Comprehensive and profound understanding of HDPE double-wall corrugated pipe

Comprehensive and profound understanding of HDPE double-wall corrugated pipe
HDPE double-wall corrugated pipe, referred to as PE corrugated pipe, was first developed successfully in Germany in the early 1980s. After more than ten years of development and improvement, it has developed from a single variety to a complete product series. It has been very mature in production technology and use technology. Due to its excellent performance and relative economic cost, it has been greatly promoted and applied in developed countries such as Europe and the United States.
Double-wall corrugated pipe is a new type of light-weight pipe made of high-density polyethylene. It has the characteristics of light weight, high pressure resistance, good toughness, fast construction and long life. Compared with pipes, the cost is greatly reduced. And because of the convenient and reliable connection, it is widely used at home and abroad. Substantially replace concrete pipes and cast iron pipes.
The Chinese name HDPE double-wall corrugated pipe is abbreviated as PE corrugated pipe. In the early 1980s, the national German feature appeared. Light weight, high pressure resistance, good toughness, fast construction and long life. High-density polyethylene
table of Contents
1 Performance characteristics
▪ Features
▪ Craft
▪ Features
▪ Advantage
2 Scope of application
3 Storage method
4 Mode of transportation
5 Installation instructions
6 Key points of pipeline repair
7 Interface processing method
Performance characteristics
Features
1. Unique product structure and strong pressure resistance;
2. The inner wall is smooth and the excess flow is large;
3. The product is easy to connect, the interface is well sealed, corrosion-resistant, zero leakage, no scaling, avoid secondary pollution, is the ideal "green pipe";
4. The product has good deflection performance and can adapt to the uneven settlement of the soil;
5. Long service life, the buried use can reach more than 50 years;
6. The product has light weight and convenient construction, which can reduce the construction cost and shorten the construction period;
7. At a speed of 15 feet per second, the wear resistance is 3 to 5 times higher than ordinary or fine-grained steel pipes.
Craftsmanship
· Centralized digital control
· Double machine co-extrusion, double-layer split
· Full vacuum tape feed
· Random flare forming at one time
Features
HDPE double-wall corrugated pipe has excellent chemical stability, aging resistance and environmental stress cracking resistance. The HDPE double-wall corrugated pipe produced from it as a raw material is a flexible pipe. Its performance is as follows:
Strong resistance to external pressure
The outer wall has a ring-shaped corrugated structure, which greatly enhances the ring stiffness of the pipe, thereby enhancing the resistance of the pipe to the soil load. In this performance, HDPE double-wall corrugated pipe has obvious advantages compared with other pipes.
Low project cost
Under equal load conditions, HDPE double-wall corrugated pipe only needs a thinner wall to meet the requirements. Therefore, compared with solid wall pipes of the same material specifications, about half of the raw materials can be saved, so the cost of HDPE double-wall corrugated pipes is also lower. This is another very prominent feature of the pipe.
Easy construction
Due to the light weight of HDPE double-wall corrugated pipe, it is convenient to carry and connect, so the construction is fast and the maintenance work is simple. Tight schedule and construction
In the case of poor conditions, its advantages are more obvious.
Small friction coefficient, large flow
HDPE double-wall corrugated pipe using HDPE as material can pass a larger flow than other pipes of the same diameter. In other words, under the same flow requirements, HDPE double-wall corrugated pipe with a relatively small diameter can be used.
Good low temperature resistance and impact resistance
The embrittlement temperature of HDPE double-wall corrugated pipe is -70 ℃. Under low temperature conditions (above -30 ℃), special protection measures are not necessary during construction. It is convenient to construct in winter, and HDPE double-wall corrugated pipes have good impact resistance.
Good chemical stability
Since HDPE molecules have no polarity, the chemical stability is excellent. Except for a few strong oxidants, most chemical mediators are not destructive. Generally, the soil, power, acid and alkali factors of the environment will not damage the pipeline, and will not breed bacteria or scale, and its flow area will not decrease with the increase of operating time.
long lasting
The HDPE double-wall corrugated pipe can be used for more than 50 years without being exposed to sunlight and ultraviolet rays.
Excellent wear resistance
Germany has used experiments to prove that the wear resistance of HDPE is even several times higher than that of steel pipes.
