What is the principle of solenoid valve?

A solenoid valve is an electromechanical device that controls the flow of fluid or gas in a system using an electrical signal. Its operation is based on the principle of electromagnetism. Here's a breakdown of its working principle:

1. Electromagnetic Coil Activation:

   • When an electric current passes through the solenoid (a coil of wire), it generates a magnetic field.
   • This magnetic field creates a force that acts on a movable core or plunger made of ferromagnetic material, such as iron.

2. Plunger Movement:

   • In its normal (de-energized) state, the plunger is typically held in position by a spring.
   • When the solenoid is energized, the magnetic field overcomes the spring force and moves the plunger.

3. Valve Actuation:

   • The plunger's movement either opens or closes the valve port, depending on the valve's design (normally closed or normally open):
     • Normally Closed (NC): In the de-energized state, the valve remains closed. Energizing the solenoid lifts the plunger, allowing fluid or gas to flow.
     • Normally Open (NO): In the de-energized state, the valve remains open. Energizing the solenoid pushes the plunger to block the flow.

4. Deactivation:

   • When the electric current is switched off, the magnetic field disappears.
   • The spring returns the plunger to its original position, restoring the valve to its default state (open or closed).

Key Components:

• Solenoid Coil: Generates the magnetic field when energized.
• Plunger or Core: Moves in response to the magnetic field.
• Spring: Restores the plunger to its default position.
• Valve Body: Contains the fluid/gas flow path and ports for connection.

Applications:

• Solenoid valves are used in a wide range of industries, including HVAC systems, automotive engines, irrigation systems, and medical equipment, due to their reliability and rapid switching capabilities.