A normally open (NO) solenoid valve is a type of valve that is designed to be in an open state when the solenoid coil is not energized. When the coil receives power, it creates a magnetic field that pulls the valve's plunger, closing the valve and stopping the flow of fluid. This design ensures that the valve allows flow in its default state and only blocks the flow when needed, making it ideal for systems that require flow under normal operating conditions and interruption only when necessary.

    These valves are typically used in applications where fluid or gas needs to be allowed to pass through a system until a specific condition, such as a pressure or flow threshold, is met. They can be used in various systems, including water treatment, HVAC, pneumatic control, and chemical processing.