How To Repair The Industrial Flange Leaks

First, Explanation of Equipment Problems

Generally, gas transmission flanges often experience leakage due to gasket failure. Flange gasket leaks can manifest in five ways: interface leakage, seepage leakage, diffusion leakage, destructive leakage, and external environmental corrosion. The causes of leakage are generally as follows:

① Uneven tightening force during installation; asymmetrical pre-tightening of bolts during construction can easily lead to uneven stress.

② Stress relaxation and torque loss; after bolts are tightened on the flange, stress relaxation will occur in the gasket during operation due to factors such as vibration of the mechanism and temperature rise or fall.

③ Surface roughness of the sealing surface; excessively high flange surface roughness will affect the sealing effect.

④ Temperature changes; leaks at flange connections often occur during temperature decrease (cooling) because the flange and bolts cool at different rates, causing a change in the gasket's tightening force and resulting in stress relaxation.

⑤ External environmental corrosion; rust on the flange and bolts can cause leaks, directly due to the presence of corrosive media in the flange gap. Without an anti-corrosion coating, the metal surface of the flange and bolts will quickly corrode after direct contact with water and air. The presence of acidic or alkaline gases in the external environment, combined with a certain amount of moisture in the air, can also accelerate the corrosion of flanges.

Second, traditional maintenance processes:

① Generally, gasket replacement is used to solve leakage problems. However, since most pipelines cannot be shut down, once the gasket fails, it cannot be replaced while the pipeline is running.

② Pre-tightening bolts poses a certain risk due to the long-term failure of pipe flanges and bolts. Common problems include loose bolts and stripped threads; in severe cases, the flange strength decreases, leading to rigidity failure. Pre-tightening bolts carries a significant risk of uncontrollability.

③ Wrapping the flange connection with adhesive tape or plastic tubing can temporarily control flange leaks, but it has significant limitations. Temperature changes in the pipe fittings or decreased adhesion can easily cause the adhesive tape to detach.

④ Using specialized fixtures or welding tools for external treatment is ineffective if the equipment is leaking, especially in environments with flammable gases or where open flames are prohibited. Installing these fixtures or welding tools will prevent further work.

⑤ For corrosive media or corrosive, humid environments, anti-corrosion paint is typically applied. However, this method is often ineffective once a leak occurs.

Third, Solutions for Flange Leaks

1. First, determine the cause of the leak: If bolts are loose or the torque is insufficient, tighten them; if gaskets are damaged, replace them. If the flange sealing surface is damaged, assess the actual operating conditions and use online flange repair machining.

2. Repair online whenever possible (significantly reducing maintenance costs and downtime losses): On-site machining technology is mature, and most flanges can be repaired without disassembly.

3. For severe damage, use additive manufacturing: If the flange sealing surface is deeply corroded or has significant defects, repair first using cold welding or laser cladding.

4. Control bolts and gaskets: Ensure proper torque control, select the correct gasket type, and perform acceptance testing. Don't skip any steps. The entire process completely resolved the issue.

Conclusion: The key to managing leaks in factory pipelines and flanges/other conveying components is adhering to the principle of prevention first. Fusilan develops reasonable and effective prevention and protection plans for different equipment and locations; it takes proactive preventative measures and systematically protects, inspects, and upgrades the equipment. Reasonable preventative measures can effectively reduce various pipeline leak accidents, mitigating their harm at the source.