A direct current (DC) solenoid valve is a valve that controls the flow of a liquid or gas by utilizing the electromagnetic properties of a solenoid. These kinds of valves have many applications, especially in industry. Typically defined by the type of actuator, there also are many variations available for these valves. There are several advantages and several disadvantages to using a DC solenoid valve, though many times the type of application will change how well a valve can work.
Solenoids are typically copper wire wrapped around a magnetic core. When a charge is run through the coil, a magnetic field is created that can be manipulated to activate machinery. The actuator of a DC solenoid valve is typically a spring that recoils when the solenoid is active and relaxes when the solenoid is deactivated. This actuator moves a plunger or armature connected to the valve, which controls the flow of liquid or gas, depending on the application.
As the name implies, a DC solenoid valve can only receive DC power, as opposed to an alternating current (AC) valve. Applications for these valves, then, are often limited to machines that typically use DC power. This characteristic often implies larger machinery, such as that used in industrial production systems or fossil fuel extraction. In most cases, a DC solenoid valve will be used to control the flow of some sort of gas or liquid.
Variations of a DC solenoid valve include direct-acting, internally piloted and externally piloted. In direct-acting DC solenoid valves, the valve is closely connected to the solenoid core without many parts between. Internally piloted valves are similar but tend to be used for high-pressure, high-volume applications. Externally piloted valves can still use a DC solenoid to actuate a valve, but the actuator is often separated from the valve by actual distance or because another device also is influencing the valve.
Advantages to using a DC solenoid valve are generally linked to the simplicity and reliability of these valves. Solenoid actuators often provide consistent performance without requiring maintenance. Additionally, DC solenoid valves are typically low power consumers compared to some other automatic valve types.
One primary disadvantage is that some DC solenoid valves can only be set in an open or closed position. This limits the amount of applications for which these valves might work. Another disadvantage is that the electromagnetic machinery can wear out over time, and temperature must constantly be monitored for some applications.