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With regard to PE pipe to the drainage system in the practical application of analysis of the situation
As China's urbanization process accelerated in the face of population, resources and environment pressures, to ensure the sustainable development of the national economy, our government has been increasing annual investment in urban infrastructure, As China's urbanization process accelerated in the face of population, resources and environment pressures, to ensure the sustainable development of the national economy, our government has been increasing annual investment in urban infrastructure, municipal utilities pipeline construction continues to accelerate, species and Specifications constantly enriched, production is increasing, the quality has been improving, particularly in the development of plastic pipe faster and become the hot spot for investment.
1933 British ICI company was the first discovery of PE. Developed to, PE is a combination of process methods of production, with a variety of structures and properties and multi-purpose series of varieties of resin, already accounts for one-third of the world's output of synthetic resin , ranking first. PE is one of the best use of transport can be used to produce inter strong acid and alkali in any medium outside the pipe, according to data from abroad spin terms, the field of the world's water supply pipe PE pipe's annual consumption of about 100 million metric tons, is widely used in water supply, gas transportation, sewage, agriculture, irrigation, mines fine particles of solid transport, as well as oil, chemicals, and postal and telecommunications and other fields.
"National Chemical Building Materials Industry" Tenth Five-Year "plan and the 2010 Development Plan," pointed out: The popularization and application of plastic pipe mainly UPV-C and PE tube-based. By 2005, the national new construction, renovation, expansion process, construction drainage channels 70% of the plastic pipe 50% of the plastic pipes, building water supply, water supply and heating pipes 60% of the plastic pipes, 50% use of urban water supply pipes plastic pipe, towns water supply pipes plastic pipe 70 percent, city gas pipeline 20% of the plastic tube, wire jacket pipe 80% of the use of plastic pipe.
First, water supply and drainage pipes used types of systems engineering and technical, economy and other aspects of comparison: Pipe Type Water supply and drainage systems engineering are: polyethylene pipe, steel pipe, ductile pipe, gray cast iron pipes, cement pipes, RPMP, UPV-C tubes.
Polyethylene Pipe According to their density polyethylene were divided into high-density polyethylene, medium density polyethylene pipes and low-density polyethylene pipes. According to different forms of polyethylene pipe can be divided into single-layer structure, solid-wall pipe, double wall corrugated pipe and spiral winding pipe and so on. Double-wall corrugated pipe and HDPE Spiral Pipe is mainly used raw material processed, mainly used in urban drainage, solid single-wall HDPE is mainly used in urban water supply, city gas transmission, single-layer solid-wall MDPE pipes are mainly used in city gas transmission , single-layer LDPE tube a large number of solid-wall pipe used for agricultural irrigation and industrial ordinary pipe.
RPMP RPMP centrifuge is used short-or long-glass fiber glass filament-wound, in the middle coarse craft production, wall slightly thick, circumferential stiffness larger, can be used to withstand internal and external pressure buried pipeline diameter from the diameter of 500 ~ diameter of 2600 millimeters, Fiberglass Reinforced Plastic Pipe crisp, only applies to large-caliber, and in the course of construction, mechanical collision occurred easily hidden injury, but injuries are not easily found in dark, affecting life.
Rigid polyethylene pipe UPV-C tube UPV-C tube has a high impact resistance and chemical resistance. It can be used according to different requirements during processing can add various additives to make it to meet the different requirements of physical and chemical properties, UPV-C pipe has a long life and good sealing characteristics, but the UPV-C for controlling the process There are heavy metal stabilizing agent in the use of the process will gradually leak and affect water resources.
Pipe Steel's biggest flaw is the short-lived, corrosion resistance, sealing is not good, easy to leak, and the price is high, poor adaptability to the surface uneven settlement.
Ductile Pipe Ductile pipe costs are high, the average price of more than PE pipes are 10% to 15%, the connection interface to the corner too easily cause leakage.
Gray cast iron pipe Gray cast iron pipe and short life span, the friction coefficient, good seal and easily leak.
PE pipe to other pipe in terms of abundance has the following advantages:
1, excellent physical properties. In performance between high-density polyethylene, low density polyethylene between the two, while maintaining the rigidity of high-density polyethylene, intensity, also has a very good flexibility, creep resistance, and high-density polyethylene is more hot-melt Connect with excellent performance characteristics are conducive to the installation of plastic pipe.
