🔍 1. Diagnosing the Cause of the Leakage (First, Identify the Root Cause)

Flange Alignment and Installation Defects

- Non-parallelism/Non-perpendicularity: Flange gap deviation > 0.8mm or center misalignment > 1.5mm can lead to localized seal failure.

- Uneven Bolt Preload: Fiberglass flanges have low rigidity; overtightening can cause flange cracking; undertightening can result in inadequate sealing. DN2400 flanges have a large number of bolts, making manual operation prone to errors.

- Vibration Loosening: External vibration (such as pump and valve startup and shutdown) can cause bolts to gradually loosen, especially when spring washers are missing.

Sealing Component Failure

- Incorrect Gasket Selection: For example, using a standard rubber gasket for acid-resistant applications, or failing to use a graphite gasket for high-temperature media.

- Aging Deformation: O-rings or flat gaskets lose their elasticity due to prolonged pressure and temperature cycling.

- Installation Damage: Gaskets may be creased, scratched, or misaligned with the press-fit surfaces.

Material and Structural Issues

- Insufficient FRP Flange Strength: DN2400 flanges are subject to significant internal pressure and bending moments, making them prone to creep or microcracks (a "cracking" sound is a typical sign).

- Thermal Expansion Difference: The linear expansion coefficients of FRP and steel flanges differ significantly (approximately 1:10). Temperature fluctuations generate shear stress, leading to seal failure.

🛠️ 2. Emergency Leak Control Measures (Quickly Control Leaks)

Bolt Retightening Operation

- Tighten the bolts in a "cross-symmetrical" sequence (three rounds of increasing torque are recommended). The final torque should be 80% to 90% of the design value (to avoid cracking the FRP).

- In vibrating environments, install a spring washer + flat washer combination to prevent loosening.

Temporary Sealing with Sealant Injection

- Use a polymer sealant (such as polysulfide) to inject the leak into the joint. This sealant is suitable for static interfaces with pressures ≤ 0.8 MPa.

Clamping Method (Baoshuo Flange Repair Clamp)

- Without shutting off the water supply, install a clamp with a rubber seal. Baoshuo half-joints can be customized to any size. Wrap the repair clamp around the damaged flange to seal the leak.

⚠️ III. Special Considerations for Large Diameter DN2400 Pipes

Lifting and Support:

- During repairs, use a multi-point lifting device to balance the pipe weight (approximately 300-400 kg/m for DN2400 FRP pipe) to prevent overloads at the joints due to bending moments.

- Bracket spacing should be ≤ 1/2 the standard value (≤ 3m recommended). Concrete supports should be added at elbows.

Compensating for Thermal Expansion:

- Install Ω-type expansion joints every 100 m of pipe, or use sliding brackets for stress relief.

Quality Control:

- FRP flanges should be ultrasonically inspected for delamination defects; bolts should be selected from B7 grade alloy steel.

🛡️ IV. Preventive Maintenance Recommendations

Regular Inspections:

- Check bolt torque quarterly and scan for abnormal temperature differences with an infrared thermal imager.

Environmental Protection:

- Cover exposed flanges with insulation and UV protection coating. Use electric heating for frost protection in areas with varying temperatures.

Leak Monitoring System:

- Install a wireless pressure sensor for real-time alarms.

> 💎 Summary:

For DN2400 FRP pipe leaks, prioritize assessing flange integrity and gasket condition. For minor leaks, inject glue or retighten bolts. For recurring leaks, steel flange repair clamps (Baoshuo flange repair clamps) are recommended. Ensure that pipe support and thermal compensation designs are verified, and establish a preventive maintenance program.