Pressure control valves are used to change the pressure in a circuit or part of a circuit. These valves are divided into three categories:

• Safety valves
• Step valves (accumulator charging valves)Pressure relief valves

Pressure control valves may be controlled by pilot or directly.

These types of valves protect the system against sudden changes in pressure. These unwanted pressure changes may be due to a decrease in flow or an unintended increase due to the opening and closing of the valves. Pressure relief, pressure reducing, sequencing, discharge, braking and neutralizing valves control gradual and constant pressure in hydraulic systems.

Sudden changes can cause an instantaneous increase in pressure of up to 4 times the normal pressure in the system, which is why it is necessary to use pressure control devices in any hydraulic circuit.The operation of different types of hydraulic pressure control valves is similar to each other.