He Weihua
Abstract: This paper comprehensively comes to the use of pipelines of water pipe networks. Keywords: water supply pipe network pipe
The fundamental task of water supply enterprises is to provide users with clean drinking water, which continuously supplies pressure water while reducing water supply costs. To this end, the water supply pipe network is an important part of the water supply system. It has the following five points for its hardware: (1) The closed performance high water supply pipe network is the pressure-press pipe network, and the pipeline only has good enclosures. It is continuous water supply. Basic guarantee. (2) Conveying water quality tap water from the water factory to the user, to pass a longer pipeline, often take a few hours and even days. The pipe network is actually a large reactor, the unfinished chemical response of the factory water will continue in the pipe network, and new contact with the wall containing the wall, producing a new reaction, these reactions have biomechanical, Sensory and physical chemistry. Therefore, the inner wall of the pipe is required to be corrosion resistant and will not precipitate harmful substances in water. (3) Hydraulic conditions good in the inner wall of the water supply pipeline, smooth, and smooth pipeline can reduce the water loss to ensure the water head. (4) Equipment Controlling a large city's water supply pipe network, with a total length of pipelines, more than a few thousand kilometers, thousands of special equipment in such large water supply networks, maintenance The good operation of the pipe network. Special equipment on the pipeline includes: valve, fire hydrant, venting valve, emptying valve, rinse drain valve, pressure reducing valve, conversion valve, water hammer eliminator, inspection person hole, telescope, slag, measurement Harmony, etc. These devices are in good condition to ensure smooth and safe water supply, safe water, avoid pollution. (5) Construction of the construction of the provincial water supply pipe network usually accounts for 50% -70% of the water supply system construction fee, so how to determine the construction scale of the water supply pipe network through technical and economic analysis, properly elected pipe and equipment are reasonable operation of pipe network way. 2, pipe category 2.1 metal pipe (1) steel pipe (SP) steel pipe includes: steel plate straight seam welded pipe and steel helical welding tube (suitable for large-diameter pipelines), seamless steel pipe (suitable for small-small diameter pipelines), stainless steel pipe (suitable for small small Cleaner pipelines), galvanized steel pipes and steel-plastic composite tubes (suitable for small-diameter pipelines). (2) Cast iron pipe (CIP) (2.1) Gray cast iron pipe (GCIP) includes a centrifugal cast iron pipe, semi-continuous gray cast iron pipe, and a rare earth cast iron pipe, a creep cast iron tube (suitable for small-small diameter pipelines). (2.2) Ductic Cast Iron Tube (DCIP) includes annealed ball ink cast iron pipe (currently suitable for small-small diameter pipelines), cast pneumo cast iron tubes (currently suitable for small and medium-sized diameter pipelines). (3) Non-ferrous metals, including copper tubes, aluminum tubes (suitable for small-diameter pipelines). 2.2 Non-metal pipes (1) Cement pressure pipe (1.1) Asbestos cement tube (ACP) is now not promoted; (1.2) Self-stress pipe (SSCP) in small towns and rural areas for small-and medium-sized diameter pipes; (1.3) prestressed Tube (PCP) includes a die wrap-filament prestressed tube (also known as three-stage tube) (CTPCP), vibrating extrusion prestressing tube (also known as a stage tube) (PVCP), steel pixel prestressing pipe (PCCP), suitable In the large school caliber pipe.
(2) Plastic tube (2.1) thermoplastic plastic tube includes hard polyvinyl chloride tube (UPVC) (suitable for small-small diameter pipes); high-density polyethylene tubes (HDPE), polyethylene chipping tubes (HAH), crosslinking Ethylene tube (PEX), polypropylene tube (PP), polybutene tube (PB), nylon tube (PA) (suitable for small-diameter pipeline); acrylonitrile monoetadiene 1styrene terpolycene Engineering Plastic Tubes (ABS) (suitable for pipelines in water plant in chlorine and clean water). (2.2) Thermoshibic plastic tube (GRP) GRP tube is also known as glass fiber reinforced resin plastic tube or glass steel pipe. The glass tube or sand-shaped glass tube is divided into two forming methods, namely the centrifugal casting method (Hobas method) and the glass fiber wound method (Veroc), and the GRP tube has a large applicable prospect on the large diameter pipe. 3. The use of pipelines in the domestic urban water supply pipe network in accordance with the investigation of 32 cities in 1990 (the comprehensive water supply capacity of this 32 cities has been 44.74% in the country, and its status is analyzed as follows: ( 1) The ratio of various caliber pipes in the pipe network, as shown in Figure 1. (2) The ratio of various types of pipes in the pipe network, as shown in Figure 2. (3) In the 80-400 mm water pipeline, various types of pipes are accounted for, as shown in Figure 3. (4) In the diameter of 450-1000mm, in the water dry tube, various tubes are proportional, as shown in Figure 4. (5) The diameter is greater than 1000 mm water supply pipe, and the ratio of various types of pipes is as shown in Figure 5. Note: There is a large extension of the annealed ball tube and the casting ball tube in the past eight years. 4. Suitability of pipe fitness 4.1 steel pipe (1) large-diameter steel pipe steel pipe is usually selected by Q235B (A3) calm steel plate, high strength, pipe and fittings, short period of construction, especially the complex terrain, Steel tubes are generally used. However, the stiffness of the steel pipe is small, easy to deform, lining, and external anti-corrosion requirements. If necessary, the combined welding work is large, and when the groundwater level is high, it can be used to overcome this difficulty. Compared with the cement pressure tube, the cost is higher. (1.1) There are two forming processes of large-diameter steel pipes, namely, straight seam welded pipes and spiral welders. Process flow of the seam welded pipe: Shearboard - Chuanglikou - Steel plate - Pressing two-headed arc - Roll tube (with spot welding) - Direct sewing (automatic welding) - pipe segment docking (including Spot welding) - weld loop port (automatic welding). The fabrication process of the spiral welded tube is divided into three stages, namely strip steel sheets, spiral forming and weld, spiral outer weld, and tubular segments. (1.2) The main requirement of steel pipe is mainly required for steel pipe welding to meet the current "Field Equipment Industrial Pipe Welding Engineering Construction and Acceptance Specification" (GBJ236-82). Important pipeline steel pipe welding level should reach the III standard. The steel pipe weld test X-ray flaw detection should comply with GB3323-87 standards, and ultrasonic flaw detection should comply with JB1152-81 standards.
