Comprehensive understanding of PVC pipe drainage pipe
Comprehensive understanding of PVC pipe drainage pipeThe PVC pipe drain pipe is made of hygienic grade polyvinyl chloride (PVC) resin as the main raw material, added with appropriate amount of stabilizers, lubricants, fillers, coloring agents, etc., extruded by the plastic extruder and injection molded by the injection molding machine, and cooled by , Curing, shaping, inspection, packaging and other processes to complete the production of pipes and fittings.
Chinese name PVC pipe drainage pipe Foreign name PVC tube drainage tube Use material underground water pipe PVC pipe ABS and other production standards GB / T5836.1-2006 Product advantages High pipe safety factor and other common specifications Outer diameters are: 32mm, 40mm
table of Contents
1 Common specifications
2 Materials used
3 Production standards
4 Performance index
▪ Drain
▪ Pipe fittings
5 Product advantages
6 Installation instructions
7 Design method
8 Construction requirements
9 Application
usual format
The conventional specifications of commonly used PVC pipe drainage pipes are as follows: the nominal outer diameters are: 32mm, 40mm, 50mm, 75mm, 90mm, 110mm, 125mm, 160mm, 180, 200mm, 250mm, 315mm, 400mm, 500mm, 630mm, etc. The length of the pipe is generally 4m or 6m, and other lengths are determined by negotiation between the supplier and the buyer.
PVC drainage pipe
PVC drainage pipe
Use materials
Underground water pipe PVC pipe ABS (acrylonitrile-butadiene-styrene copolymer) unplasticized polyvinyl chloride (UPVC) CPVC (post-chlorinated polyvinyl chloride) PP (polypropylene)
Production standards
National standard: GB / T5836.1-2006
Performance
Drainpipe
Item
standard requirement
Tensile yield strength
≥40MPa
Vicat softening temperature
≥90 ℃
Flat test
No rupture
Drop weight impact test
≤10%
Exterior
The inner and outer walls are smooth and flat, no bubbles, cracks and obvious marks, depressions, uneven color and discoloration lines are allowed
Standard sizes
Outer wall thickness
Compliant with GB / T5836.1-2006 Compliant with GB / T5836.1-2006
Wall thickness deviation of the same section
≤14%
Longitudinal retraction rate
≤5%
Pipe fittings
pvc tube
pvc tube
Item
standard requirement
Vicat softening temperature
≥74 ℃
Oven test
The sample should be free of blistering, fragmentation and cracking of the joint; defects around the injection point that do not penetrate 50% of the wall thickness of the point are allowed; cracking phenomenon that does not penetrate the full wall thickness is allowed at the joint line
Drop test
No rupture
Exterior
The internal and external surfaces of the pipe fittings are smooth and flat, and no bubbles, cracks and obvious marks, depressions, uneven color decomposition and discoloration lines are allowed. The pipe fittings should be complete and free of defects, and the gate and overflow edges should be repaired flat and the color is white
Dimensions (MM)
Inner diameter of socket middle wall socket depth wall thickness
Meet the tolerance requirements meet the minimum wall thickness of GB / T5836.2-2006 greater than or equal to the same specification pipe
Product advantages
1. The surface hardness and tensile strength of the pipe are excellent, and the safety factor of the pipe is high.
2. Good aging resistance, normal service life can reach more than 50 years.
3. The pipeline has excellent corrosion resistance to inorganic acids, alkalis and salts, and is suitable for industrial sewage discharge and transportation.
4. The friction coefficient of the pipeline is small, the water flow is smooth, it is not easy to block, and the maintenance workload is small.
5. The material has a high oxygen index and is self-extinguishing.
6. The coefficient of linear expansion of the pipe is small, 0.07mm / ℃, and the deformation is small due to temperature. The thermal conductivity and elastic modulus are small, and the frost resistance is excellent compared with cast iron drain pipes.
7. The connection of pipes and fittings can be bonded, the construction method is simple, the operation is convenient, and the installation efficiency is high.
8. Good water tightness: The installation of PVC-U pipes, whether they are connected by adhesive or rubber ring, have good water tightness.
Installation Notes
1. Saw tube and groove:
The length of the saw tube is determined layer by layer based on the actual measurement and the size of each connecting pipe. Pipe saw tools should use fine-tooth saws, cutters and pipe cutters. The fracture should be flat and there must be no deformation at the fracture. The socket part to be bonded can be filed into a 15o ~ 30o bevel with a medium-sized board file. The length of the groove is generally not less than 3mm, and the thickness of the groove should be 1/3 ~ 1/2 of the thickness of the pipe wall. After the bevel is completed, the debris should be removed.
2. Protection of socket interface:
After the socket interface is connected, the extruded adhesive should be wiped clean with cotton yarn or dry cloth dipped in a little detergent such as acetone. According to the performance of the adhesive and climatic conditions until the interface is cured. The curing time should be properly extended during winter construction.
Design method
Plastic pipe formula design method
1. PVC plastic pipe technology and design principles
(1) The resin should choose PVC-SC5 resin or PVC-SG4 resin, that is, polyvinyl chloride resin with a polymerization degree of 1200-1000.
