Cross linked polyethylene wire and cable
DATE：2022/11/21 8:48:57 / READ： / SOURCE：This station
Cross linked polyethylene wire and cable
Cross linked polyethylene wire and cable are made of cross-linked polyethylene cable material and conductive metal wire (copper wire or aluminum wire) as raw materials. The cross-linked polyethylene cable material is plasticized and melted by an extruder. After both materials pass through the molding mold, the plastic is coated on the conductive metal wire to become cross-linked polyethylene wire and cable. The production process sequence is as follows:Cable material - Extruder extrusion melting → Composite molding die → Composite wire cooling shaping - Heat treatment metal core - Cooling → Finished product winding
The heat resistance and hardness of wires and cables coated with cross-linked polyethylene cable compound are higher than those of ordinary polyethylene cable compound. The wires and cables covered with cross-linked polyethylene cable material are mainly used in medium and high voltage transmission line projects.
(1) Cross linked polyethylene wire and cable special materials are selected as raw materials, such as DJ200, DJ200A and DJ210 of Sinopec Shanghai Petrochemical Company; LD100BW of Sinopec Yanshan Petrochemical Company; 19E and other raw materials of PetroChina Daqing Petrochemical Company are extrusion grade polyethylene cross-linked cable materials suitable for 10kV or 35kV. It can also refer to Formula 2 in Table 10-7. According to the needs of the working environment of wires and cables, the use of auxiliary materials in the formula can be adjusted appropriately to produce PE wires and cables. The conductors can use aluminum or copper wires as metal cores. The specification and diameter of a single core are 176mm, 2.24mm, 2.73mm, etc; After the wire core is coated with PE material layer, the corresponding value between the diameter of the plastic coated wire and the specification of the metal wire core is ф 3mm, middle 3.6mm ф 4.3mm
(2) Equipment conditions
Wires are available for the extruder. The plastic tubular coating extruded from the mold is concentric with the metal wire core, but the plastic coating does not contact the wire core. The gap between the pipe and the wire core is vacuumized, so the plastic tubular coating shrinks onto the wire core. For wires and cables formed by this method, generally, the core has been covered with an insulating layer, and the tubular plastic layer acts as a sheath.
(3) Forming process
① If the moisture content of the cable material is too high (damp), it should be dried in a hot air circulation oven at about 80 ℃ before being put into production.
② Note that the metal wire core before entering the molding mold should be straightened and preheated to a certain temperature to ensure good adhesion with the molten plastic and small deformation. The preheating temperature of the wire is about 100 ℃.
③ The process temperature control of raw materials plasticizing in the extruder is: 130~150 ℃ in the barrel feeding section, 150~170 ℃ in the plasticizing section, and 160~180 ℃ in the homogenizing section. Forming mould 175~185 ℃.
The heat treatment condition in a 40~50m long drying tunnel is to heat it with a 147MPa steam drain pipe to promote the cross-linking of polyethylene. The steam heating drying channel shall have a downward tilt angle (about 35 °) to facilitate the discharge of steam condensate.
Author：admin