The number of steel pipe welds is 5% in the factory, at the site of 10%. When the actual test, it can be optionally used, and when ultrasonic flaw detection is selected, the ultrasonic flaw detection is adjusted for X-ray flaw detection, and the recovery length is 20% of the quantity of the test. Before the steel pipe factory, it should be tapered, and the test value is 1.25 times the pressure of the pipeline test. The appearance of the seam welded pipe weld should be in accordance with the corresponding requirements, and the geometry of the throttle is allowed to deviate, and it should comply with Table 1. Table 1
Project allowed deviation (mm) perimeter D ≤ 600 ± 2.0 d> 600 ± 0.0035D Elliptical tube end 0.005d; Other parts 0.001d end face vertical degree 0.001D, no more than 1.5 Note: The elliptical is corresponding to the same end Vertical maximum diameter and minimum diameter. When the tube is assembled, the longitudinal weld is 400mm, and when the tube is less than 600 mm, the spacing should also be greater than 100 mm. (1.3) The main requirement of the steel pipe liner is mainly required to have a cement mortar or epoxy resin. A, the quality requirements of the cement mortar liner A, the inner disconnection pipe elliptical rate is not more than 2% of the inner diameter of the pipe, the inner wall without floating rust, debris, oil, etc., the height of the pipe is not greater than the lining thickness 1 / 3. B, cement use 525 silicate cement, sand is clean medium (particle size 0.15 ~ 1.2mm), cement mortar weight ratio is selected in 1: 1 ~ 2, slump is 60 ~ 80mm, pressure pressure Strength ≥ 30 MPa. C, the lining thickness and the allowable tolerance are shown in Table 2.
Table 2
Nominal tube diameter (mm) lining thickness (mm) thickness tolerance (mm) mechanical spray handmade applied mechanical spray handmade applied 500-7008 ± 2 800-100010 ± 2 1100-15001214 3-2 3-21600-18001416 3- 2 3-22000-22001517 4-3 4-32400-26001618 4-3 4-3> 26001820 4-3 4-3 d, the inner wall rough coefficient of the cement mortar is N ≤ 0.012. E, the inner lining caused by the crack caused by shrinkage, when its width is ≤0.8mm, and the axial length is not more than the garden week length and no more than 2m, it is not repaired, otherwise it should be repaired. F, surface defects (sequatics, sand, empty sleeves) are more than 5 cm2, and the depth is greater than the liner thickness allows tolerance, and the empty drum area is greater than 400 cm2 should be repaired. B, the quality requirements of the epoxy resin in the steel pipe in the wall sand blasting and the like to reach the requirements of the SA2.5 standard of GB8923-88, so that the walls are present in metal. B, the lined epoxy resin should have a health license for the health department, and the human body is harmless during the construction process. C, the total thickness of the liner is ≥ 400 μm. D, the coating adhesion strength ≥ 10 MPa. E, surface cloth hardness 16.2. F, surface resistivity 2.22 × 1015 (Ω). G, laminating the thickness of the coating, pore, bubble, mechanical damage, etc., and repair the discovered defects. H, the coating material should be acid and alkali resistant. C, the quality requirements of the steel pipe external anti-corrosion A, the surface of the steel pipe should reach the GB8923-88 index SA2.5 standard, exhibit a metal true color, an unacceptable oil, dirt, rust and other adhesion. B, anti-corrosion material should be acidic, alkali, microbial erosion, steel plate coated with anti-corrosion materials in 10% sulfuric acid and 10% caustic solution, soaking for 60 days, the antiseptic layer does not fall off, and the steel plate is not rust. C, the anti-corrosion layer should be cured within 24 hours, the thickness is uniform, the thickness, no more wrinkles, not empty, not colored, not sticky, the appearance is complete. D. After the anti-corrosion layer is cured, the tongue cutting is scavenging with a knife, and the coating cannot be separated from the coating and the primer and the metal surface is good. E, the surface of the anti-corrosion layer is good, the wear resistance is good, and the wire rope hung does not produce a trace of 0.1 mm. f, after the solidification of anti-corrosion coating, after three months, the insulation performance is good, requiring the breakdown voltage of the electric spark detection to 1000V, minimum is not less than 6000V, and only two of the 2,000 V above-6000V per square meter area breakdown. G, easy to operate, harmless to the human body and the environment. D, cathodic protection measures of steel pipes A, buried steel pipes in corrosive soils with cathodic protection measures. The soil is determined by the measured soil resistivity (ω) value to determine its corrosiveness, as in Table 3. table 3
The degree of corrosiveness is strong and weak, non-soil resistivity (Ω · m) <2020 ~ 5050 ~ 100> 100 b, cathode protection measures have sacrificial anode and external current method, should be selected and design according to specific conditions. (Omitted) (2) Galvanized steel pipes are mainly used on small-diameter pipes in China. It is mainly used to galvanized steel pipes (white iron pipes), but due to rust problems, the water quality and useful use are. The galvanized steel pipe of the inner lining polyethylene or polypropylene is usually referred to as a steel-plastic composite tube, which improves the above defects. The galvanized steel pipe is in two ways, one is the inner liner coated polyethylene, and the other is a thin galvanized steel pipe extruded polyethylene tube. At present, there are two products in the country. The prior coating layer is not easy to stick, it is not easy to lining, it is easy to lay over; the latter mode is better, the pipe is also lined with polyethylene, the pipe is not sleeve, using fast The joint process, and the comprehensive price class with galvanized steel pipe, has a good application prospect. In addition, the cold galvanized steel pipe sold in the market, the galvanized layer is thin, the inner wall is worse, and even unscated, it affects the water quality. It uses 3 to 5 years to corrode the perforation. It does not meet the water supply pipeline. As a counterfeit product, Disable. 4.2 Cast iron tube cast iron tube is a pipe for use in the water supply network. At present, the annual output of cast iron pipes in the world is about 7 million tons, and increment is incremented by 3%. (1) Foreign Cast Iron Tube Production Overview Foreign industrial developed countries have gradually eliminated ordinary gray cast iron pipes from the 1960s, generally adopted ductile iron pipes, and the production of about 6 million tons, the product specification is DN50 ~ 2900mm, of which the US year The output is 150-8 million tons, the annual output of Japan is 900,000 tons, and the annual output of France has an annual output of Germany. The annual output of Germany is 400,000 tons, and the British annual output is 200,000 tons. France Mo Songqiao company, Japan Kuiota company is a large-scale, technological advanced ball tube manufacturer. At present, there are three main models in the development of the production technology of ball ink cast iron pipes. Such as Western Europe, Canada and other countries, the water-cooled metal type centrifugal casting tube technology produces all kinds of pipes; Japan uses water-cooled metal type centrifugal casting technology for DN ≤ 300mm pipe, while large diameter pipe resin sand type centrifugal casting technology; former Soviet area to DN ≤ ≤ Semi - continuous casting technology of large diameter pipe for water-cooled metal type centrifugal casting technology. (2) China's cast iron pipe production, my country has more than 200 cast tube mills, with an annual output of more than 1.2 million tons. These manufacturers have mainly produced the production of gray cast iron tubes mainly with semi-continuous casting technology, with an annual output manufacturer of more than 100,000 tons. Angang Casting Tube Factory, Shougang Casting Tube Factory, Guangzhou Casting Tube Factory, Maanshan Casting Tube Factory, Yingkou Casting Tube Factory. In 1985, my country has introduced water-cooled metal centrifugal casting tube technology and equipment from Germany, USA, and has a previous year production of 25-300,000 tons. Such as Houma Feng Lei Machinery Factory, Dalian Enterprise Pipe Plant, Jinan Casting Tube Factory, Huangshinbao Casting Tube Factory, Maanshan Casting Tube Factory, 邯郸 Emerging Casting Tube Factory, Benxi North Tube Plant, Xuzhou Guangda Casting Tube Factory, Qingdao North Steel Tube Factory, etc.邯郸 The Emerging Casting Tube Factory has also digested, absorbs domesticated equipment, and has developed domestic equipment. At present, these manufacturers are supplied no more than 1000mm, and the Shijiazhuang Emerging Casting Tube Factory uses a resin sand type centrifugal process to produce DN1200 ~ 14000mm large diameter from the heart balloon tube. There are also many cast tube manufacturers in China, using the original equipment to properly renovate, producing a rare earth cast iron tube (creep cast iron tube) and a micro-eluking cast iron tube. Among them, there is a large-scale Sngng Casting Tube Factory, Shougang Casting Tube Factory, Guiyang New Casting Tube Factory, Sichuan Yuan Tong Machinery Factory. The resin sand-type centrifugal tube process production line designed by the Anshan Steel Casting Tube Factory has been put into use.
