Production Technology of Plastic Double Wall (Dual Wall) Corrugated Pipe

Production Technology of Plastic Double Wall (Dual Wall) Corrugated Pipe

Plastic Machinery

Overview of PE Double Wall Corrugated Pipe

Abbreviation: High-density polyethylene (HDPE) double-wall corrugated pipe. The so-called PE double-walled wave tube is a kind of smooth and flat inner wall with trapezoidal or arc-shaped corrugated ribs on the premise of optimizing the cross-section of the pipe on the premise of saving raw materials without reducing the ring stiffness of the pipe. The corrugated wall of the outer wall is hollow and is made by the extrusion molding process. Because its main raw material is polyethylene (PE), it is simply referred to as PE double-wall corrugated pipe. Referred to as PE corrugated pipe History review: HDPE double-wall corrugated pipe is a new type of pipe with a ring-shaped outer wall and a smooth inner wall. It was first successfully developed 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. At present, it is very mature in the production process and uses technology. Due to its excellent performance and relatively economical cost, it has been greatly promoted and applied not only in developed countries such as Europe and the United States but also around the world.

With in-depth research, double-wall corrugated pipe equipment suitable for more materials has been developed, such as PVC， PP double-wall corrugated pipe equipment is also widely used around the world.

All over the world, the promotion and application of HDPE, PVC and PP double-wall (dual wall) corrugated pipes are on the rise, and all technical indicators have reached the standard of use. The color of the inner wall of the double-wall corrugated pipe is usually blue and black, and some brands will use the inner wall of yellow.

Double-wall corrugated pipe is a new type of lightweight pipe made of high-density PE, PP and PVC. It has the characteristics of lightweight, high-pressure resistance, good toughness, fast construction and long service life. Its excellent pipe wall structure design, and compared pipes with other structures, the cost is greatly reduced. And because the connection is convenient and reliable, it is widely used at home and abroad. Substantial replacement for concrete and cast iron pipes.

Performance & Features

Performance

  • Unique product structure and strong pressure resistance;
  • The inner wall is smooth and the flow rate is large;

The double-wall corrugated pipe  is easy to connect, the interface is well sealed, corrosion resistance, zero leakage, no scaling, avoids secondary pollution, and it is an ideal “green pipe”;

  • The double-wall corrugated pipe  has good flexural properties and can adapt to the uneven settlement of soil;
  • Long service life, buried use can reach more than 50 years;
  • The double-wall corrugated pipe is light in weight and convenient for construction, which can reduce the construction cost and shorten the construction period;
  •  At a speed of 15 feet/second, the wear resistance is 3 to 5 times higher than that of ordinary or fine-grained steel pipes.

Technology

  • Digital centralized control across the board
  • Double-machine co-extrusion, double-layer diversion
  • Full vacuum track drive
  • Online flaring  

Features

PE, PP and PVC double-wall corrugated pipes have excellent chemical stability, aging resistance and environmental stress cracking resistance. The plastic double-wall corrugated pipe produced is a flexible pipe. Its main 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 soil load. In this performance, the HDPE double-wall corrugated pipe has obvious advantages compared with other pipes.

Easy to construct

Due to the light weight of the plastic double-wall corrugated pipe, the handling and connection are very convenient, so the construction is fast and the maintenance work is simple. Tight schedule and construction In the case of poor conditions, its advantages are even more obvious.

Small friction coefficient, large flow

The plastic double-wall corrugated pipe can pass a larger flow than other pipes of the same diameter. In other words, under the same flow requirements, plastic double-wall corrugated pipes with relatively small diameters can be used.

Good low-temperature resistance and impact resistance

The embrittlement temperature of the plastic double-wall corrugated pipe is about -70°C. Generally, it is not necessary to take special protective measures during construction under low temperature conditions (above -30 ℃), and construction in winter is convenient. Moreover, the plastic double-wall corrugated pipe has good impact resistance.

Good chemical stability

Since plastic molecules are not polar, they are chemically stable. Except for a few strong oxidants, most chemical media have no destructive effect on them. The soil, electricity, acid and alkali factors of the general use environment will not damage the pipeline, breed bacteria, and scale, and its flow area will not decrease with the increase of operating time.

Long service life

The service life of plastic double-wall corrugated pipes can reach more than 50 years under the condition of not being exposed to sunlight and ultraviolet rays.

Excellent wear resistance

Germany has used tests to prove that the wear resistance of HDPE is even several times higher than that of steel pipes.

Proper deflection

A certain length of plastic double-wall corrugated pipe can be slightly deflected in the axial direction, not affected by a certain degree of uneven settlement on the ground, and can be directly laid in a slightly uneven groove without pipe fittings.

