Density-Based Plastic Separation
Sink-Float Separation Tank
Energycle sink-float separation tanks use water density to separate PET, PP, PE, PVC, ABS, and other polymers with stable purity, continuous discharge, and low water consumption. They are built for PET bottle recycling lines, mixed rigid plastic recovery, and other applications where heavy and light fractions need a reliable split before drying, optical sorting, or pelletizing.
Key Advantages
Why Recyclers Choose This Sink-Float Tank
Built for industrial-scale density separation with minimal downtime and maximum material purity.
High-Purity Separation
Natural density differences let PET, PVC, and other heavy plastics sink while PP and PE float, helping produce clean output streams without chemical additives.
Multi-Polymer Versatility
One tank can support PET bottle recycling, PP and PE recovery from mixed streams, PVC sorting, and other rigid plastic separation applications.
Automated Continuous Workflow
Screw conveyors, paddles, and rotating drum screens feed, separate, and discharge material continuously, reducing manual handling and line interruptions.
Water-Efficient Design
Closed-loop recirculation with settling and screening can reduce freshwater consumption by up to 80 percent compared with once-through systems.
Durable SS304 Construction
All wetted surfaces use stainless steel for long service life in aggressive wash-water environments, while the frame keeps the machine stable under continuous load.
Easy Maintenance Access
Removable screens, accessible conveyors, and replaceable wear parts make service faster and reduce the downtime usually associated with dense-fraction separation equipment.
How It Works
How Sink-Float Separation Works
Materials denser than water sink while lighter materials float. Once pre-washed flakes enter the tank, the machine uses that physical principle to split mixed plastic streams into cleaner fractions.
Material Infeed
Pre-washed and crushed flakes enter the separation tank through a stable conveyor or feeder.
Density Separation
PET, PVC, and other heavy fractions sink while PP and PE remain near the water surface.
Collection and Discharge
Floating material is skimmed from the top while sinking material is collected through bottom conveyors or scrapers.
Water Recirculation
Settling chambers and screens remove solids before process water returns to the tank.
Material Infeed
Pre-washed and crushed flakes enter the separation tank through a stable conveyor or feeder.
Density Separation
PET, PVC, and other heavy fractions sink while PP and PE remain near the water surface.
Collection and Discharge
Floating material is skimmed from the top while sinking material is collected through bottom conveyors or scrapers.
Water Recirculation
Settling chambers and screens remove solids before process water returns to the tank.
Applications
Applications by Material Type
These tanks are configured for the main polymer recovery scenarios found in modern plastic recycling plants.
PET Bottle Recycling
PET sinks while PP and PE caps, labels, and film fragments float, helping achieve the high flake purity required for food-grade and fiber-grade rPET production.
PET linesPP and PE Recovery
Polyolefins float in water, making the tank a practical way to recover PP and PE from heavier contaminants in mixed plastic waste streams.
PolyolefinsPVC, PC, and PS Sorting
Dense fractions such as PVC, PC, and some PS grades can be separated from lighter contamination before finer downstream sorting stages.
Heavy fractionMixed Rigid Plastics and E-Waste
Post-consumer rigid plastics, automotive scrap, and WEEE housings often use sink-float separation as a purification step before extrusion or pelletizing.
Mixed rigidEngineering
Engineering and Design Features
Every section of the machine is designed to improve separation efficiency, reliability, and maintenance access.
W-Shaped Sedimentation Bottom
The tank bottom channels sinking material toward central conveyors, reducing dead zones and accelerating heavy-fraction discharge.
Primary and Polishing Zones
A two-zone layout helps capture residual cross-contamination and can improve final purity compared with simpler single-zone designs.
Triple-Row Upgrade Path
For larger plants, a triple-row configuration increases throughput while keeping the same separation principle and footprint efficiency.
Integrated Mesh Screens
Screens at discharge points catch fines and small contaminants while remaining accessible for cleaning and replacement.
Modular Scalability
Tank width, length, discharge systems, and downstream connections can be tailored to material type, line speed, and expansion plans.
Closed-Loop Water System
Settling, screening, and recirculation equipment can be integrated so the separation stage uses less fresh water and creates less wastewater burden.
