the inlet, 50l/min per section
ELS101 for agricultural applications up to 280bar, 80l/min at inlet, 30l/min per section
