PVC porous tube knowledge you should know
PVC porous tube knowledge you should knowThis entry was reviewed by the "Encyclopedia of Science Popularization" scientific encyclopedia entry preparation and application work item.
PVC porous tube, using polyvinyl chloride resin as the main raw material, and adding appropriate amount of stabilizers, lubricants, flame retardants, processing modifiers and impact modifiers, etc., plastic products after extrusion molding. The products are suitable for industries such as highways, municipal roads, bridges, radio and television, telecommunications and telecommunication cable bushings.
Chinese name PVC porous pipe foreign name PVC porous pipe tensile yield strength ≥ 30 longitudinal shrinkage rate ≤ 5 Vicat softening temperature ≥ 75
table of Contents
1 Concept
▪ Definition
▪ Product mechanical properties
▪ Product features
2 Popularization and application of buried porous pipes for electricity and telecommunications
▪ Features and instructions of PVC porous pipe
▪ Comparison of traditional pipes with PVC and PE porous pipes
3 Application of PVC porous pipes in urban weak current pipeline engineering
▪ Project overview
▪ Construction points
▪ Foundation cushion
▪ Pipe laying
▪ Application prospects
concept
definition
PVC porous tube is a flexible plastic tube, white, the material is hard polyvinyl chloride, commonly used are seven-hole plum tube and seven-hole honeycomb tube, and its specification model is 110/32 × 7. The PVC porous pipe adopts a socket type interface, and is sealed and waterproofed with PVC glue. It has the advantages of good water tightness, fast construction speed, corrosion resistance, and large elastic modulus. The water tightness at the interface is much better than the previous ones. Cement pipe block. In addition, PVC porous pipe also has the advantages of large capacity, small quality, strong impact resistance and large ring stiffness. It can be used with single-hole pipe to adapt to the multiple needs of large logarithmic cable and optical cable, which can effectively save pipes and cities Limited underground space resources. [1]
Product mechanical properties
Product standards are implemented in accordance with GB / T5836.1-92 and GB / T5836.2-92.
Serial number
project
Technical index
1
Tensile yield strength (MPa)
≥30
2
Longitudinal retraction rate (%)
≤5
3
Vicat softening temperature (℃)
≥75
4
Drop weight impact test
0 ℃, D90 type hammer 1kg1m impact, 9/10 will not break
5
External load resistance performance (KN / 200mm)
Plum shaped porous tube
Grid porous tube
Honeycomb porous tube
≥1.0
≥9.5
≥1.0
6
Static friction factor
≤0.35
Features
(1) Strong pressure resistance
Adopt high-quality aging-resistant improved PVC engineering plastic in one extrusion, high compressive strength, honeycomb (grid) shape
Weitong porous tube
Weitong porous tube
The reasonable mechanical structure makes the pipe 10-100 times higher than the ordinary plastic pipe in compression performance. Under normal circumstances, no foundation or encapsulation is required, anti-settlement, it can replace the steel pipe to cross the road safely, flame retardant (good flame extinction), resistant Corrosion, aging resistance, service life of more than 50 years.
(2) Complete specifications
The product portfolio is diverse and the appearance is beautiful. The main specifications are single hole, 3 hole, large, medium and small 4 holes, 5 holes with the same diameter and 6 holes, 7 holes, 7 holes, 8 holes, 9 holes in size and other series with different diameters of light (electricity) The cable is matched with the original cement pipeline, corrugated pipeline and other pipelines, and can be freely transitioned and combined, and has corresponding fittings, blockages, cable ties, special glue and other accessories to facilitate construction operations.
(3) Structural innovation
Saving pipe position, compact pipe structure, and small pavement excavation, only 10% of cement pipe position, effectively saving urban underground pipe position resources, and having little impact on road traffic and municipal administration.
(4) Good toughness
The bending freedom is generally 6 meters of pipe, and the bending radius can reach 4 meters. It can be easily avoided when encountering obstacles or other pipelines during construction.
(5) Convenient construction
Save labor and time. The jacket is integrated with the sub-tube, and the cable can be passed without laying the sub-tube for one time, avoiding the deformation and kinking of the second sub-tube, chaotic sorting, and the trouble of repeated construction; light weight and convenient handling; inner wall Smooth, effort-saving threading; strong compressive strength, burial depth only requires 0.3-0.5 meters without foundation and cement encapsulation, first backfill fine sand and stone 20 cm and then backfill soil to open to traffic, without crossing the road without foundation and cement encapsulation. Use PE / corrugated pipe (large amount of steel pipe, high cost, welding, heavy construction, short service life), cement pouring requires maintenance period, secondary sub-pipe can only wear optical cable, easy to rot, use grid honeycomb pipe construction than use PE sub + pipe bellows shortens the soil period by nearly 1/2, and shortens the construction period by 3/5 compared to using cement and steel pipes.