(2) must be added to the thermal stability system. Choose according to the actual requirements of production, pay attention to the synergistic effect and confrontation effect between heat stabilizers.
(3) Impact modifier must be added. CPE and ACR impact modifiers can be selected. According to the other composition in the formula and the plasticizing ability of the extruder, the addition amount is 8-12 parts. The price of CPE is low, the sources are wide, the aging resistance of ACR and the strength of the welding angle are high.
Construction requirements
First, before the subbase construction of the subgrade unit, the horizontal mid-segment drainage pipe should be buried.
2. Slotting: manual slotting is carried out according to the design pile position measured by the drawing design and surveying personnel. The width of the PE pipe slot is slightly wider than the pipe diameter by 1 ~ 2 cm, and the slot depth is 23 cm below the surface of the road bed. It is required that the inner side is 10 cm away from the center line, the outer side extends to the slope, and the excavation section extends to the inner wall of the side ditch. The slope of the groove should be along the horizontal drainage slope of the road, and the slope must not be reversed to ensure that the water in the road is discharged outside the subgrade. Pull the wire to make sure it is straight.
3. Take over: The two ends of each PVC pipe must be tightly fitted with a rubber ring to avoid water leakage.
4. Down tube: After cleaning the bottom of the groove, connecting the tube according to the length of the groove, put the tube into the groove, and use the sack cloth to tighten the mouth at the end of the side of the central divider to prevent debris from entering the pipe and causing blockage.
5. Backfilling: Select the backfill of the fine-grained soil excavated, or use sand to backfill. The large stones must be removed. After backfilling, it must be manually tamped. The top surface of the backfilled soil should not be higher than the roadbed, and should be 1 ~ below the surface of the roadbed. 2 centimeters is suitable, otherwise it will be crushed by the vehicle and unable to discharge water.
6. Cleanup: The remaining soil after backfilling should be immediately cleared and transported out of the field to clean the road surface. The remaining soil of the PE pipe should be unloaded in designated places such as the borrow pit and should not be unloaded on the road at will.
7. After the construction of the bottom base of the filling section is completed, on the brushed slope, according to the design size at the water outlet, a trapezoidal water outlet pad is cast-in-place. The pad is cast using a shaped wooden mold and the slope is cut before pouring. And nailed into three bamboo sticks 25 cm long for stability.
8. It should be noted that at the lowest point of the vertical curve of the route, there must be a drainage pipe to ensure that the pavement does not accumulate water. The embedding of ultra-high pressure pipes requires that in the ultra-high road section of the fill, after the road bed is inspected, the layout shall be measured and set out in time according to the position designed by the drawing. Determine the location of the pipeline and well, manually slot with a small excavation machine, the slope of the bottom of the groove meets the design requirements, ensure smooth drainage, the width of the groove is not less than, the width of the groove is not less than the design of 47cm, and the excavated waste residue is promptly cleared and shipped out of the site. In the square section, in order to ensure the thickness of the top soil of the pipe and ensure that the PVC pipe is not crushed, the bottom of the groove is reduced by 20 cm. For the super-high roadbed in the stone excavation section, the back excavation construction is completed after the bottom base layer is completed.
application
PVC drainage pipes have been more and more widely used in various industries. The most important material of PVC drainage pipes is polyvinyl chloride, which has strong heat resistance and corrosion resistance, which is why polyvinyl chloride One reason for its widespread use.
For the purpose of making the building facade more beautiful, indoor rainwater drainage systems are more and more widely used. Indoor rainwater pipes are generally designed according to the pressureless flow, but due to the large and concentrated rainwater flow, the pipelines are simultaneously There are two states of gravity flow and pressure flow, so it is required that indoor rainwater pipes have stronger pressure resistance than other drainage pipes.
PVC drainage pipe is an alternative product of traditional drainage pipe material, which has better physical and chemical properties. Its inner wall is smooth and has less frictional resistance than conventional drainage materials, so the horizontal pipe installation slope is small, which can increase the indoor height of the building. At the same time, The PVC drainage pipe is light in weight and is one-fifth of the cast iron pipe, which is easy to transport and operate; it adopts adhesive connection, which is convenient for installation and maintenance; the price is cheaper than conventional drainage pipes, which greatly reduces the cost of the project; the corrosion resistance is strong, and it is used in construction Sewage and rainwater piping systems are widely used. In addition, the widespread use of PVC drainage pipes is conducive to saving steel, which is of great significance to alleviate the situation of steel shortage in China. Compared with cast iron pipes and steel pipes, PVC-U drainage pipes have to bear. The disadvantages of low pressure and weak impact resistance. In addition, although the PVC-U drain pipe is a flame-retardant material, for indoor exposed pipes, there is a possibility of fire spreading upward along the drain riser.
The coefficient of linear expansion of the PVC drainage pipe is large, and the expansion joint needs to be installed to solve its expansion and contraction problem during construction. According to the calculation formula of the expansion and contraction amount caused by the environmental temperature change of the PVC-U drainage pipe:
△ L = L · a · At
Where △ L-pipe expansion and contraction amount (m);
L-pipe length (mk
a- Linear expansion coefficient, using 6 × 10-5 ～ 8X10-5-m / (m · ℃);
△ t-temperature difference (℃)
