Perfect combination of the hottest aluminum and pl

2022-07-30
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Perfect combination of aluminum and plastic

with an annual production of about 300million meters and a growth rate of about 10%, aluminum-plastic composite pipes are conquering the pipeline industry in Europe. Even in the period when the construction industry is depressed and the overall sales of pipes are weak, the growth rate of aluminum-plastic composite pipes continues to increase

the increasing demand for aluminum-plastic composite pipes can be attributed to the great advantages of composite pipes, which combine the simplicity of installation, dimensional stability of metal pipes and the corrosion resistance and non crusting of plastic pipes

application field of aluminum-plastic composite pipe

in addition to the above advantages, aluminum-plastic composite pipe has been increasingly recognized in the use of underground heating in the past five years. Compared with known and previous multi-layer PP, Pb, PVC or PE-X pipes, it represents a relatively simple solution for the individual needs of the industry. The diameter of aluminum-plastic composite pipes in the market today ranges from 16 to 63mm, with a five layer structure: the central aluminum layer has a bonding layer on both the upper and lower sides, and the outer and inner layers also have a PE-X layer. Because there is an inner layer made of metal, the pipe is absolutely free of oxygen and air leakage, and has an ultraviolet resistant PE-X outer layer and a chlorine resistant PE-X inner layer, which are needed especially in the United States. Experts believe that the future of underground heating belongs to aluminum-plastic composite pipe. The tubes are also used for hot and cold water supply, as well as heating systems using radiators

in order to prevent premature cross-linking, the extruder is specially designed to process copolymers or graft copolymers.

in order to obtain integrity, it is necessary to mention other types of plastics, such as PE-RT, which is used to replace aluminum-plastic composite pipes, but few

quality control is particularly important

no doubt, the manufacturing process of aluminum-plastic composite pipe is very complex, because various processing technologies and process steps must be combined in an ideal way. Therefore, especially quality control in these production lines has become particularly important. At many locations along the production line, modern measurement systems are used to detect whether the pipe size is correct. In this method, the actual thickness of each layer can be continuously detected and recorded. Depending on the tensile testing machine, the adhesion between the layers of the finished pipe can be further tested by random sampling

in the process of producing 5-layer tubes, it is absolutely necessary to detect the measurement process of layer thickness and tube size, and the laser system provides the required accuracy

record production speed

in a "factory opening" activity, German templet company and bartonfield Extrusion Technology Co., Ltd. showed a complete set of 83m long aluminum-plastic composite pipe production line. In this case, the production line is placed in an S shape. But in principle, it can be arranged in a straight line or in a U shape

although the common composite pipe production speed is about 35m/min, the system shown has reached a record speed of 52m/min

silane crosslinked PE XB commonly used in the market is used as plastic. Before the actual pipe extrusion, in the initial processing step, PE with silicon side chain is produced through copolymerization or grafting polymerization, which then provides crosslinking

this two-step process has been proved to be universally available and quite reliable, so it is recommended by machinery manufacturers

similarly, the direct production of five ply tubes on a single production line is also recommended today. Although it is possible to produce inner plastic pipes independently and supply them to the suppliers of composite pipes by winding them on the shaft, it is rare to do so

from raw materials to the initial bonding layer

although the outer layer of the aluminum-plastic composite pipe is often colored, this kind of linear pipe usually uses natural color. With the help of gravimetry metering table, the main components, together with catalyst and processing aids (the proportion of total weight is 5%), are added to the single screw extruder, which is specially treated by bartonfield company for processing pe-x. In order to prevent premature crosslinking, the extruder with groove feeding area and barrier screw is designed to have no stagnation area, and the residence time is controlled to be short to ensure the best product uniformity. The screw is directly connected with the mold core support so that there is no gap. Once the pipe has the required diameter after flowing through the double chamber vacuum caliber measuring device, the thickness of the pipe is detected by ultrasonic measurement. When the pipe comes out of the cooling water tank at the end, the pipe diameter is checked again by the laser measurement system. Laser measurement is extremely accurate, ensuring that strict pipe diameter deviation is maintained. After the traction and drying steps, the PE adhesive layer is applied immediately to ensure the best adhesion to the aluminum layer. For reasons of cost, the applied thickness of adhesive layer is very small. In the process of producing pipes, the adhesive layer can be directly applied by CO extrusion

in the particularly compact forming station ball system

from the inner liner to the metal sheath

during the production of the inner liner, the necessary preparation of the metal occurs at the same time. Starting from the mandrel uncoiling station with two reels, the aluminum strip first passes through a transverse welding station. Here, the ends of the two mandrels are welded together, and it is expected that one mandrel will be replaced. Next, the metal enters the accumulator equipped with a certain length of belt, so it will not affect the continuous production of pipes when changing the shaft. In the system described, the accumulator is equipped with 120 meters of aluminum strip. When the aluminum strip moves along the production line, it now passes through a station, where it is washed without the function of heat preservation, in order to remove any surface dirt or dust and increase the surface roughness. In the accumulator, the aluminum strip is pushed by the retracting device and also maintains the necessary tension of the aluminum strip. It advances to the actual forming and welding position together with the inner liner. This arrangement is particularly compact and space efficient. Using the setting roller, the aluminum strip is gradually formed by winding the inner lining pipe from the lower part to the final butt welding. Following this procedure, the eddy current device checks the joint for complete welding

the aluminum strip accumulator ensures that the tube has the required size after the current three-layer tube is brought to the calibration position by the retracting device, the aluminum layer on the inner lining tube is compacted, and the laser measuring device is used for another inspection. Now the tube enters the induction furnace, where the aluminum layer is heated to activate the internal bonding layer. Maintaining the correct temperature at this location is important and requires a lot of experience. one side. Too low temperature will cause insufficient bonding between the bonding layer and the aluminum layer. On the other hand, too high temperature will cause the loss of tension. Finally, all experimental machines for pipe production are absolutely in line with the national standard. After double-layer T-shaped die, the second bonding layer and PE-X layer are also equipped with a weight measuring measurement system at this stage, and have been improved for the processing of the mixture. The tubes are made after passing through an aftercooler, take-up and cutting device or coiling shaft. After extrusion with hot water or steam, crosslinking of two PE-X layers occurred

summary: aluminum plastic composite pipe has many advantages whether it is used for drinking water in household equipment or heating system. Although the smooth surface of the non encrusted anti-corrosion PE-X inner liner provides the most ideal and long-term hydraulic conditions in the pipeline system, the outer layer of PE-X protects the outer layer. At the same time, the aluminum layer ensures high dimensional stability and flexibility. The bending of small radius can only be completed by hand to cope with the limited space. The simple cold connection technology through the extrusion device means that the minimum installation is a promising environmental protection material. Due to the development of appropriate equipment and the cooperation between extrusion equipment manufacturers and metal coating equipment manufacturers, such pipes can be produced economically at high production speeds today. So far, the market potential has not reached its limit. It will continue to expand its position at a double-digit development rate. The problems of low industry concentration of traditional metal pipes are at stake

this article is taken from the German Kunststoffe international magazine

international plastics business information (end)

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