🧿 I. Repair Methods for Leaking DN1500 Fiberglass Pipe Elbows

For pressure pipelines with such a large diameter (DN1500, i.e., 1.5 meters in diameter), repairs must be meticulous, safe, and reliable. The following are several commonly used repair methods, which are usually selected or combined based on the size of the leak, the pressure rating, and site conditions.

Method 1: Using a Special Fiberglass Pipe Leak Repair Clip (Preferred Method)

This is currently the most common, quickest, and most reliable repair method, especially suitable for axial cracks, holes, and leaks at sockets.

1. Preparation: Stop the water supply, drain the water, and reduce the pressure to ensure there is no pressure inside the pipeline. Thoroughly clean the area around the leak point, removing dirt, silt, and the aged layer on the original pipe surface to expose the robust structural layer. The surface should be dry, clean, and roughened.

2. Install the Leak Repair Clip:

Apply the leak repair clip to the leaking area, ensuring it completely covers the defective area with some slack.

After aligning the leak repair clamp, evenly tighten the bolts at both ends (for clamp-type leak repair clamps) or follow the product instructions (for sleeve-type).

Ensure the leak repair clamp fits tightly against the pipe wall, forming a preliminary mechanical seal.

Final tightening and testing: Double-check and tighten all bolts. Slowly pressurize by passing water; once no leakage is observed, normal operation can resume.

Method Two: Fiberglass Hand Lay-up Repair (Suitable for irregular cracks or localized damage)

This is a traditional but very robust repair method, essentially "patching" the damaged area. It requires a professional fiberglass worker.

1. Surface Treatment: Same as Method One, but with stricter requirements. The leak area needs to be ground to create a bevel approximately 150-200mm wide (feathering treatment) to increase the contact area.

2. Primer Application: Evenly apply a layer of prepared epoxy resin or unsaturated polyester resin to the treated surface.

3. Reinforcing Material Laying: Impregnate the cut fiberglass cloth (mat) with resin and lay it layer by layer on the damaged area. Compact each layer with a roller to remove air bubbles. Typically, 5-8 layers or more are needed, and the final repair layer thickness should be slightly greater than the original pipe wall thickness.

4. Curing: Allow to cure at a suitable temperature until the resin is completely cured. Curing time is greatly affected by temperature.

5. Surface Treatment and Testing: Trim edges and polish smooth. Conduct a water flow test.

Method Three: Composite Repair Method (Leak Repair Clip + Hand Lay-up Reinforcement)

For stress concentration areas such as elbows, or in cases of severe damage, a combined method can be used to ensure complete safety.

First, perform hand lay-up repair according to Method Two to restore the pipe's structural strength.

After the hand lay-up layer has completely cured, install a leak repair clip (Method One) on the outer layer.

This method provides both internal structural reinforcement and reliable external sealing and mechanical restraint, offering the highest level of safety.

🧿II. Precautions for Large-Diameter Pipeline Repair

Repairing large-diameter pipelines like DN1500 differs significantly from repairing small-diameter pipelines, posing greater risks and control difficulties. The following points require special attention:

1. Safety First, Comprehensive Assessment:

Water Shutdown and Pressure Reduction: Water supply must be completely stopped, and the pipeline must be emptied. Large-diameter pipelines have large water storage capacity, and the residual pressure or water hammer effect is extremely powerful and dangerous.

Ventilation and Gas Detection: Before entering wells or pipelines, forced ventilation must be implemented, and oxygen content and toxic gases (such as methane and hydrogen sulfide) must be tested.

Pit Support: If the repair point is underground, the excavated pit must be reliably supported according to soil conditions to prevent collapse.

Lifting Safety: When lifting heavy objects such as leak repair clamps and equipment, a designated person must direct the operation, ensuring the safety of the lifting equipment and keeping personnel away from danger zones.

2. Precise On-Site Inspection:

Damage Assessment: Accurately measure the shape, size, and direction of the leak (is it a circumferential or axial crack? Axial cracks are more dangerous). Inspect the elbow itself for structural damage (such as breakage or deformation).

Operating Condition Confirmation: Determine the pipeline's operating pressure, temperature, and medium to select appropriate repair materials and solutions.

3. Team Collaboration and Large Equipment:

Large-diameter repairs cannot be done by one person alone; a well-defined and experienced team is required (command, operation, safety monitoring, etc.).

Large water pumps, generators, ventilation equipment, cranes, and other heavy equipment are necessary.

4. Quality Control is Key:

Surface Treatment is Crucial: Regardless of the method used, the quality of the surface treatment directly determines the success or failure of the repair. It must be "new, dry, and rough."

Follow the Process: Strictly adhere to the mixing ratios, operating procedures, and curing conditions provided by the material supplier, especially for hand lay-up repairs and adhesive injection processes.

5. Develop an emergency plan:

Pre-plan for possible unforeseen circumstances (such as sudden water inrush, water entering the foundation pit, material failure, etc.) and develop corresponding emergency response measures.

🧿III. Benefits of using leak repair clips

For emergency repairs of DN1500 FRP pipes, using leak repair clips (especially glue-injection type leak repair clips) has significant advantages:

1. Fast and efficient: The installation process is relatively simple, and in most cases, no hot work or welding is required. Repairs can be completed within hours, greatly shortening water outage time and reducing economic losses and social impact.

2. Safe and reliable:

Utilizing a dual seal of mechanical fastening and chemical glue injection, it has high pressure resistance and excellent sealing effect.

The leak repair clip itself has high structural strength and can share some of the pipe stress.

3. High adaptability:

It can adapt to certain irregularities on the pipe surface.

It is suitable for various types of damage, such as cracks, holes, and leaks at joints.

Available in various specifications and models to meet the needs of large-diameter pipes such as DN1500.

4. Easy Operation:

Typically adopts a split design, making it relatively lightweight and easy to transport and install on-site.

The technical requirements for operators are lower compared to hand lay-up repair.

5. Good Predictability: The product is standardized, and its performance (such as pressure resistance and sealing) has been tested. The predictability of the repair effect is higher than that of hand lay-up repair, which relies entirely on manual labor.

The housing is typically made of metals such as ductile iron and carbon steel, which are corrosion-resistant and high-strength. It can last the same life as the original pipe, eliminating the need for frequent repairs. Baoshuo brand carbon steel half joints are available in a variety of rubber materials, including NBR, EPDM, FKM, and silicone rubber. The half joint body is available in Q235 carbon steel and 304 and 316L stainless steel.

The following are Baoshuo brand oil-resistant pipe repair clamps, high-temperature-resistant pipe repair clamps, acid- and alkali-resistant pipe repair clamps, stainless steel pipe repair clamps, high-pressure-resistant pipe repair clamps, and large-diameter pipe repair clamps.

Summary and Recommendations:

For your DN1500 FRP elbow leakage problem, the preferred solution is to use a DN1500 injection-type FRP pipe leak repair clamp that is suitable for the elbow shape. If the damage is severe or located in a high-stress area, a combined repair method of "hand lay-up repair + leak repair clip overlay" is recommended to ensure maximum safety and durability.

Please note that this type of repair work is highly specialized. It is strongly advised to contact a professional pipeline repair company or fiberglass product manufacturer so that they can send technicians to the site for assessment, develop a detailed construction plan, and implement it.