Pneumatic Cryogenic Control Valve
1. Product Introduction
This pneumatic cryogenic control valve features an S-shaped streamlined flow channel, delivering low pressure drop loss, large flow capacity, precise flow characteristics and convenient maintenance. It is a modified version of the single-seat control valve. Different from normal-temperature control valves, it adopts an extended bonnet to ensure the packing operates at normal temperature, making it suitable for ultra-low temperature media such as liquid oxygen and liquid nitrogen at -60℃ ~ -196℃. To guarantee accurate regulation performance, the valve must be equipped with an electric valve positioner. It is widely applied in petroleum, chemical, pharmaceutical, air separation and other industries.
The valve consists of a multi-spring pneumatic actuator, single-seat valve body and extended stem. All valve bodies, accessories and extended stems undergo special cryogenic treatment. A 4~20mA signal transmitted from the valve positioner is delivered to the air chamber of the pneumatic diaphragm actuator to generate thrust, which drives the valve plug via the connecting rod to adjust the plug position and flow cross-sectional area, so as to realize precise regulation of medium flow rate.
A 4~20mA signal from the valve positioner is transmitted to the air chamber of the pneumatic diaphragm actuator to generate thrust. The connecting rod drives the valve plug to adjust its position and flow area, so as to control and regulate the medium flow rate.
2. Main Specification & Technical Parameters
Parameter Item | Specification |
Nominal Diameter | DN15~DN200 |
Nominal Pressure | PN1.0~PN2.5, Class150 |
Operating Temperature Range | -196℃ ~ 200℃ |
Connection Type | Flanged, Welded |
Valve Body Material | CF8, CF8M, CF3M, LF4, LF2 |
Trim Material | 304, 304+STL, 316, 316+STL, 316L, 316L+STL |
Bonnet Type | Extended type, Bellows seal type |
Flow Characteristic | Equal percentage, Linear |
Leakage Class | Hard seal: Class IV, Class V; Soft seal: Class VI (Standard: ANSI B16.104) |
Diaphragm Actuator Model | PZM200, PZM280, PZM400, PZM600, PZM1000, PZM1600 |
Spring Range & Air Supply Pressure | 40~200KPa (Air supply: 0.25MPa); 80~240KPa (Air supply: 0.3MPa) |
Input Signal | 4-20mA.DC |
3. Actuator Technical Parameters
Item | Specification | ||||
Actuator Type | ZHA/B Multi-spring Diaphragm Actuator | ||||
Actuator Model | ZHA/B-22 | ZHA/B-23 | ZHAB-34 | ZHA/B-45 | ZHA/B-56 |
Effective Area (cm²) | 350 | 350 | 560 | 900 | 1400 |
Stroke (mm) | 10, 16 | 25 | 40 | 40, 60 | 100 |
Spring Range (kPa) | Standard: 20～100; Optional: 20-60, 60-100, 40-200, 80-240 | ||||
Diaphragm Material | Nylon fabric reinforced NBR, Nylon fabric reinforced EPDM | ||||
Air Supply Pressure | 140～400 kPa | ||||
Air Port | RC1/4" | ||||
Ambient Temperature | -30℃ ~ +70℃ | ||||
Optional Accessories | Valve positioner, air filter regulator, lock-up valve, limit switch, valve position transmitter, handwheel mechanism, etc. | ||||
Action Mode | Air to Close (B): Fail Open (FO) Air to Open (K): Fail Close (FC) |
4. Main Performance Indicators
Item | Without Positioner | With Positioner |
Basic Error (%) | ±10.0 | ±1.0 |
Hysteresis (%) | ≤6.0 | ≤1.0 |
Dead Zone (%) | ≤6.0 | ≤0.4 |
Onset & Terminal Deviation (%) | ||
Air-to-open: Onset Deviation | ±5.0 | ±1.0 |
Air-to-open: Terminal Deviation | ±10.0 | ±1.0 |
Air-to-close: Onset Deviation | ±10.0 | ±1.0 |
Air-to-close: Terminal Deviation | ±5.0 | ±1.0 |
Rated Stroke Deviation (%) | ≤±2.5 | |
Leakage Rate (L/h) | 0.01% of valve rated capacity | |
Rangeability (R) | 30:1 |
5. Main Connection Dimensions (Unit: mm)
DN | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 |
L (PN16/25) | 181 | 184 | 200 | 222 | 254 | 276 | 298 | 352 | 410 | 451 | 600 |
L (PN40) | 194 | 197 | 200 | 235 | 267 | 292 | 317 | 368 | 425 | 473 | 610 |
L (PN64) | 206 | 200 | 210 | 251 | 286 | 311 | 337 | 394 | 440 | 508 | 650 |
H (PN16/25) | 52.5 | 57.5 | 75 | 75 | 85.5 | 92.5 | 100 | 110 | 142.5 | 158 | 170 |
H (PN40) | 52.5 | 57.5 | 75 | 75 | 82.5 | 92.5 | 100 | 117.5 | 150 | 167.5 | 187.5 |
H (PN64) | 65 | 40 | 85 | 85 | 90 | 102.5 | 107.5 | 125 | 172.5 | 195 | 207.5 |
H1 | Custom extended stem size based on actual on-site low temperature | ||||||||||
H2 | 298 | 298 | 298 | 298 | 298 | 380 | 380 | 380 | 510 | 510 | 510 |
H3 | 180 | 180 | 180 | 180 | 180 | 236 | 236 | 236 | 310 | 310 | 310 |
L1 | 289 | 289 | 289 | 289 | 289 | 347 | 347 | 347 | 476 | 476 | 476 |
A | 282 | 282 | 282 | 282 | 282 | 360 | 360 | 360 | 470 | 470 | 470 |
D | 220 | 220 | 220 | 220 | 220 | 270 | 270 | 270 | 320 | 320 | 320 |