(3) Domestic Ball Tube Development Dynamics (3.1) According to the analysis of relevant information, my country needs 1.5 million tons / year before 2000, and my country's current cast iron pipe annual output is about 1.2 million tons, mainly It is a continuous cast or centrifugal cast tube, 15 produces equipment from the trend iron pipe from abroad, and this year's actual production is only 25-300,000 tons. Relatively, in the past ten years, the domestic ball tube has developed rapidly. On the one hand, some ball iron pipe manufacturers have introduced the equipment and technology of the entire set of ball iron pipes from abroad, strengthen the test of raw materials, and use direct reading. Spectrometer quickly analyzes the spheroidization rate of iron water, and uses computer production process quality control; and then digests, absorbs foreign technology to make the ball iron pipe production line equipment domestic; on the other hand, some cast pipe factories adhere to the self-study and revolutionary renovation, establish A production process of a cast tube. Thus, my country's ball tube casting level rushed to the advanced level of the world's 1990s. Of course, the problem is existing. In addition to a few manufacturers, most of them are not good, from these manufacturers themselves, use the introduction equipment to increase costs, some pipelines have been put into production, and the quality of employees and management has a fairly gap, but Ball iron management, high technology, has advanced hardware, no super hardware, is not good, some manufacturers have less than 90%, and the company is in a loss of loss, so the production of the ball tube Use, there is a process of supporting and promotion. (3.2) Several questions to be discussed in the quality control of Ball Iron Tube Factory A. Tube Interface Test Questions The ball iron pipe plants are hydraulically tests for each pipe, but the flexible interface is not testing. There is iron tumor in the mouth, and there is no need to check and correct it. As a big household, we are concerned about this. It is recommended that the water pressure test equipment is transformed, the interface participates in the inspection, and the interface is not dripped under test pressure. It is important to emphasize that the cement pressure tube is in the water pressure test. B, pipe, pipe fittings Some plants have clearly replaced the soldering measures, some of which are oral expressions that do not replenish the welding, and in fact, there is a case where the soldering is present. As a user, in principle, do not agree to the pipe, pipe fittings; foreign-related standards mentioned, if the pipe and pipe fittings are soldered, and the corresponding review test is adopted, it is recommended to explain the reason for the user to sell. (3.3) Differential differences in the annealed ball iron pipe and the casting ball iron pipe According to the requirements of ISO2531-91 international standards, the indicators of the ductile mechanics are: tensile strength ≥ 420 MPa; yield point strength ≥ 300MPa; elongation ≥10% Brinent hardness ≤ 230. The control indicators of the chemical composition of the ball iron pipe are: carbon 3.8 ~ 2.3.75%; silicon 1.8 ~ 2.2.1%; manganese ≤ 0.08%; phosphorus ≤ 0.08%; sulfur is ≤0.02%; magnesium 0.03 ~ 0.05%; rare earth element 0.01 ~ 0.03% . The ball tube is printed in the GB9441-88 standard, requiring the spherulation level to be primary; the spheroidization rate is greater than 80%; the graphite size is 6 ~ 7 (under 400 times the field of view, the scaller is 1.5 ~ 4mm), the graphite ball reached 600 ~ 800 / mm2; carburgeon ≤ 1%; small diameter tube ferrite ≥90%, large diameter tube is around 85% (pearlite controlled within 8 ~ 12%).
The above data is basically the control range of the annealed ball tube, but the cast ball iron tube should also meet the above requirements, the main gap is small in the elongation, only 3 ~ 5%, the surface hardness of the cast ball iron is large, existence The over-cooling layer made of the carburized body, brittle, affecting tensile strength, and is difficult for sawing. And the extension of foreign ball tubes in foreign countries is also controlled by about 7%. Therefore, it is controversial to the tertiary elongation of the ball iron pipe. Some cast pipe plants should not be too high. They propose, the resin sand-shaped centrifugal cast ball tube process and thermometrics of the self-developed, can be centrifugal. The elongation is 5%, and the annealing step can be more than 10%. In summary, the pipe welding pipe should be used as the main forest pipe, and the medium and small diameter ball iron tube elongation is controlled within 10 to 15%; the large diameter ball iron tube elongation is controlled within 5 ~ 10%. It is good. (3.4) Digestion, absorb foreign technology, improve my country's annealed ball iron pipe management process, in recent years, Hebei Xinxing Casting Co., Ltd. has successfully domestically produced water-cooled metal centrifugal iron pipe production line, Angang Casting Tube Factory and other units are also successful The resin sand-type centrifugal casting ball tube and thermoforming method were developed. These marks that my country's ball iron management production level has begun to move towards the world's advanced ranks. Of course, these production lines are still being improved. For example, some plants are not yet perfect in quality control; some of the qualified rates of some plant products are still low; some factories still have many problems in cement mortar (not smooth, floating weight, thickness deviation large) Wait, so that existing equipment can not make full play. In addition, these backbone ball iron pipes are distributed in Northeast, North China, Huazhong, and South China, Southwest, and Northwest China have not yet, we hope to build correspondingly to these regions through the introduction or existing manufacturers. Ball tube production base. 3.5 The use prospect of the casting ball tube has nearly 200 connected tube factories in China. They produce the coating cinettes, the strength and toughness are low, and the external load is not affected, so in the water supply pipe network. The explosive tube, leak accidents have repeatedly occurred, but these pipelines will be naturally eliminated in the competition of the market economy. It is recommended that the state is oriented by corresponding regulations, accelerating elimination. However, the management level is better, through the improvement in the tooling equipment and the process, can be easily transformed into a cast ball iron pipe factory, and the rigid interface is changed to a flexible interface, and the cement sand pulpers is added. Due to the foregoing reasons, I hope that the thickness of the pipe wall should not be too much thinner, still have a broad market demand, in order to promote the annealed ball tube, cutting the casting ball iron tube and cut it, and the connection of the rigid interface The cast ash cast tube, the water supply enterprise is no longer purchased and it must be emphasized. (3.6) The production of ball iron pipe fittings The current domestic annealing ball tube production has been close to the level of the 1990s, but the production gap between the ball tube pipe fittings is large. Some ball tube plants have equipment for the production of ball iron pipes in the 1990s, but the production of pipe parts is still in the 1950s, and the contrast is obvious. It is reported that Chifeng Pipe Casting Co., Ltd. has established a relatively complete EPC (disappeared mold casting method) Brain rail pipe production line, which enables the production of Brassic tube to achieve the international advanced level (the only tubular specification is small, the price is high). Of course, only the quality of the pipe is similar to the quality of the pipe, and the spread of the ball tube can reach the actual effect.
