1) good corrosion resistance, no effect on water quality: frp pipes can resist the erosion of acid, alkali, salt, seawater, untreated sewage, corrosive soil or groundwater and many chemical fluids. it has a longer service life than traditional pipes, and its designed service life is generally more than 50 years. for sand-filled frp pipelines, it is more used in municipal and urban transmission and distribution pipeline networks. because of its non-toxic, rust-free, odorless, no secondary pollution to water quality, no anti-corrosion, greatly extended service life, the advantages of easy installation, etc., therefore, are welcomed by the water supply and drainage industry.
2) anti-fouling and anti-moth:
the surface of unsaturated polyester resin is clean and smooth, and will not be stained and moth by microorganisms such as shellfish and fungi in the ocean or sewage, so as to increase the roughness. reduce the cross section of the water and increase the maintenance cost. frp pipes do not have these pollutions and are clean after long-term use. at the same time, due to its smooth inner wall and excellent anti-corrosion performance, it will not produce scale and microorganisms, effectively ensure the water quality and maintain the stability of water resistance. however, the traditional pipes still have the phenomenon of increased water resistance and surface scaling in the future.
3) good heat resistance and frost resistance:
at -30℃, it still has good toughness and extremely high strength, and can be used for a long time in the range of -50℃-80℃ , the resin with special formula can also work at a temperature above 110 ℃.
4) light weight, high strength, convenient transportation and installation:
the specific gravity of sand-filled glass fiber reinforced plastic pipes produced by fiber winding is 1.65-2.0, only 1/4 of steel, but glass fiber reinforced plastic. the circumferential tensile strength of the tube 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 various internal and external pressure requirements according to different requirements of users. for the single weight of the same pipe diameter, the frp pipe is only 1/2.5 of the carbon steel pipe (steel coil pipe), 1/3.5 of the cast iron pipe, and about 1/8 of the prestressed reinforced concrete pipe, so the transportation and installation are very convenient. the length of each section of frp pipes is 12 meters, which can reduce two-thirds of the joints compared with concrete pipes. its socket connection method is quick and easy to install, while reducing the hoisting cost and improving the installation speed.
5) low frictional resistance and high conveying capacity:
the inner wall of the glass steel pipe is very smooth, and the roughness and frictional resistance are very small. the roughness coefficient is 0.0084, while the n value of the concrete pipe is 0.014 and that of the cast iron pipe is 0.013. 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:
①when the conveying capacity is the same, the frp pipeline with a smaller inner diameter can be selected for the project, thereby reducing the one-time project investment; compared with other material pipes, frp pipes can reduce head loss and save pumping costs.
③ it can shorten the pumping time and reduce the long-term operation cost.
6) good electrical and thermal insulation:
frp is a non-conductor, and the electrical insulation of the pipeline is excellent. minefield; the heat transfer coefficient of frp is very small, only 0.23, which is 5‰ of steel, and the thermal insulation performance of the pipeline is excellent.
7) good wear resistance:
the water containing a lot of mud and sand is put into the pipe to carry out the comparative test of the effect of rotating wear. after 3 million revolutions, the wear depth of the inner wall of the detection tube is as follows: 0.53mm for steel coated with tar and enamel, 0.52mm for steel coated with epoxy resin and tar, and 0.48mm for case-hardened steel , frp is 0.21mm. this shows that it is quite wear-resistant.
8) low maintenance costs:
frp steel pipes do not need anti-rust, anti-fouling, insulation, heat preservation and other measures due to the above-mentioned properties such as corrosion resistance, wear resistance, frost resistance and pollution resistance. overhaul. there is no need for cathodic protection for buried pipes, which can save more than 70% of engineering maintenance costs. 9) strong adaptability: frp pipes 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 rates, different pressures, different burial depths and load conditions.
10) long engineering life, safe and reliable.
according to laboratory simulation tests, the service life of frp pipes can be as long as more than 50 years.
11) the comprehensive benefit of the project is good:
comprehensive benefit refers to the long-term benefit formed by various factors such as construction investment, installation and maintenance costs, service life, energy saving and steel saving, etc. the comprehensive benefit of frp pipes is desirable especially, the larger the pipe diameter, the lower the cost. when it is further considered that the buried pipeline can be used for several generations without annual maintenance, it can give full play to its superior comprehensive benefits.