The AT Aluminum Alloy Three-Position Pneumatic Actuator is a quarter-turn pneumatic actuator designed to provide three defined valve positions, typically 0°–45°–90° or 0°–90°–180°. Unlike conventional two-position pneumatic actuators, the three-position design allows the valve to stop accurately at an intermediate position, enabling more flexible process control.
Featuring a rack-and-pinion mechanism and lightweight aluminum alloy housing, the actuator delivers smooth rotary operation, fast response and reliable positioning. It is suitable for ball valves, butterfly valves, plug valves and other quarter-turn valves where an intermediate opening position is required, such as flow regulation, mixing, bypass control and process switching applications.
The AT three-position pneumatic actuator can be configured with solenoid valves, limit switches, positioners and air filter regulators, making it suitable for automated valve control in chemical processing, water treatment, petrochemical, HVAC, food and beverage and general industrial applications.
AT Aluminum Alloy Three-Position Pneumatic Actuator – Working Principle
Fully Closed Position (0°)：Compressed air enters the outer main air chambers, driving the dual pistons toward the center of the cylinder. The rack-and-pinion mechanism rotates the output shaft to 0°, bringing the valve to the fully closed position.
Intermediate Position (Adjustable Opening, e.g. 45°)：The main air supply drives the pistons toward the fully open position. At the same time, compressed air is supplied through the auxiliary air port, extending the auxiliary piston to create a mechanical travel stop. When the main pistons reach the preset stop position, their movement is blocked by the auxiliary piston. The output shaft then remains securely at the preset intermediate angle, such as 45°, maintaining a fixed valve opening for controlled throttling.
Fully Open Position (90°)：The auxiliary air port is depressurized, causing the auxiliary piston to retract and release the intermediate travel stop. The main pistons can then continue moving to the end of their stroke, rotating the output shaft to 90° and bringing the valve to the fully open position.
A pneumatic actuator converts the energy of compressed air into mechanical motion, enabling the valve to open, close, or continuously modulate its position for reliable and automated valve control. For pneumatic actuator selection and procurement, please contact our technical team and provide the relevant operating parameters so that we can recommend the most suitable actuator model for your application. （Unit: mm）
| Size | Part No | L | A | B | C | D | E | F | G | H | I | J | K | M | M1 | N | φO | Air | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 52 | XLXAT-052-3P | 375 | 150 | 73 | 67 | 93 | 30 | 42 | 14 | 80 | 30 | F05-50 | F03-36 | M6X11 | M5X10 | 11 | φ22 | G1/4 | |
| 63 | XLXAT-063-3P | 425 | 170 | 89 | 82 | 109 | 36 | 47 | 18 | 80 | 30 | F03-36 | F07-70 | M8X15 | M6X12 | 14 | φ27 | G1/4 | |
| 75 | XLXAT-075-3P | 465 | 186 | 101 | 95 | 121 | 43 | 54 | 18 | 80 | 30 | F03-36 | F07-70 | M8X15 | M6X12 | 14 | φ27 | G1/4 | |
| 83 | XLXAT-083-3P | 532 | 213 | 110 | 99 | 130 | 46 | 57 | 20 | 80 | 30 | F03-36 | F07-70 | M8X15 | M6X12 | 17 | φ27 | G1/4 | |
| 92 | XLXAT-092-3P | 665 | 266 | 118 | 112 | 138 | 51 | 59 | 21 | 80 | 30 | F03-36 | F07-70 | M8X15 | M6X12 | 17 | φ33 | G1/4 | |
