Ultra high molecular weight polyethylene pipe
2020-06-28 16:05:32
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Ultra-high molecular weight polyethylene (UHMW-PE) is a new kind of engineering thermoplastics with more than 3 million viscosity-average molecular weight.

What is UHMWPE

Ultra-high molecular weight polyethylene pipe has superior performance over conventional HDPE pipe such as very high wear resistance, impact resistance, excellent resistance to internal pressure strength, resistance to environmental stress cracking, intrinsically self-lubricating, anti-adhesion, low temperature resistance and excellent chemical resistance.

Ultra-high molecular weight polyethylene (UHMW full name is ultra-high molecular weight polyethylene pipe) is a thermoplastic engineering plastics with an average molecular weight greater than 1.5 million, which is polymerized by ethylene and butadiene monomer under the action of a catalyst.

Ultra high molecular weight polyethylene is superior in comprehensive performance, abrasion resistance, low temperature, corrosion resistance, self lubrication, impact resistance in all plastic for the highest value, wear-resistant properties than PTFE, nylon, carbon steel and other materials, can be long-term in-169 to +80℃ conditions, known as "amazing" engineering plastics, Ultra-high molecular weight polyethylene Engineering Plastics (UHMW---PE) pipeline technology is becoming more and more mature in China, more and more projects adopt this kind of pipeline, become a kind of new thermoplastic engineering plastics with good price, it almost concentrates the advantages of various plastics, wear-resisting impact, self-lubricating, corrosion resistance, low temperature, hygienic non-toxic, Non-adhesion, water and other comprehensive properties, is an ideal pipe, can be widely used in mining (ore powder, pulp, tailings discharge pipelines) metallurgy, electricity, petroleum, textile, papermaking, food, chemical, mechanical, electrical and other industries.

Role of Molecular Weight

UHMWPE denotes Ultra High Molecular Weight Polyethylene which is a polyethylene polymer with an average molecular weight is greater than 3,100,000 as defined by ASTM D4020 – Standard specification for UHMWPE polymers. This molecular weight is well above the molecular weight of most typical polymers which are between 1,000,000 and 400,000 thus earning the title Ultra-High Molecular Weight Polyethylene. Polyethylenes with molecular weight in the 3.1 -4.5 Million range have been found to exhibit the best combination of impact strength and abrasion resistance.

For Polyethylene molecular weight classification the following guidelines can be used:

  • HDPE (High Density Polyethylene): 100,000 – 400,000 MW
  • HMWHDPE (High Molecular Weight High Density Polyethylene) 500,000 – 1,999,999
  • VHMWHDPE (Very High Molecular Weight High Density Polyethylene) 2,000,000 – 3,100,000
  • UHMWPE (Ultra High Molecular Weight Polyethylene) > 3,100,000 + MW

Attributes of UHMWPE Pipes

  • Abrasion resistance – UHMWPE pipes have excellent abrasion resistance providing long life in abrasive slurry applications.
  • Chemical resistance – outstanding resistance to a wide range of chemical reagents allows the use of UHMWPE systems in tailings pipelines and chemical treatment applications used in mining operations.
  • Flexibility – UHMWPE pipes can be bent to a minimum of 30 times the pipe’s outside diameter for HDPE. This flexibility and resiliency allows the pipe to absorb surge pressures, vibration and stresses caused by soil movement. This makes the pipes particularly useful in submarine pipe lines, mine subsidence and earthquake prone areas.
  • High flow capacity – low friction compared with materials such as fibre reinforced cement and resistance to material deposit buildup give UHMWPE pipes long lived high flow capacity.
  • Lower pumping cost due to greater hydraulic capacity as compared with steel and HDPE pipes.
  • Ease of installation – UHMWPE is easy to install with light weights and flanged couplings.

Excellent characteristics of piping

Ultra-high molecular weight polyethylene pipe (UHMWPE) wear-resistant plastic crown, is carbon steel, stainless steel 3-7 times. Low friction coefficient, self-lubricating, anti-adhesion, no scaling, reduce the energy transmission of materials. Top of the plastic in the impact strength column. The impact energy absorption value is highest in all plastics and has a silencing nature. Good chemical stability. Excellent low-temperature resistance. Sanitation is non-toxic to food and drugs.

very high wear resistance, UHMW products unique molecular structure, so that it has a very high ability to resist sliding. Wear resistance is higher than the general alloy steel 6.6 times times, stainless steel 27.3 times times. is phenolic resin 17.9 times times, nylon six 6 times times, polyethylene 4 times times the annual wear rate of 0. 58㎜, the service life of pipeline is greatly improved.

extremely high impact resistance, in the existing engineering plastics, the impact toughness of this product is the highest, many materials in severe or repeated explosions of the impact of cracks, breakage, crushing or surface stress fatigue. This product according to the GB1843 standard, carries on the cantilever beam impact experiment to achieve no breakage.