Proper deflection
A certain length of HDPE double-wall corrugated pipe can be slightly deflected in the axial direction, and is not affected by the uneven settlement of the ground to a certain extent. It can be directly laid in a slightly uneven groove without using pipe fittings.
Advantage
1. Unique structure, high resistance to external pressure, impact resistance, ring flexibility, smooth inner wall friction and small friction, pipes with the same inner diameter can pass a larger flow; socket interface, flexible connection, convenient connection, high reliability, not easy leakage.
2. Light weight, quick construction and lower cost.
3. The service life of the buried ground is more than fifty years.
hdpe corrugated pipe
hdpe corrugated pipe
4. Polyethylene is a hydrocarbon polymer. The molecule is non-polar and resistant to acid and alkali corrosion.
5. The raw materials are green and environmentally friendly materials, non-toxic, non-corrosive, non-scaling, recyclable.
6. The applicable temperature range is wide, the pipeline does not break in the environment of -60 ℃, and the maximum temperature of the conveying medium is 60 ℃.
7. The cost of the comprehensive project is basically the same as that of concrete, and the operating cost is low.
8. No foundation is required when the soil quality is good.
Application range
1. Municipal drainage and sewage pipeline system engineering;
2. Underground drainage and sewage in apartments and residential quarters;
3. Pre-buried pipelines on expressways and seepage water pipe networks under the golf course;
4. Water conservancy projects such as irrigation and water delivery and drainage of farmland water conservancy;
5. Chemical industry and mining are used for fluid transportation and ventilation;
6. Protective casing of underground pipelines and jackets of communication cables, etc.
Storage method
HDPE double-wall corrugated pipes should be stored in a dry warehouse at room temperature. Straight pipes should be laid flat, and the stacking height should not exceed 2 m. The porous tubes can be laid flat, but should not be stacked under pressure or squeezed.
HDPE double-wall corrugated pipes are not allowed to be mixed with toxic and hazardous substances, and should be kept away from heat sources. A clear fire prohibition sign should be set up in the storage place.
The storage period is generally not more than 2 years from the date of production.
Mode of transport
HDPE double-wall corrugated pipe can be transported by various vehicles.
During transportation and loading and unloading, throwing, impacting, heavy pressure, long-term exposure or close to heat sources are not allowed. Mixed transportation with toxic and hazardous substances is not allowed. Disk-shaped porous tubes cannot be transported flat.
The technology of HDPE double-wall corrugated pipe connection has gradually matured in continuous use. Its hot melt connection includes the following three methods:
1. Electrofusion connection
The electric fusion connection is generally used in the space constrained by the installation site and unable to perform the hot fusion connection. When the same thermoplastic pipe is connected, a special electric fusion pipe is inserted, and the electric fusion pipe is energized to the electric fusion pipe. The heat is generated by the resistance wire embedded in the electric fusion pipe. The cooled pipe and the electric fusion pipe Even become a whole. The characteristics of electrofusion connection are convenient connection, fast speed, good joint quality, and little disturbance from external factors [1].
2. Socket hot melt connection
In order to improve the application pressure of the socket connection, it is also possible to add a bushing to the socket part. The socket-type hot-melt connection is to separate the insertion end of the pipe and the socket end from the heating and softening. Contrast strong connections.
3. Direct hot-melt connection: heat the connection parts of the pipe fittings, and directly carry out the hot-melt connection.
Installation instructions

1. The installation of HDPE double-wall corrugated pipe must be carried out by qualified personnel.
2. When handling materials, it is strictly prohibited to throw, drop, roll and drag to avoid damage to the pipeline. Before connecting the pipeline, check both ends. If there is any damage, please cut off the damaged part.
3. Hot melt connection of pipes and fittings. The welding temperature should be set at 260 ± 10. If there is any discoloration, decomposition, combustion, smoke or other adverse effects, please replace the welding machine.
4. Although the threaded fittings are connected to other parts, they must not be over-tightened to avoid damage to the threaded fittings.
5. Please strictly follow the HDPE double-wall corrugated pipe arrangement and business standards to ensure quality.
6. After the installation is completed, a hydrostatic test must be conducted to confirm that there are no leaks, and then the pipe channel can be closed or filled. The test pressure should be 1.5 times the design pressure. The recommended test pressure is 10kg / cm2 (MPa) -15 kg / cm2 (pressure 1.5MPa).
