The pilot diaphragm solenoid valve is a pilot-operated + diaphragm combined 2/2-way valve, using small electromagnetic force to control the pilot valve, creating a pressure difference across the diaphragm, which drives the main valve switch. It is suitable for large bore, high flow, and medium-high pressure applications.
Core Structure (Two-Stage)
Pilot Head (Upper Chamber): Coil, moving/static iron core, spring, pilot valve core, pilot orifice (Φ0.5–1.2mm)
Main Valve Body (Lower Chamber): Diaphragm (EPDM/NBR/PTFE), main valve port, balance hole, inlet/outlet
Diaphragm: Separates upper and lower chambers; the upper chamber has a slightly larger pressurized area than the lower chamber, driven by pressure difference
Technical Parameters
Parameter
Value
Bore
DN15–DN200 (Thread/Flange)
Pressure
0.03–1.6MPa (Minimum pressure difference of 0.03MPa required for startup)
Temperature
-5°C~80°C (PTFE up to 200°C)
Medium
Water, gas, oil, weak corrosive liquids (no particulate impurities allowed)
Voltage
AC220V, DC24V (mainstream)
Power Consumption
DN15–50 approx. 17VA; DN65+ approx. 50VA
Key Features
Advantages
High flow, low power consumption: Small coil controls large valve, suitable for DN50 and above
Excellent sealing: Full diaphragm seal, no internal leakage
Debris-resistant: Diaphragm buffering, better impurity resistance than piston type
Fast response: ≤30ms (0.1MPa)
Notes
Requires minimum pressure difference: Cannot start at zero pressure/vacuum (except special dual-diaphragm types)
Pilot orifice prone to clogging: Media must be filtered (≥80 mesh)
Selection and Installation Guide
Select bore based on flow requirements; for DN50 and above, pilot diaphragm type is preferred
Confirm that the minimum working pressure difference is ≥0.03MPa; otherwise, select direct-acting or dual-diaphragm type
When the media contains impurities, a filter of at least 80 mesh must be installed before the valve
Install with the valve body arrow aligned with the fluid flow direction, coil vertically upward
For high-temperature applications (>80°C), select PTFE diaphragm material
Keep voltage fluctuations within ±10% to prevent coil burnout