1. Product Overview

A pneumatic control valve is assembled, installed and commissioned with a pneumatic actuator and valve body. Pneumatic actuators fall into two types: single-acting and double-acting. The single-acting actuator is equipped with built-in return spring, while no spring is arranged inside double-acting type. In case of air supply loss or sudden fault, the single-acting actuator can automatically reset the valve to preset fully open or fully closed position.

Based on operation mode, control valves are divided into air-to-open and air-to-close types (normally open & normally closed). Air-to-open or air-to-close function is realized by matching different actuator action directions and internal valve assembly structures.

2. Structural Composition

The valve mainly consists of three parts: pneumatic actuator, valve body and auxiliary accessories. Driven by clean compressed air, the actuator receives 420mA electric signal or 20100KPa pneumatic signal to drive plug movement, changing flow area between plug and seat so as to adjust pipeline flow. A valve positioner is commonly matched to optimize linearity, eliminate stem friction and disturbance caused by medium temperature & pressure fluctuation, enabling accurate valve positioning corresponding to input control signal.

• Actuator components: diaphragm/piston, spring, handwheel, actuator stem, coupling etc.

• Valve body components: cage, plug, seat, valve stem, cage retainer ring etc.

• Standard accessories: solenoid valve, pressure reducing valve, air filter, I/P converter, positioner, flow booster.

For critical process safety, key valves are fitted with solenoid valve, lock-up valve and quick exhaust valve to realize emergency fast open/close or locking protection under air cut-off, power failure or signal loss (three-loss protection). Three-loss protection covers loss of air supply, loss of power supply and loss of control signal.

3. Main Technical Parameters

3.1 Basic Size & Flow Coefficient

Nominal Pressure: 1.6, 2.5, 4.0, 6.4, 10.0MPa Rated Stroke(mm): 16,25,40,60,100 Matching Actuator Model: ZHA/B-22, ZHA/B-23, ZHA/B-34, ZHA/B-45, ZHA/B-56

Bonnet Type: Standard(-17℃+250℃), High Temp(+250+450℃), Cryogenic(-40-196℃), Bellows Seal(-40+350℃) Gland Style: Bolted compression type Packing: V-type PTFE packing, V-type flexible graphite packing Plug Type: Single port plunger plug Flow Characteristic: Linear, Equal Percentage

3.2 ZHA/B Multi-spring Diaphragm Actuator Parameter

Spring Range(KPa): Standard 20~100; Optional:20-60,60-100,40-200,80-240 Diaphragm Material: NBR with nylon fabric, EPDM with nylon fabric Air Supply Pressure:140~400KPa Air Connection: RC1/4" Ambient Temp:-30℃~+70℃ Optional Accessories: Positioner, Air filter regulator, Lock-up valve, Limit switch, Valve position transmitter, Handwheel assembly Action Type: Air to Close(B)-Fail Open(FO); Air to Open(K)-Fail Close(FC)

3.3 Performance Index

Rated Stroke Deviation: ≤2.5% Leakage Rate:0.01% of rated valve capacity Rangeability R:30:1

4. Main Component Material List