7. Although the transitional connection with water heater, metal pipe or hose connection pipe is desirable, its length should not be less than 300mm.
8. Outdoor piping should be considered as having heat insulation, sun protection and anti-freezing measures.
9. In winter, when the temperature is close to 5, accidental damage to pipes and fittings can be prevented during transportation and construction. After the pressure test is completed, the discharged water. For long-term shutdown in winter, there is no reliable water discharge in the pipeline Insulation measures to prevent pipeline cracks.
10. At the same time carry out waterproofing works, do not apply paint, asphalt and other contaminated materials on the surface of the pipeline, so as to avoid the smell of water.
Key points of pipeline repair
1.After the HDPE double-wall corrugated pipe is laid, the wall of the pipe is partially damaged due to unexpected factors. When the area of the damaged part or the length and width of the crack does not exceed the specified, paste repair measures can be taken.
2. When the diameter or side length of the partially damaged HDPE double-wall corrugated pipe wall is not more than 20mm, a PVC plastic adhesive solvent can be used to paste a circular plate with a diameter of not less than lOOmm and the same material as the pipe.
3. When the partial damage of the pipe wall is 20 ～ 100mm, a round plate with the same material as the pipe and not less than the maximum size of the hole plus l00mm can be pasted on the outside with a polyvinyl chloride plastic bonding solvent.
4. Cracks appear locally on the wall of the pipe.When the length of the crack is not greater than 1/12 of the circumference of the pipe, you can paste a plate with a length greater than the length of the crack plus 100mm and a width of not less than 60mm with the same material as the pipe. Cut into a circular arc shape.
5. Before repairing, the water in the pipeline should be drained out, and the damaged part of the pipe wall surface should be trimmed and cleaned with a scraper, and cleaned with water. For the special-shaped wall pipe, the ribs in the patch range must be removed, and then smoothed with sandpaper or file.
6. Before bonding, the base surface of the bonding part should be brushed with cyclohexanone, and the bonding solvent should be applied as soon as possible after drying. The plate for external sticking should be used, and the arc should be cut from the corresponding part of the same diameter pipe The inner side of the outer plate must also be cleaned first, and the base surface is painted with cyclohexanone, and then the bonding solvent is painted.
7. For the holes no larger than 20mm, they can be fixed with geotextile after the paste is completed, and the soil can be returned after curing for 24 hours; for the holes and cracks larger than 20mm, they can be fixed with lead wire after the paste is completed.
8.After the pipeline repair is completed, the hollowed-out part of the bottom of the pipe must be backfilled with coarse sand according to the requirements of the support angle.
9. To take repair measures for damaged pipelines, the construction unit should obtain the consent of the management unit and the site supervisor in advance; for the damage that occurs at the bottom of the pipe, the design unit must also obtain the consent of the design unit before implementation.
10.If the plugging repairing measures such as electrode welding repair or chemical water stopper are used, it must be approved by the management unit before it can be implemented.
11. When the size of the damaged part of the pipeline exceeds the provisions of the above provisions, the damaged pipe section should be replaced. When there is no special connection pipe between the replaced PE double-wall corrugated pipe and the paved pipeline, the inspection well or connection can be built Well connected.
Interface processing method edit
The socket connection is as follows (DN≤500):
HDPE double-wall corrugated pipe joints should use socket joints connected by elastic sealing rubber rings, and rubber ring interfaces should comply with the following regulations:
1. Before connecting, check whether the rubber ring is in good condition, confirm the placement of the rubber ring and the insertion depth of the socket [2].
2. When connecting, first clean the inner wall of the socket, and apply lubricant to the inner wall of the socket and the rubber ring of the socket, and then align the center axis of the end surface of the socket.
3. The interface method should be carried out according to the following procedure: DN400 and below pipelines, one person first hangs the socket of the installed pipeline with cotton yarn rope, the other uses a long spudger to insert the foundation diagonally, and resists the center position of the pipe end The horizontal baffle, and then slowly insert the pipe into the socket of the HDPE double-wall corrugated pipe to be installed to a predetermined position; the pipe above DN400 can be pulled into place by two hand-held hoist. When the interface is closed, the handle hoists on both sides of the pipe joint should be pulled synchronously so that the rubber sealing ring is properly seated without twisting or falling off.