2, corrosion resistance, long service life in our coastal areas, high groundwater levels, land humidity, corrosion and make the use of seamless steel pipe to be installed yang pattern outward temper, and the life span of only 30 years, while the PE tube can withstand a variety of Chemical erosion of media, without embalmed. In addition, it will not promote algae, bacteria or fungal growth, life of up to 50 years.
3, toughness, good flexibility. PE pipe is a high-toughness pipe, its elongation at break of more than 500%, based on the possession uneven settlement and dislocation ability to adapt is very strong resistance to shock, therefore, best suited to a seismic risk area, the practice all over the world confirmed that PE pipe is the best channel seismic nature. Saying goes that the 1995 earthquake in Kobe, Japan, PE pipes and water pipes are not only the damaged pipe. In addition, PE is the PE pipe flexible tube can be coiled to reduce a large number of connecting tubes. The trend of PE pipe construction method in accordance with the requirements of easy to make changes. During the construction, it would be within a radius of tube bending agreed to bypass the obstacles, Reduce the construction difficulty.
4, distribution capacity, economically viable. PE pipe wall is smooth, not scaling. PE pipe inner surface rough equivalent ratio is an absolute pipe 1 / 20, the same diameter, same length, the same PE pipe under pressure of its flow capacity of about 30% larger than the pipe, so the economic advantages are obvious. Compared with metal pipes, PE pipes can be reduced about one-third of project investment can be a small diameter coiled tubing can further reduce the project cost.
5, the connection convenient, simple construction, and methods varied. PE pipe body light, easy handling, welding easily, welding mouth less, when the pipeline can be used when a longer laying of PE pipe coil pipe trench requirements than the ditch that require low, and when conditions are subject to restrictions, can be used Electrofusion Welding . In addition, the method can be used in the underwater pipe laying sunk greatly reduce the construction difficulty and cost of the project.
Good sealing. PE pipe welding to connect themselves with, in essence, to ensure the interface material, structure and management body's own identity, achieve the integration of joint and pipe. Its interface is higher than the tensile strength and bursting strength of pipe body, which can effectively resist the pressure inside the hoop stress generated by the axial stress. Thus, collusion, or rubber ring type compared to other mechanical joints, there is no risk of collusion of distortion caused by leaks, sealing performance are very good. Easy maintenance, you can turn off the water, gas maintenance and installation.
Good stress cracking resistance: PE pipe with a low notch sensitivity, high-shear strength of the segment-specific anti-trace capabilities, resistance to environmental stress very prominent.
Good low temperature impact resistance: PE pipe at low temperature brittle low temperature can be -60 degrees Celsius temperature range of safe to use. In the northern areas of China in the winter laid the wild when the polyethylene underground water, summed up an experience is not suitable for laying in the sub-zero on the construction, because when polyethylene pipe easily brittle fracture. Good wear resistance. The wear resistance of polyethylene pipe and tube comparison experiments show that: it's 4 times the wear resistance of steel pipe.
11, has a good ability to resist scratches 222. Study confirmed, PE grade PE pipe has good resistance to SCG's capacity and scratch-resistant ability. PE100-class pipe will have a more excellent anti-scratch capability.
Good resistance to rapid crack transmission capacity. Pipe cracking is cracking occurs when the crack speed to quickly pass, and instantly make pipeline sabotage could lead to disastrous consequences. Practice shows that in the plastic pipe in the crack resistance of PE pipe to pass stronger capacity than other channels.
