Hydraulic valves are a vital feature of hydraulic power systems. They regulate the flow and pressure of water or oil in the systems. Valves also control volume of fluid that flows through the system. This helps to sustain a balanced state of power dynamics in various mechanical systems. Different types of valves can be used in a single system. Each type of valve is designed to perform some specific activity which contributes to the overall smooth operation of the unit. Hydraulic valves can be broadly divided into three categories. These are the flow control, pressure and directional valves.