| 105 | XLXAT-105-3P | 680 | 272 | 135 | 124 | 155 | 58 | 65 | 24 | 80 | 30 | F03-36 | F10-102 | M10X18 | M8X14 | 22 | φ33 | G1/4 | |
| 125 | XLXAT-125-3P | 762 | 305 | 157 | 146 | 187 | 68 | 75 | 27 | 130 | 30 | F03-36 | F10-102 | M10X18 | M8X14 | 22 | φ43 | G1/4 | |
| 140 | XLXAT-140-3P | 950 | 396 | 174 | 162 | 204 | 76 | 78 | 32 | 130 | 30 | F03-36 | F12-125 | M12X22 | M10X18 | 27 | φ50 | G1/4 | |
| 160 | XLXAT-160-3P | 1160 | 465 | 199 | 185 | 229 | 88 | 88 | 32 | 130 | 30 | F03-36 | F12-125 | M12X22 | M10X18 | 27 | φ50 | G1/4 | |
| 190 | XLXAT-190-3P | 1250 | 532 | 232 | 217 | 263 | 103 | 103 | 40 | 130 | 30 | F03-36 | F14-140 | M16X23 | / | 36 | φ60 | G1/4 | |
| 210 | XLXAT-210-3P | 1355 | 542 | 257 | 236 | 288 | 114 | 114 | 40 | 130 | 30 | F03-36 | F14-140 | M16X25 | / | 36 | φ72 | G1/4 | |
| 240 | XLXAT-240-3P | 1500 | 610 | 291 | 265 | 321 | 130 | 130 | 50 | 130 | 30 | F03-36 | F16-165 | M20X25 | / | 46 | φ80 | G3/8 | |
| 270 | XLXAT-270-3P | 1825 | 730 | 326 | 301 | 356 | 147 | 147 | 50 | 130 | 30 | F03-36 | F16-165 | M20X25 | / | 46 | φ80 | G1/2 | |
| 300 | XLXAT-300-3P | 2055 | 822 | 354 | 330 | 384 | 140 | 173 | 55 | 130 | 30 | F03-36 | F16-165 | M20X25 | / | 46 | φ80 | G1/2 | |
| 350 | XLXAT-350-3P | 2325 | 930 | 410 | 383 | 440 | 164 | 195 | 55 | 130 | 30 | F03-36 | F16-165 | M20X25 | / | 46 | φ80 | G1/2 | |
| 400 | XLXAT-400-3P | 2400 | 960 | 466 | 456 | 496 | 259 | 259 | 60 | 130 | 30 | F03-36 | F16-165 | M20X25 | / | 55 | φ80 | G1/2 |
AT Aluminum Alloy Three-Position Pneumatic Actuator – Key Advantages
Three-Position Mechanical Positioning for Segmented Flow Control：Unlike conventional two-position actuators that provide only fully open or fully closed operation, the AT three-position pneumatic actuator delivers three defined positions: 0° (fully closed), an adjustable intermediate position, and 90° (fully open). The intermediate stop angle can be adjusted externally, typically within 20°–75°, without disassembling the actuator. A mechanical stop securely locks the intermediate position, providing high repeatability and resistance to minor air-supply fluctuations. This makes the actuator ideal for batch dosing, flow diversion and bypass throttling applications.
Proven Rack-and-Pinion Design for Smooth and Reliable Operation：The AT series features a symmetrical dual-piston rack-and-pinion mechanism that provides balanced force distribution, stable output torque and smooth operation with minimal impact. The housing is manufactured from hard-anodized aluminum alloy, offering a lightweight, compact and corrosion-resistant construction while reducing installation space requirements.
Field-Adjustable Intermediate Position：The intermediate stop angle can be adjusted directly through the external adjustment screw, without dismantling the actuator housing. This allows the same actuator to be easily configured for different intermediate opening requirements, providing greater flexibility for changing process conditions and flow-control applications.
Standard Interfaces for Flexible Valve Integration：The actuator mounting dimensions comply with ISO 5211, while the pneumatic accessory interface follows the NAMUR standard, enabling convenient installation on ball valves, butterfly valves, plug valves and other quarter-turn valves. It can be equipped with solenoid valves, limit switches and air filter regulators to provide automated three-position control and reliable valve position feedback.
