A solenoid valve is an electromechanical device that is commonly used to control the flow of fluids or gases in a wide range of applications. It works by using an electric current to generate a magnetic field, which then activates a plunger that opens or closes the valve.

The triggering of a solenoid valve depends on the specific type of valve and its intended use. In general, there are two main types of solenoid valves: direct acting and pilot operated.

Direct acting solenoid valves are simple and reliable devices that are commonly used in low flow applications. They consist of a coil, a plunger, and a valve seat. When an electric current is applied to the coil, it generates a magnetic field that pulls the plunger towards the coil. This movement causes the valve seat to open, allowing the fluid or gas to flow through the valve.

Pilot operated solenoid valves are more complex and are typically used in high flow applications. They consist of a pilot valve and a main valve. When an electric current is applied to the coil of the pilot valve, it generates a magnetic field that opens or closes the pilot valve. This movement then allows or blocks the flow of a small amount of fluid or gas, which in turn generates pressure that acts on the diaphragm of the main valve. This pressure then opens or closes the main valve, allowing or blocking the flow of the fluid or gas through the valve.

In both types of solenoid valves, the triggering is controlled by the application of an electric current to the coil. This current generates a magnetic field that causes the plunger or pilot valve to move, which then controls the flow of the fluid or gas through the valve.

Overall, solenoid valves are reliable and versatile devices that are used in a wide range of applications across many different industries. They are commonly used in industries such as oil and gas, water treatment, and manufacturing, and can be found in everything from small appliances to large industrial machinery.