Lining process of rubber lined pipes

Rubber lining is a process in which a rubber-based material, typically in the form of sheets or extruded tubes, is applied to the internal surface of steel pipes. This is followed by vulcanization at a controlled temperature to achieve the desired hardness and bonding strength. This protective lining helps prevent corrosion and abrasion, extending the lifespan and functionality of the pipe.

The rubber lining process generally consists of the following steps:

1. Inspection of Piping Components

The first step involves inspecting the pipes to ensure their suitability for the rubber lining process. Key factors to consider include:

Accessibility of the internal surface for lining application.

Suitability of the internal contours to achieve a defect-free lining.

Note: To provide sufficient access to the pipe's internal surface, the pipe profile may need to be disassembled into smaller, flanged spools or fittings of predetermined dimensions.

2. Surface Preparation

Before applying the rubber lining, the internal surface of the pipe must be thoroughly cleaned to ensure proper adhesion. This is typically achieved by removing scale, rust, and other contaminants. Methods such as wire brushing, sandblasting, or shot blasting are commonly used to prepare the surface for optimal rubber adhesion.

3. Application of Rubber Solution or Lining Material

Once the pipe surface is properly prepared, the rubber solution or lining material is carefully applied. This may be done through manual application of rubber sheets or extrusion of rubber tubes. The material is then molded to fit the pipe’s internal contours.

4. Curing and Vulcanization

The rubber lining is then cured (vulcanized) at the required temperature to achieve the necessary hardness and durability. This process can be carried out by using hot water or steam to apply consistent heat. In some cases, vulcanization can be done at ambient temperatures using accelerators and fillers mixed with the rubber compound to expedite the curing process.

5. Inspection for Defects

After the vulcanization process, the lined surface is thoroughly inspected for any defects such as pinholes, blisters, or areas of poor adhesion. Ensuring a flawless lining is crucial for the long-term performance of the rubber-lined pipe.

6. Hydrostatic Testing

Finally, the lined components undergo hydrostatic testing, where water pressure is applied to the pipe to check for leaks or weaknesses in the rubber lining. This ensures that the lining can withstand the operating conditions and provides a reliable, long-lasting solution.

By following these steps, rubber-lined pipes are prepared for use in environments that demand high resistance to corrosion and abrasion, such as in the chemical, mining, and water treatment industries.