(3.7) The quality of the rubber ring is related to the quality of the rubber circle to the life of the ball iron pipeline, but the casting tube manufacturers, the rubber circle has its own workshop alone, and some manufacturers are supplied by the foreign rubber factory; Some use natural rubber, some use of synthetic rubber, the manufacturing standards of each selected, is a non-tight-procedure for hysteresis health requirements. It is recommended that the state should formulate corresponding standards or regulations, the production of rubber circles, should be returned to a quality control The department is recognized or the designated minority factory is supplied. (3.8) Perfecting the corresponding standard annealing ball tube pipe and pipe fittings, but not covered all specifications; castball tubes and pipe parts have no corresponding national standards; design specifications for ball iron pipelines And the construction acceptance specification has not been introduced. The formulation and improvement of these standards and standards is the premise of promoting the use of new pipes. For example, the tube wall of the ball tube is thin, according to the experience of foreign use, it is embedded in the corrosive soil, which is easy to corrupted, so that the outer wall of the tube must be sprayed into the asphalt coating before the use of the production of the gray cast iron pipe, domestic counterpart This has not been attached. In addition, large-diameter ball iron pipes must be calculated by structural calculations, and they can ensure safe operation of the ball tube pipeline. 4.3 Cement Pressure Tube (1) Asbestos Cement Tube In the 1960s, some cities have used almost no use. (2) Self-stress tube self-stress tube is made of self-stress and configure a certain number of steel bars. The self-stress cement for the pipe uses 425 or No. 525 ordinary silicate cement, 325 or No. 425 alumina cement and dihydrate, according to appropriate proportional processing, the steel wire used is low-carbon cold chiropolor or wire mesh . The domestic production of self-stress tube is between 100 and 600mm. Due to its simple process, the management cost is low, more than 100 manufacturers, the annual output is nearly 1000km, but since it is prone to expansion and horizontal breakage, mainly In small towns and rural water supply systems. (3) The prestressed positive prestressing tube includes a stage tube, a three-stage tube, and a steel cylinder prestressing tube. (3.1) Phase 1-stage pipe process is to put the steel skeleton as a ring-to-prestressed steel wire into the assembled tube mold, arrange the longitudinal steel bar, and the longitudinal steel bar is obtained by electric heating or mechanical method. Stress, then pouring the concrete, which is subsequently water-proof to the special rubber endometer, which causes the glue mold expansion, the, the outer mold and the steel bar to be expanded, and the moisture in the concrete is crowded. The ring has been prestressed and steam maintenance immediately, and the water pressure in the inner model is discharged, and the mold is deposited. This kind of process was successfully tried in 1952, which is called "Xun himself" in 1968. my country has been successfully developed in 1968, with Xi'an Hongqi Cement Products Factory, Beijing Cement Products Factory and Zhuzhou Cement Production of the product factory and other units, the maximum diameter of 2m, including the Zhuzhou Cement Products Factory also introduced the management technology and equipment from Sweden. This process is characterized by strength and infiltration, thin tube wall, but the outer mold seam is easily leaked, the repair rate is high, and the inner should be grinded. (3.2) Three-stage tube three-stage tube refers to the three stages of pipelines, first makes a rumor core with longitudinal prestressed steel wire, tube core wrapped around the prestressed wire, and then made cement mortar protection Floor. The die forming process is separated from the heart method and the suspension method. Domestic Liaoyang Cement Products Factory, Sichuan Shuangliu Cement Products Factory and other units, Liaoyang Factory also introduced suspension rolls and method technology and equipment from Australia. Such process consumption is low, suitable for fluidity production, poorly resistant to infiltration, high repair rate, cumbersome tubes.
(3.3) Steel pump prestressing tube The prestressing tube is a thin steel cylinder of about 1.5 mm in the middle of the die, and then a layer or a layer of prestressed wire is applied to the ring. This technology is the most developed by Bonna, France, and has been developed by Europe, the United States. At present, the United States and French have hundreds of thousands of kilometers, of which the US has the fastest development, Ameron, and Price is in the world. Leading level. It can be divided into two types: interluble tubes and embedded tubes. The difference between the lined cylinder type and the embedding cylinder type, the former's stress steel wire is directly wound on the steel cylinder, and the latter is wound on the concrete layer outside the steel tube; the former uses centrifugal process to form, caliber Large (DN ≤ 1200mm), the latter uses a vertical vibration process, and the diameter is large (DN> 1200mm). Steel cylinders intended to reach 2.0 to 40 MPa, and the working pressure is usually 1.5 ~ 3.0MPa, which can reach 5.0 MPa, and the range range is DN400 ~ 4000mm, the maximum DN7600mm. Manufacturers in the world mainly manufactured steel pixels (DN1200 ~ 4000mm), US "Price Brather" companies (DN600 ~ 4000mm), France "Bonna" companies (DN600 ~ 4000mm), France "Bonna" (DN600 ~ 2500mm), Germany's "Dyckerhoff-Widmann" companies (DN600 ~ 2500mm). The country in the world uses the most popular tube in the United States and Canada. At present, the world's largest steel cylinder expectation stress tube project is in Libya, 1900KM, a diameter of 4m, and 2.8MPa in diameter. It has been completed. Domestic is a factory in the 1990s introduced this process, and there are three factories that have been bracusted to produce steel cylinders, namely Shenzhen Sun Pipeline, Wuxi Huayi Pipeline Co., Ltd. and Shandong Xinghou Electric Pipeline Engineering. Shenzhen Sun Pipe Co., Ltd. was built in 1992, officially completed in 1995. The company's technical source is fully introduced to the US Price Brothers (PB Company) technology, all production equipment is also from PB. Among them, the main equipment has thin steel plate seam welding tubular equipment, steel pipe water pressure testing equipment, die-shaped shaped steaming equipment, stirring, lifting equipment, prestressed wire wind winding equipment, mortar spraying equipment, tension, socket, circulation, High frequency pair of welding equipment. The company can make a series of pipes such as DN900 ~ DN4000, with a single tube length of 6m, working pressure 0.2 ~ 2.5MPa, with an annual production capacity of 38km, and the maximum tube diameter of the current manufactured is DN2600. The company's production standards use US AWAC301 standards, with a perfect warranty system and advanced test testing means to ensure product quality.
