In various buildings or during the progress of various projects, various pipelines are always used, some of which are buried underground or directly exposed in places where we can see them. Regardless of the situation, it is very necessary to carry out anti-corrosion and insulation treatment for pipelines. I believe most friends are not very familiar with these two techniques. Below, the editor will introduce the commonly used insulation methods for pipelines and four anti-corrosion methods.

1、 Common insulation methods for pipelines

1. The anti rust coating of the pipeline should be applied with anti rust paint. The mixture of anti rust paint and asbestos powder should be coated with mortar, and asbestos cement should be coated with asbestos cement to protect the shell, and anti rust paint should be applied.

2. Rust removal of pipes → anti rust paint painting → binding of perlite floor tiles → galvanized iron wire → asphalt felt damp proof layer → outsourcing of galvanized iron sheet protective layer → finish paint.

3. Anti rust and antirust coating for pipes shall be made of ultra-fine glass wool shell (or rock wool, polyurethane foam tile), aluminum foil (or asphalt felt) damp proof layer, galvanized iron sheet protective layer and painting.

4. Pipeline rust removal → Brush anti rust paint → Spray polyurethane vinegar directly into the pipeline for foaming → Aluminum foil → Galvanized iron sheet protective layer → Top coat.

The insulation of overhead pipelines requires a dense gap in the insulation layer, with a uniform and smooth insulation layer. The overlap width of the moisture-proof layer should meet the requirements of the specifications. The joints should be opened and overlapped as much as possible, and the protective layer should not be wrapped in glass cloth.

2、 Four anti-corrosion methods for pipelines

1. Outer wall anti-corrosion coating

Types and service conditions of coating materials for the outer wall of pipelines.

2. Inner wall anti-corrosion coating

A thin film applied to the inner wall of a pipe to prevent corrosion, reduce frictional resistance, and increase throughput. Commonly used coatings include amine cured epoxy resin and polyamide epoxy resin, with coating thicknesses of 0, 038-0, and 2 millimeters. To ensure that the coating adheres firmly to the pipe wall, surface treatment must be carried out on the inner wall of the pipe. Since the 1970s, there has been a trend towards using the same material for the coating of the inner and outer walls of pipes, so that the coating of the inner and outer walls can be carried out simultaneously.

3. Anticorrosive and thermal insulation coating

To reduce the heat dissipation from the pipeline to the soil, a composite layer of insulation and anti-corrosion is added to the outside of the pipeline for transporting crude oil or fuel oil with medium and small diameters. The commonly used thermal insulation material is rigid polyurethane foam, and the applicable temperature is - 185~95 ℃. This material has a soft texture. To improve its strength, a layer of high-density polyethylene is added outside the insulation layer to form a composite material structure to prevent groundwater from seeping into the insulation layer.

4. Other situations

If the outer protective pipe is polyethylene, there is no need to apply anti-corrosion measures. Polyethylene is odorless, toxic, and wax like in hand. It has excellent low temperature resistance, good chemical stability, and resistance to most acids and alkalis. It is insoluble in general solvents at room temperature, and has low water absorption. However, because it is a linear molecule, it can slowly dissolve in some solvents, and does not swell, so it has excellent electrical insulation performance.