What are solenoid valves?

These are electrically controlled valves that are used wherever fluid must be automatically controlled. They are used in different equipment and various designs and are selected according to their applications.

It has two main parts: the valve body and the solenoid coil. The solenoid has a wound copper wire surrounding the core and a movable closing plunger. The coil creates a magnetic field by passing an electric current. It moves a piston that can open or close the valve.

Types

The main categories of solenoid valves are:

Direct-acting valves

The solenoids in these valves open the valve magnetically using direct action. They need full power to operate the valve.

Pilot-operated valves

These solenoids use the fluid pressure in the line for opening the valve. They use lesser electrical power, but the available pressure must be enough to operate the valve.

These valves can also be categorised as:

• 2-way valves: The operations of these valves need a higher flow and a quick response. They can easily replace a lever for automating a process.
• 3-way valves: These valves have three ports and can be in one or two states.
• 4-way valves: In these valves, all the ports are in an off position by default. There are two states and two exhaust ports. The speed of the actions can be controlled by having a flow valve attached to each exhaust port.

Applications

Solenoid valves ensure ease of control and have a compact profile. They are used in hydraulic and pneumatic circuits. They can be found in air compression and refrigeration systems. These valves are also used where the fluid flow can be automatically controlled. Other common uses are in anaesthesia systems, dialysis machines and ventilators.