Compared with pipes made of other materials, FRP pipes have the following obvious advantages:
1. FRP pipe is corrosion-resistant and pollution-free. It can resist the erosion of acid, alkali, salt, seawater, untreated sewage, corrosive soil or groundwater and many chemical fluids. Glass fiber reinforced plastic pipe (FRP) has the advantages of non-toxic, rust free, tasteless, no secondary pollution to water quality and no need of anti-corrosion, so it is widely used in water supply and drainage industry.
2. FRP pipe is anti fouling and anti moth. Unsaturated polyester resin is used on the surface of FRP pipe, so its surface is clean and smooth, and will not be contaminated by shellfish, fungi and other microorganisms in the sea or sewage, so as to increase the roughness, reduce the water cross-section and increase the maintenance cost. The pipeline has no such pollution and is clean as before after long-term use.
3. FRP pipe is heat-resistant and frost resistant. It still has good toughness and high strength at - 30 ℃. It can be used for a long time in the range of - 50 ℃ - 80 ℃. The resin with special formula can also work at the temperature above 110 ℃.
4. FRP pipe is light in weight, high in strength, convenient in transportation and convenient in installation. The specific gravity of FRP pipe produced by filament winding process is 1.65-2.0, only 1 / 4 of that of steel. However, the circumferential tensile strength of FRP pipe is 180-300mpa, and the axial tensile strength is 60-150mpa, which is similar to alloy steel. Therefore, its specific strength (strength / specific gravity) is 2-3 times that of alloy steel, so that it can be designed to meet the requirements of various types of internal and external pressure. For single FRP pipes with the same pipe diameter, there are only 1 / 2.5 of carbon steel pipe (steel plate rolling pipe), 1 / 3.5 of cast iron pipe and 1 / 8 of prestressed reinforced concrete pipe. Therefore, the transportation and installation are very convenient. The length of each section of glass fiber reinforced plastic pipe is 12 meters, which can reduce two-thirds of joints compared with concrete pipe. Its socket connection mode is quick and easy to install, reduces the hoisting cost and greatly improves the installation speed.
5. The friction resistance of FRP pipe is small, the conveying capacity is high, the inner wall of FRP pipe is very smooth, and the roughness and friction resistance are very small. The roughness coefficient is 0.0084, while the n value of concrete pipe is 0.014 and that of cast iron pipe is 0.014. Therefore, the FRP pipe can significantly reduce the fluid pressure loss along the way and improve the conveying capacity. Therefore, it can bring significant economic benefits: when the transmission capacity is the same, the FRP pipe with smaller inner diameter can be selected to reduce the one-time project investment; if the pipeline with the same inner diameter is used, the FRP pipe can reduce the head loss and save the pumping cost compared with other materials. In addition, the FRP pipe can shorten the pumping time and reduce the long-term operation cost.
6. Fiberglass reinforced plastic (FRP) pipe has good thermal insulation. Glass fiber reinforced plastic (FRP) is a non-conductor. The electrical insulation of the pipeline is excellent. The insulation resistance is 1012-1015 Ω. Cm. It is most suitable for power transmission. The heat transfer coefficient of FRP is very small, only 0.23, which is five thousandth of that of steel.
7. FRP pipe has good wear resistance. The water containing a large amount of mud and sand is put into the pipe to carry out the comparative test on the influence of rotary wear. After 3 million rotations, the wear depth of the inner wall of the pipe is as follows: 0.53mm for steel pipe coated with tar and enamel, 0.52mm for steel pipe coated with epoxy resin and tar, and 0.21mm for steel pipe with surface hardening treatment. Therefore, the wear resistance of FRP is good.
8. The maintenance cost of FRP pipe is low. Due to the above performance of corrosion resistance, wear resistance, frost resistance and pollution resistance, the project does not need to take measures and maintenance such as rust prevention, antifouling, insulation and thermal insulation. There is no need for cathodic protection for buried pipe, and the maintenance cost can be saved by more than 70%.
9. FRP pipe has good designability. FRP pipe can be designed and manufactured into pipes with different pressure levels and stiffness levels according to various specific requirements of users, such as different flow, different pressure, different buried depth and load conditions.
The service life of FRP pipe is long and the comprehensive benefit is good. According to the simulation test in the laboratory, the service life of FRP pipe can be more than 50 years. Comprehensive benefit refers to the long-term nature formed by various factors such as construction investment, installation and maintenance costs, service life, energy saving and steel saving. The comprehensive benefit of FRP pipe is desirable, especially the larger the pipe diameter, the lower the cost. When further consideration is given to the long service life of buried pipelines and the need for annual maintenance, the comprehensive benefits are good.
