Plastic pipe replacing traditional pipe becomes inevitable

The historical experience of countries in the modernization process indicates that the development speed of plastic pipes exceeds the speed of economic development in the same period. The use of plastic pipes to replace traditional pipes is an irresistible trend in historical development. Even in developed countries that have built up densely-packed plastic pipe networks, the application of plastic pipes is still increasing year by year. For example, in 1986, the total usage of plastic pipes in Europe was 2.334 million tons. In 1998, it increased to 3.465 million tons, with an average annual growth rate of 5.2%. , over the same period of national economic growth. In the past 10 years, the average annual growth rate of China's plastics pipe market was 20%. In 2000, 2002 and 2003, the output reached 700,000-800,000 tons, 1.3 million tons and 1.5 million tons respectively, with a growth rate of 15%. Among them, PVC pipes account for 55% and PE pipes account for 40%. It is estimated that by 2010, the average annual growth rate of domestic plastic pipe will still exceed 20%.

Advantages of plastic pipe

Plastic buried pipes have been widely used abroad because buried pipes have many advantages over conventional buried pipes such as cast iron pipes, steel pipes, and cement pipes.

Strength and rigidity

The strength and rigidity of plastic buried pipes on the surface are inferior to that of cement pipes, especially reinforced concrete pipes. In fact, the plastic buried pipes are “flexible pipes”. Under the correct design and laying conditions, the plastic buried pipes and the surrounding soil will bear together. The load, therefore, the plastic buried pipe does not need to achieve the same strength and rigidity as a "rigid tube" such as a concrete pipe, and can satisfy the mechanical performance requirements in the use of the buried.

Hydraulic characteristics The inner wall of the plastic pipe is smooth, with low resistance and large water flow. The water flow of the plastic pipe is larger than that of the concrete pipe under the same caliber. When the terrain has slope, the pipe diameter of the plastic pipe can be reduced and the construction volume is small.

Comprehensive economy

In terms of comprehensive economy, the advantages of plastic pipes are being recognized by more and more users. Although the unit price of plastic pipes is slightly higher than that of cement pipes, the total construction cost is not higher than that of cement pipes. In 1992, Tianjin Municipal Engineering Design Institute systematically studied the UPVC double-wall corrugated pipe and the application of PE double-wall corrugated pipe in the buried drain pipe in 1998. The conclusion is: “The project cost of double-wall corrugated pipe and concrete flat mouth The pipe is equivalent, 30% lower than the concrete pipe of the socket, and the construction period is significantly shortened and the economic benefit is significant.

Large-caliber outdoor PE buried pipe is the development trend of the world

In the past 10 years, an obvious trend in the development of plastic pipes in the world has been the rapid development of water supply and gas PE pipes. Since 1998, the LCU Gas Distribution Committee of the Munich International Coal Union unanimously recommended the use of PE buried gas pipelines as distribution pipelines. After more than 10 years of research and development in various countries in the world, PE pipelines have developed into multi-variable and multi-application pipe materials. Starting from gas distribution, PE pipelines have entered urban water supply and drainage, farmland irrigation, sewage disposal, mining oil fields, floor heating, chemical and pharmaceutical fields. Statistics show that PE pipes increase at a rate of 10%-15% every year.

The main reason why the amount of PE pipe exceeds the UPVC pipe is that the PE material for the pipe material has continuously achieved significant development.

At the beginning of the development of plastic pipes, the amount of PE pipes was much smaller than that of PVC pipes, and the main reason was economical. At that time, high-performance PE pipe materials had not yet been developed, and only PE materials with performance equivalent to PE63 grades could be used. Due to the low strength, the wall thickness of PE pipes under the same conditions was more than 1 times larger than that of PVC pipes, which not only had high material costs but also Only apply on lower pressure, smaller diameter tubing, otherwise the wall thickness is too large to be used. With the continuous increase in research and development efforts, new-generation PE materials for high-strength pipes continue to emerge, not only PE80 grades, but also PE100 grade products. Material upgrades have made PE pipes significantly higher in stress, with thinner and thinner tube walls and even lower than PVC pipes.