What Is a Hydraulic Solenoid Valve?

A solenoid valve is a voltage-actuated valve, meaning it is activated by an electrical charge. Hydraulic machines use oil under pressure as their prime source of energy, and so a solenoid valve becomes a hydraulic solenoid valve when the fluid is introduced into its ports, or openings. The fluid is used to perform a variety of activities, such as moving a cylinder or backhoe, or tilting and angling a snowplow. The valve’s job is to either direct the fluid’s flow, or to stop or begin the fluid’s flow.

The electricity used to power the valve may be either alternating current (AC) or direct current (DC). AC is usually used in industrial applications, while DC is used in mobile applications, such as in a forklift or backhoe.

The main types of hydraulic solenoid valves are Japanese, American and German, and there are geographic differences built into each. These types are not interchangeable, nor are they compatible. Two-port hydraulic solenoid valves are the most common, and there are also types of solenoid valves that are designed with three ports or more. A two-port hydraulic solenoid valve does not necessarily allow the hydraulic fluid to flow in a bi-directional manner, or in two directions such as in and out, although it is possible for a solenoid’s design to allow bi-directional flow.

Hydraulic solenoid valves are used in a wide variety of applications, including wood chippers, stump grinders, bucket trucks and car crushers. They are also used in automobile transmissions, snowplows, backhoes, steamrollers, road pavers, excavators and cranes, to name just a few applications. In general, anything that moves under hydraulic power has a hydraulic solenoid and a hydraulic solenoid valve to actuate movement. Special hydraulic solenoid valves that are used in chemical plants are designed to be explosive-proof because a spark in a chemical plant can be extremely hazardous.

The job of replacing a hydraulic solenoid valve will vary based on the solenoid’s application. The job could entail replacing only the coil if that is the only part that needs replacing, without replacing the entire solenoid valve. This leads to ease of repair and maintenance. If the entire valve must be replaced, it has to be removed first from its hoses and threaded connections.