Double-head Extrusion Granulation Equipment

Updated: 2026-07-18

Overview

Twin-screw extrusion granulation equipment is a versatile industrial machine designed to transform powdered or paste-like raw materials into uniform granules through continuous extrusion. Unlike single-screw systems, it utilizes two intermeshing screws (co-rotating or counter-rotating) that provide superior mixing, compression, and conveying capabilities. The technology originated from polymer processing but has been adapted for diverse industries including pharmaceuticals (tablet excipients), food (instant drink mixes), and specialty chemicals (fertilizers). Modern variants incorporate PLC controls, touchscreen interfaces, and interchangeable screw configurations to handle formulations ranging from heat-sensitive biologics to abrasive ceramic powders.

Structure and Working Principle

The core components include a feeding system (hopper), barrel segments with heating/cooling jackets, twin screws with specialized kneading elements, a die plate for shaping, and a cutter for granule sizing. Material undergoes sequential processing zones: feeding → mixing → compression → extrusion → cutting. Screw design (pitch, helix angle) and barrel temperature profiles are critical for product quality. Co-rotating screws (common in food/pharma) provide gentle mixing, while counter-rotating screws deliver higher shear for tough materials. Advanced models feature segmented barrels for zone-specific temperature control and venting ports for volatile removal during processing.

Key Features

1) **High Flexibility**: Modular screw/barrel configurations accommodate materials with different viscosities and melting points. 2) **Precision Control**: PID-regulated temperature (±1°C) and variable screw speed (typically 50-600 RPM) ensure batch consistency. 3) **Scalability**: Bench-top to production-scale models maintain similar shear rates for easy process transfer. Additional advantages include short residence time (2-5 minutes) for heat-sensitive compounds, self-wiping screw design to minimize cross-contamination, and optional features like liquid injection ports or vacuum degassing. Energy efficiency is 20-30% higher than single-screw alternatives due to better material conveyance.

Application Areas

**Pharmaceuticals**: Wet/dry granulation of API-excipient blends for tablet compression. GMP-compliant models feature polished surfaces (Ra<0.4µm) and validated cleaning systems. **Food Industry**: Production of textured vegetable protein (TVP), pet food kibbles, and functional ingredient carriers with 0.3-3mm granule sizes. **Chemicals**: Catalyst supports, detergent powders, and slow-release fertilizers benefit from the equipment's ability to incorporate coatings during extrusion. Niche applications include ceramic precursor shaping and battery electrode material processing. Throughput ranges from 5 kg/h (lab) to 5,000 kg/h (industrial).

Maintenance and Precautions

Daily checks should include screw wear inspection (especially for glass-filled compounds), barrel alignment verification, and lubrication of cutting mechanism bearings. Monthly maintenance involves torque testing on screw connections and calibration of temperature sensors. Critical precautions: 1) Never run the machine empty to prevent screw scoring 2) Use ramp-up/down procedures for thermal-sensitive materials 3) Install magnetic separators in feed systems to protect screws from metal contaminants. Wear parts like die plates typically require replacement every 1,000-2,000 operating hours depending on material abrasiveness.

B2B Procurement Guide

When evaluating suppliers, prioritize manufacturers with ISO 9001 certification and industry-specific experience (e.g., USP Class VI compliance for pharma). Key specifications to compare: 1) L/D ratio (20:1 to 40:1 – longer barrels enable more processing zones) 2) Motor power (typically 0.5-500 kW) 3) Maximum pressure rating (commonly 50-200 bar). For CAPEX optimization, consider retrofitting options for existing lines versus turnkey systems. Lead times range from 12 weeks (standard models) to 6 months (customized solutions). After-sales support should include on-site installation qualification (IQ) and operator training. Total cost of ownership analysis should account for energy consumption (≈0.1-0.3 kWh/kg) and spare parts availability.