Ningbo Fangli Technology Co., Ltd. is a mechanical equipment manufacturer with nearly 30 years’ experiences of plastic pipe extrusion equipment, new environmental protection and new materials equipment. Since its establishment Fangli has been developed based on user’s demands. Through continuous improvement, independent R&D on the core technology and digestion & absorption of advanced technology and other means, we have developed PVC pipe extrusion line, PP-R pipe extrusion line, PE water supply / gas pipe extrusion line, which was recommended by the Chinese Ministry of Construction to replace imported products. We have gained the title of “First-class Brand in Zhejiang Province”.
Parallel twin-screw extruder and conical twin-screw extruder can be used to directly produce PVC-U pipe with dry powder. Due to the full engagement of two screws, a closed C-shaped chamber is formed in the twin-screw extruder. The two screws rotate outward in different directions to make the C-shaped chamber move forward axially, so it has the function of forced conveying (positive displacement conveying) of materials; There is a speed difference at the engagement between the screw edge and the screw groove, which forms an extrusion and grinding effect on the material, which is conducive to the plasticization of the material. At the same time, the material adhered to the screw is self-cleaning, and the process experienced by the material in the barrel is relatively close to avoid local material degradation due to overheating.
Both parallel twin-screw extruder and conical twin-screw extruder can produce high-quality PVC-U pipes, but they have their own characteristics in structure. The distance between the two centers at the tail of conical twin-screw extruder is large, which can place strong thrust bearing and gear; The screw diameter at the feeding place is large, which is conducive to the addition and heating of powder; The head diameter of the screw is small, which can avoid degradation due to excessive friction heat, and the axial thrust of the screw is also small; The whole screw is conical, which is conducive to the establishment of high melting pressure at the discharge port of the barrel, and the gap between the screw and the barrel is easy to adjust. However, the manufacturing technology of conical twin-screw and barrel is high, and the screw and barrel are seriously worn in use.
Taking the conical twin screw extruder as an example, the one with large aspect ratio, large cone angle and optimal groove depth should be selected, which is beneficial to improve the quality and output of material plasticization. The screw and barrel shall be wear-resistant and corrosion-resistant. For the transmission system of twin-screw extruder, the main motor and feeding motor shall be DC motor or frequency modulation motor, which shall be controlled by digital speed regulation device to make it have wide stepless speed regulation range, high speed regulation precision, good mechanical performance, sensitive and reliable overload protection. For the heating of the barrel, the system adopts cast aluminum heating ring, mica heating ring, porcelain ring heating ring and other elements, which requires uniform heating and long service life. PID automatic temperature control module has high temperature control precision and reliable operation. The surface of the barrel is made into a wing shape, which is convenient for air cooling. Screw core temperature regulation uses closed liquid temperature regulation tube for small-size extruder and external circulation constant temperature silicone oil for large-size extruder. Water ring vacuum pump is selected for vacuum exhaust system. The whole set of equipment adopts professional industrial computer and man-machine interface operating system, so that various process parameters such as temperature, speed and pressure can be set, stored and queried, so as to realize intelligent control.
If you need more information, Ningbo Fangli Technology Co., Ltd. welcomes you to contact for a detailed inquiry, we will provide you with professional technical guidance or equipment procurement suggestions.