Manual ball valves, as common control components in industrial piping systems, are widely used in various fields, including petroleum, chemical, power, and water treatment, thanks to their simple structure, excellent sealing performance, and convenient operation. To ensure the long-term stable operation of manual ball valves, scientific and reasonable daily maintenance and timely and effective troubleshooting are crucial.
The Importance of Daily Maintenance of Manual Ball Valves
Over the long-term operation of manual ball valves, problems such as seal wear, impurity blockage, and valve stem corrosion can lead to valve leakage or operational difficulties. Regular maintenance can promptly identify and eliminate hidden dangers, avoid production downtime or safety accidents caused by valve failure, and improve equipment reliability and service life.
Daily Maintenance Steps for Manual Ball Valves
1. Visual Inspection
Regularly inspect the valve body, stem, handle, and connecting components for cracks, corrosion, deformation, and oil leakage. Any damage should be repaired or replaced promptly.
2. Operability Test
Manually operate the ball valve smoothly and without any sticking. If there is increased rotational resistance, check the stem seal, bearing lubrication, and the ball for buildup. 3. Sealing Performance Check
After closing the valve, observe whether the system pressure remains stable and detect any media leakage. For critical operating conditions, regular air tightness or hydrostatic testing is recommended to ensure that the sealing performance meets design requirements.
4. Cleaning and Lubrication
Clean dust and oil from the valve body and handle surfaces. Apply an appropriate lubricant to the stem seal and rotating bearing to prevent dry friction that could lead to seal failure and poor operation.
5. Fastener Inspection
Check the tightness of all bolts, nuts, and connecting flanges to prevent looseness that could cause leakage or mechanical damage. Retighten to the specified torque if necessary.
Common Manual Ball Valve Faults and Troubleshooting Methods
1. Valve Oil or Media Leakage
This is often caused by aging seals, damaged sealing surfaces, or loose fasteners. When troubleshooting, first check the integrity of the external sealing ring. Remove the valve cover and replace the sealing ring if necessary. If the sealing surface is scratched or severely worn, repair it or replace the ball.
2. Difficult or Sticking Valve Operation
This is often caused by insufficient valve stem lubrication, internal dirt, or corrosion. It is recommended to disassemble the valve to clean internal dirt and inspect the stem seal for dryness or damage. Lubricate or replace the seals promptly.
3. The valve does not open fully or close properly.
This is usually caused by a loose stem connector, misaligned ball, or damaged handle. During troubleshooting, confirm that the handle is securely connected to the stem and the ball is correctly positioned. Adjust or replace the handle if necessary.
4. Abnormal media flow.
This may be caused by internal valve scale or ball damage, leading to increased flow resistance. After disassembling the valve, remove the scale and inspect the ball surface for a smooth, intact surface to ensure flow capacity.
5. Leakage due to failed stem seals.
Deterioration or improper tightening of stem seals, such as packing or O-rings, can cause leakage. During maintenance, adjust the packing gland tightness and replace the packing or seals if necessary.
Maintenance Precautions:
Maintenance operations must be performed after the system is depressurized and drained to ensure safety.
Use manufacturer-recommended lubricants and seals to avoid failures caused by material mismatch. Maintenance records should be kept in detail, including inspection time, any problems found, and the corrective actions to facilitate follow-up management.
For ball valves used with high temperatures, high pressures, or corrosive media, maintenance frequency should be increased appropriately, with key parameters monitored promptly.
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