What is a sectional directional control valve?
Sectional directional control valves are the core control components of hydraulic systems. They use a unique modular design, combining multiple independent functional units (or “sections”) to form a complete valve assembly capable of controlling multiple actuators (such as cylinders or motors).
The key lies in the "sectional" structure. A complete valve is longitudinally assembled from the following basic modules and secured with long bolts:
Supply section: Connects to the hydraulic pump to introduce pressurized oil and usually contains a main safety valve.
Multiple working sections: These are the core functional units of the valve. Each section contains a directional control spool (operated by a manual lever, solenoid, etc.) dedicated to controlling the action of a single actuator (such as lifting or lowering). Moving the spool switches the oil flow direction.
Return section: Guides the system oil back to the tank.
Once these modules are assembled, their interior forms common oil passages that run through all sections, including pressure and return lines, providing a shared hydraulic source and drainage path for each working section.
This design offers significant advantages:
High flexibility: The number of working sections can be assembled like building blocks according to the required functions of the machine, allowing for customization.
Easy maintenance and upgrade: If a single working section fails, it can usually be replaced individually without discarding the entire valve body.
Compact structure with fewer leakage points: Integrating multiple valve functions into one unit reduces the need for external connecting pipes and the risk of oil leaks.
As a result, sectional directional control valves are the preferred choice for complex hydraulic systems in engineering machinery. They are widely used in equipment requiring precise coordination of multiple actions, such as excavators (controlling boom, bucket, swing, etc.), agricultural tractors, cranes, and more. Essentially, they are the custom-designed, freely configurable "nerve center" for modern high-performance hydraulic equipment.