Advantages

  1. Unique structure, high external pressure resistance, impact resistance, ring flexibility, smooth inner wall and low friction, pipes of the same inner diameter can pass through a larger flow; socket interface, flexible connection, convenient connection, high reliability, not easy to leak.
  2.  Light weight, fast construction and low cost.
  3. The buried service life of more than 50 years.
  4. Polyethylene is a hydrocarbon polymer, the molecule is non-polar, and it is resistant to acid and alkali corrosion.
  5. The raw materials are green and environmentally friendly materials, non-toxic, non-corrosive, non-scaling, and can be recycled and reused.
  6. The applicable temperature range is wide, the pipeline will not break in the environment of -60 °C, and the maximum temperature of the conveying medium is 60 °C.
  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 under the condition of good soil quality.

Scope of application

  1. Municipal drainage and sewage pipeline system engineering;
  2. Drainage and sewage are buried underground in apartments and residential quarters;
  3. Pre-buried pipelines of expressways, underground water seepage pipe network of golf courses;
  4. Water conservancy projects such as farmland water conservancy irrigation, water supply and drainage;
  5. The Chemical industry and mine are used for fluid transportation and ventilation, etc.;
  6. Protective casing of underground pipelines and communication cable casings, etc.

Storage method

Plastic 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. Disassembled and coiled porous tubes can be laid flat, but should avoid heavy pressure or compression stacking. plastic double-wall corrugated pipes are not allowed to be mixed with toxic and harmful substances, and should be kept away from heat sources. A striking fire prohibition sign should be set up in the storage place. The storage period shall generally not exceed 2 years from the date of production.

Shipping method

Plastic double wall corrugated pipe can be transported by various vehicles. During transportation, loading and unloading, it is not allowed to throw, hit, press, expose for a long time or get close to heat sources. Mixed transport with toxic and hazardous substances is not allowed. The perforated tube in the form of a disc cannot be transported flat.

Connecting method

The socket connection is as follows (DN≤500): Plastic double-wall corrugated pipe joints should be socket-type interfaces connected by elastic sealing rubber rings, and the rubber ring interfaces should comply with the following regulations:

Plastic double-wall corrugated pipe flare

Plastic （PE, PP, PVC）double-wall corrugated pipe flare

  1. Before connecting the interface, check whether the rubber ring is in good condition, and confirm the position of the rubber ring and the insertion depth of the socket.
  2. When connecting, first clean the inner wall of the socket, apply lubricant on the inner wall of the socket and the rubber ring of the socket, and then align the central axis of the end face of the socket and socket.
  3.  The connecting method should be carried out according to the following procedures: For pipes of DN400 and below, first, one person hangs the socket of the installed pipe with a cotton yarn rope, and the other person uses a long crowbar to insert the foundation obliquely, and press against the center of the pipe end Then, forcefully insert the pipe slowly into the socket of the plastic double-wall corrugated pipe to be installed to the predetermined position; for pipes above DN400, two lever hoists can be used to pull the pipe section into place. When the connector is closed, the lever hoists on both sides of the pipe section should be pulled synchronously, so that the rubber sealing ring is correctly seated, and does not twist or fall off.

If you have a plan to purchase plastic double-wall corrugated pipe equipment, If you are not sure to do a successful sourcing job and just have a need, Chnic can help you do it successfully.

How to One Stop Select A Turnkey Plastic (PE, PP, PVC)Dual (Double) Wall Corrugated Pipe Line from China?

How to One Stop Select A Turnkey Plastic (PE, PP, PVC)Dual (Double) Wall Corrugated Pipe Line from China?

Plastic Machinery

One-stop Turnkey High Speed Water Cooling Large Plastic Corrugated Pipe Line

How to One Stop Select A Turnkey Plastic (PE, PP, PVC)Dual (Double) Wall Corrugated Pipe Line from China? 

The double-wall corrugated pipe equipment for direct extrusion molding is divided into three types according to its material: PE, PP and PVC. The production line‘s configuration includes extruder, corrugated molding machine, spray cooling tank, planetary cutting machine, and blanking rack.

Brief introduction and development of double-wall corrugated pipe equipment

Before China could produce double-wall corrugated pipe equipment, there were less than ten foreign companies producing double-wall corrugated pipe equipment. China’s first PE double-wall corrugated pipe was a production line (diameter 500mm) introduced by Shanxi Plastics General Factory in 1997. With the continuous enhancement of China’s economic strength, some powerful domestic plastic machine companies have begun the research and development of large-diameter double-wall corrugated pipe production lines. On the basis of absorbing foreign advanced production equipment, these enterprises have successfully launched a large-diameter double-wall corrugated pipe production line at the international advanced level through technical research, comparing the advantages and disadvantages of various foreign equipment, and taking advantage of complementary advantages.

Development history of double-wall corrugated pipe equipment

The first generation of technology is the air-cooled cooling setting technology.