The company has strictly demand for raw materials, such as cement must be a silicate cement, which must be labeled 525, does not blended with slag, aluminate (C3A) content should not exceed 8%; thin steel plates do not need cold rolled products; prestressed steel wire The limit stress is not less than 1740 MPa, and the steel sampling is tours. It is required that the wire is required to reach the minimum torsion ring before the break is not less than 8 laps; the thin steel plate can weld the surface oxide layer before welding, and use a submerged arc welding; After the steel cylinder is formed, it is necessary to perform a water pressure test; in the process of winding the ring, spray cement net pulp, growth of friction and improve wear resistance, and use computer and hydraulic control system to ensure the uniformity of the appended steel wire. The accuracy of the wire spacing; the prestressed steel wire is not bundled, but the riveting connection; the insert steel ring is extruded with the overall mold, the high frequency pair of welder; uses high-speed cement mortar gun to ensure the quality of the outer protective layer The insert steel ring working surface is applied to the zinc-shaped anti-rust-resistant paint to ensure corrosion quality; the size of the tube socket sealing the groove should make the "O" type film ring after the teas, accounting for the groove All space; after the on-site pipe is tramped, the inside and outside clearance ensures cement mortar full irrigation and improves the anti-corrosion effect of the metal surface of the socket. After checking the quality of the product, it was found that in the field-stacked pipe, the longitudinal crack did not, the duct crack repair is small, the end of the socket end surface is prevailing, the insertion, the annulus is general, generally before the pipe is factory, supplement A anti-rust paint. The company can use most equipment to use the company's introduced drawings for localization. The automatic welder, air-conditioning vibrating head, computer prestressed control system needs to be introduced. The company can produce a variety of pipe parts such as bending pipe, T-type tube, Y-type pipe, and variable tube, and the production process is roughly: first cutting welded steel plate isoform, and its socket work surface welding special socket ring, Then, the steel wire is applied inside and outside the steel sheet, and the cement mortar protective layer is applied, and it is appropriately trimmed after steaming. The company's products are also used in the urban water supply pipe network, which is also used in the water supply, drainage projects and nuclear power plants. The company's largest user is a Dongguan Municipal Construction Committee. It has been found in the site of the site. DN2200MM pipeline has a 200mm thick sand cushion; the internal and external gap is less than 10mm, and the inner and outer gaps are filled with cement mortar. According to the introduction, there are 7km, DN2200 steel pixel and some steel pipes in November 97, did not find problems. Wuxi Huayi Pipeline Co., Ltd. was built in 1994, and the DN1400 ~ DN3000 steel cylinder prestressed pipe, single tube length 5m long. In the year, the large-diameter pipe capacity was manufactured by 24km, and the DN1400 ~ DN2400 tube has been manufactured 35.255km. The company has a focus on the technology and equipment of American Ameron. Main equipment: spiral equipment, steel cylinder water pressure test equipment, die vertical vibration molding and steaming equipment, vertical differential winding prestressed steel wire equipment, vertical roller spraying equipment, undertaking port ring forming equipment (Using a layered manual docking welding). The process flow is shown in Figure 6. Insertion jacket production ↓ Steel tube welder ------- →
Making steel cylinders ↓ test press ------- →
Water pressure test ← ----------- ┒ │ ┠ ┠ ------- →
Electric welding repair
Core formation ↓
Tube maintenance ↓
Stripping ← ---------- ┒ │ ┠ ↓ ------- →
Surface correction winding machine ------- →
Wire wire ← ---------- ┛ ↓ roll speculator ------- →
Protective layer production │ ┠ ↓ ------------ ┒ ↓
Finished product inspection ← -------
Appearance repair ↓
Finished Stacking Figure 6 Steel Pressure Prestressed Tube Brand During the company's steel pocket prestressed pipes for DN ≥ 200mm, the seal is used in a double rink, and the sealing property is tested in the tube body, so that the problem is expected to be early Rework. The company has no concrete facilities, providing merchants in adjacent Wuxi Cement Products Factory. The company's venue is small, and the pipe is all vertically stacked, and the insertion jack ring rust problem is present, and the end is repaired, and the inner ring of the pipe is large. According to Wuxi Shui Water Company, the DN1800 Tube has been installed for two years, and the test pressure is 1MPA. It has not been issued; the DN2000 tube has been installed 6km, of which 1km has been pressed, no problem; DN2200 Tube has been installed 1km. In general, the steel pixel pre-stress tube installation speed is fast, and 22 DN2200 tube is installed one day, that is, 110m, which is better than the original phase of the prestressed tube interface. Shandong Xingwei Electric Pipeline Engineering Company was established in 1957, in 1989, the first product introduced key equipment and technology from American Ameron, in 1989, can manufacture a variety of specifications of two types of two processes, one DN600 ~ 1200 Continental production line, annual output 30km; a DN1400 ~ 3400 buried tube production line, annual output 15km. Huayi's company is compact, less coverage, more reasonable process, with the following advantages: (1) The spiral cylinder compares to half of the straight seam welding tubular equipment, and the process is simple, the welding quality is more reliable. (2) The company's key equipment for the diorexial forming of the die has been domesticated. (3) Use the canvas cover body and the structure. (4) Take the tube core, the shield protective layer is open-disciplined, no plant, small land. (5) Framework, sand mill, and power supply. The company has digested, absorbed the introduction technology, and existing equipment can be domesticated. 4.4 Plastic Tube (1) Thermoplastic Plastic Tube (1.1) Hard Polyvinyl Chloride Tube (UPVC): This pipe is developed in Europe, the United States, Japan, etc. in the 1940s, promoted, and promoted in DN ≤ 200mm water supply pipelines. Important market. In the 1960s, my country has introduced production equipment and technology from Austria in 1983. Since the production of production equipment and technology, China has established production lines, with an annual production capacity of more than 500,000 tons, with an annual output of about 100,000 tons. It is now promoted in towns and rural areas. In order to solve the disadvantage of hard polyethylene chloride tube crispy, there have been impact type pipes. The interface mode of the hard polyvinyl chloride tube can also be bonded to the flexible interface, and the adhesion must be used to ensure the quality, the flexible interface is good, and the installation is simple. In recent years, urban, Qingdao, Wuhan and other cities have used or is using or being flexiblely joined by a flexible tube of a rubber ring without using galvanized steel pipes. Jiangyin Dawei Plastic Products Factory is actively developed by the DN ≤ 200mm hard polyethylene flexible pipe fittings in the construction community, which has created conditions for the use of hard polyethylene tubes in the construction community. (1.2) High-density polyethylene tube (HDPE): This pipe can be flexible with electric melt, hot melt welding, and a film ring. Its advantages are non-toxic, corrosion resistant, tensile, non-crack, small diameters On the reel, the installation is fast, the amount of interface is small; the disadvantage is that the anti-aging performance is poor, buried in the underground susceptible to the mouse.
