The buried polyethylene PE pipe for gas is a PE polyethylene pipe . The pipe is corrosion-resistant, does not leak, and has high toughness. Has excellent flexibility, scratch resistance and good resistance to rapid crack transmission. In the next few years, China's natural gas pipeline construction will enter a golden period. China's urbanization construction and large-scale water supply and water conservation projects in various places have created a huge market for plastic pipes for water supply. It has been confirmed by international standards that PE polyethylene pipes have a long service life of more than 50 years. Favored by domestic and foreign markets, it is widely used in hot and cold water supply systems, purified water systems, gas transmission, pipes for wires and cables, and has good investment value and market prospects.
Buried polyethylene PE pipes for gas use Gas polyethylene pipes have many excellent properties and are used in the field of gas transportation. Corrosion of steel pipes and cast iron pipes and joint leakage problems will be completely solved, thereby ensuring the safe operation of the gas pipe network system. The PE material selected for the PE gas pipe is an inert material that can withstand the erosion of various chemical media. The pipe wall has a low coefficient of friction, a small flow resistance, and a strong transport capacity. It is connected by electric heating, the joint strength is higher than the pipe body, and the high-toughness PE fractures are extended. The growth rate is generally more than 500%. PE gas pipes have good seismic performance, resistance to slow crack growth (SCG), rapid crack growth (RCP), flexibility and scratch resistance.
The buried polyethylene PE pipeline for gas has a strong adaptability to uneven settlement of the pipe base, and has a strong abrasion resistance. Various non-excavation methods can be used, which greatly facilitates work and construction, and has a low system cost and maintenance costs. Less, which can significantly reduce engineering costs.
《燃气埋地聚乙烯管材》的要求组织生产和检验,本公司生产的聚乙烯(PE)燃气管按壁厚可分为:SDR11、SDR17、SDR21\SDR26四个系列。 The buried polyethylene pipes for gas are organized in accordance with the new national standard GB / 15558.1-2015 ` ` Gas buried polyethylene pipes '' for production and inspection.The polyethylene (PE) gas pipes produced by our company can be divided into: SDR11 , SDR17, SDR21 \ SDR26 four series.
The biggest problem of traditional gas pipelines, such as steel pipes and cast iron pipes, is the corrosion and joint leakage that commonly occur during use. High-density polyethylene gas pipeline (HD PE gas pipe ) has many excellent characteristics, corrosion resistance, low temperature resistance, good toughness, safe and reliable joint connection, and successfully solved the two major problems of corrosion and joint leakage of traditional pipelines. The field is widely used.
Internationally, the materials of polyethylene pipes are divided into five grades: PE32, PE40, PE63, PE80, and PE100. The materials used for gas pipes and water supply pipes are mainly PE80 and PE100. China does not classify the special materials for polyethylene pipes, which makes it difficult for domestic manufacturers of polyethylene gas pipes and water supply pipes to choose raw materials, and it also brings a lot of hidden dangers to the use of polyethylene pipes.
Performance technical indicators of buried polyethylene PE pipes for gas
1. Standards Our company's PE gas pipes are in accordance with GB 15558.1, and comply with the European standard prEN 1555-2 and the international standard ISO4437.
2. Color The color of our company's PE gas pipe is black, and the surface has a striking yellow stripe.
3． Series and specifications Our company's PE gas pipes are divided into two series: SDR11 and SDR17.6. SDR11 indicates the ratio of the nominal outer diameter of the pipe to the nominal wall thickness of the pipe. The same SDR17.6 indicates the nominal outer diameter of the pipe. The ratio to the pipe wall thickness en is 17.6. There are 17 specifications including D32, D40, D50, D63, D75, D90, D110, D125, D140, D160, D180, D200, D250, D315, D355, D400, etc.
4． Length The straight pipe produced by our company generally produces 6 meters or 12 meters, and can also be supplied according to customer requirements. Pipes with an outside diameter of less than 63mm can also be coiled and can be 50 meters, 100 meters or 150 meters in length, and can also be supplied according to customer requirements.
Standard for buried polyethylene PE pipes for gas use: GB 15558.1-2003
Gas PE pipe is a replacement product of traditional steel pipe and polyvinyl chloride gas.
The gas pipe must withstand a certain pressure, and usually a PE resin with a large molecular weight and good mechanical properties, such as HDPE resin. LDPE resin has low tensile strength, poor pressure resistance, poor rigidity, poor dimensional stability during molding, and difficulty in connection, and is not suitable as a material for water pressure pipes. However, due to its high sanitary index, LDPE, especially LLDPE resin, has become a common material for gas pipes. LDPE and LLDPE resins have low melt viscosity, good fluidity and easy processing, so the range of choice of their melt index is also wide, usually MI is between 0.3-3g / 10min.
