Introduction of PVC tube
PVC tube
PVC is short for Polyvinylchlorid, which is mainly polyvinyl chloride, adding other ingredients to enhance its heat resistance, toughness and ductility. The top layer of the surface film is the paint, the main ingredient in the middle is polyvinyl chloride, the lower layer is the back coating adhesive.
It is one of the most popular and widely used synthetic materials in the world. Its global use is the second highest among synthetic materials. According to statistics, in 1995 alone, the production volume of PVC in Europe was about five million tons, while its consumption was 5.5 million tons. In Germany, PVC production and consumption averaged 1.4 million tons.
Basic overview
PVC tube
PVC tube (PVC -U tube) rigid polyvinyl chloride tube, which is extruded by hot pressing method after being combined with polyvinyl chloride resin and stabilizer and lubricant, is the first plastic tubing to be developed and applied. PVC – U tubes strong corrosion resistance, easy adhesion, low prices, quality of a material is solid, but with PVC -u monomer and additive seepage, applies only to transfer temperature is not more than 45 ℃ in the water supply system. Plastic pipes are used for drainage, wastewater, chemicals, heating and coolant, food, ultra-pure liquid, mud, gas, compressed air and vacuum systems.
Category editing
PVC can be divided into soft PVC and hard PVC. Hard PVC accounts for about 2/3 of the market, and soft PVC accounts for 1/3. Commonly used in soft PVC floor, ceiling, and the surface of leather, but because of the soft PVC plasticizer is contained in (this is the difference between the soft PVC and hard PVC), poor physical properties (above the pipe need to bear a certain pressure, soft PVC is not suitable for use), so its use range was limited. Hard PVC does not contain plasticizer, so it is easy to form and has good physical properties. Therefore, it has great development and application value. In the process of production of polyvinyl chloride, several auxiliaries will be added, such as stabilizers, plasticizers, etc., if all environmental protection agents are adopted, the PVC pipe is also a non-toxic and odorless and environmentally friendly product.
Development history editor
The PVC profile products experienced the introduction period and the high speed development period. From time to time, they can be defined respectively from the 1980s to the mid 1990s and from 1995 to 2002. After 2003, the PVC profile industry entered the transformation period. In the period of the product: is the pursuit of low cost, simplify the doors and Windows profile section, formula of filling calcium carbonate, cause the product performance is very low, a lot of quality problems affect the appearance of the product promotion.
Beginning in 1995, a number of powerful enterprises, began to digesting and absorbing foreign European profile technology essence, developed their own doors and Windows series, become the leading domestic plastic doors and Windows, promote technical updating and development of Windows and doors, also make the whole industry obtained the unprecedented development and growth. From entering the product after the mature period, namely from 2003, many disadvantages it out reaction, high profit margins led to too much investment blindly, make industry comprehensive production capacity of nearly 3 million tons, far higher than the market demand; Many newly entered investors do not start with product innovation and technological innovation, but simply imitate, even cutting corners, fake and shoddy, and the competition in the industry is unhealthy. The rising prices of raw materials have intensified the unhealthy competition and caused some enterprises to operate in a difficult situation.
Status quo of PVC profile industry
Within the industry there are production enterprise quantity (nearly 400), can yield miscarried big (2.8 million tons), demand small (2003 national profile sales 2003 tons), production capacity can’t play, the contradiction of the annual output of more than 20000 tons of less than 10 enterprises, product quality is uneven, inferior products still have market, industry of quality and technical standard is too low, is not conducive to technological progress, lead to substitute for aluminum back. The high-end market (30%) is occupied by foreign brands, the middle and low market is unprofitable and competitive, and the final pattern has not yet been formed.
According to the distribution of factories, there are 392 manufacturers of profile products, 37 percent in the southeast, 12 percent in shandong, 17 percent in the central region, 19 percent in the northeast and 15 percent in the west. From the capacity division, China’s capacity of 2.8 million tons in 2003, 9% in shandong, 1% in the central region, 32% in the northeast, 7% in the western region and 39% in the southeast.
