TITLE: PE natural gas pipe
Scope of application:


PE natural gas pipe

PE pipe China municipal pipe market, a plastic pipe is steady development, PE pipe, pp-r pipe, UPVC pipe, including PE pipe strong momentum of development is most impressive. The PE pipe is widely used. It is the two largest market for water pipes and gas pipelines. PE resin, which is composed of vinyl monomer polymerization, due to the aggregation due to different polymerization conditions such as pressure, temperature, can give different density of resin, thus has high density polyethylene, medium density polyethylene and low density polyethylene. In the process of processing different kinds of PE pipes, according to the different application conditions, the combination of resin number is chosen, and the requirements of extruder and die are different. PE gas management standard: GB 15558.1-2003

The international polythylene pipe material is divided into PE32, PE40, PE63, PE80 and PE100, while the main materials used for gas and water pipes are PE80 and PE100. Of polyethylene pipes for no classification in our country, which makes the domestic polyethylene gas pipe and feed pipe manufacturers choose raw materials, it is difficult to use the polyethylene pipe has brought a big hidden trouble.

So the national bureau of standards in the new standard GB/T13663-2000 made a lot of revision, set to different level PE100 and PE80 pipes for different pressure strength, the tensile strength and remove old standard performance, and increase the elongation at break (greater than 350%), emphasizing basic toughness.

PE gas management standard: GB 15558.1-2003

The PE pipe is a new product of traditional steel tube and PVC gas.

The gas tube must be under certain pressure, usually to choose the PE resin with high molecular weight and mechanical properties, such as HDPE resin. The tensile strength of HDPE resin is low, the pressure difference, the rigidity is poor, the dimension stability is poor in the forming process, and the connection difficulty is not suitable as the material for the water pressure pipe. But because of its higher health indicators, LDPE, especially LLDPE, has become a common material for gas pipes. LDPE, LLDPE resin melt viscosity is small, liquid is good, easy to process, so the choice range of the melt index is also wider, usually MI is between 0.3-3g / 10min.

PE gas tube performance characteristics

A good pipeline, should not only have good economy, but also should have stable and reliable interface, impact resistant material, cracking resistance, aging resistance, corrosion resistance and a series of advantages, compared with the traditional pipe, HDPE pipe system has the following advantages:

⑴The connection is reliable: the connection between the pipe system and the strength of the pipe is higher than the strength of the pipe.

⑵Good low-temperature impact resistance: polyethylene in the low temperature embrittlement temperature is extremely low, can be in - 60-60 ℃ temperature range safe use. During the winter construction, the pipe will not be brittle because of good impact.

⑶The anti-stress cracking is good: HDPE has low notch sensitivity, high shear strength and excellent resistance to scratches, and environmental stress cracking performance is outstanding.

⑷Chemical resistance is good: the HDPE pipeline can withstand the corrosion of a variety of chemicals, and the chemicals in the soil will not cause any degradation of the pipe. Polyethylene is an electrical insulator, so there is no rot, rust or electrochemical corrosion; It also does not promote the growth of algae, bacteria or fungi.

⑸Ageing resistance, long service life: contains 2-2.5% of the uniform distribution of carbon black polyethylene pipe can be used in outdoor or in open air for 50 years, will not damage by uv radiation.

⑹Good wear resistance: HDPE pipe and steel tube abrasion test show that HDPE pipe has four times the wearability of steel pipe. Compared with steel pipes, the HDPE pipeline has better abrasion resistance than steel pipes, which means the HDPE pipeline has longer life and better economy.

⑺Flexible, flexible makes it easy to bend, HDPE pipe engineering by changing the way for piping around obstructions, on many occasions, the flexible pipe can reduce the dosage of pipe fittings and reduce the cost of installation.

⑻Water resistance is small: the HDPE pipe has a smooth inner surface, and the manning coefficient is 0.009. The smooth performance and non-adhesion feature ensure that the HDPE pipeline has higher throughput than traditional pipes, and also reduces the pressure loss and energy consumption of the pipeline.

⑼Handling convenient: HDPE pipe than concrete pipes, galvanized pipe and steel pipe is lighter, it is easy to handle and install, less manpower and equipment needs, means that the project installation cost greatly reduced.

⑽A variety of new construction methods: HDPE 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 the only option, so HDPE pipe wider application fields.

1、Softness: because PE - RT is softer. Therefore, the construction cost is relatively low.

