Views: 6 Author: Site Editor Publish Time: 2019-03-13 Origin: Site
Internationally, the materials of polythylene pipe(HDPE PIPE) are divided into PE32, PE40, PE63, PE80 and PE100, while the materials used for gas pipe and water supply pipe are mainly PE80 and PE100. There is no classification of PE gas pipe materials in China, which makes it difficult for domestic PE gas pipe and water pipe manufacturers to choose raw materials, and also brings a lot of hidden dangers to the use of PE pipe materials.
Therefore, the national bureau of standards has made a large number of revisions in the new GB/ t13663-2000 standard, stipulating that different grades of water supply pipes, PE80 and PE100, correspond to different pressure strengths, and removing the tensile strength performance in the old standard, but increasing the elongation at break (greater than 350%), that is, emphasizing basic toughness.
PE gas pipe implementation standard: GB 15558.1-2003
PE gas pipe is the replacement of traditional steel pipe and PVC pipe. Gas pipe must bear a certain pressure, usually to choose a large molecular weight, better mechanical properties of PE resin, such as HDPE resin. HDPE resin has low tensile strength, poor pressure resistance, poor rigidity, poor dimensional stability during molding and processing, and difficult connection, not suitable for water supply pressure pipe material. However, due to its high hygiene index, LDPE, especially LLDPE resin has become a common material for gas pipe. The melting viscosity of LDPE and LLDPE resins is small, the fluidity is good, and it is easy to process, so the selection range of their melt index is wide, usually MI between 0.3-3g/10min.
A good pipeline, not only should have good economy, but also should have a stable and reliable interface, material impact resistance, anti-cracking, aging resistance, corrosion resistance and a series of advantages, compared with the traditional pipe, HDPE gas pipe line system has the following series of advantages:
1. Reliable connection: polyethylene pipe system between the use of electric fusion connection, the strength of the joint is higher than the strength of the pipe body.
2. Good low-temperature impact resistance: polyethylene of low temperature brittle temperature is extremely low, can be in 60-60 ℃ temperature range for safe use. Winter construction, due to the impact resistance of the material is good, will not occur pipe brittle crack.
3. Good stress cracking resistance: HDPE has low notch sensitivity, high shear strength and excellent scratch resistance, environmental stress cracking resistance is also very outstanding.
4. Chemical corrosion resistance: HDPE gas pipe line can withstand a variety of chemical medium corrosion, the presence of chemicals in the soil will not cause any degradation of the pipeline. Polyethylene is an electrical insulator, so it does not decay, rust or electrochemical corrosion. Nor does it promote the growth of algae, bacteria or fungi.
5. Anti-aging, long service life: it contains 2-2.5% evenly distributed carbon black polyethylene pipes can be stored outdoors or used for 50 years, it will not be damaged by radiation.
6. Wearing resistance: the comparison test of HDPE gas pipe and steel gas pipe showed that the wear resistance of HDPE gas pipe was 4 times higher than that of steel pipe. In the field of mud transportation, HDPE gas pipe has better wear resistance than steel pipe, which means that HDPE gas pipe has longer service life and better economy.
7. Flexibility: the flexibility of HDPE gas pipe, it is easy to bend, engineering can change the pipeline trend way around the obstacle, in many occasions, the flexibility of the pipe can reduce the amount of pipe fittings and reduce the installation cost.
8. Resistance: HDPE gas pipe has a smooth inner surface, the manning coefficient is 0.009. The smooth performance and non-adhesion characteristics ensure that HDPE gas pipes have higher delivery capacity than traditional pipes, and at the same time reduce pipeline pressure loss and water transmission energy consumption.
9. Easy to carry: HDPE gas pipes than concrete pipes, galvanized pipes and steel pipes lighter, it is easy to carry and install, lower manpower and equipment requirements, means that the cost of installation greatly reduced.
10. Multiple new construction methods: HDPE gas pipe has a variety of construction technology, in addition to the traditional excavation method may be used for construction, can also use a variety of new trenchless technologies such as pipe jacking, directional drilling, liner, in the form of pipe and construction, for some do not allow the excavation sites, is a good choice, so the HDPE gas pipe wider application fields.