The Pneumatic Low Flow Control Valve is an ultra-small size pneumatic control valve specially designed for precise regulation of micro flow rates. Driven by compressed air and receiving standard 4–20 mA control signals from DCS/PLC systems, it provides highly accurate control of extremely small liquid, gas and steam flow rates.
Featuring a precision-engineered throttling trim with an ultra-fine flow passage, this valve delivers excellent low-opening stability, high resolution and accurate flow adjustment compared with conventional control valves. It eliminates valve hunting and unstable operation under small opening conditions, ensuring reliable performance in demanding micro-flow applications.
The Pneumatic Micro Flow Control Valve is widely used in fine chemical dosing systems, pharmaceutical ingredient metering, ammonia water injection for flue gas denitrification (SNCR/SCR systems), laboratory fluid control and other precision process applications where accurate low-flow regulation is critical.
Working Principle of Pneumatic Micro Flow Control Valve
The DCS control system sends a standard 4–20 mA current signal to the valve positioner according to the required process flow set point.
The valve positioner converts the electrical signal into corresponding pneumatic pressure, driving the diaphragm actuator to precisely move the valve stem up and down with a small stroke.
The precision micro-flow trim moves vertically, adjusting the extremely small throttling clearance between the valve plug and valve seat. Even a slight change in the flow passage gap can accurately regulate the flow rate of micro-volume fluids.
The valve positioner continuously performs real-time closed-loop stroke correction, eliminating positioning errors, improving control resolution and preventing instability or hunting during low-opening operation.
Control valves are used for precise regulation of pipeline flow, pressure, temperature and other process parameters. To ensure correct valve selection and optimal performance, please provide detailed technical data before placing an order. Non-standard sizes and customized designs can be manufactured according to customer requirements.(Unit: mm)

| DN | NPS | Type/Class | Part No | L | H | A | L1 | H1 | A1 | |
|---|---|---|---|---|---|---|---|---|---|---|
| 6 | 0.25 | WXLLBZ-150LB | XLXWXLL150X | 80 | 280 | 160 | 80 | 305 | 160 | |
| 15 | 0.5 | WXLLBZ-150LB | XLXWXLL150X | 100 | 285 | 160 | 100 | 310 | 160 | |
| 20 | 0.75 | WXLLBZ-150LB | XLXWXLL150X | 120 | 290 | 160 | 120 | 315 | 160 | |
| 25 | 1 | WXLLBZ-150LB | XLXWXLL150X | 140 | 295 | 160 | 140 | 320 | 160 | |
| 6 | 0.25 | WXLLBZ-300LB | XLXWXLL300X | 80 | 280 | 160 | 80 | 305 | 160 | |
| 15 | 0.5 | WXLLBZ-300LB | XLXWXLL300X | 100 | 285 | 160 | 100 | 310 | 160 | |
| 20 | 0.75 | WXLLBZ-300LB | XLXWXLL300X | 120 | 290 | 160 | 120 | 315 | 160 | |
| 25 | 1 | WXLLBZ-300LB | XLXWXLL300X | 140 | 295 | 160 | 140 | 320 | 160 | |
| 6 | 0.25 | WXLLBZ-600LB | XLXWXLL600X | 80 | 280 | 160 | 80 | 305 | 160 | |
| 15 | 0.5 | WXLLBZ-600LB | XLXWXLL600X | 100 | 285 | 160 | 100 | 310 | 160 | |
| 20 | 0.75 | WXLLBZ-600LB | XLXWXLL600X | 120 | 290 | 160 | 120 | 315 | 160 | |
| 25 | 1 | WXLLBZ-600LB | XLXWXLL600X | 140 | 295 | 160 | 140 | 320 | 160 | |
| 6 | 0.25 | WXLLBZ-900LB | XLXWXLL900X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 15 | 0.5 | WXLLBZ-900LB | XLXWXLL900X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 20 | 0.75 | WXLLBZ-900LB | XLXWXLL900X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 25 | 1 | WXLLBZ-900LB | XLXWXLL900X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 6 | 0.25 | WXLLBZ-1500LB | XLXWXLL1500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 15 | 0.5 | WXLLBZ-1500LB | XLXWXLL1500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 20 | 0.75 | WXLLBZ-1500LB | XLXWXLL1500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 25 | 1 | WXLLBZ-1500LB | XLXWXLL1500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 6 | 0.25 | WXLLBZ-2500LB | XLXWXLL2500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 15 | 0.5 | WXLLBZ-2500LB | XLXWXLL2500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 20 | 0.75 | WXLLBZ-2500LB | XLXWXLL2500X | TBD | TBD | TBD | TBD | TBD | TBD | |
| 25 | 1 | WXLLBZ-2500LB | XLXWXLL2500X | TBD | TBD | TBD | TBD | TBD | TBD |
Key Advantages of Pneumatic Micro Flow Control Valve
Ultra-Precise Micro Flow Regulation: Equipped with a fine needle-type / V-port valve plug, the valve provides smooth and accurate flow adjustment even at extremely small openings. It eliminates the problems commonly found in conventional valves, such as flow overshoot, unstable operation and valve hunting under low-opening conditions.
Compact and Space-Saving Design: Featuring a miniature valve body and compact overall dimensions, the pneumatic micro flow control valve is ideal for installation in control cabinets, laboratory test benches, compact equipment systems and space-limited piping layouts.
Excellent Sealing Performance: The single-seat soft sealing design ensures extremely low leakage after shutoff, effectively preventing leakage of valuable or sensitive micro-flow media and improving process reliability.
High Pressure Resistance: The integrally forged valve body structure provides excellent mechanical strength and pressure resistance, making it suitable for high-pressure micro dosing, injection and precision flow control applications.
Pneumatic Explosion-Proof Safety: Driven by compressed air without electrical power, the valve eliminates the risk of electrical sparks and is highly suitable for flammable and explosive chemical processing environments requiring safe automatic control.
Easy Maintenance and Service: The threaded connection design enables quick installation and disassembly. Key components such as the valve plug and packing assembly can be replaced individually, reducing maintenance time and operating costs.