When transporting natural gas, liquefied petroleum and artificial gas, the design pressure should not be greater than the maximum allowable working pressure of the pipeline, and the maximum allowable working pressure should meet the requirements of the following table.
Construction requirements for buried polyethylene PE pipes for gas
Due to the many advantages of gas PE pipes, our company has adopted a large number of PE pipes in the laying of new natural gas pipeline networks and the reconstruction of old pipeline networks. After many years of PE pipe construction, it has accumulated some technical and construction experience. Construction PE pipe has become the current favorite PE pipe.
1. Trench: Our company's current gas source is natural gas. Therefore, trench excavation requires a good slope control. If over-digging or soil replacement, the returned soil must be tamped to prevent the pipeline from sinking due to the backslope water accumulation. The level measurement shall meet the design requirements before the pipe is lowered.
2. Connection of PE pipe: The connection adopts thermal fusion connection and electric fusion connection:
(1) Hot-melt connection: Before and after the hot-melt connection, the dirt on the two heating surfaces of the heating plate of the connection tool should be cleaned with clean gauze to prevent affecting the thermal efficiency and the quality of the joint. The heating time, heating temperature, holding pressure, and cooling time during connection shall comply with the requirements of the pipe and pipe fitting manufacturers. During the holding and cooling, no movement or external force shall be applied, otherwise the joints that have not reached the maximum compressive strength cannot be formed uniform The flange affects the joint evenly compressed. Butt ends should be pin-milled to make the vertical joints on both ends well and ensure good edges. Otherwise the contact area is reduced and the strength is weakened.
(2) Electrofusion connection: When the electrofusion connection is made, the connection of the electrofusion tool should be ensured, and the setting of the current and time should meet the requirements of the electrofusion accessories. The fused socket surface needs to be clean, and the two ends of the pin and the mill should be vertically joined. Use a knife to scrape off the oxide layer on the fused surface, make the fused surface rough, and increase the contact surface. Before inserting the pipe, it is necessary to mark the insertion length position to ensure sufficient length to ensure the fused connection area and enhance the quality of the connection joint.
The saddle-type fused connection must also clear the surface, and tighten the flat fixing screws of the pipe to make the contact surfaces coincide.
3. Backfill: The strength and rigidity of gas PE pipe is not as high as that of steel pipe, and there should be no sharp and hard objects such as bricks and stones around the pipe. Lay a layer of sand to ensure the safety of the pipeline.
4. Gas-operated operation: For PE pipes above De110 connected to straight pipes or open tees, you can choose a special fixture for PE pipes according to the gas source (single and double gas sources), and then use an electric melting sleeve to connect the gas source. If the end of the pipe is blocked by a flange head, the flange head can be used without stopping the gas when the pipe is directly connected. When opening a branch pipe smaller than De63 on a PE pipe above De110, an electric melting saddle tee is used without stopping the air. After the saddle tee is installed on the pipe, a knife is used to open the original pipe for ventilation.
Product Features of Buried Polyethylene PE Pipe for Gas:
preservative. Polyethylene is an inert material. With the exception of a few strong oxidants, it is resistant to a variety of chemical media, has no electrochemical corrosion, and does not require an anticorrosive layer.
Not leaked. PE gas pipelines are mainly welded (fused or electrofused). Compared with rubber ring joints or other mechanical joints, there is no danger of leakage due to twisted joints.
Good scratch resistance. It can effectively resist the stress concentration of the material caused by scratches and greatly reduce the possibility of pipeline damage.
High toughness. PE gas pipe is a kind of high toughness pipe. Its elongation at break generally exceeds 500%, and it has a strong ability to adapt to uneven settlement of the pipe base. It is also a pipe with excellent seismic performance.
Excellent flexibility. The flexibility of polyethylene allows PE gas pipes to be coiled. For non-grooved construction, the orientation of PE gas pipelines can be easily changed according to the requirements of the construction method.
Advanced fused pipe structure. Non-exposed spiral electric heating wire guarantees uniform heat conduction in the welding area and effectively eliminates the short circuit phenomenon when the pipe is inserted. At the same time, it avoids the defects of exposed electric heating wire that are prone to aging and corrosion, and the inner wall of the pipe is smooth and flat, which is convenient for installation. .
Good resistance to rapid crack propagation. Rapid cracking of a pipeline means that when the pipeline is accidentally cracked, the crack grows at a speed of several hundred meters / second, causing a major accident that the pipeline ruptures several tens of meters or even thousands of kilometers in an instant. Rapid cracking of polyethylene gas pipes has not been found in actual use.
Long service life, can reach more than 50 years.