1. Operating Principle

• Double acting actuators use compressed air for both opening and closing movements
• Air pressure alternates on opposite sides of a piston/diaphragm to rotate the valve
• Single acting actuators use air pressure for one direction and spring return for the other
• Spring mechanism automatically returns to default position when air is released

2. Structural Differences

• Single acting models include a spring chamber, increasing bulk
• Double acting designs are more compact without springs
• Single acting actuators typically heavier due to spring components
• Torque-to-size ratio favors double acting for space-constrained applications

3. Performance Traits

• Double acting provides faster cycle times and consistent bidirectional torque
• Ideal for high-frequency operations
• Single acting has slower return strokes (spring-dependent)
• Torque imbalance: stronger in air-driven direction, weaker in spring return

4. Application Suitability

• Double acting best for non-critical systems with reliable air supply
• Single acting preferred for safety-critical environments
• Spring return provides fail-safe closure during air loss
• Double acting offers better precision for process control applications

5. Maintenance Needs

• Single acting requires spring inspection for fatigue prevention
• Double acting has fewer moving parts
• Both types need seal maintenance and air supply checks
• Spring replacement is common maintenance for single acting models