(6) High utilization rate
The overall cost is low, the sheath and the sub-tube are integrated, the effective space of the inner hole is large, and it can be connected and used after truncation, saving material consumption and less engineering investment. Compared with the use of PE / bellows, it saves nearly 20% of the cost, and can replace steel pipes, saving about 50% of investment.
Popularization and application of buried porous pipes for electric power and telecommunications
Features and instructions of PVC porous pipe
With the development of communication and electric power businesses, a new type of PVC porous pipe is being more and more widely recognized by the market. It integrates the sheath and the sub-tube, and is formed by one-time back-pressure molding, with beautiful appearance. It is made of PVC engineering plastic, with high compressive strength, light weight, long service life, smooth inner wall, low friction, easy construction, and resistance to external forces. The function of protecting light and cable; the inner grid is approximately square or round, and the effective space is large, which is convenient for putting light and cable.
Since the sheath and the sub-tube are integrated, it can be completed in one laying. The pipe is connected with the pipe by a sleeve connection, and is marked, and the construction is extremely convenient. As long as the construction unit digs the pipeline trench according to the design requirements, the pipe can be laid, and the soil can be immediately returned to the soil, which greatly shortens the construction period and eliminates the need to wear the sub-pipe again. The standard length of the pipe is 6 meters (some construction units require a length of 8 meters). In actual construction, the short section that is cut off at the end can still be used in a suitable section. The material utilization rate is high, and the construction cost is relative to the use of secondary wear. The sub-pipe method can reduce the cost per sub-hole by more than 30%.
The selection of the communication pipeline route is based on the design documents and documents approved by the city planning department for construction measurement. The construction team decides the width and depth of the trench to be excavated according to the design of the pipe group. Generally, the top of the pipeline on the carriageway is 0.7 meters away from the road surface, and the sidewalk is 0.5 meters. The bottom of the pipeline trench should be leveled to avoid digging too deep and destroying the soil structure. It can be excavated along the terrain when the slope is encountered, and the net height of the pipe top should be maintained; when the route needs to be bent, it should be bent slowly, as long as it is within the bendable range of the pipe, no sharp turns are allowed, and the construction personnel can master it.
When laying more than 2 PVC pipes, when the pipe is placed at the bottom of the ditch, the construction personnel are required to tie two lines with 3.0 iron wires at the joint and 1/2 of the pipe length to make the pipe neatly arranged at the bottom of the ditch and then fill the soil. . When connecting the pipe and the pipe, it must be clear that there is no foreign matter in the sub-pipe. The connection is equipped with PVC glue. First apply PVC glue to the connection, then sleeve, and use a hammer to knock the pipe to the positioning line. If a 5-hole tube is buried, don't get it wrong by the manufacturer. After the pipeline is laid, the relative position of the sub-pipes will not change, the inner wall is smooth and light is passed through, and the resistance when the cable is small, reducing the labor intensity and speeding up the project.
When buried with PVC porous pipes, the pipeline trench without special conditions (soft soil) does not need to be used as a foundation, and it should not be encapsulated with concrete. In order to prevent someone from opening the control in the future, red bricks were laid on the plastic pipe after 100 mm of soil was returned to avoid damage to the pipe. Due to the high compressive strength of PVC pipes, especially when crossing the highway, as long as the construction unit is buried deeply according to the design requirements, the pipes are neatly arranged at the bottom of the ditch, first backfill 20 cm of fine soil, and then formally backfill the soil to prevent the large stones from directly pressing on On the tube. If there is no fine soil, it can be sanded, which can completely replace the commonly used highways with steel pipes, which can save a lot of engineering costs and reduce labor intensity. When the depth is not reached when crossing the highway, the concrete encapsulation method can be used. When there is stone at the bottom of the ditch, first lay a layer of sand about 10 cm thick before laying the pipe. At the end of the hand hole, the sub-pipe is equipped with a plug. Unused holes are plugged with a plug to prevent plugging of the pipe hole with little mud or foreign objects.
Comparison between traditional pipeline and PVC, PE porous pipe
(1) Cement pipeline
Manholes must be used, and trees must not be planted on the construction road. If trees are planted, the roots of the trees will enter the joints of the cement pipes, which will block the pipe holes and prevent secondary construction, resulting in waste of materials. The casing pipe in the cement pipe must be pumped in the manhole well first, which will hinder the traffic. When the pipe is pulled, it will turn in circles, and the cement pipe will be damaged during construction, the construction is difficult, the amount of excavation is large, the construction period is long, the cement The radius of curvature of the pipe is not less than 36 meters, and the material waste is extremely large, and the construction cost is high.
(2) PVC porous tube
It adopts one-time forming technology, which is 47 times higher than the ordinary plastic pipe ring. It can safely cross the road, is resistant to corrosion and aging, and has a service life of more than 50 years. The jacket and the sub-tube are integrated, and can be laid in one time without the need to wear the sub-tube; light weight, easy to carry; smooth inner wall, labor-saving threading; interface with factory marking, orderly arrangement; strong compression resistance, open communication The requirements for digging and backfilling are low, with little damage to the road, low construction intensity and short construction period.
