Detailed Installation Guide for Pneumatic Butterfly Control Valves

In industrial piping systems, pneumatic butterfly control valves are commonly used for flow regulation due to their flexible opening and closing characteristics and wide range of flow adjustment. These valves are widely applied for controlling the flow of various liquids and gases. Proper installation is crucial to ensure the stable and efficient operation of the pneumatic butterfly control valve. Below is a detailed guide on the installation process, commissioning steps, and precautions to help ensure optimal performance of the valve after installation.

Preparations Before Installation

 
Thorough preparations are key to ensuring the smooth operation of a pneumatic butterfly control valve. Careful inspection and testing before installation can help avoid potential issues and ensure a trouble-free process. The following steps outline the essential tasks to complete before installing the valve.

1. Visual Inspection

 
Before installing the pneumatic butterfly control valve, a detailed visual inspection should be performed. Check for any mechanical damage or manufacturing defects on the valve body. For valves operating under pressures greater than 1.0 MPa or used as shutoff valves in main pipelines, strength and tightness tests must be conducted prior to installation.
Strength Test: The test pressure should be 1.5 times the nominal pressure, and the test should last no less than 5 minutes. Ensure no leakage from the valve body or packing during the test.
Tightness Test: Ensure there is no leakage when the valve is fully closed before proceeding with the installation.

2. Component Inspection

 
Ensure all parts are present and intact. Special attention should be given to the valve body, cylinder, solenoid valve, and muffler, ensuring there are no obstructions. Also, verify that the pneumatic actuator matches the valve model and that both the valve and cylinder are in a closed position.

Installation Steps

 
Once the preparations are complete, the pneumatic butterfly control valve must be installed in accordance with specific procedures to ensure efficient operation. Below are the detailed installation steps.

1. Valve and Cylinder Assembly

 
Attach the cylinder to the butterfly control valve. During installation, ensure the cylinder is aligned parallel or perpendicular to the valve body. Check that the bolt holes are aligned properly; if there is a slight misalignment, rotate the cylinder body slightly for adjustment before tightening the screws. Ensure the cylinder and valve are securely assembled to prevent any loosening or misalignment during operation.

2. Flange Connection

 
Flange connection is a crucial part of the installation process. Verify that the flange specifications match the butterfly control valve's flange standard. It is recommended to use dedicated butterfly valve flanges instead of flat-welded flanges. Pay attention to the following points:
Flange Welding: Ensure proper alignment after welding the flanges. Do not weld flanges after the valve is installed, as high temperatures can damage the valve seals.
Flange Bolt Installation: Tighten all bolts symmetrically and evenly, preferably in a diagonal sequence. Washers are not required. Avoid over-tightening the bolts to prevent valve seat deformation or increased operating torque.

Commissioning and Operation Testing

 
After installation, commissioning and operational testing are crucial to ensure the valve functions correctly. Proper adjustments and tests will confirm smooth valve operation and system stability.

1. Commissioning Steps

 
Once installed, the pneumatic butterfly control valve requires commissioning. Supply air pressure should be maintained between 0.4 to 0.7 MPa to ensure normal operation of the pneumatic actuator. During commissioning, manually operate the solenoid valve's open/close function (with the solenoid valve coil de-energized) and observe whether the valve opens and closes smoothly.

2. Stroke and Operating Torque Adjustment

 
If the valve operates sluggishly at the start of commissioning but stabilizes during operation, adjust the cylinder stroke. Adjust the stroke adjustment screws at both ends of the cylinder slightly inward until the valve operates smoothly, with no leakage.

Installation Precautions

 
Several key factors must be considered during the installation of the pneumatic butterfly control valve to ensure optimal performance and longevity.

1. Valve Installation Position and Direction

 
Follow the manufacturer's installation guide to ensure the valve's position, height, and inlet/outlet direction meet design specifications. Pay particular attention to the flow direction of the medium, ensuring it matches the arrow marked on the valve body. The connection should be secure and reliable.

2. Disc Opening and Closing Position

 
The valve disc should remain in the closed position during installation to prevent accidental damage. When opening the valve, ensure the disc reaches the fully open position according to the specified rotation angle. If the valve is equipped with a bypass valve, open the bypass before opening the main valve to ensure smooth medium flow.

3. Valve and Actuator Compatibility

 
The valve's operating torque should match the selected actuator. When operating the valve manually, the opening and closing resistance should be moderate to ensure smooth and flexible operation.

Installation Environment and Storage Requirements

 
The pneumatic butterfly control valve should be stored in a dry environment and not exposed to the elements to prevent corrosion or performance degradation. Before installation, check the piping for debris such as welding slag to ensure the pipeline is clean, preventing obstruction during valve operation.

Post-Installation Maintenance and Inspection

 
After installation, regular inspections and maintenance should be conducted, especially on key components such as the pneumatic actuator, solenoid valve, and muffler. For butterfly control valves that operate frequently, inspect the number of opening and closing cycles regularly and adjust the cylinder stroke or related components as needed to prevent wear and malfunctions from prolonged use.

Conclusion

 
The installation of a pneumatic butterfly control valve requires meticulous attention to detail and adherence to best practices. Following the outlined steps and precautions will ensure the valve operates effectively and has an extended service life. Proper installation, commissioning, and maintenance are essential for maximizing the performance and reliability of the pneumatic butterfly control valve in industrial systems, enhancing the safety and reliability of pipeline operations.