115/230 Conical Twin Screw Barrel

Executive Summary

• Configuration: The 115/230 conical twin screw barrel is a flagship plasticizing unit designed for the absolute pinnacle of industrial extrusion capabilities. This massive assembly group, with a monumental feed section of 230 mm tapering to a 115 mm outlet, is specifically manufactured for mega-scale operations requiring the extreme continuous output of rigid PVC, UPVC, and heavy-duty Wood-Plastic Composites (WPC).
• Capacity and Standard: The 115/230 unit, produced according to Polytech Middle East's (Polytechme) premium engineering standards, confidently achieves production rates between 1,000 and 1,500 kg/hour, pushing the limits of efficiency.
• Durability: Processed from premium nitrided alloy steel and protected with highly wear-resistant bimetallic coatings, this product provides unique melt homogeneity and pressure stability while processing high-filled and abrasive formulations.

Design and Materials

Producing a barrel of this magnitude requires advanced metallurgy to prevent structural deviation under immense torque and internal pressure. The counter-rotating, intermeshing conical design offers an extraordinary surface area by optimizing the natural compression ratio to manage solid raw material intake.

• Base Structure: Precisely forged from superior 38CrMoAlA (DIN 1.8509) alloy steel. This guarantees the core flexibility and tensile strength required to withstand continuous heavy-duty operations.
• Advanced Heat Treatment: Components undergo a comprehensive gas/ion nitriding process (up to 0.8 mm depth) for 120 hours, providing a surface hardness of 950–1050 HV (~58–62 HRC).
• Premium Bimetallic Protection: To combat the severe abrasive forces of solid $\text{CaCO}_3$ and wood fiber volumes, a 3–6 mm thick tungsten carbide or Ni/Co-based bimetallic sheet (up to 65 HRC) is applied to the barrel hole via centrifugal casting and PTA welding to the screw flights.
• Micro Precision Machining: Despite its massive scale, the internal geometries are polished to a tight surface roughness of $\text{Ra} \le 0.4\ \mu\text{m}$ to prevent PVC buildup and degradation.

📊 Technical Specifications Table

Technical Advantages

• Unmatched Efficiency: The massive 230 mm feed area easily sustains outputs of 1,000–1,500 kg/hour by consuming raw materials at an unprecedented speed, making it the most efficient option for high-tonnage factories.
• Exceptional Melt Homogeneity: The extended conical profile provides a precise yet comprehensive kneading effect. This perfects the distribution of pigments, impact modifiers, and heavy mineral fillers without leading to degradation caused by excessive shear stress.
• Energy Efficient Plasticization: The immense internal friction generated by the screws significantly reduces the need for external heating, optimizing the kW/kg energy ratio of the entire extrusion line.
• Extreme Durability: The reinforced bimetallic layer designed by Polytechme for heavy industrial environments offers a long service life by preserving critical gaps much longer compared to standard nitrided barrels.

Applications and Industries

• Mega-Diameter PVC Pipelines: The primary choice for the extrusion of solid thick-walled UPVC and CPVC pressure pipes used in municipal water, sewage, and deep well casing projects.
• Solid PVC and WPC Structural Sheets: Provides the massive melt volume and stability required for the wide mold extrusion of thick structural WPC panels and mold sheets.
• High Volume Compounding and Pelletizing: Easily meets the intense shear requirements of continuous PVC and composite masterbatch compounding processes.
• Extra Wide Sheet Extrusion: Guarantees flawless, uninterrupted flow for wide PVC roofing sheets and industrial waterproofing membranes.

Installation and Compliance Notes

• Heavy Lifting and Laser Alignment: The monumental size and weight of the 115/230 barrel (typically exceeding 3 metric tons) require specialized heavy lifting infrastructure. Flange alignment with the massive high-torque distribution reducer should be calibrated using laser-guided tools; axial play must be kept below 0.02 mm to prevent destructive shaft fatigue.
• Gradual Preheating Protocol: A rigorous thermal expansion protocol is mandatory. The barrel must be preheated in a phased manner for 4 to 5 hours to allow the massive steel core to expand uniformly before any rotational torque is applied. Operating the drive system in a cold barrel will lead to sudden internal shear failure.

Maintenance and Service Life

• Pressure and Gap Monitoring: Due to the pure volume of the processed material, operators must implement a strict monitoring regime for motor load and melt pressure. A continuous drop in head pressure indicates that the screw-barrel gap is widening (the optimum standard gap for this scale is 0.25–0.40 mm).
• Comprehensive Cleaning (Purging) Protocol: It is absolutely critical to perform comprehensive cleaning with high-grade thermal stabilizers before scheduled downtimes; residual PVC in a barrel of this size can produce dangerously high levels of highly abrasive HCl gas.
• Expected Service Life: With proper maintenance protocols, a bimetallic 115/230 barrel can safely exceed 40,000 to 50,000 operating hours.