The present situation of PVC pipe industry
As a product of the development of science and technology, PVC pipes can be found in daily life. In Europe, the growth rate of plastic tubes in 1980 and 1990 was 8%, and the annual output reached 3.5 million tons in 2001, with PVC pipe accounting for 60%. The United States produced 1.6 million tons of plastic tubes in 1985, with a total output of about 3.6 million tons in 1999, with PVC pipe accounting for 78%. China’s first UPVV expanding pipe was born in shenyang plastic factory in 1983. Since then, China has the capacity to produce PVC pipes and drains. In the late 1990s, it was a period of rapid development of PVC pipe in mainland China. During the period, some factories with annual capacity of more than 50,000 tons will be put into production, and more than 30 PVC pipe factories will be produced in a scale of over 10,000 tons. The annual production capacity of plastic pipe is 2 million tons.
The PVC pipe has been praised by the engineering community for its light weight, corrosion resistance, high compressive strength and safety and convenience. In recent years, with the rapid development of domestic economy, the development of PVC pipe in China is very rapid.
Industry analysts pointed out that PVC pipe production accounted for 55% of the total volume of PVC pipe in 2010, supported by a complete supporting industrial chain and domestic raw materials. In recent years, the PVC pipeline market has been affected by various factors and its market share has been declining constantly. There are three main aspects of the decline of PVC pipeline market share:
First, the market of PVC pipe is impacted by other plastic pipes, such as PE and PPR, and has been seized a certain market share.
Secondly, the use of lead stabilizer in PVC pipes with food products has a negative impact on the development of PVC pipe.
Three is: at present, the development of PVC pipe in high speed development, the industry expanding capacity, many small and medium enterprises to seize market, reduce costs, a large number of filling calcium carbonate in the formula, shoddy, affect the image of PVC pipe industry, directly affecting the PVC market share, speed up the loss of the PVC market share.
But overall, although the share of PVC pipes is decreasing, it still dominates the market for plastic pipes. And the attractive prospect of the plastic pipe industry is still a bright spot for the development of PVC piping industry.
According to the research report of China chemical pipeline market analysis and investment strategy 2011-2016, the processing capacity of small and medium-sized enterprises in domestic PVC pipeline is mainly concentrated in PVC drainpipe. During the 12th five-year plan period, housing construction and municipal projects still provide steady domestic demand, which will increase the demand growth of PVC drainpipe. In the future, the demand for PVC pipeline will continue to be driven by the construction demand, especially in the construction of a large number of affordable housing. But it is worth noting that the PVC pipe enterprises should also be combined with the actual situation to adjust product structure, environmental protection and quality as the core key development conforms to the market demand for building materials products, such ability in the plastic pipe market and invincible position.
Development status
From the beginning of the 1980s, the state vigorously promoted the application of upvc tubes, and formulated a series of policies, systems and standards, and accumulated a lot of experience. Development to today, have perfect product standard, testing method and testing means, construction engineering technology standard and so on, and unified the product size and quality indicators, implements the interchangeability of the product. This shows that the development of PVC water supply pipeline has entered the mature stage, and the quality of products and construction quality are guaranteed, thus ensuring the use of PVC water supply pipeline.
The international standard for water supply for PE pipes (ISO4427) was not officially released until 1996. In 1999, the national standard GB/T13663 was prepared in reference to iso 4427 and implemented in 2000. However, the standards of PE fittings and engineering specifications are still being improved. This indicates that the quality of domestic PE pipe material is not stable and the pipe fittings are not perfect, so it is impossible to ensure the quality of production and construction.
outlook
The production capacity of China’s plastic pipe is 3 million tons, mainly including PVC, PE and pp-r pipeline, and PVC pipe is the largest plastic pipe with market share, accounting for nearly 70% of the plastic pipe. PVC pipe production line 1600. Annual production capacity of more than 2.5 million tons, 2003 PVC pipe (pipe fitting) annual output of more than 1.2 million tons. In the plastic pipeline, the share of PVC is 70%, PE is 25%, pp-r is 4% and other 1%.
Although the rapid development of PVC pipe attracts a lot of enterprises to enter the industry investment, but in the domestic production of many manufacturers (2000), the annual capacity in 10000 only more than 70 tons, annual output of 30000 tons of enterprises for more than 20 and has 60% of the industry’s output.
