Low flow control valves
Low flow control valves are a type of top-guided single-seated control valve, characterized by their simple structure, good sealing performance, and reliable operation.
The effective and sufficient top guide system overcomes vibrations at small openings, resulting in a longer effective service life. The smaller flow coefficient expands the valve’s range of applications.
The actuator can be selected from various options, including multi-spring pneumatic diaphragm mechanisms or electric actuators.
Performance
- Flow characteristics: Linear, Equal percentage, Quick opening
- Adjustable range: 50:1 (when CV <6.3, 30:1)
- Rated CV value: Equal percentage CV 1.6~630, Linear CV 1.8~690
- Allowable leakage rate: Hard seal: Class IV (0.01% of valve rated capacity) Soft seal: Class VI (Bubble tight)
- Leakage standard: GB/T 4213
Actuator Selection
| Pneumatic Diaphragm Actuator | Fully Electronic Electric Actuator
|
| Multi-spring Type | Integrated Smart Type with Internal Control Box
|
Application | Regulation, On/Off | Regulation |
Air Supply Pressure/Voltage | Supply Pressure (Spring Range)） 140(20-100) Kpa G 240(400-200) Kpa G 280(80-240) Kpa G
| Power Supply AC 200 V±10% 50Hz or Power Supply AC 380 V±10% 50Hz |
Connection | Air pipe connection RC1/4 | Standard: Cable entry 2-PE (G1/2″) Explosion-proof: Protective sleeve PE (3/4″) can be installed
|
Direct Action | Increasing air pressure moves stem downward, valve closes | Increasing input signal moves stem downward, valve closes |
Reverse Action | Increasing air pressure moves stem upward, valve opens | Increasing input signal moves stem upward, valve opens |
Hysteresis | ≤1%FS (with positioner) | ≤0.8%FS |
Linearity | 2%FS (with positioner) | ≤±1%FS |
Ambient Temperature | -10°C ~+70°C | Standard type: -10°C ~ +60°C With space heater: -35°C ~ +60°C Explosion-proof type: -10°C ~ +40°C |
Surface Coating | Green, acrylic polyurethane enamel | Blue, acrylic polyurethane enamel
|
Optional Accessories | Electric (pneumatic) valve positioner, filter regulator, valve transmitter, solenoid valve, limit switch | Space heater |
Standard Specifications
Valve body type | Straight-through cast globe valve body |
Valve plug type | Unbalanced single-seat piston plug |
Nominal diameter | DN15/20/25 NPS 1/2”-1” |
Nominal pressure | PN16~100, CLASS 150LB~600LB |
Connection type | Flange FF, RF, MF, RTJ; Welding SW, BW |
Face-to-face dimension | Complies with IEC 60534 |
Bonnet types | Standard type (-5°C~230°C); Extended bonnet with cooling fins (for temperatures above 230°C); Low-temperature extended type (-196°C~-45°C); Bellows sealed type, Jacketed type |
Packing | V-ring PTFE packing, flexible graphite packing, etc. |
Gasket | Metal-reinforced graphite gasket |
Actuator | Pneumatic multi-spring diaphragm actuator, piston actuator, electric smart actuator |
Surface coating | Green acrylic polyurethane paint |
Special Specifications
| Special inspections | Body material penetrant testing (PT), radiographic testing (RT), flow characteristic test, low-temperature test. |
| Special treatments | Nitriding treatment for internal parts, hard alloy coating for sealing parts |
| Special cleaning | Completely oil-free, dehydration treatment |
| Special specifications | Special piping or special air fittings, vacuum service conditions, stainless steel fasteners, special coatings |
| Special dimensions | Customized according to user’s structural length or external dimensions |
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