excellent chemical stability, this product can withstand strong chemical erosion, in addition to certain acids at elevated temperatures there is a slight corrosion, in other lye, acid solution is not corrosion. Can be used in concentrated hydrochloric acid with a concentration of less than 80%, the performance is fairly stable in nitric acid with a concentration of less than 75% and a concentration of less than 20%.

good self-lubricating, because this product contains wax-like material, and its own lubrication is good. The coefficient of friction (196n,2 hours) is only 0.219mn/m (GB3960). Self-sliding performance is superior to oil-lubricated steel or brass. Especially in the environment, dust, sand and many places, the product of its own dry lubrication performance more fully displayed. Not only can exercise freely, and protect the related workpiece does not wear or pull injury.

non-toxic to the biological, ultrahigh molecular weight Polyethylene Engineering Plastics (UHMW----PE) pipeline to adapt to water quality fluids, solid particles, powders, slurry, etc., the traditional metal pipe difficult to meet the requirements of ultra-high molecular weight polyethylene (UHMW----PE) pipeline can be replaced by extremely high corrosion resistance, high wear resistance, Self-lubricating absorption shock and other comprehensive properties, in various industries have a wide range of applications in solid particles, powder, slurry, gas transport, has a unique advantage.

the unique low-temperature resistance, this product is excellent low-temperature resistance, its impact resistance, wear resistance in Minus 269 degrees Celsius basic unchanged. It is the only kind of engineering plastics which can work at a temperature close to absolute 0 degrees at present. At the same time, the temperature of the product is wide, can be long-term in the 269 ℃ to 80 ℃ of work.

the surface is not adhered to, this product because of the small friction coefficient and the infinite, it has a good surface adhesion. The existing materials generally in the ph value of more than 9 of the medium are scaling, this product is not scaling, the characteristics of fire power plant for the discharge of fly ash system has great significance. In crude oil, mud and other transportation pipelines are also very suitable.

the best resistance to environmental stress cracking, resistance to environmental stress cracking >4000h, elastic modulus is 1.5 times times more than PE100, anti-fatigue strength of 500,000 times.

other characteristics, the product also has absorption, noise absorption, anti-static, the neutron has shielding capacity, do not absorb water, light weight. Easy machining, coloring and other outstanding characteristics.

Benefits of Ultra High MW

UHMWPE by virtue of its extremely high molecular weight yields several unique properties, including the highest abrasion resistance and highest impact strength of any plastic.

Beware of competitive products claiming to be UHMWPE as some techniques for processability of UHMWPE are not without an attendant disadvantage since effective amounts of intermediate molecular weight polyethylene causes a marked decrease in some of the most desirable properties of the UHMWPE, such as impact strength and abrasion resistance.

The high molecular weight is what gives UHMW-PE a unique combination of high impact strength, low coefficient of friction and abrasion resistance that outwears carbon steel 10 to 1 making it more suitable for many applications where lower molecular weight grades fail.

UHMWPE pipes can be used in a broad range of mining and industrial slurry applications due to its three main characteristics: high impact strength, outstanding abrasion resistance and extremely low coefficient of friction.

Ultra-high molecular weight polyethylene (UHMW) is a tough, abrasion-resistant thermoplastic with a molecular weight of greater than 3 million. UHMWPE pipes have reduced coefficient of friction, improved abrasion resistance, lower wear rates over conventional HDPE pipes such as PE100.

Exceptionally High Wear

Ultrahigh molecular weight polyethylene (UHMWPE) shows unusually high wear resistance compared to most materials. This is due to a combination of very high molecular weight and the resulting entanglements and relative surface softness with a slippery waxy surface.

UHMWPE Lined Steel Pipe

UHMWPE lined steel pipe also named high wear resistant PE-steel composite pipe, it is combined by carbon steel pipeline and UHMWPE pipeline through special technical method, and the diameter of the composite pipe is available from DN200~DN1200.

The UHMWPE -steel composite pipeline is combined from steel pipeline and UHMWPE pipeline .

Steel pipeline: Q235 or as client's request;

UHMWPE pipe: Raw material is UHMWPE(Ultra High Molecular Weight Polyethane), UHMWPE usually refers to the linear polyethylene with a viscosity average molecular weight more than 1.5 million Dalton.With at least 3~5 times higher of molecular weight than HDPE, the UHMWPE materials have better performances of excellent wear resistance, lower temperature resistance, corrosion resistance, self lubrication, anti-impact. The wear resistance is the beast among plastics, and it can work under -110℃ to 70℃for a long time.

Outer layer of the composite pipe is a steel pipe with steel flange, inner layer is UHMWPE pipe, inner UHMWPE pipe at both ends should be 60mm longer than steel pipe. Then flange the inner UHMWPE pipe, with this UHMWPE flange, the UHMWPE pipeline and steel pipeline can be plying-up very well, and it also increases the strength of the two side connection part. There is a sealing face on the UHMWPE flange to protect the pipeline from leakage.