Overall, domestic small-bore, low value-added pipeline enterprises, large caliber, high technology content of small enterprises. The processing capacity distribution of PVC pipe is not reasonable. The processing capacity of small and medium-sized enterprises mainly focuses on PVC drainpipes, while a large number of non-standard tubes are still flooding the market, resulting in a disorderly and chaotic market competition.
In some traditional PVC pipe fields, PE and pp-r have obvious alternative momentum. The encroachment of other varieties on market share and the use of lead stabilizers in PVC pipes that are in contact with food products will have a negative impact on the development of PVC piping. Especially PVC raw materials generally take up 70-80% of the total cost, the main raw material of PVC price changes has significant effects on enterprise, 1998 years later, the capacity expansion, the intensified market competition, prices, PVC raw materials prices, industry profits decline. Many small and medium-sized enterprises cut corners to make life harder and harder to survive. The PVC pipe itself is a waste of transportation space, and the new road traffic laws and regulations have been introduced, which further increases the transportation cost.
Other information editing
Production process + auxiliary raw material preparation, mixing and conveying feeding to forced feeding, conical double screw extruder to extrusion die, the sizing set – spray vacuum shaping box – soaking water cooling tank to ink printer, pedrail haul-offs to carry knife cutting machine, pipe pile frame and product packaging testing.
PVC is being produced and applied worldwide with a growth rate of 4%. The growth rate of PVC in southeast Asia is particularly significant, thanks to the urgent need for infrastructure construction in southeast Asia. In materials that can produce three-dimensional surface film.
Process conditions
Dry treatment: usually not drying.
Melt temperature: 185~ 205C.
Mold temperature: 20~ 50C.
Injection pressure: can be large to 1500bar pressure pressure: can be large to 1000bar injection speed: to avoid material degradation, it is generally used to give a considerable injection speed.
Runner and gate: all regular sprue can be used. If you are working with smaller parts, it is better to use a needle gate or a submerged gate. For thicker parts, it is best to use a fan gate. The minimum diameter of needle-pointed gate or submerged gate should be 1mm; The thickness of the fan gate should not be less than 1mm.
Typical use: water supply pipe, household pipe, housing wallboard, commercial machine shell, electronic packaging, medical device, food packaging, etc.
Material properties
ABS (acrylonitrile-butadiene-styrene copolymer)
ABS is used to carry drinking water, mud and chemicals. The most common use of DWV applications.
Unplasticized polyvinyl chloride (UPVC) and CPVC (post-chlorinated polyvinyl chloride)
UPVC has excellent chemical resistance and wide working pressure zone. Due to long-term high strength characteristics, stiffness and cost effectiveness, UPVC system accounts for a large proportion of plastic piping installation.
CPVC is a variety of acid, alkali, salt, alkane, halogen and alcohols. This is an anti-solvent, aromatic and some chlorinated hydrocarbon.
PP (PP)
Polypropylene is suitable for use in food, drinking water and ultra-pure water, as well as in pharmaceutical, chemical and other industries.
PE (PE)
Polyethylene has been successfully used for years of drinking water and wastewater, hazardous waste, and the safe delivery of compressed gases.
Pipe advantages
1. It has good tensile strength and compressive strength: but its flexibility is not as good as other plastic tubes.
2. Fluid resistance small, PVC -u pipe wall is very smooth, the fluid resistance is small, the roughness coefficient of only 0.009, its carrying capacity than the equivalent diameter of cast iron pipe increased by 20%, 40% higher than that of concrete pipe.
3. Good corrosion resistance, resistance to drugs: PVC -u pipe with excellent acid, alkali resistance, corrosion resistance, is not affected by water and damp soil ph value, without any preservative treatment when the pipeline laying.
4. Good water tightness: the installation of PVC-U pipe material, whether using adhesion or rubber ring connection, has good watertightness.
5. Anti-gnawing rodent: PVC-U tube is not a nutrient source, so it will not be eroded by rodents. According to a study by the national health foundation in Michigan, rats don’t bite the rope-u tubes.
6. Performance test: the tensile strength of the curing time systole is the release of harmful substances in the period storage period.
The dimensions
Hard PVC pipe has a nominal outer diameter of 50CM, but the maximum of soft PVC pipe is 50
mm.
