Special FRP pipes and fittings: with flame retardant level, corrosion resistance, aging resistance, ultraviolet resistance, antistatic, airtightness, flexibility and other properties, can bear various

1. Structural composition of FRP pipes:

Glass fiber reinforced plastic is also known as glass fiber reinforced composite materials. Among them, the glass fiber reinforced plastic pipes are new composite pipes composed of glass fiber, epoxy vinyl resin, unsaturated polyester resin, quartz sand, and non-metallic mineral fillers. This product is mainly formed by computer-controlled reciprocating cross-winding and centrifugal casting methods. It has a series of excellent characteristics. It is one of the widely used industrial and municipal pipes in developed countries such as the United States and Europe, and has formulated complete pipeline product standards and engineering design and installation specifications.

2. Advantages of FRP materials:

2.1 Light weight, high specific strength, and good fatigue resistance

l The specific gravity of FRP is1.6-2.0g/cm³between, that is, only ordinary steel1\4-1\6, lighter than aluminum1/3Because the continuous fiber in FRP has high tensile strength and elastic modulus, its mechanical strength can reach or exceed the level of ordinary carbon steel, and the specific strength is that of steel.4times.

l FRP materials have good fatigue resistance, and the fatigue failure of metal materials develops suddenly from the inside out, often without warning in advance; while the interface between fiber and matrix in fiber composites can prevent crack growth, and its fatigue failure always starts from the weak link of the material. Starting from the weak link, FRP pipes can be changed according to the difference in circumferential and axial forces, and the structural fiber ply can be changed to make the pipes have different circumferential and axial strengths, so as to match the stress state.

l Easy to transport and install, while being able to withstand large internal and external pressures and impact loads

l The following table shows the main mechanical properties of reinforced glass fiber and the mechanical and physical properties of FRP pipes

(1)Mechanical and physical properties of glass fiber

(2) Comparison of performance indicators between FRP and steel pipes

2.2, excellent hydraulic characteristics

· (1) Comparison of hydraulic characteristics between special glass fiber reinforced steel pipes and steel pipes

· Glass reinforced pipes not only have a small friction coefficient and a large conveying capacity, but also can significantly reduce liquid pressure loss along the way and improve liquid conveying capacity. The absolute roughness of glass reinforced pipes is determined.For the value after 50 years, the steel pipe is the value in the later stage of operation. The glass reinforced steel pipe is a smooth pipe. When the transmission power and flow are the same, the glass reinforced steel pipe is selected, and the pipe diameter is 1-2 pipe diameter smaller than that of the selected steel pipe.

· The following is an example calculation explanation

· (2) Example analysis

· Assuming that the first type of pipe is a steel pipe and the second type of pipe is a glass steel pipe, the roughness of the inner wall of the first type of pipe is a steel pipe.n1=0.012; the inner wall roughness of the second type of pipe is n2=0.009. Through the relationship between Darcy's formula (1) and Manning's formula (2) in hydraulics, the following comparisons can be obtained:

Q=AC（Ri）^1/2 （1）

C=1/n · R^1/6          (2）
In the formula:Q--Flow rate; A=π/4 · D² A is the cross-section area of the pipeline through water

C--Xie Cai resistance coefficient; i--Hydraulic slope;
n--Roughness coefficient of the pipe; R--Hydraulic radius, for circular pipes, R=D/4

· Will (Substituting equation 2) into equation (1) yields:

·       Q=K/n · D^8/3 i ^1/2 （3）

· (C)In the formula:D--Pipe diameter;
　　    K=π/4 · 1/4^2/3
When the pipeline water delivery flow is consistent, the diameter of the steel pipe is assumedD₁=2400mm
Then according to the formula:

· (C)D₂/D₁ = (n₂/n₁)^3/8 = (0.009/0.012)^3/8 = 89.77%

· (C)Glass fiber steel pipes can be obtainedD2=2154.48mm

· (C)Conclusion: Therefore, when the design diameter of the steel pipe isAt DN2400mm, glass

· (C)Steel pipes are designed toDN2200mm is enough, which can greatly save the cost of pipes.

· (C)Investment costs.

2.3, strong corrosion resistance

· The main raw materials of glass steel pipes are composed of vinyl and unsaturated polyester resin with polymer components and glass fiber and carbon fiber with mineral componentsTherefore, it is different from the electrochemical corrosion mechanism of ordinary metals. No ions will be dissolved in the electrolyte solution. It has good adaptability especially in strong non-oxidizing acids and media within a wide range of pH values. In the past, some corrosive media that could not be solved with stainless steel, such as hydrochloric acid, chlorine gas, carbon dioxide, dilute sulfuric acid, sodium hypochlorite and sulfur dioxide, can now solve corrosion problems well. FRP has good chemical stability to the atmosphere, water and medium of general concentrations such as acids, alkalis, and salts, so it effectively resists the corrosion of acids, alkali salts and other media, as well as untreated domestic sewage and industrial sewage, corrosive soil and erosion of chemical wastewater and many chemical liquids.

