A magnetic solenoid valve (often referred to as a "solenoid valve") is an electromechanical device that uses electromagnetic force to control the flow of fluids (liquids, gases, or vapors). It converts electrical energy into mechanical motion to open or close the valve core, thereby regulating fluid on/off, flow direction, or pressure. With advantages such as fast response (millisecond-level), compact size, and easy integration into automated systems, magnetic solenoid valves are essential components in fields like HVAC (Heating, Ventilation, and Air Conditioning), automotive engineering, medical equipment, and industrial fluid control.

The basic structure of a magnetic solenoid valve includes a solenoid coil, valve body, valve core, spring, and sealing element. The solenoid coil is wound around a hollow bobbin—when energized, it generates a magnetic field that magnetizes the valve core (usually a ferromagnetic material like iron). The magnetized valve core is attracted upward (or downward) against the spring force, changing the position of the valve core relative to the valve seat. This movement either opens the fluid channel (allowing fluid to flow) or closes it (blocking fluid flow). When the coil is de-energized, the magnetic field disappears, and the spring pushes the valve core back to its original position, resetting the valve state. The sealing element (e.g., nitrile rubber or PTFE gasket) ensures tightness between the valve core and valve seat, preventing fluid leakage.

Magnetic solenoid valves are categorized based on fluid type and working principle. Direct-acting solenoid valves have a simple structure: the valve core is directly driven by the solenoid coil, suitable for small flow rates and low pressures (e.g., 0-1MPa), and are commonly used in medical nebulizers to control the flow of medicinal . Pilot-operated solenoid valves use a small direct-acting valve (pilot valve) to control the pressure difference on both sides of the main valve core, enabling the main valve to open/close under high pressure (e.g., 1-10MPa) and large flow rates—they are widely used in air compressors and hydraulic systems. According to the number of working positions, they can be divided into 2/2-way (on/off control), 3/2-way (flow direction switching), and 5/2-way valves (multi-channel control), meeting different fluid control needs.

In real-world applications, magnetic solenoid valves ensure precise and efficient fluid management. For example, in an automotive fuel injection system, a 2/2-way magnetic solenoid valve controls the fuel injection timing and duration: when the engine ECU (Electronic Control Unit) sends an electrical signal, the valve opens to inject fuel into the combustion chamber; when the signal stops, the valve closes to cut off fuel supply, improving fuel efficiency and reducing emissions. In HVAC systems, solenoid valves regulate the flow of refrigerants—opening to cool the room when the temperature is too high and closing when the set temperature is reached, maintaining a comfortable indoor environment. In medical equipment like hemodialysis machines, solenoid valves control the flow of blood and dialysate, ensuring the safety and accuracy of the treatment process.