Foreign high-density polyethylene tubes in recent years is rapid growth, mainly for small-diameter water pipes for water supply pipes to residential. In China, there are DN ≤ 200mm series products, usually make the factory for hard polyvinyl chloride tubes can be manufactured, and only the material is temporarily imported. The use of the household line is estimated to increase year by year. (1.3) Crosslinking Polyethylene tube (PEX): Add silane graft material in ordinary polyethylene raw materials to modify the linear molecular structure into a three-dimensional cross-network structure, which has temperature resistant (-70 ° C ~ 110 ° C) ), Pressure, stability, and durability, and non-toxic, tasteless, generally mechanically connected, is a tube recommended by the indoor hot and cold water. (1.4) Polyethylene Clamp (HAH): The structure of such a composite tube is between the thin aluminum tube and the outer layer high density polyethylene tube, contains a polymer plywood, which maintains polyethylene tubes. And the advantages of aluminum tubes, avoiding their disadvantages. It can be bent (bend radius = 5d), and heterodal resistance ( 110 ° C to -100 ° C), high pressure (1.0 MPa or more). It mechanically extruded with copper pipes, usually the product specification DN ≤ 25mm, which is a new type of pipe recommended on the indoor hot and cold water supply pipeline in recent years. (1.5) Polypropylene tube (PP): This pipe is non-toxic, heat resistant, cold-resistant, aging, high strength, half the price is half-plated, but easy to crack, small-diameter polypropylene tube in rural water supply Use it on the pipe. (1.6) Pyrene Tube (PB): Polybutene is a high molecular inert polymer, and the polybutylene tube has high temperature, cold-resistant characteristics, good chemical stability, strong plasticity, odorless, non-toxic, A variety of connection modises (thermally bonded joint welding, thermal spiral on-site welding, mechanical clamping), is the ideal small-diameter water supply pipe new pipe, has been widely used by some countries in the European Community, America, and Asia. There is existing products in China, but the raw materials must be imported. (2) The thermosetting plastic tube thermosetting plastic tube (GRP) is usually referred to as glass tubes, also known as glass steel pipes. (2.1) The manufacturing process has two types of manufacturing processes: centrifugal casting method (HOBAS method) fiber wound method (VEROC method) fiber wound method continuous winding method and reciprocating winding method. In order to increase the stiffness of the pipe, the above three types of row of processes can be sanded during the process. In the 1980s, we have begun to develop equipment and technology from Italy, the United States, Japan, etc. in the 1990s, and has formed nearly 50 production lines, mainly nearly ten. A, centrifugal casting process - During the process of pipe, cut glass fiber reinforcement materials and sand, fed into the steel mold fixed to the bearing, the steel mold is driven by the motor, and the steel mold is rotated, in steel The mode end is injected into a catalyst resin to impregnate the reinforcing material, under the action of centrifugal force, the resin converts the air in the fiber and the filler, thereby producing a porous dense composite. Due to the centrifugal force, the inner wall of the tube forms a smooth and smooth resin, and the pipe is cured at a higher temperature. Beijing Beichen Modern Pipe Co., Ltd. and Zhejiang Oriental Group Pipeline Company have introduced Hobas's equipment and technology, forming a half-activated production line controlled by computer, and manufacturing a sand-bearing glass steel pipe for creating a cured method.
Under the conditions of centrifugal rotation, the feeder is controlled by the computer by a computer to transmit a different raw material. Its tube wall can be simplified into liner, enhanced, structural, enhanced, five layers of external protection. The materials and effects of each layer are shown in Table 4. Table 4
Name material action outer protective layer enhanced layer structure layer liner glass fiber, resin, sand glass, resin glass, resin, sand resin, resistant to ultraviolet, so that the wall has an inner and outer pressure of the axial, ring The intensity allows the wall to withstand the deformation strength, hydrodynamic characteristics, the internal and outer walls of the pipe, the tube wall is dense, due to the shape of the outer shape, once the breakage is conducive to the use of the cardoon method. This pipe does not with the mouth, South Africa uses a two-way flexible casing connection, which has doubled the number of interfaces than the insert tube, and increases the fault probability. The sleeve is a structure in which ternary ethylene ethylene ethylene ethylene ethylene rubber is used in a di-water sealing lip, usually the sleeve and pipe first combine in the factory, but put on the yield and rain, the glass steel shell of the sleeve The coefficient of expansion with the rubber liner is different, and it is easy to deform. B, continuous winding process - in the core mold, use long fiber glass, continuously wrapped in a certain bevel radial direction, in the die resin, and a certain proportion of stained fiber and sand, such a management process Type of Denmark, can produce any long tube segment, which is generally below 1.6MPa, and the pipe diameter is between 300-3000mm, and there are also in this area in China, such as the Anyang Composite Materials Factory, Henan Province from Italy. Introduced equipment, Jilin Province Changchun Composite Materials introduced related technologies and equipment from the United States. C, reciprocating winding process - on the core mold, with long fiber glass wire with a certain angle, radially cross-wrapped, and the tubing with high stiffness can be sand. However, the pipe with high internal pressure is generally not sand. More manufacturers in China, are more manufacturers, such as Hebei Province Zhongyi FRP Co., Ltd., Jiangsu Lianyungang Composite Materials Factory, Sichuan Zigong Zhongjie Port Co., Ltd. Its tube barrier structure is shown in Table 5.
