How should daily inspections and maintenance be carried out on flue dampers?

Conducting routine inspections and maintenance on flue gate valves is crucial for ensuring their proper operation and extending their service life. The following outlines specific steps and recommendations:

I. Routine Inspections

Visual Inspection:

Regularly clean debris from the valve body surface and inspect for defects such as peeling, cracks, or sand holes.

Check that bolts at flange connections are securely tightened and that sealing gaskets remain intact.

Sealing Performance Inspection:

Periodically assess the gate valve's sealing integrity to confirm no leakage exists. Internal leakage may be detected by observing abnormal temperature increases on the valve stem or downstream metal surfaces of the valve body, indicating potential valve closure failure or damaged sealing surfaces.

Pay particular attention to inspecting gasket areas and sealing surfaces for leakage indications.

Valve Stem Inspection:

Examine the valve stem for bending, damage, or corrosion.

Verify the fit between the stem and components such as the stem nut, bracket, and gland, ensuring no binding occurs.

Inspect the packing within the gland box for integrity and check the packing gland for wear.

Actuator Inspection:

For electrically or pneumatically operated gate valves, verify the actuator functions correctly with no abnormal noise or vibration.

Verify secure connections to power or air sources and the integrity of control circuits.

II. Routine Maintenance

Lubrication:

Periodically lubricate components such as the valve stem and stem nut to minimise friction and wear.

Employ suitable lubricants, such as molybdenum disulphide or graphite powder. For high-temperature valves, pay particular attention to the lubricant's heat resistance.

Cleaning and Maintenance:

Regularly clean the valve body interior and sealing surfaces to remove accumulated dust and contaminants.

Utilise kerosene or specialised cleaning agents to clean components such as valve stems and stuffing boxes.

Fastener Inspection and Tightening:

Periodically inspect and tighten all fasteners, including bolts and nuts, to ensure secure and reliable connections.

Replace fasteners prone to loosening or wear promptly.

Seal Replacement:

Replace seals immediately if gaskets show signs of ageing, damage, or severe wear on sealing surfaces.

Ensure replacement seals are compatible with the valve material and operating conditions.

Stem Straightening and Replacement:

Straighten or replace the valve stem promptly if it is bent or severely damaged.

When correcting or replacing the valve stem, ensure precise fitment with components such as the stem nut and bracket.

Drive Mechanism Maintenance:

Regularly inspect and maintain the drive mechanism, including replacing worn gears, bearings, and other components.

For electric or pneumatic actuators, periodically check the operational status of motors or cylinders and clean dust from their heat sinks.