Benefits of UHMWPE lined Steel Pipe:

  • Bear high pressure, the UHMWPE -steel composite pipe can bear pressure from 5~8 Mpa.
  • High wear-resistant ability, among all the plastic materials, UHMWPE is the best one for wear-resistant ability, cause its average molecular weight is above 1.5million, while the HDPE material is only 0.3~0.5 million, and by test, the UHMWPE pipeline is 4 times wear-resistant than HDPE pipeline. By lining the UHMWPE pipeline inside the steel pipe, which can increase 6 times wear-resistant ability.
  • Low water-resistant, low friction coefficient, nonscaling, save fuel engine cost, because the roughness of the UHMWPE pipeline is only 0.00022, while HDPE is 0.01 and steel is 0.1. By lining the UHMWPE Pipeline inside the steel pipeline, the whole pipeline will save at least 20% fuel engine cost.
  • Anti-corrosion, the inner UHMWPE pipe with very stable chemical property, it is anti-corrosion from a strong acid, alkali, salt, water, sewage, soil corrosion, which increase the using life of the whole pipeline perfectly.

Application of UHMWPE pipe:

Compare with existing plastic pipes, Wear resistant UNMWPE pipe has the most excellent wear resistance which is 4 to 7 times that of Q235 steel pipe and 2.7 times that of wear-resistant steel 16Mn. Therefore it increases pipe flow rate and improves the transmission efficiency of more than 20%. The working life of UHMWPE pipes is more than 3 times that of wear-resistant steel pipe. Wear resistant UHMWPE pipe has great advantages to replace traditional metal pipes in delivering abrasive media.

UHMWPE Pipe for Dredging Applications

UHMWPE pipes are widely used in the industries of dredging, mining, metallurgy, electric power, oil, textile, paper, food, chemical, mechanics, gas, tunneling ect.

UHMWPE Slurry Pipe

UHMWPE has the following impressive statistics: up to 15 times the abrasion resistance of steel while being 8 times lighter than steel and having 5 times lower coefficient of friction than steel and offering as low as 1/10 the pressure loss of steel pipes.

  • UHMWPE PIPE for mine tailings and slurry in the mining industry
  • UHMWPE PIPE for dredging mud and sand
  • UHMWPE PIPE for thermal power system coal ash transport
  • UHMWPE PIPE corrosive particles and liquids
  • UHMWPE PIPE transport pulverized coal and coal-water slurry
  • UHMWPE PIPE for food transport

What are the characteristics of UHMWPE Pipe?

Because UHMWPE Pipe has a high molecular weight, it has good comprehensive properties and has become a new type of thermoplastic engineering plastic with excellent performance. It has almost the advantages of various plastics and has unparalleled wear resistance and resistance to ordinary polyethylene and other engineering plastics. Impact, self-lubrication, corrosion resistance, low-temperature resistance, hygienic non-toxic, non-adhesion, non-water absorption and other comprehensive properties. It has unique advantages in the transportation of solid particles, powder, slurry and gas.

At present, ultra-high molecular weight polyethylene pipes have achieved industrial continuous production in China. However, due to the characteristics of the UHMWPE raw materials, it is difficult to process UHMWPE pipes. Although the production of UHMWPE pipes has realized continuous extrusion production by a plastic extruder, its production speed is only ordinary plastics. The pipe production speed is 1%, so increasing the production rate of ultra-high molecular weight polyethylene pipes and improving the wear resistance index has become the focus of industry research.

Because the ultra-high molecular weight polyethylene pipe has excellent characteristics such as friction resistance, corrosion resistance, impact resistance, self-lubrication, non-adhesion, non-absorption of water, etc., it is recognized by the market, so the application range of ultra-high molecular weight polyethylene pipe is expanding.

The unique properties of the UHMWPE pipe material determine the slow speed of the pipe production line. The main equipment is the extruder and the mold.

As a Polyethylene UHMWPE Sheet Manufacturer, share with you the characteristics of UHMW-PE pipe products.

Ultra-high molecular weight polyethylene pipe refers to the pipe that is formed by using ultra-high molecular weight polyethylene as the main raw material. Its main characteristics are shown in the following points:

1.No leakage

China's water supply and drainage pipelines mainly use PCCP pipes, cast iron pipes, and glass steel pipes. They are connected by sockets, sealed by rubber rings, and have serious leakage in the pipe network. The average leakage rate is about 15-30%, which wastes resources and increases pipe maintenance costs. The ultra-high molecular weight polyethylene pipe successfully solved this problem with excellent performance and brought major changes to the water supply and drainage engineering.

2.Low energy consumption

The ultra-high molecular weight polyethylene pipe has a roughness of 0.0065, the steel pipe has a roughness of 0.012, and the cement pipe has a roughness of 0.013. The water flow rate of ultra-high molecular weight polyethylene pipes of the same caliber is greater than that of PCCP pipes and cast-iron pipes. At the same flow rate, UHMWPE pipes can save energy by 25%.

Ultra-high molecular weight polyethylene pipe has a series of characteristics such as corrosion resistance, low-temperature resistance, non-scaling, and no leakage. Therefore, the pipe does not need to be rust-proof, decontaminated and overhauled for decades after operation, which can save more than 95% of operating and maintenance costs.

 
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