Labotek Conti-Crystallizer Continuous PET Crystallizers
Technical Structure, Operating Principle, and Detailed Product Description
Labotek Conti-Crystallizer systems are industrial process units developed for the continuous and controlled crystallization of amorphous PET granules and PET regrind (flake or pellet form). These systems play a critical role in PET injection moulding, extrusion, blow moulding, and recycling applications where crystallization prior to drying is essential for stable and reliable processing.
When PET material is in an amorphous state, it tends to soften, stick, and agglomerate at elevated temperatures. Conti-Crystallizer systems convert PET into a crystalline phase under controlled temperature and airflow conditions, resulting in free-flowing, non-sticky, and homogeneous material. This ensures stable downstream drying and processing with improved productivity and product quality.
General Design and Machine Structure
Labotek Conti-Crystallizer systems are designed as continuously operating, vertical, and space-efficient crystallization units. The series is available in two main conveying concepts:
• CC-V: Vacuum conveying version
• CC-S: Screw conveying version
This description focuses on the CC-V vacuum conveying models.
Main system components include:
• Vacuum conveying inlet hopper
• Crystallization hopper
• Crystallization screw with geared drive unit
• High-capacity crystallization blower
• Electric heating elements
• Closed-loop air circuit with cyclone and cartridge filters
• Dust collection chamber
• PLC-based control system with touch-screen operator interface
All components are mounted on a heavy-duty frame suitable for continuous industrial operation.
Operating Principle - Continuous PET Crystallization
Conti-Crystallizer systems operate using a closed-loop hot air circulation combined with continuous mechanical agitation. The crystallization process proceeds as follows:
• Amorphous PET material is conveyed via vacuum into the upper feed hopper
• Level sensors regulate the controlled transfer into the crystallization hopper
• The crystallization screw keeps the material in constant motion
• Heated air is introduced into the hopper, gradually increasing material temperature
• Crystallization begins at approximately 80 °C
• Full crystallization occurs in the 160-180 °C temperature range
• Continuous mechanical mixing prevents agglomeration
• Once crystallization is complete, hot air supply is stopped
• Crystallized PET is discharged from the bottom outlet
During operation, the process air is continuously filtered through cyclone and cartridge filters and recirculated within the closed loop, ensuring high energy efficiency and stable process conditions.
Key Process Parameters
All relevant process parameters are adjustable and monitored via the PLC control system:
• Inlet air temperature: 0-200 °C
• Return air temperature: 0-200 °C
• Optimal crystallization temperature: 160-180 °C
• Crystallization time:
- Amorphous PET granules: approx. 20 minutes
- PET flakes or film regrind: approx. 15 minutes
• Airflow rate: 0-100 percent
• Filling and discharge times: 0-999 seconds
The control system can store up to 10 different recipes, allowing quick and repeatable changeovers between different PET grades and material forms.
Model Range and Technical Data
The Labotek Conti-Crystallizer CC-V series is available in two standard models:
CC 80-V
• Crystallization capacity:
- At bulk density 0.3 kg/l: approx. 72 kg/h
- At bulk density 0.5 kg/l: approx. 120 kg/h
- At bulk density 1.0 kg/l: approx. 240 kg/h
• Crystallization hopper volume: 190 litres
• Heater power: 18 kW
• Crystallization blower power: 3.1 kW
• Vacuum blower power: 1.3 kW
• Total installed power: approx. 23.7 kW
• Net weight: approx. 950 kg
CC 160-V
• Crystallization capacity:
- At bulk density 0.3 kg/l: approx. 144 kg/h
- At bulk density 0.5 kg/l: approx. 240 kg/h
- At bulk density 1.0 kg/l: approx. 480 kg/h
• Crystallization hopper volume: 290 litres
• Heater power: 50 kW
• Crystallization blower power: 7.5 kW
• Vacuum blower power: 1.3 kW
• Total installed power: approx. 55.7 kW
• Net weight: approx. 1050 kg
Both models operate with 380-480 V, 50/60 Hz three-phase power supply and require compressed air at 5-7 bar.
Control, Safety, and Standards
Conti-Crystallizer systems are designed in compliance with industrial safety and quality standards:
• PLC-based automation system
• Touch-screen operator interface
• Multiple safety interlocks and limit switches
• Over-temperature protection using 250 °C bimetal thermostats
• Level-controlled feeding and discharge
• Integrated alarm and fault diagnostics
All systems are manufactured in accordance with CE requirements and under ISO 9001 quality management standards.
Areas of Application
Labotek Conti-Crystallizer systems are widely used in:
• PET injection preform production
• PET blow moulding and ISBM lines
• PET extrusion and sheet production
• PET recycling plants
• PET flake and regranulate preparation lines
• Processing of high-IV PET materials
Key Advantages
• Continuous and stable crystallization process
• Agglomeration-free, free-flowing PET output
• Ideal preparation before drying
• Energy-efficient closed-loop air system
• Recipe-based flexible process control
• Low maintenance requirements and long service life
• Compact design with minimal floor space requirement
The Labotek Conti-Crystallizer series represents an advanced engineering solution that makes the PET crystallization step reliable, repeatable, and energy-efficient in both virgin and recycled PET processing lines. By eliminating sticking and agglomeration risks associated with amorphous PET, these systems significantly improve the performance and stability of downstream drying and processing operations. With robust mechanical design, sophisticated automation, and proven process reliability, Conti-Crystallizer systems are a reference solution for modern PET production and recycling facilities.
