The pneumatic micro‑flow control valve consists of a pneumatic diaphragm actuator and a micro‑flow control valve body. The multi‑spring actuator features low height, light weight and simple installation. Its plug adopts plunger‑type structure. Compared with ordinary single‑seat valves, it delivers stable performance and high regulating accuracy. When handling unclean media, attention shall be paid to prevent blocking and jamming caused by small throttling gaps.
Structural Features
The pneumatic micro‑flow control valve has compact size, light weight and high performance, designed for precise control of tiny flow rate.
Component Parameters
| Component | Material |
| Valve Body | WCB | 304 | 316 | 316L |
| Gasket | PTFE / Graphite | PTFE / Graphite | PTFE / Graphite | PTFE / Graphite |
| Valve Seat | 304 | 304 | 316 | 316L |
| Plug | 304 | 304 | 316 | 316L |
| Valve Bonnet | WCB | 304 | 316 | 316L |
| Valve Stem | 304 | 304 | 316 | 316L |
| Packing | PTFE / Graphite | PTFE / Graphite | PTFE / Graphite | PTFE / Graphite |
| Packing Gland | WCB | 304 | 316 | 316L |
Technical Parameters of Pneumatic Micro‑Flow Control Valve
| Nominal Diameter(DN) | G3/8", 1/2", G3/4", G1" |
| Seat Diameter(dn) | 1.5 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 15 |
| Rated Flow Coefficient KV | 0.025 | 0.05 | 0.08 | 0.12 | 0.20 | 0.32 | 0.50 | 0.80 | 1.00 | 1.40 | 1.55 | 1.85 | 2.23 |
| Allowable Pressure Differential(MPa) | ≤ Nominal Pressure |
| Nominal Pressure(MPa) | 1.6, 2.5, 4.0, 6.4, 10.0, 16.0, 25.0, 32.0 |
| Flow Characteristic | Equal Percentage, Linear |
| Matching Actuator Model | ZHA/B‑11 |
| Rated Stroke(mm) | 8, 10, 12 |
| Bonnet Type | Standard(-17～+250℃), High Temperature(+250～+450℃), Low Temperature(-40～-196℃), Bellows Seal(-40～+350℃) |
| Gland Type | Bolt Tightening Type |
| Sealing Packing | V‑shaped PTFE Packing, V‑shaped Flexible Graphite Packing |
| Plug Type | Single‑seat Type |
Pneumatic Diaphragm Actuator Parameters
| Actuator Type | ZHA/B Multi‑Spring Diaphragm Actuator |
| Actuator Model | ZHA/B‑22 | ZHA/B‑23 | ZHA/B‑34 | ZHA/B‑45 | ZHA/B‑56 |
| Effective Area(cm²) | 350 | 350 | 560 | 900 | 1400 |
| Stroke(mm) | 10, 16 | 24 | 40 | 40, 60 | 100 |
| Spring Range(KPa) | 20～100(Standard), 20‑60, 60‑100, 40‑200, 80‑240 |
| Diaphragm Material | Nitrile Rubber with Nylon Fabric, EPDM with Nylon Fabric |
| Supply Air Pressure | 140～400KPa |
| Air Supply Connection | RC1/4" |
| Ambient Temperature | -30～+70℃ |
| Optional Accessories | Positioner, Air Filter Regulator, Lock‑up Valve, Limit Switch, Valve Position Transmitter, Handwheel Mechanism, etc. |
| Action Form | Air‑to‑Close(B)‑Fail Open(FO); Air‑to‑Open(K)‑Fail Close(FC) |
Performance Parameters
| Item | Without Positioner | With Positioner |
| Basic Error % | ±5.0 | ±1.0 |
| Hysteresis % | 3.0 | 1.0 |
| Dead Band % | 3.0 | 0.4 |
| Start‑end Deviation % | Air‑to‑Open |
| ±2.5 | ±1.0 |
| Air‑to‑Close |
| ±5.0 | ±1.0 |
| Rated Stroke Deviation % | ≤2.5 |
| Leakage L/h | 0.01% × Valve Rated Capacity |
| Rangeability R | 30:1 |
Application Scenarios
The pneumatic diaphragm micro‑flow control valve is suitable for working conditions with strict leakage requirements. It is widely used in automatic industrial process control systems requiring low noise, small pressure differential and high‑precision regulation.
