We’re excited to unveil our newly designed dual-purpose sink-float separation tank—an innovative, all-in-one solution that’s reshaping plastic recycling. Engineered with durable stainless steel and a modular design, this system is built to handle both floating and sinking plastic materials efficiently within a single unit.
Designed for Versatility
What sets this tank apart is its ability to process different types of plastic using the same system, just from opposite ends. Whether you’re working with HDPE, PET, or a mix of materials, this machine adapts seamlessly to your workflow.
Step 1: Floating Plastic – HDPE
In one section of the tank, we process HDPE (High-Density Polyethylene)—a plastic known for its buoyancy. As HDPE enters the water, its lower density causes it to float to the surface, while heavier contaminants and mixed materials sink.
An integrated paddle system keeps the material moving for thorough separation, while clean HDPE is efficiently discharged from one end, ready for the next stage of washing or drying.
Step 2: Sinking Plastic – PET
Now let’s flip the process. On the opposite end, the same tank is used to process PET flakes, which naturally sink due to their higher density. These flakes settle at the bottom and are gently moved along by a screw or chain conveyor, leading them to the cleaning stage without cross-contamination.
Why It Matters
This dual-end structure means you can handle two types of plastic in one tank, reducing equipment footprint, cutting costs, and simplifying the recycling line. It’s a space-saving, cost-effective, and highly flexible solution for recyclers looking to improve efficiency without compromising on quality.
Whether you’re upgrading an existing facility or building a new line, our dual-purpose sink-float tank offers the performance, reliability, and adaptability you need to stay ahead in today’s recycling industry.
INQUIRIES
Frequently Asked Questions
How does a sink-float separation tank work?
It uses water density to separate plastics: materials lighter than water (like HDPE and PP) float to the surface, while denser plastics (like PET and PVC) sink to the bottom. An integrated paddle system keeps floating material moving for thorough separation, and a screw or chain conveyor gently moves sunken flakes toward discharge — all without cross-contamination between the two streams.
What makes this tank “dual-purpose”?
Unlike conventional tanks that handle one material at a time, this design processes floating plastics (such as HDPE) from one end and sinking plastics (such as PET flakes) from the opposite end of the same unit. The dual-end structure means two plastic types are separated simultaneously, reducing equipment footprint and simplifying the recycling line.
Which plastics can be separated in this tank?
Any plastics with clearly different densities: HDPE, LDPE, and PP float, while PET and PVC sink. The tank is commonly used in PET bottle washing lines to remove floating caps and label films from sinking PET flakes, and in HDPE lines to float clean HDPE away from heavier contaminants.
Where does the sink-float tank fit in a recycling line?
It typically sits after size reduction and label separation and before hot washing. At this point the mixed flake stream is sorted by density, so downstream equipment — hot washers, friction washers, and dryers — only processes the target material. See our PET bottle recycling process guide for the full line sequence.
What are the construction and maintenance features?
The tank is built from durable stainless steel with a modular design for easy installation and servicing. Routine maintenance involves checking the paddle system, screw or chain conveyor, and water quality. Because there are no high-speed wear parts, operating costs stay low compared to mechanical separation equipment.
What water supply does the tank need?
The tank requires a steady water supply to maintain the separation bath, plus drainage for periodic water changes. Many plants pair it with a water treatment system that recycles the process water, cutting freshwater consumption. Contact us with your throughput target and we will specify the tank size and utility requirements for your line.