The product specifications can be large or small, from 3 holes to 13 holes, the inner diameter of the square hole (round hole) is from 28mm-45mm, or the inner diameter of the extraordinarily large hole 43mm-51.5mm is made according to user requirements. The inner grid structure is square or round, the expansion sleeve and the sub-tube are integrated, the effective space is large, the manufacturing length is 6 meters or 8 meters, and some can be bent, and can be used after being cut off, and the material utilization rate is high. The shape and structure are arc-shaped, occupying a small pipe position, and excavating less earthwork, which is only 1/10 of the cement pipe.
(3) General PE pipe
The general PE pipe has an inner diameter of 90mm and an outer diameter of 102mm, each with a length of 6 meters and 15 yuan / meter. Using direct burial, each PE tube is covered with three sub-tubes. Because the PE pipe is soft and the ring steel is low, it is necessary to lay the precast concrete pipe 6 mm thick or 8 cm thick cast-in-place concrete (after condensation) foundation when laying the pipeline, and then encapsulate it with concrete after laying. The construction period is long, and it takes time and effort to pull the optical cables in the three sub-pipes. The PE pipe is deformed after being compressed, and the sub-pipe is wasted during construction. [2]
Application of PVC porous pipe in urban weak current pipeline engineering
Project Overview
The weak current pipeline project in Laoshan District of Qingdao is a common pipeline that brings together many operators such as Netcom, Telecom, Mobile, China Unicom, Radio and Television, Railcom, and government charity. It is an important part of Qingdao ’s urban planning. The first-phase planning of the weak current pipeline is 149km, of which the main ring (24-hole) pipeline is 24.76km, the second
Dry ring (16 holes) pipeline is 59.92km, branch ring (10 holes) pipeline is 64.32km. Among the pipe hole requirements, except for Netcom, Telecom, and Tietong, which require some single-hole pipes, the remaining operators are mainly based on optical cables, and the demand is for PVC porous pipes. The ratio of the number of PVC perforated pipes to the number of single-hole pipes in the pipeline is 2: 1. The urban weak current pipe network system after completion will greatly improve the information transmission capacity.
Construction points
(1) Pipe requirements
The pipe requires smooth and flat inner wall, uniform color and consistency, no cracks, bubbles, discoloration lines and obvious impurities in the pipe body, and no damage, cracks or deformation of the pipe mouth. The cut section of the pipe should be flat and perpendicular to the axis of the pipe. The outer diameter of the socket of the pipe and the inner size of the socket should meet the requirements of the specification.
Foundation cushion
The geological conditions in the Laoshan District of Qingdao are good, and only 5 to 8 cm thick sand cushions are needed for the basement treatment. The local geological conditions are slightly worse or cross (pass) the road
The section uses 150 # concrete cushion.
Pipeline laying
Before laying, the specifications and appearance quality of pipes and fittings should be checked to ensure the arrangement order of the pipes, and the sealing of the pipe port plugs should be ensured without falling off. The pipes should be handed into the trenches by hand. Pipe cutting should use special cutting tools, according to the size of the pipe selection of different specifications of pipe cutting knife. The cross section of the pipe interface should be straight and free of burrs. When connecting, use the sleeve plug-in type. After applying special glue at the nozzle, align the pipe positioning mark. Then squeeze and fix the plug-in connector. During the connection, care should be taken to prevent debris from entering the pipe, and the pipe and the interface should be kept clean and free of dust, water, and oil. If the pipeline is displaced, floated, or has foreign objects in it after assembly, it should be corrected and reworked in time. Apply a plug seal to the pipe introduced into the hand hole.
Due to the large longitudinal slope of the project, the pipeline mainly adopts a straight slope. Without affecting the slope and buried depth, the relative height of the pipe holes on both sides of the manhole should be as close to horizontal as possible, and the degree of stagger should be controlled at 50cm Within.
Application prospect
(1) When the PVC porous pipe is used in the construction of weak current pipelines, it saves 24% of the pipe material and increases the capacity by 130% compared with the three-hole sub-pipe placed in the single-hole pipe.
Save 130% of underground space resources, shorten construction period by more than 60%.
(2) Compared with the use of single-hole straight-walled pipes, the trenches of PVC porous pipes excavate less pavement and reduce the amount of earthwork, saving a lot of labor costs, mechanical table shift fees and municipal compensation costs.
(3) The use of PVC porous pipes will save a lot of raw materials, effectively save the city's underground space, shorten the construction period, reduce the engineering cost, reduce the excavation of roads, reduce the work and people's work caused by construction. The impact of life beautifies the urban environment and has great social and economic benefits.
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