As with most energy-consuming technologies, the quest for greater economy is driving development in hydraulics. One of the most important innovations is the arrival of load-sensing systems in machinery that experiences frequent changes of load in normal use.
The simplest hydraulic systems operate at the maximum pressure and flow for which they were designed. Excess power, being a function of pressure and flow, is rejected through pressure relief valves, a process that requires work from the power unit and is therefore wasteful. Some savings are to be had by the use of pressure-regulated flow control. This still means, though, that while flow is varied according to demand, pressure is maintained at the maximum. In the many operations where neither maximum pressure nor maximum flow is required, there is still a wasteful power loss. Load sensing addresses these issues.
Load sensing operates by measuring the pressure drop across a directional valve and using
it as an analogue for the load on the actuating device. Fluctuations in this pressure are fed back to the variable pump, adjusting its displacement so that flow, and the work needed to produce it, rises or falls to restore pressure stability.
For machines like excavators, load-sensing control saves fuel, of course, but with less heat being produced through power losses, fluid and component lives are extended.
If you’d like to learn more about how load sense technology can benefit your business, call Gerrard Hydraulics or send us a contact request here.