Because PE pipe has the above-mentioned advantages, such as corrosion resistance, toughness, hardness and softness, pipes will be installed and so on, so more and more companies are tables gaze. Such as transportation and installation, the traditional steel pipe, cast iron pipe, the length of generally not more than 10 meters and the diameter PE pipe, especially small, even disk volume, length can be freely controlled. The greatest benefit this brings is to reduce the interface, that is, reducing the frequency of leak, both the safety of energy saving. In addition, PE pipe can serve as intubation into the old pipeline contractors to repair and update pipelines. A large number of land use can also be corrosive, seismic areas, mountains, wetlands, etc. Lot of extraordinary pipeline. Another big advantage is good economic returns. According to foreign data, with the PE in the gas or water pipes and the developed countries, PE pipe installation costs are generally lower than 50% of the pipe installation costs, while the interspersed method directly off than PE pipes buried in France to save construction costs 30 ~ 40%. Domestic gas, water supply, with the PE pipe installation cost is also evident in low-cost than the steel pipe laying works. HDPE double-wall corrugated pipes used in sewage works is so light weight, convenient transportation connections, reducing labor costs and various hoisting costs: construction of fast, smooth inner wall, grinding resistance coefficient is small, flow, large scale, to reduce the use of the maintenance work can not do directly spread on the basis of The groove, the connection reliability is not high water permeability, so economic and environmental benefits are significant. Again from the price in terms of pipe, gas, water supply pipes with PE also have certain advantages, the general diameter of the PE pipe DN160-effective than those cheap steel and HDPE double-wall corrugated pipe in this area with the more obvious advantages compared to conventional tubes. Of course, since the characteristics of PE pipe material itself, PE pipe also has certain weaknesses, such as low intensity, hit solid rock, metal extrusion collision could easily cause a pit until perforation; no flame retardant; to the highest restrictions on the use of pressure ; In addition, PE pipe stacked high demand can not be a long time the sun and rain, or easily aging, reduce the service life.
In other countries, plastic tube is continuously replaced by metal or other traditional materials, pipes, developing very rapidly. From 1980 to 1990 decade, in addition to plastic pipes, other pipes of various materials, the total growth rate of less than 2%, while the plastic tube growth rate is the sum of other types of channels 4 times the growth rate reached 8%, enter non-nineties the demand for plastic pipe will remain an annual rate of 4.2% growth in its output of about 8% a year rate of increase.
Polyethylene pipe Currently there are more than 150 production enterprises, the annual production capacity of 50 million tons. PE pipe production scale of 5,000 tons / year or more enterprises have more than ten, PE pipe installed in the new urban middle pressure gas pipeline network in the utilization rate of around 30% in 2000, amounted to 8,000 tons of projects around the use of, PE pipe for Urban water supply has also increased year by year.
Polyethylene pipe can be used for urban water supply, urban drainage networks and urban gas network, especially on city gas network to use almost all of plastic pipe is used polyethylene pipe; secondly, because of polyethylene pipes has good performance and recyclability of Health , as well as hot melt can be used to connect, connection quality, reliable, convenient construction, from 1990 to 1998, average annual growth rate of PVC pipe 2%, PE pipe average annual growth rate was 7% in 1998 to reach 2.6 million tons, the United States in 1997 than in 1996, an increase of 26%, to 37.4 million tons in 1998 increased 11.9% off than in 1997, far higher than the growth rate of polyethylene pipe PVC pipe; Third, In the development of our country "15" chemical building materials and plastic pipe development plans put forward, "15" during the promotion and application of plastic pipe PVC-U based mainly in the "Tenth Five-Year Plan", the PE pipe and PVC - U tube placed equal importance. And, PE pipe applications in China started late, great space for development.
From 40 developed countries in the world economy has begun to study the late polyethylene pipe, and applied to the drainage and gas works, from 60 years in succession in the water supply transmission and distribution systems, transmission and distribution system, drainage and gas transmission and distribution systems used in polyethylene pipe, and the using the ratio gradually expanded. Such as the UK the amount of polyethylene in order to control the use of natural gas as a turning point in 1968, use increased dramatically in 1979, laid dry, branch pipes and polyethylene pipes accounted for 80% of the United States were planted in 1983 are 88.6% gas tube for the PE pipe, and now the international community in Europe, the United States, Japan and other developed countries have been used in all polyethylene pipe.
Polyethylene pipe production equipment, some achieve automatic control, raw material drying can automatically join, can automatically adjust the mold, automatic OD, wall thickness automatic control, automatic cut off or the disk volume and so on. China is now the basis of polyethylene gas pipe equipment all imported from abroad.
In general, PE tubes superiority is unquestioned, so over the past decade, people in many large and medium cities in the gas, water supply to meet the low-pressure pipeline construction units, government departments to meet such a kind of virtuous circle. |
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