2、Heat conduction: the pipe that is used for the heating of the floor needs to have good heat conduction. The thermal conductivity of PE -rt is better than that of PP - R and PP. Very suitable for floor heating use.

3、 High temperature resistance: PE - RT resistance to high temperature can reach 90 ℃, and PEX can reach 65 ℃. Low temperature impact: PE - RT is better for low temperature impact resistance. During winter construction, the pipe is not vulnerable to shock, and the flexibility of construction arrangement is increased.

5、Environmental protection: PE - RT and PP - R can be recycled and not pollute the environment. And PEX can't be recycled to produce secondary pollution.

6、Performance stability: PEX has the problem of controlling the crosslinking degree and the uniformity of the crosslinking, and the processing complex and the processing directly affects the performance of the pipe. The PE - RT, and PP -r are easy to process, and the performance of the tube is basically determined by the raw material, and the performance is stable. Short for PE - RT is Polyethylene Raised Temperature, it is made of vinyl monomer and 1 - octene copolymer, and are specially designed for heating system and the density of ethylene/octene copolymer, which has a narrow molecular weight distribution, octene uniform distribution in polymerization of owner chain special molecular structure, it keeps the original PE health performance and machining performance advantages, and strengthened the high Temperature durability of a new type of special pipe material. With the raw material to produce the pipe is mainly used in building hot water/heating tube, its durability and the structure of the same life, the minimum can be up to 50 years, at the same time also has a good recovery, high added value.

PE gas pipe product characteristics

■ Good hygienic properties: PE pipe processing without adding heavy metal salt stabilizers, material of non-toxic, no fouling layer, not breed bacteria, well solved the city the secondary pollution of drinking water.

■ Excellent corrosion resistance: in addition to a few strong oxidizing agents, it can withstand the erosion of various chemical media. No electrochemical corrosion.

■ Long service life: under the rated temperature and pressure, the PE pipe can be safely used for more than 50 years.

■Good impact resistance: the PE pipe is strong, the impact strength is high, the weight is directly pressed through the pipe, and it will not cause the pipe to break.

■ Reliable connection performance: PE pipe hot melt or the strength of the electrical fusion interface is higher than the pipe body, and the seam will not be disconnected due to the action of soil movement or live load.

■ Good construction performance: the quality of the pipe is light, the welding process is simple, the construction is convenient, the project comprehensive cost is low.

Pipeline connection:

■ Electrical fusion: the direct tube is connected directly to the pipe by a special electric welding welding machine. Commonly used in 160mm tube.

■ Fusion connection: the use of a dedicated butt welder pipe connection, usually more than 160mm pipe.

■ Steel plastic connection: can be connected by means of flange, screw thread, etc.

■ In order to facilitate construction and ensure the quality of construction, the corresponding tools should be prepared.

For example: rotary cutting knife a cut tube; Rotary spatula - the removal of the skin on the surface of the pipe; Wall scraper - remove skin from the surface of the large diameter pipe; Gas disconnecting tool - the operation of the disaerated site.

PE gas tube performance requirements

The serial number performance requirements Test parameters

1 Hydrostatic strength (Hs) damage time 100 h 20 ℃ or higher stress (ring) PE80(9.0Mpa) PE100(12.4Mpa)  Damage time 165 h 80 ℃ or higher stress (ring) PE80(4.5Mpa) PE100(5.4Mpa)   80 ℃ (stress) PE80(4.0Mpa) PE100(5.04Mpa)

2 Elongation at break ≥350  

3 Hou resistance (only applicable to the black tube) climate ageing, stability performance meet the requirements under the HS (65 h / 80 ℃), elongation at break E + D3.5 GJ/m2

4Crack expansion (RCP) b 

5Full size (FS) test: dn 250 mm or higher or S4 test applies to all full size diameter test critical pressure (Mpa) of PC, the FS acuity 1.5 x MOP S4 test critical pressure (PC), S4 MOP / 2.4 0.072 ℃ or higher

6 Slow crack growth en> 5 mm 165 h, 80 ℃ and 0.8 Mpa (test pressure) c

80℃,0.92MPa(Test pressure)d

7 a Thermal stability >20min 200℃

8 Longitudinal retraction rate ≤3% 110℃

9 Melt mass flow rate (MFR) of MFR 0.01 Mpa, dn is greater than 250mm.

Maximum work pressure, MOP> 0.4 Mpa, dn is greater than 90mm's distribution system.