Technical Data
Technical Specifications
Standard configurations are listed below. Width, length, and power selection can all be adjusted around your target output and facility layout.
| Parameter | Specification |
|---|---|
| Interior Width | 1000 to 2000 mm |
| Total Length | 4 to 7 m, customizable |
| Interior Material | SS304 stainless steel |
| Exterior Frame | Carbon steel, painted or galvanized |
| Screw Conveyor Motors | 5.5 kW + 3.7 kW |
| Drum Screen Motors | 2.2 kW + 0.37 kW |
| Paddle Motors | 1.5 kW x 2 |
| Control System | PLC with HMI touchscreen or independent control panel |
| Certification | CE |
| Warranty | 1 year, parts and labor |
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Gallery
Sink-Float Separation Tank Gallery
Reference images from Energycle sink-float tank installations and test layouts.
Selection Guide
How to Choose the Right Sink-Float Tank
Three factors usually determine the right configuration for your recycling line.
Material and Contamination Profile
The main polymer, contamination level, and whether multiple dense fractions are present all affect whether you need a standard tank, a polishing zone, or a multi-stage setup.
Capacity and Throughput
Tank width and length scale with line speed. Small lines may use a compact single tank, while higher-throughput systems may need longer retention time or a triple-row layout.
Water and Discharge Layout
Your available floor space, water-treatment setup, and discharge preference determine whether screws, paddles, scrapers, and extra filtration stages should be added.
Why Energycle
How Energycle Compares with Conventional Alternatives
The main differences are separation stability, water efficiency, maintenance access, and future expandability.
| Feature | Energycle | Conventional |
|---|---|---|
| Separation Stability | Two-zone design with polishing stage and 99 percent plus purity potential | Single-zone layout with lower average purity stability |
| Maintenance Access | Removable screens and serviceable wear parts | More difficult screen access and longer service shutdowns |
| Water Efficiency | Closed-loop recirculation with lower freshwater demand | Once-through or partial recirculation is more common |
| Expandability | Modular design with polishing and triple-row upgrade options | Fixed configuration is more common |
| Global Support | Worldwide installation support and faster wear-part response | Support often depends on local reseller availability |
FAQ
Frequently Asked Questions
Common questions from buyers comparing sink-float separation tanks for PET and mixed rigid plastic recycling.
A sink-float separation tank is used in plastic recycling to separate polymer types by density. Materials denser than water sink while lighter materials float, producing cleaner single-polymer streams from mixed plastic waste.
Typical separations include PET from PP and PE caps or labels, PP and PE from heavier PVC or ABS contamination, and dense rigid fractions from lighter polyolefins in mixed plastic streams.
No. In standard water-based sink-float separation, PP and PE both float because both are lighter than water. They need another sorting method if they must be separated from each other.
With well-prepared feedstock, properly configured tanks can support very high purity output. Actual results depend on flake size consistency, contamination level, and whether a polishing stage is used.
The right size depends on throughput, target polymer, contamination level, and residence time. Higher-capacity systems usually need wider tanks, longer chambers, or multi-row layouts.
A standard tank uses one separation channel. A triple-row design uses three channels in one frame to increase throughput while maintaining the same basic density separation principle.
Water leaves the separation chamber, passes through settling and screening stages, and then returns to the tank. This reduces water use and lowers wastewater treatment requirements.
Routine maintenance usually includes screen cleaning, conveyor inspection, bearing checks, lubrication, and periodic replacement of wear parts depending on contamination level and line hours.
Yes. Energycle sink-float separation tanks can be supplied with CE documentation and the supporting electrical and operating records needed for international projects.
Send your material type, contamination profile, target throughput, local voltage, and whether the tank will be used in a complete washing line or as a stand-alone separation stage.
Warranty and Support
Support That Continues After Installation
Sink-float tanks are usually part of a larger washing line, so support quality matters as much as the machine itself.
1-Year Limited Warranty
Structural components, motors, conveyors, and controls are covered under a standard limited warranty. Wear parts are handled separately based on normal operating conditions.
Commissioning Guidance
Remote support is available for installation and setup, and on-site commissioning can be arranged for projects that need process tuning, operator training, and startup assistance.
Request a Sink-Float Tank Recommendation
Tell us about your material, target throughput, and contamination level. Our team will recommend the right tank size, discharge configuration, and water-loop setup for your recycling line.
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