ABSTRACT
Most valves, controlling how much energy is delivered to the load, do so by determining the amount of energy dissipated before it reaches the load. This method
has two negative aspects associated with it: excessive heat buildup and large input power requirements. Alternative power management techniques are discussed later in this chapter in Section 12.6. Since using valves to control the amount of energy dissipated provides good control of our system, it remains a popular method of controlling fluid power actuators. This concept of tracking energy levels throughout our system is shown in Figure 2. We see the initial energy input provided the pump, slight losses occurring in the hoses and fittings, energy loss over the relief valve (auxiliary component) to provide constant system pressure, and the variable energy loss determined by the spool position in the control valve. The remaining energy is available to do useful work.
