Q1. What is a pneumatic actuator?
A pneumatic actuator is a mechanical device that converts compressed air energy into rotary or linear motion. The Kailing AT series is a 90° rotary rack-and-pinion actuator widely used to automate ball valves, butterfly valves and dampers in industrial fluid control systems.
By switching air supply to the actuator ports, it rotates the valve stem open or closed, enabling remote or automated valve control without manual operation.
Q2. What is the difference between single-acting and double-acting pneumatic actuators?
A double-acting actuator uses air pressure in both directions to open and close the valve, giving higher torque output. A single-acting (spring return) actuator uses air to move in one direction and a set of springs to return it to the fail-safe position when air is removed.
• Double-acting: higher torque, no spring, compact, used where air supply is reliable and fail-safe is not required.
• Single-acting: lower torque, built-in spring return provides fail-safe (open or closed), ideal for safety-critical applications such as emergency shutdown.
For the Kailing AT series, double-acting models run at 3–8 bar; single-acting models require 5–8 bar due to spring resistance.
Q3. How does a rack and pinion pneumatic actuator work?
Inside the actuator, two opposite pistons move linearly when compressed air enters the chamber. Rack teeth on the pistons engage a central pinion gear, converting linear piston motion into 90° rotary output that drives the valve shaft. When air is vented, the return springs (single-acting) push the pistons back to the fail-safe position.
The rack-and-pinion design delivers high torque output with a compact footprint, which is why it is the most common type for quarter-turn valves.
Q4. How to select the right pneumatic actuator size?
Select the actuator by matching its torque output to the valve requirement. As a rule of thumb, choose an actuator whose output torque at your working pressure is about 1.25–1.5 times the valve torque needed (including safety margin).
• Step 1: confirm valve torque (break torque) at your operating conditions.
• Step 2: decide single-acting or double-acting based on fail-safe needs.
• Step 3: pick the AT size whose torque at your air pressure exceeds the required torque with margin.
The Kailing AT series covers torque from about 3.6 N·m (AT-32) up to about 4500 N·m (AT-300), so we can help you match the right size for your valve.
Q5. What are the working pressure and temperature ranges of the AT series?
The Kailing AT series operates at a maximum working pressure of 10 bar. Double-acting models work at 3–8 bar, and single-acting models at 5–8 bar.
Standard temperature range is −20 °C to 80 °C. For special environments, low-temperature (−35 °C to 80 °C) and high-temperature (−20 °C to 150 °C) options are available.
Q6. What is the rotation angle of the AT series actuator?
The Kailing AT series provides 90° rotation (±5%), which is the standard quarter-turn travel for ball valves and butterfly valves. The mechanical travel stops allow fine adjustment to ensure the valve seals fully open and fully closed.
Q7. What mounting standards does the AT series comply with?
The Kailing AT series is built to international standards for easy integration: the top flange follows VDI/VDE 3845 NAMUR for direct mounting of solenoid valves and limit switch boxes, and the bottom flange follows ISO 5211 and DIN 3337 for mounting onto valves.
This standardized interface means the actuator fits most quarter-turn valves and standard accessories from any brand.
Q8. How to mount a pneumatic actuator to a ball valve or butterfly valve?
Mounting is straightforward thanks to the ISO 5211 bottom flange. Align the actuator output drive with the valve stem, bolt the actuator to the valve mounting pad, then connect the air supply lines. A solenoid valve can be mounted directly on the NAMUR top interface to control the actuator.
We can supply the actuator as a complete valve package (actuator + ball/butterfly valve + accessories) pre-tested to save you installation time.
Q9. What accessories does a pneumatic actuator need?
Common accessories to complete an automated valve include:
• Solenoid valve: for electrical on/off control of the actuator.
• Limit switch box: for remote position feedback (open/closed signals).
• Positioner: for proportional control / precise flow regulation.
• Filter regulator (FRL): to ensure clean, regulated air supply.
All these are available as standard matching accessories from Kailing.
Q10. What are the common applications of pneumatic actuators?
Pneumatic actuators are used wherever quarter-turn valves need remote or automated control. Typical applications include water and wastewater treatment, chemical and pharmaceutical processing, food and beverage production, oil and gas pipelines, HVAC, and general industrial automation.
The Kailing AT series is suitable for both on/off and modulating service on ball valves, butterfly valves and dampers.
Q11. How to maintain a pneumatic actuator and what is its lifespan?
Pneumatic actuators are low-maintenance. Recommended practices: use dry, filtered and lubricated air (via an FRL); inspect seals and O-rings periodically; check air leakage and torque output; and keep the actuator free of debris and moisture.
With proper air preparation and regular inspection, a rack-and-pinion actuator can typically last many years in normal service before seal replacement is needed.
Q12. What is the air consumption of a pneumatic actuator?
Air consumption depends on the actuator bore size, stroke volume and the number of cycles. Larger actuators consume more air per cycle, and faster cycle rates increase total consumption.
When sizing an air compressor for a system, sum the air consumption per cycle of all actuators and multiply by the expected cycles per minute to estimate total demand.
Q13. What certifications does the Kailing AT series have?
Kailing Pneumatic holds ISO 9001:2008 quality management certification and CE certification, and offers explosion-proof options (Exia II BT6, Exdm II BT6) for hazardous environments. Our factory in Ningbo, China, provides consistent quality with full inspection and testing before shipment.
Q14. What are the MOQ, warranty and lead time?
We offer flexible order quantities for distributors and end users, and we welcome small trial orders to test product quality. Standard warranty applies to manufacturing defects. Lead time depends on order size and configuration, but standard items ship promptly. Contact our team for MOQ, warranty terms and current lead times.
Q15. Do you offer OEM / ODM customization?
Yes. Kailing supports OEM and ODM customization, including private labeling, custom paint/finish, special shaft configurations, and custom torque or temperature options. We provide complete technical support from sample stage through mass production.
