How to correctly install and maintain butterfly valves
The correct installation and maintenance of butterfly valves must follow standardized processes, covering inspection preparation before installation, technical specifications of the installation process, and systematic maintenance after operation. The specific measures are as follows:
I. Preparation and inspection before installation
1. Specification verification and integrity inspection
Confirm that the butterfly valve specifications (pressure level, temperature range, corrosion resistance) match the pipeline design parameters, and check whether the valve body, valve stem, sealing surface and other components are damaged or loose.
Check the nominal diameter, pressure level and connection method of the pipeline to ensure that the inside of the pipeline is clean and free of debris.
2. Cleaning and pretreatment of the sealing surface
Use air spray to remove foreign objects from the pipeline and rinse the inner wall with clean water; thoroughly clean the sealing surface of the butterfly valve to remove dust, oil and metal debris.
Wafer-type butterfly valves require special flanges to avoid dislocation of the sealing rubber.
3. Confirmation of installation position and direction
Choose a location that is easy to operate and maintain, and leave enough space; avoid installing near vibration sources or high-temperature heat sources.
Confirm that the arrow mark on the valve body is consistent with the flow direction of the medium. The one-way sealing butterfly valve must be installed strictly in the direction of the arrow.
2. Technical specifications for the installation process
1. Flange connection and spot welding fixation
Place the butterfly valve between the pre-installed flanges, align the bolt holes, insert the bolts and nuts, and tighten them slightly to correct the flatness of the flange surface.
Spot weld the flange to prevent welding deformation; complete the flange welding after removing the butterfly valve, and reinstall it after the weld cools down.
2. Valve reset and tightening requirements
Ensure that the butterfly plate is in the closed state during installation to avoid collision with the pipeline flange; cross-tighten the bolts evenly after correcting the valve position to avoid local overload.
Open the valve to check the freedom of the valve plate, and cross-tighten the nuts again after slightly opening to ensure that there is no jamming and the valve plate does not contact the pipeline.
3. Special requirements for wafer-type butterfly valves
Ensure that the valve has enough space for movement in the flange to prevent welding stress from causing deformation of the valve body; use a torque wrench to tighten the bolts according to the specification value to avoid uneven force on the sealing surface.
3. Maintenance measures after operation
1. Daily inspection and cleaning
Regularly check the appearance of the valve body to confirm that there is no rust, paint loss, or deformation; remove surface dust, oil stains, and medium residues to prevent the accumulation of corrosive substances.
Check the tightness of the connecting bolts to prevent leakage; perform leakage detection on the stuffing box and flange gasket, and replace failed parts in time.
2. Maintenance of seals and transmission parts
Regularly check the wear, scratches, or corrosion of the sealing surface. Minor damage can be repaired by grinding, and serious damage requires replacement of the seal ring or valve seat.
Lubricate and maintain the transmission parts such as valve stems, bearings, and gears, and select lubricants suitable for the medium environment; check the straightness and surface finish of the valve stem, and repair or replace bent or worn parts.
3. Maintenance of actuators and electrical systems
Pneumatic actuators: Check the cleanliness and pressure stability of the air source, and regularly discharge the water accumulated in the air filter; check the wear of the piston, cylinder, spring and other parts, and replace leaking seals.
Electric actuator: Test the motor operation status, check the winding temperature, vibration and noise; check the travel limit and torque protection device to ensure that the valve moves within the safe range.
Electrical system: Check the cable connection firmness, check for short circuit and damage; clean the inside of the control box to prevent dust from causing electrical failure.
4. Troubleshooting and preventive maintenance
Seal leakage: Check the cleanliness of the sealing surface, installation accuracy and bolt clamping force, adjust the limit screw or replace the seal.
Abnormal movement: Check for valve stem jamming, valve core jamming or actuator failure, remove impurities and repair deformed parts.
Develop a maintenance plan: Determine the maintenance cycle according to the working conditions, record operating data and fault history, and optimize spare parts inventory and maintenance strategy.