· It has strong corrosion resistance and can resist the erosion of various chemicals such as acids, bases, salts and organic solvents, and is suitable for use in various corrosive environments.

· Due to the superior corrosion resistance of Qifeng special FRP, under general circumstances, can maintain safe operation of the pipeline for a long time. It greatly increases the service life of the pipe, thereby reducing the cost of later maintenance and replacement of the pipe.

Corrosion Resistance Performance Table of Qifeng Special FRP Pipe (1)

Corrosion resistance performance table of Qifeng special FRP pipes (2)

Corrosion resistance performance table of Qifeng special FRP pipes (3)

2.4, excellent aging resistance and heat resistance

FRP is an excellent insulating material, and its thermal conductivity is generally1.254-1.672KJ/(m.h.℃) is only 1/100-1/1000 of that of metal. When there is a temperature difference, the thermal stress generated is much lower than that of metal. It can be used as a good thermal insulation material and instantaneous high temperature resistance material. Glass fiber steel pipes can be used for a long time in the temperature range of-40℃ to 150℃. Qifeng uses specially formulated high-temperature resistant resin that can also work normally at temperatures above 220℃. It is used for pipes used in the open air for a long time. The outer surface is added with ultraviolet light stabilizer to eliminate ultraviolet radiation on the pipes, thereby solving the aging problem of the pipes.

2.5, long engineering life, safe and reliable

under normal circumstances, steel pipes, cement pipes, and ductile iron pipes generally have a service life of 15-30 years, while special glass fiber reinforced plastic can be used for more than 50 years, and the service life of 50 years has been written into domestic and foreign standards.

2.6 Convenient installation and maintenance

Due to its light weight, high strength, strong plasticity, and easy transportation and installation, Qifeng Special FRP Pipe can also be made into a flexible pipe., can prevent damage to pipes caused by uneven settlement of the foundation. It is also easy to install various branch pipes and is not limited by various conditions. The maintenance of FRP pipes is simple and easy. Under normal circumstances, construction can be carried out as long as the repair working surface is dry. The repaired position can generally pass through water after 30 minutes of curing. The entire working process generally takes no more than 4 hours after removing stagnant water, while for other pipes, it takes more than 10 hours.

2.7, obvious energy-saving effect, environmental protection and energy conservation
Loss of different pipes with the same diameter(Energy consumption) comparison (design values of tube inner diameters are D=2200mm)

The calculation formulas for pump capacity and power consumption in the above table are:

Pump capacity:N=10Qhf/0.65

Annual power consumption:E=N^*8760 (degrees)

Assuming total pipe length:L=36000m

Dynamic viscosity of liquid medium =0.00001m²/s

2.8, good designability, flexible design and strong adaptability

Qifeng Special FRP is a kind of composite material that can change the type, quantity ratio and arrangement of its raw materials to adapt to the requirements of various working conditions. Generally, its performance can be improved through the following ways to meet various requirements. Requirements and special requirements such as high temperature resistance, low temperature resistance, wear resistance, antistatic, and flame retardant.

(1) Change the type of resin and increase the resin content of the surface layer in contact with the medium to improve corrosion resistance and temperature resistance;

(2) Select different fiber types and control the fiber content in FRP to adapt to different corrosion resistance and strength requirements

(3) Change the arrangement of fibers to adapt to the strength design requirements in different directions such as circumferential and axial directions

2.9, excellent environmental protection

For steel pipes, due to corrosion and fouling on the inner surface, this will affect the water quality or other liquids and gases transported. Special glass fiber steel pipe (FRP) is different from steel pipes. Due to its smooth inner surface and unique corrosion resistance, it will not be contaminated during the infusion and gas transmission process. The inner lining layer of the FRP pipe is a resin-rich layer, which plays an anti-corrosion and anti-seepage role. The resin is cured to food grade, which meets national health requirements and will not cause damage to water quality. The main components of the glass fiber and non-metallic minerals in the reinforcement layer are SiO₂, will not have adverse effects on the human body, and the special glass fiber reinforced pipes have a long service life, does not corrode, does not leak, and does not produce secondary pollution, so it has good environmental protection.

2.10, other advantages

l Excellent electrical and thermal insulation properties:FRP air pipes have good electrical insulation and heat insulation properties, which help reduce heat loss and improve energy efficiency. FRP pipes with good electrical conductivity can also be customized

l No rust or burning:Made of non-metallic materials, FRP air pipes will not rust during use, and areAClass A non-combustible material with excellent fire resistance.

l Low thermal conductivity:It has excellent thermal insulation properties, which helps reduce heat loss and improves energy efficiency.

design flexibility: The design can be customized according to the actual needs of the exhaust system to ensure stable operation of the system.