FRP sand-embedded pipe

FRP sand-embedded pipes are a new type of composite material made of resin as the matrix material, glass fiber and its products as the reinforcement material, and quartz sand as the filler material. With its excellent corrosion resistance, hydraulic characteristics, lightweight and high strength, large transport flow, easy installation, short construction period, and low comprehensive investment, it has become the best choice for the chemical industry and drainage engineering.

1. Performance and Advantages of Fiberglass Sand-Embedded Pipes

Fiberglass sand-embedded pipes have a sand-embedded layer in the pipe wall design, which not only provides lightweight and high-strength performance compared to pure fiberglass pipes but also has the high rigidity and low cost required for underground pipes. Since its introduction, it has been widely welcomed. Its applications in fluid transport and other aspects are increasing. According to relevant data, by the mid-1990s, the United States had installed 160,000 kilometers of fiberglass sand-embedded pipeline. In Europe, the installation length of fiberglass sand-embedded pipes accounts for about 35% to 50% of newly laid large and medium-sized water supply and sewage pipes. In Japan, this type of pipe also holds a considerable market share, with an installation length exceeding that of steel and concrete pipes combined. In the Middle East, almost all large and medium-sized water supply, sewage, and seawater desalination pipelines are made of fiberglass sand-embedded pipes.

2. Characteristics of Fiberglass Sand-Embedded Pipes

2.1. Lightweight, high strength, high rigidity

Fiberglass sand-embedded pipes consist of inner lining, winding layer, resin mortar layer, and outer anti-corrosion layer. Their specific gravity is 1.7 to 2.1, which is only 1/5 of steel pipes, 1/4 of cast iron pipes, and 3/4 of prestressed concrete pipes. The fiber content of the winding reinforcement structure layer is 70%, which fully meets the strength requirements of the pipeline. Additionally, the resin mortar layer is located in the low-stress area between the winding reinforcement layers, significantly improving the stiffness of the pipe without reducing its strength.

2.2. Corrosion resistance

The corrosion resistance of fiberglass sand-embedded pipes mainly depends on the corrosion resistance of the resin in the inner lining, which can be selected according to the requirements of the medium. The inner lining of fiberglass sand-embedded pipes is made of fiber-reinforced resin with a resin content of 80%, ensuring corrosion resistance and leak prevention.

2.3. Excellent hydraulic performance

The inner surface of fiberglass sand-embedded pipes is very smooth, with a small roughness coefficient. Even after several years of use, the inner wall remains as smooth as new, without the attachment of algae or other aquatic derivatives. The hydraulic coefficient C can be maintained in the range of 145 to 150 for a long time. Tests have shown that the friction loss coefficient f of water flow is 0.000915, significantly reducing pressure loss along the pipeline compared to concrete pipes (f=0.00232) and steel pipes (f=0.00179), increasing the transmission capacity by more than 20%. Therefore, when the transmission capacity is the same, fiberglass sand-embedded pipes with smaller inner diameters can be selected to reduce the one-time investment in the project.

2.4. Sanitary performance of fiberglass sand-embedded pipes

The raw materials used for fiberglass sand-embedded pipes are unsaturated polyester resin and fiberglass, which are processed through a certain process. The inner surface of the pipe is very smooth, with a Barcol hardness of over 40. Unsaturated polyester resin has been certified by the national health and epidemic prevention department, and the finished fiberglass pipes have also passed the inspection of the national health and epidemic prevention department. Therefore, fiberglass sand-embedded pipes can fully meet the hygienic standards for drinking water, with more than 20 years of domestic examples.

2.5. Seismic performance

Because fiberglass sand-embedded pipes are between rigid and flexible pipes, they have better seismic performance and will not deform or break under strong external forces. This is because the deformation of fiberglass pipes does not delaminate or crack at 25%.

2.6. Wear resistance

The addition of wear-resistant materials to the inner surface of fiberglass sand-embedded pipes can greatly improve the wear resistance of the product and thus extend its service life.

2.7. Low-temperature resistance

Fiberglass sand-embedded pipes do not crack at -40°C, and their strength does not decrease.

2.8. Environmental adaptability

Fiberglass sand-embedded pipes can be used in various environments, such as beaches, underwater, rivers, mountains, swamps, deserts, and plains, with features such as quick installation, convenient transportation, and long service life.