When the system requires automated control, rapid response, safety protection, special medium handling or space constraints, solenoid valves are the best choice.
When selecting the type, a comprehensive judgment should be made in combination with control requirements, working condition parameters (pressure/temperature/medium), and installation conditions.
| Parameter Category | Key Parameters | Selection Guidelines |
|
Fluid Characteristics |
Medium Type | Gases/liquids/steam/corrosive media determine valve body material |
| Medium Temperature | Standard (-20~80℃), high-temperature (>150℃), low-temperature (<-40℃) affect seal material | |
| Medium Viscosity | Viscosity >20cSt requires large-bore or pilot-operated structure to prevent spool jamming | |
| Medium Cleanliness | Particulate-containing media need filters (≥80μm) or piston-type structure | |
|
Operating Conditions |
Operating Pressure | Minimum/maximum operating pressure (e.g., 0~1.6MPa) must match valve rated pressure |
| Operating Voltage | AC220V/DC24V (industrial mainstream) must match control system | |
| Environmental Conditions | Temperature (-30~60℃), humidity (<95%), explosion-proof rating (Ex d IIB T4) | |
|
Structural Parameters |
Connection Method | Threaded (NPT/BSPT), flanged (DN15~DN100), welded |
| Nominal Diameter | DN10~DN200 (corresponding to 1/4"~8") affects flow capacity | |
| Valve Body Material | Cast iron/cast steel/stainless steel/brass, adapted to medium and pressure | |
| Seal Material | NBR/EPDM/Viton/PTFE, adapted to temperature and medium | |
|
Control Characteristics |
Actuation Method | Direct-acting (small-bore/vacuum), pilot-operated (large-bore/high-pressure) |
| Control Method | Normally Open (NO)/Normally Closed (NC)/3/5-way (center-exhaust/center-pressure/center-blocked) | |
| Response Time | 5~500ms affects control accuracy | |
| Protection Class | IP65 (industrial standard)/IP67 (outdoor)/IP68 (submersible) | |
|
Additional Functions |
Explosion-Proof Rating | Ex d IIB T4/Ex ia IIC T6 for hazardous areas |
| Manual Device | Emergency manual operation | |
| Feedback Device | Limit switches/proximity switches provide position signals | |
| Flow Characteristics | Quick-opening/linear/equal percentage adapted to regulation needs |
Main Functions of Solenoid Valves
Fluid On-Off Control: Through energization/de-energization of the electromagnetic coil, spool displacement is achieved to control the connection or disconnection of fluids. As the most basic actuating component in automation systems, it is widely used for on-off control in piping systems.
Flow Regulation Control: Proportional solenoid valves can realize proportional spool displacement by controlling coil current, thereby adjusting fluid flow to meet the system's demand for precise flow control, such as speed regulation in hydraulic systems.
Direction Control: In hydraulic/pneumatic systems, switching spool positions changes fluid flow direction to achieve forward and reverse movement of actuators (cylinders/hydraulic cylinders). For example, 3/5-way valves can control cylinder extension, retraction and stopping.
Pressure Control Assistance: Used with pilot pressure reducing valves, relief valves, etc., as pilot control components to achieve remote or sequential control of system pressure, such as electromagnetic control of pilot-operated relief valves.
Safety Protection: Under emergency conditions (e.g., system power failure, overpressure), the normally closed/normally open characteristics of solenoid valves automatically cut off dangerous fluid paths to protect equipment and personnel safety, such as emergency shut-off valves during gas leaks.
Automated Interlocking : Receives signals from control systems such as PLC and DCS to achieve interlocking with other equipment, such as automatically switching fluid paths according to sensor signals in production lines to improve production efficiency.