table 5
Name raw material resin content% fiber content% inner lining inner surface layer anticorrosive resin 90-955-10 dense resin layer, anti-seepage, anti-corrosion, thickness 2-3mm secondal lack fiber structure resin 7030 structure layer winding fiber structure Resin 24-3268-76 High-intensity structural layer-containing resin 100 forming the resin 100 of the ultraviolet absorber forms an anti-aging external protective layer In recent years, some domestic manufacturers can self-produce equipment, and use a glass steel pipe for a rewound process. (2.2) Pipe evaluation A, three processes compared, reciprocating winding process with high water pressure capacity, few interfaces, less investment in continuous winding technology, less investment; centrifugal casting process is good, the management cost is lower , Pipe is favorable. B. The glass steel pipe can be structurally designed and manufactured according to different conditions of use. Different resins and fibers will affect its quality and prices. The resin used in general structural layers is a phytically unsaturated polyester resin or a modified edible phytopolyester resin; an inner surface anti-permeability layer, generally use a benzene unsaturated polyester resin, and the product quality requires high. The internal anti-permeability layer also has a vinyl ester resin, and the difference in these resins is very large. C, the glass steel pipe is like other plastic tubes, and there are strain corrosion problems, usually the creep coefficients are expressed. The definition of creep is the strength of the strength of the pipe, declines with the extension of the time of use, and thus determines the performance index of the pipe material under conditions that ensure the life of the pipe. The needs of plastic tubes is related to the own performance of the materials available, and also related to the wall structure, the creep coefficient of the glass steel pipe rigidity, the pressureless tube is 0.4, and the pressure pipe is 0.5. D, the glass steel pipe is used by the process, and the quality control means and the improvement of the quality control means and the improvement method during the management process are all important, otherwise it is difficult to guarantee the quality. E, the pipe has always had the regeneration recovery of waste materials, incinerability treatment, the final incineration of the thermoplastic tube and the thermosetting plastic tube, most sensitive to the environmental damage to the environment. At present, only the old scraps of the tubes such as polybutene can be incremented with the domestic garbage into thermal energy. Since its molecular structure is free of halides, the combustion product does not produce corrosive and toxic substances, and does not harm the environment. F, the glass steel pipe for water supply, its inner liner should be wear-resistant, toughness, surface light, thick thickness, good resin curing effect, and is not allowed. Crack. Otherwise affect its anti-permeability, the fibers of the structural layer may be free to water, affecting the sanitary conditions of water supply. In general, large-diameter glass steel pipes are used on the source water reference pipeline, and there are more domestic and foreign use. There are fewer use in the water supply network. 5, the interface of the pipe (1) welding, bonded pipelines, should consider hot and shrinking countermeasures, properly installing a flexible interface stretch or U-shaped bend. (2) At present, in various types of pipeline flexible interfaces, it is basically adopted in the push-in type sliding, so that the instrument of the instrument should be coated with lubricants, and the choice of lubricant should be harmless. . The inner gap after the teas should not be too large, the rubber ring does not open the work surface, and it is easy to leak water when local settling; the inner gap is not, the flexibility of the interface is weakened. (3) The rubber cluster of the flexible interface must be supplied according to the standard fixed point. For cast iron tubes, the wedge film is compliant with international standards (ISO2531), but is strict to the size of the inner casting size; the ladder lip glue circle pushed in China is large, and the inner side cast is formed. (4) The flexible interface is required to put the pipeline, the centerline is aligned, and it is teasing. If the top tube is too large, it should be exited and rewind after finding the cause. Forcibly, the film is curled, it is difficult to quit. (5) Pipe, pipe fittings do not recommend rigid interface, which is to blast and repair, strive to install flexible fast repair joints, which reduces downtime, and improves the safety of pipelines.
(6) Pipes with poor stiffness, and the support facility should be supported in front of the teasten socket. (7) The flexible interface of large-diameter pipe fittings, and strives to have specific measures such as stop locking devices to reduce the sizes. (8) The valve is connected to the pipe and there should be detachable movable parts. For DN ≤ 300mm, a live flange (single disk connector) may otherwise use the reinforced stretch. 6, the selection of pipes 6.1 Comparison of hydraulic conditions for pipes for easy comparison, each type of tube is a cement pressure tube, a metal tube of cement sander, and a second type of tube is a thermosetting plastic tube and a thermoplastic plastic tube, and the first type of pipe The rough coefficient of the tube N1 = 0.013; N2 = 0.009 of the second type of pipe. The following comparison can be obtained by the relationship between Darcy formula (1) and Manning formula (2) in hydraulics: (1)
(2)
Where: Q - flow; A-- pipeline break area for round tube A = (π · d2) / 4 C - Xie Jing resistance coefficient; I - hydraulic slope; N-pipe rough coefficient R - hydraulic radius, for the garden r = D / 4. The (1) formula (1) is obtained: Therefore, the above factors should be considered when reviewing various types of pipes. 6.2 Comprehensive performance comparison (1) Large, medium-diameter pipes will now be large, medium-diameter pipe, steel pipe, ductile iron pipe, cast pneumo-cast iron pipe, semi-continuous gray cast iron pipe, glass steel pipe performance comparison As Table 6.
Table 6
Project steel tube annealing tube cast tube semi-consecutive cast tube glass steel tube tensile strength (MPa) ≥ 42 ≥ 42 ≥ 14 ≥ 32 elongation (%) 24 ≥ 1050 hardness (HB) 140 <230 <230 <21040 Elastic modulus (103MPa) 214150 ~ 170 100 ~ 12015.2 Yield limit (MPa) ≥ 30 ≥ 30 10 to 17 corrosive differences in good priority excellent use period (year) 25 ~ 505050> 50> 50 (2) Common plastic tube Comparison of comprehensive performance (small diameter tube) hard polyvinyl chloride tube, polyethylene tube, polypropylene tube, and ABS engineering plastic tube performance comparison, Table 7.
