How to Install and Calibrate Pneumatic Actuator?

The installation and calibration of pneumatic actuators and valves are essential for ensuring the reliability and precision of automated control systems. Proper procedures enhance system efficiency, extend equipment lifespan, and reduce the likelihood of malfunctions. This guide provides a detailed approach to the installation and calibration process, ensuring that pneumatic actuators and valves are connected and adjusted accurately for optimal performance.

Pre-Installation Inspection and Preparation

Before installation, perform these essential checks and preparations to ensure the system is ready for calibration:

Cylinder Model and Status Check: Verify that the cylinder model matches the design requirements. Check the cylinder's position to confirm whether it is open or closed. For larger valves, installation may require an open position; otherwise, ensure the cylinder is in a closed position for proper initial operation.

Rotation Direction Confirmation: Confirm the rotation direction of the cylinder. Typically, counterclockwise rotation opens the valve, while clockwise rotation closes it. The direction must align with the valve's control requirements to ensure proper valve operation.

Alignment of Cylinder and Valve Connection Holes: Check the alignment of the cylinder and valve connection holes. Ensure the center distance between the cylinder's connection holes matches the valve flange holes, providing a stable connection.

Connecting the Cylinder and Valve

A precise connection between the cylinder and valve is critical for performance.

Shaft Alignment: Ensure the cylinder shaft is aligned with the valve shaft. If misalignment occurs, use a square sleeve for adjustment. Both the cylinder and valve should be in the same position (either both open or closed) to avoid incorrect rotation directions.

Valve Type and Actuator Angle Requirements:

For butterfly valves, install the actuator at a 90-degree angle to the valve.

For ball valves, install the actuator parallel to the valve.

Installation and Calibration of Solenoid Valves

Solenoid valves, as vital components of pneumatic actuators, need proper installation and calibration for accurate system performance.

Solenoid Valve O-Ring Inspection: Inspect the O-ring for damage before installation, as a damaged O-ring can cause gas leakage and malfunction the actuator.

Solenoid Valve Installation and Calibration: After installation, conduct an air test to ensure the valve closes fully. If it doesn't, rotate the solenoid valve 180 degrees and reinstall it. It should close completely to function properly.

Installation and Calibration of Positioners

Positioners are key components in pneumatic actuators, providing feedback on the valve's position.

Positioner Connection: Remove the indicator cover on the cylinder. Insert the positioner's shaft into the cylinder's central shaft groove and secure it with bolts. Open the positioner cover and confirm that the travel stops align with the valve's open/close positions.

When the valve is open, the yellow stop should engage the switch.

When the valve is closed, the red stop should engage the switch.

Indicator Alignment: Verify that the indicator on the positioner cover matches the valve's open/close position for precise feedback and system control.

Adjustment of Limit Screws

Limit screws control the valve's open/close positions. Adjust these to calibrate the actuator's movement:

Limit Screw Calibration: Supply air from one end of the actuator and verify the valve's fully open or closed position. If the valve does not reach the desired position, slightly loosen the limit screw and adjust it. Typically, the left side controls the open limit, and the right side controls the close limit. Adjust by turning the screw counterclockwise (increasing travel) or clockwise (decreasing travel).

Safety and Protective Measures

Ensure safety and protect equipment during installation, especially when working with electrical components and high-temperature equipment.

Sealing and Explosion-Proof Measures: Maintain the integrity of seals, explosion-proof covers, and surfaces during installation. Apply anti-rust oil to prevent moisture from affecting electrical equipment.

Protective Surface Treatment: Ensure explosion-proof surfaces are dry, free from rainwater, and that electrical covers remain tightly closed to avoid environmental damage.

Calibration and Operation of Pneumatic Actuators

After installation, calibration is essential to verify proper operation.

Open/Close Calibration Test: Initiate the air supply and test the valve's opening and closing functions. Check for smooth operation without jamming. Adjust the actuator's travel to fine-tune the fully open and fully closed positions. Troubleshoot and resolve any issues that arise.

Air Supply Requirements: Ensure that the air supply remains dry and clean. Impurities in the air can affect the actuator's performance by damaging internal components.

Regular Maintenance: Perform operational checks on the actuator at least once a month for up to 10 minutes to maintain reliable performance over time.

Connection and Fit Precision Requirements

Accurate fitting between the actuator and valve is critical for efficient operation.

Fit Tolerance and Precision: The fit tolerance should meet standard requirements to ensure correct actuator working angles and prevent valve leakage due to poor fit. The connection between the shaft head and the shaft hole should meet the H11/d11 standard, with parallelism and symmetry adhering to 9th-grade geometric tolerances.

Ball Valve and Actuator Installation: The actuator and ball valve connection is usually achieved through a bracket and connecting sleeve. In some cases, a custom valve stem can be inserted directly into the actuator’s shaft hole. Ensure the shaft head does not exceed the actuator's shaft hole depth, as it could cause malfunctions.

Conclusion

By following these steps for proper installation and calibration, you can ensure that the pneumatic actuators and valves function effectively, improving system stability and reliability. Regular inspections, calibration, and maintenance are crucial to prevent potential issues and ensure long-term operational efficiency. Proper calibration, in particular, enhances equipment performance, reducing the risk of failure and operational downtime.