Vertical plastic (PE, PP, PVC) double-wall corrugated pipe forming machine

Vertical plastic (PE, PP, PVC) double-wall corrugated pipe forming machine

 

Performance: The inner and outer layers of the corrugated pipe are independently supplied by two extruders, which can realize the production of different colors and different raw materials for the inner and outer layers.
The molding machine is divided into upper and lower machines. The cooling method is a combination of water cooling and air cooling, but it is still air cooling in the traditional sense. It has the function of online flaring.
The second generation technology is the open water-cooled forming technology.
Module cooling cycle: intermittent water cooling
Performance: The forming machine adopts a horizontal structure, shuttle drive, intermittent water cooling, vacuum forming, and supports online double-layer flaring.
The third-generation technology is the sealed pressure water-cooled forming technology.

(Third generation) One-stop Turn-key double-wall plastic (PE, PP, PVC) double-wall corrugated pipe forming machine

(Third generation) One-stop Turn-key PE (PP, PVC) double-wall corrugated pipe forming machine

 

Module cooling cycle: uninterrupted continuous water cooling
Performance: Sealed high-pressure circulating continuous water cooling, high cooling efficiency and higher output. Compared with the air-cooled model and the second-generation intermittent water-cooled model, the output can be increased by 3 times.

The technical key of double-wall corrugated pipe equipment

For the production of high-quality double-wall corrugated pipes, the corrugation forming system plays a vital role, and all the key technologies for producing plastic double-wall corrugated pipes are also concentrated here. The subdivision of corrugated molding system can be divided into three parts: corrugated molding machine, corrugated molding block, extrusion die, cooling and forming system.

First, look at the corrugated forming machine. The function of the corrugated forming machine is to make the corrugated forming block installed on it run continuously and stably and to provide the necessary vacuuming and cooling functions for corrugated forming. In order to make the corrugated molding block run continuously and stably, the design of the module running track of the molding machine is particularly important. The excellent block running track design of the corrugated molding machine can greatly improve the service life of the machine. A good track design should have very little friction. The lower the friction, the lower the wear and the longer the life. In the production of double-wall corrugated pipes, the corrugated molding block also plays a crucial role. First, because the corrugated molding block directly determines the shape of the wave crest, and second, because the manufacturing process of the corrugated molding block directly affects the quality of the pipe.

The die head for producing double-wall corrugated pipe is very different from the die head for producing solid wall pipe due to technological reasons. When producing, on the one hand, the die head is required to have a double-layer flow channel structure, and on the other hand, the requirements for the die head material are relatively high. The ideal material should be the same material as the barrel and screw of the extruder – 38CrMoALA, After nitriding treatment, it has high precision, high strength and good stability. Although the price is high, it is reliable to use and can ensure the product quality of the pipe.

If the die head, the barrel and the screw of the extruder are made of non-standard materials, trouble will accompany the entire life of the machine.

Status Quo of China’s Double Wall Corrugated Pipe Forming Equipment Technology

According to the current double-wall corrugated pipe forming method and pipe wall structure, the diameter of the PVC double-wall corrugated pipe should not be too large, generally 630mm. It is said that some manufacturers can manufacture 1000mm PVC double-wall corrugated pipe equipment, but they have never seen it; and for HDPE double-wall corrugated pipe If the inner diameter is larger than 1000mm, the meter weight will increase significantly, and its cost will greatly limit its application field; in addition, since the double-wall corrugated pipe cannot be used for the current construction without excavation, people have to buy a winding reinforced pipe with a larger meter weight or GRP pipe. Therefore, the development of new structural wall pipes and their forming methods is the next research focus in the field of plastic buried drainage pipes, and it is also an inevitable choice for China to surpass the Western developed countries in the manufacture of buried drainage pipes.

How to select the right turnkey plastic double wall (dual wall) corrugated pipe forming machine(production line)?

There are dozens of manufacturers that claim (advertise) can manufacture plastic double-wall corrugated pipe equipment with good quality, Apart from China, there are not so many manufacturers in the world. 

For clients who are planning to purchase equipment, how to choose the right equipment is a huge challenge, after all, the value of this equipment is relatively high. For clients who don’t know much about the situation, some choose the manufacturer based on the size of the manufacturer, thinking that the large-scale one is powerful. If you don’t understand its operating background, you may fall into a trap. Some manufacturers do not have R&D strength, but only get relevant drawings and manufacture plastic double-wall corrugated pipe equipment according to the drawings. This equipment often has problems during operation, resulting in being sued for not being able to deliver products according to the contract. There are other reasons that affect the performance quality of the plastic double-wall corrugated pipe equipment. For HDPE double-wall corrugated pipe equipment some manufacturers produce single-screw equipment, some produce twin-screw equipment, and some produce conical double-screw equipment. 

 Equipment breakdown

Equipment breakdown with cheap price

China’s vast territory has created huge differences in the characteristics of people in different regions, which leads to very different ways of thinking and behavior and values ​​of people, which in turn affects business behavior. These intangibles cannot be shown on the surface. Foreigners who have little knowledge of Chinese culture think they know China very well, so they often fall into the pitfall and cause losses.

If you are not sure to do a successful sourcing job and just have a need, Chnic can help you do it successfully.