Table 7
Project hard polyvinyl chloride tube polyethylene tube polypropylene tube ABS tube density (kg / cm3) 1.35 ~ 1.460.92 ~ 0.960.91.02 ~ 1.08 Tensile strength (MPa) 48 ~ 5018 ~ 2030 ~ 3942 ~ 60 bending strength (MPA 86 ~ 1007042 ~ 5670 ~ 85 Elastic modulus (103MPa) 3.20.91.32.4 Hardness (R) 12060 ~ 70 (Shao) 95 ~ 105105 ~ 115 thermal expansion (10-5 / ° C) 710119 operating temperature (° C) - 5 ~ 60-20 ~ 600 ~ 60-30 ~ 80 6.3 Comparison of pipes (1) Large diameter pipeline
Table 8 (kg / m)
Three stages and pipe diameter pipe (mm) steel tube a steel cylinder tube stage prestressed steel pipe glass tube 120029610509141020160140041414691198146021516005521972152219402751800710240219682300345200078829732471270042522009773376 334062524001065 3840705260012824988 4520 (2) of large diameter pipes in Table 9 (kg / m)
Tube Diameter (mm) steel tube bulb gray cast iron pipe from a pipe stress pipe stage three stages prestressed steel cylinder tube glass tube steel tube (3) of small diameter pipe 4007914680175236199 544457580761000247653336 2150099207112268293244 3060014827714735437831734047800197444232 767667840112
Table 10 (kg / m)
Tube (MM) steel tube-machoy cast pipe ball iron tube self-stress tube polyvinyl chloride tube polyethylene tube polypropylene tube 100152416302.653.132.634.61824385.506.634.61200305532608.634.61.2030044965415721.0025.60 (4) small diameter pipe
Table 11 (kg / m)
Tube (MM) galvanized tube polyvinyl chloride tube polyethylene tube 252.910.180.17323.770.270.28506160.560.67657.880.861.0.67657.880.861.0.67657.880.861.0.67657.880.861.05 6.4 Price comparison (1) Large diameter pipe
Table 12 (yuan / m)
Tube Diameter (mm) steel tube stage a three-stage tube tube tube prestressed steel cylinder FRP pipe winding process centrifugation 12001742795671100028442369140023041030916150039243120160029501395123920005130401418003667 192925006480495020004075 213930007920601022004919 400011484854626006327 35009504720324005362 4500 (2) of large diameter pipes
Table 13 (yuan / m)
Tube Diameter (mm) steel tube gray cast tube (3) of small diameter pipe ductile iron pipe from the stress tube three-stage tube stage tubular steel cylinder prestressed pipe FRP pipe winding process centrifugation 400503350360160 185431 500583497504217 590,600,871,665,622 320276300897936800116010661044 420387500140613341000145415671512 59048970019441800
Table 14 (yuan / m)
Tube Diameter (mm) steel tube bulb gray cast iron pipe stress from polyethylene pipes PVC pipes polypropylene tubes 1001085872 3241191501589110854668660200215132144651031346130031523024398252333 tube (4) Small diameter pipes 86
Table 15 (yuan / m)
Diameter (mm) cold-galvanized pipe galvanized pipes PVC pipes Polyethylene pipes 2513.1016.002.522.383216.9720.743.783.925027.7233.887.849.386535.4643.3410.3213.65 Note: Prices include steel inner liner, an outer corrosion and cathodic protection Fees; some tubes are not yet queried. 6.5 Engineering cost comparison (1) Large diameter pipe table 16 (10,000 yuan / km)
Diameter (mm) steel tube stage of three-stage tube prestressed steel cylinder tube glass pipe winding process centrifugation 1200293.95158.14138.79190.12467.94459.841400396.50199.22181.43272.54651.26622.311600522.39272.66248.33367.04855.06814.891800648.69 360.29449.361069.891014.812000875.50 396.26532.311322.881254 Large diameter pipelines in China
Table 17 (10,000 yuan / km)
Pipe diameter (mm) Steel Tube Gray Cast Tube Ball Tube Self - stress Tube Three - stage Tube Steel Point Prestressed Pretty Fiberglass Tube Wound Formation 40065.3361.6363.032.50 37.38 75.44 50081.7786.3787.1642.63 100.90 600118.03113.53112.78 63.6656 82.30153177.09181.23177.80 82.1977.0494.67236.5233.41100197.52264.31255.73 113.9698.20131.12325.19320.00 (3) small-small diameter pipeline
Table 18 (10,000 yuan / km)
Diameter (mm) steel pipe gray cast pipe from ductile iron pipes PVC pipes polyethylene pipe stress polypropylene tube 10013.7511.4913.45 7.218.615.1815018.9416.6719.3311.5212.7715.8911.8420025.1323.5025.3713.8918.9823.8112.4230036.8140.1242.0020.2043 .5556.19 (4) Small diameter pipeline
Table 19 (10,000 yuan / km)
Pipe diameter (mm) Cold galvanized tube hot galvanized tube Polyvinyl chloride polyethylene tube 252.482.930.830.81323.163.971.751.99 Note: (1) Pipe unit price is pressed (6.4); 2) Pipes and valve costs are 20% for pipe fees; (3) unscrupulous disorder, road compensation fees, farmland compensation fees, etc. (4) The other rates are based on the 30% direct fee. 6.6 Comprehensive evaluation of the recommended opinion of pipe selection should conduct technical economic analysis, assessed from the following five aspects: (1) The performance of pipeline is reliable, and the internal pressure and external load of the requirements can be affected; (2) Pipe source is guaranteed The pipe fittings are convenient, low transportation costs or short-term consolidation of the plant factory; (3) Construction machines have easy installation; (4) Long service is long, less maintenance work; (5) Water supply capacity can remain under the same conditions for a long time The project cost is low. Specific recommendation comments in Table 20 Table 20
Pipe diameter (mm) Recommended Opinion (in order] DN ≥ 1800 steel pipe, steel pixel prestressing pipe, sandwich glass steel pipe, three-stage prestressed pipe DN <1800DN ≥ 1800 steel positive pipe, steel pipe, three-stage prestress Tube, sandwich glass steel pipe DN <1800 ≥ 300 annealed ball ink cast iron pipe, cast pneumo iron pipe, three-stage prestressed pipe, steel pipe DN <300 ≥ 100 polyvinyl chloride tube, cast puzzle iron pipe, annealed ball ink cast iron pipe DN <100 indoor mandate steel-plastic composite tube, polyethylene 铝 复 管, crosslinked polyethylene tube, hot-dip galvanized steel pipe outdoor bury tube hard polyvinyl chloride pipe, high density polyethylene tube, steel-plastic composite tube note: region The specific situation is different, the recommended opinion is not necessarily applicable. Appendix Steel Tube SP --STEEL PIPE Cast Iron Tube CIP - Cast Iron Pipe Gray Cast Iron Tube GCIP - Grey Cast Iron PIPE Ductile Cast Tube DCIP - Ductile Cast Iron Pipe Asbestos Cement Tube ACP - SSTES CEMENT PIPE Self Stress Tube SSCP - prestressed pipe -Self stressing concrete pipe PCP --Prestrpessed concrete pipe three-stage tube CTPCP --Core type prestressed concrete pipe stage tube PVCP --Prestressed vibrohydropressed concrete pipe prestressed steel cylinder pipe PCCP --Prestressed concrete cylinder pipe hard PVC Ethylene tube UPVC --unplastic PIPE PE - POLYETHYLENE PIPE Polyethylene Crucifidal Aluminum Composite Tube HAH - HDPE-Al-HDPE PIPE Polypropylene Tube PP --Polyprietyne Pipe Pyrene Tube PB - PLOYBUTYLENE PIPE Engineering Plastic Tube ABS - Acrylonitrile-Butadiene-Styrene Pipe Glass Steel Tube Grp --Glass Reinfoced PLASTICS