Hard PVC pipe specification: GB/t13020-1991
2.5, 3, 4, 5, 6… 355, 400, 450, 500, 560, 630, 710, 800, 900, 1000, etc
The difference between pvp-u and UPVC
PVC-U and UPVC are what we usually call PVC pipes, but in a different order.
In the process of PVC production, in order to increase the plasticizing properties of PVC and increase production efficiency, the plasticizer (such as DOP,DBP, DINP, etc.) will be added, and the PVC products with plasticizer will be soft.
We generally refer to the PVC products that did not add plasticizer in the process of processing as UPVC, or the PVC- U.
Pipe difference
Influence pipeline materials and equipment, the quality of these pipes. These factors are now the same in both domestic and foreign manufacturers.
Identify methods
1: look at the surface finish, and the whiteness.
2: sample fall, easy to break is a high calcium product, of course it is ok to meet your requirements.
3: take the sample with the foot of the tube to see if it can crack, or break the fracture elongation. (usually try to put the pipe in first, haha, or else they won’t let you step on it.)
4: weather resistance. The most direct way is to take the high-temperature high-light place for a few days, to look at the surface rate of change, but it’s a waste of time. I’m going to look at the first three.
The application situation
The essence of PVC pipe is a vacuum plastic film, which is used in the surface packing of various panels, so it is also called decorative film and adhesive film, which is used in many industries such as building materials, packaging and medicine. Among them, the building materials industry accounts for the largest proportion, 60 per cent, followed by the packaging industry, and a number of other small-scale applications.
PVC industrial suction pipe
PVC industrial suction pipe (3 sheets)
PVC pipe is divided into PVC pipe and drain pipe, which is used for municipal water supply and drainage, industrial water supply and drainage, civil water supply and drainage, irrigation, vegetation, etc.
Construction of the maintenance
The connection mode of PVC pipe mainly includes sealing ring, bonding and flange connection. Pipes with diameters greater than or equal to 100 mm generally adopt the rubber ring interface; Pipes with less than 100 mm diameter are generally used for bonding, and some are using live joints. Pipes are normally used when crossing sewers or other pipes, when the plastic pipe is connected to the metal pipe by flanges. Flange connections are also used to connect the valve to the piping.
1. When the small diameter pipe is adhered to by solvent, it is necessary to pour out the corner of the socket to form the groove and ensure that the fracture is smooth and vertical axis so that it can be bonded firmly and avoid leakage.
2 PVC tubes with normal diameter greater than or equal to 100 mm are made of rubber ring interfaces. Before installation, the staff must be arranged to corner the pipe and check the quality of the rubber ring. The socket and rubber ring must be cleaned during installation.
The pipe ditch excavation of traditional pipe installation only requires that the pipe can be put into the pipe groove and can be sealed. When the original soil layer is not loose, it can not be pressed to tamper with the cushion layer.
4 general PVC pipe open fork can be opened with three or vertical stops. When construction can add a saddle parts half composite tee, and U bolt clamping, thus increasing the tube wall, and then directly above drilling teeth, with external thread plastic pick up again. The test shows that this method can meet the requirement of specification after construction. In addition, the position of the thrust of the water flow in the tube, such as elbow, tee and tube end seal should be set up to withstand the thrust of the flow.
5 PVC pipe as a new type of non-metallic pipe, use the existing metal pipeline detection equipment, can’t detect its location, but if the pipeline buried on the pipe during the construction of embedding a wire can be easily solve the problem.
PVC pipe mounting structure and line installation
PVC pipe architecture thought has been the preferred material, is widely applied to various fields of industry, from its own characteristics can be fully reflected in the waterway system, so, what are we going to need to pay attention to during the installation process at ordinary times?
1, in order to guarantee the safety of the PVC pipe with clean, should use the use of stents in them to pipe, to ensure that pipe without put anywhere and been crowd on build, pipe can use clean, also can prevent mud residue is in the pipe;
2. Before installation, the layout of the construction pipeline should be inspected clearly, not only in order, but also in the structure.
3. When installing, gently release the tubing to avoid causing damage during handling, and pay attention to stone or mud to stay in the pipe;
4. After installation, we will test the test for a period of time. After the test, we should check that there is no leakage in each of the interfaces, such as the replacement immediately.
