Double Shaft Shredder

Double shaft shredders operate through precisely synchronized mechanical action: Material enters a reinforced hopper where hydraulic press rams (50-400 ton force) pre-compress bulky items before introduction to the cutting chamber. Two parallel shafts with helically arranged cutting discs rotate inward at 15-60 RPM, creating three distinct size-reduction zones. In the intake zone, large hooks grab and feed material; the primary shear zone features intermeshing discs generating 50,000-200,000 N·m torque; finally, the sizing zone uses screen-controlled recirculation to ensure uniform output. Particle size is determined by interchangeable bottom screens (10-300mm) and adjustable cutting disc clearance (1-20mm).

Integrated smart systems optimize performance: Strain gauges measure real-time cutting forces, automatically adjusting hydraulic pressure to maintain optimal shaft synchronization within 0.5° precision. Advanced models feature water-cooled rotor bearings and infrared temperature monitoring of cutting tools. Material purification occurs through optional in-process components: Overband magnets extract ferrous metals, eddy current separators remove non-ferrous metals, and air knives eject lightweight contaminants. Post-shredding, the fragmented output is conveyed to downstream systems, with regenerative drives capturing up to 30% of deceleration energy. The entire process operates within sound-insulated enclosures maintaining noise levels below 82 dB(A), with dust extraction systems ensuring OSHA-compliant particulate control.

Selecting the optimal double shaft shredder requires comprehensive evaluation of material characteristics and operational requirements:

• Material Type: For e-waste and WEEE, choose models with hardened steel discs and integrated PCB separation; for tires, select slow-speed (15-25 RPM) high-torque units
• Throughput Needs: 1-10 tons/hour (compact units), 10-30 tons/hour (standard industrial), 30-50+ tons/hour (heavy-duty systems)
• Output Specifications: Coarse fragmentation (100-300mm) for waste-to-energy, medium (30-100mm) for recycling, fine (10-30mm) for SRF production
• Drive System: Hydraulic drives (variable torque), electric drives (constant torque), or hybrid systems balancing energy efficiency and power

Critical evaluation factors include wear protection (tungsten carbide disc coatings), safety systems (ATEX compliance for explosive dust), and automation features like predictive maintenance alerts. For facilities processing hazardous materials, prioritize models with sealed chambers and negative pressure systems. Always conduct material testing with actual waste samples, evaluating throughput, particle size distribution, and wear rates during trial runs.

Automotive Shredder Residue: Recycling plants process 20 tons/hour of post-shredder fluff into 50mm fragments, recovering residual metals and producing RDF for cement kilns through integrated air classification.

Electronic Waste Recycling: Specialized facilities shred mixed e-waste into 25mm particles, with downstream separation recovering 98% copper content from PCBs while isolating hazardous materials for proper disposal.

Municipal Solid Waste: Waste-to-energy plants preprocess 30 tons/hour of MSW into 80mm fragments for efficient combustion, with integrated removal of inert materials and metals.

Industrial Plastic Scrap: Manufacturing facilities convert production purge and rejects into 15mm regrind for direct reuse, achieving 99.5% purity through in-line metal separation and optical sorting.

Construction & Demolition: Recycling centers process mixed C&D debris into 100mm fragments, separating wood, metals, and inert materials for respective recycling streams.

Tire Recycling: Plants shred 10 tons/hour of OTR tires into 50mm chips, with subsequent removal of steel cord for production of rubber-modified asphalt.

Implement a comprehensive predictive maintenance program:

• Daily:
  • Laser measurement of cutting disc wear (0.05mm accuracy)
  • Infrared scans of electrical panels and bearings
  • Hydraulic fluid level and contamination checks
• Weekly:
  • Ultrasonic thickness testing of shafts
  • Gearbox oil condition monitoring
  • Screen integrity inspections
• Monthly:
  • Bearing lubrication with high-temperature grease
  • Torque verification of all fasteners
  • Dust collection system maintenance

Quarterly overhauls should include rotor removal for magnaflux inspection, gearbox oil analysis (ISO 4406), and recalibration of all sensors. Maintain critical spare parts inventory: Cutting disc sets, hydraulic valves, and shaft coupling assemblies.

Advanced monitoring techniques include:

• Vibration spectral analysis for early bearing failure detection
• Oil spectroscopy identifying component wear metals
• Acoustic emission monitoring for crack detection
• Thermal imaging of electrical systems

Annual recertification encompasses safety system validation (SIL-2), explosion protection testing, and control software updates. Store spare cutting tools in humidity-controlled environments with VCI corrosion inhibitors. Implement operator training on synchronized shaft operation and emergency jam-clearing procedures using hydraulic reversal systems.