Equipamentos Auxiliares

Tanque de Separação por Flutuação para PET, PE/PP e Escamas de Plástico Misto

Um tanque de separação por flutuação e afundamento (ou tanque de lavagem) divide as escamas de plástico misto por gravidade específica num banho de água controlado. A Rumtoo dimensiona o tanque com base na sua alimentação real (garrafas PET, frascos PEHD, tampas PP, película, PVC), na pureza pretendida e na taxa de reutilização de água.

Solicitar Proposta de Tanque de FlutuaçãoVer Especificações
Scroll
Plastic floating separation tank for PET, PE and PP flakes

Como Escolher o Seu Tanque de Separação por Flutuação

Tank volume alone never predicts real-world purity. The machine must be matched to the feed density spread, flake size, contamination load and water-reuse target — here is the selection path that actually works.

1

Mapear a dispersão de densidade e ponto de corte

Liste cada polímero: PE 0,91-0,94, PP 0,85-0,91, PET 1,38-1,40. Se a diferença for inferior a 0,02 g/cm³, a Rumtoo adiciona etapas de hidrociclone ou eletrostática.

2

Escolher comprimento do tanque e tempo de retenção

Um tempo de retenção de 60–120 segundos é o ideal. A Rumtoo dimensiona o tanque para que as escamas viajem a 0,05–0,10 m/s.

3

Dimensionar o loop de reutilização de água e lamas

A Rumtoo especifica um tanque de sedimentação e loop DAF para que 70–85% da água seja reutilizada e a lama descarregada como bolo seco.

4

Integrar removedor de rótulos e lavagem a quente

O tanque opera com carga estável graças à integração com as fases anteriores, protegendo a linha de incrustações de papel.

O que os Compradores Precisam de um Tanque de Flutuação

The business reason to install a sink float tank is not the technology — it is a measurable jump in PE/PP and PET purity, a lower reject rate at the extruder, and a closed water loop that avoids wastewater permits and 30–50 m³/day of fresh water consumption.

Separação de Densidade de Alta Pureza

Pureza típica de 98–99% numa passagem. Designs de duplo tanque com ajuste de salmoura permitem alcançar 99,5%+ para rPET grau alimentar.

70–85% de Reutilização de Água

O consumo de água de reposição desce para 3–5 m³ por tonelada, poupando milhares de euros por ano em custos de água e esgotos.

Elimina Papel, Película e Finos Metálicos

É a fase chave que elimina o PVC e papel antes da extrusora. Os intervalos de troca de filtro da extrusora costumam triplicar.

Capacidade de 500 a 5000 kg/h

A Rumtoo dimensiona o comprimento e velocidade do skimmer. Uma linha de 5000 kg/h cabe em cerca de 18 metros com baixo volume de lamas.

Common Sink Float Problems and Real Fixes

Most poor-separation reports trace back to five production conditions — not the tank itself. This table shows what actually goes wrong in running lines and how Rumtoo corrects it during commissioning.

Problem

PET pellets float instead of sink — extruder rejects rPET for PVC contamination.

Rumtoo Solution

Rumtoo adds a short de-foaming baffle and lowers paddle speed; most "PET floating" cases are actually entrained air in thin bottle-wall flakes. Persistent cases get a brine dosing line that lifts water density to 1.05 g/cm³ for a guaranteed PET-PS separation.

Problem

Water turns gray, filters clog within two shifts and discharge fails limits.

Rumtoo Solution

Rumtoo sizes the sedimentation tank, bag filter and DAF loop so fine label, paper and glue particles are removed continuously. Sludge is de-watered to 60–70% solids in a screw press instead of being pumped out as liquid.

Problem

Paddle agitators foul with film and rope — tank shuts down twice a week for cleanout.

Rumtoo Solution

Rumtoo specifies an upstream trommel and film-rope separator so ribbons and long strands never reach the tank. Paddle geometry is adapted (cut-blade vs flat paddle) to the dominant flake shape in your feed.

Problem

Winter start-up produces black sludge and foul odor from caustic carry-over.

Rumtoo Solution

Rumtoo isolates the hot-wash caustic loop from the sink float bath with a rinse buffer tank and specifies a weekly tank drain/scrub SOP. A pH and turbidity sensor warns before biological growth crosses odor thresholds.

Referência de Máquina e Princípio de Separação por Densidade

As escamas mistas entram num banho de água onde agitadores de pás e um fluxo transversal transportam as frações de baixa densidade (PE/PP, 0,90–0,94 g/cm³) para um skimmer superior, enquanto as escamas de alta densidade (PET, PVC, metais) afundam e são descarregadas por um transportador de parafuso no fundo do tanque.

Stainless steel sink float tank with paddle agitator and skimmer

Vista de Máquina: agitador de pás, skimmer de vertedouro e parafuso de fundo

O corpo do tanque é construído em aço inoxidável 304 ou 316L para resistir à lavagem cáustica. Os agitadores mantêm o banho em movimento para evitar a aglomeração; um skimmer de superfície retira a fração flutuante; um parafuso de descarga extrai as escamas pesadas com perda mínima de água.

  • Agitadores de pás de velocidade variável sintonizados ao tamanho da escama
  • Altura de vertedero ajustável para um controlo preciso do ponto de corte de densidade
  • Design de dupla etapa disponível para purificação secundária de alta precisão

Vista de Processo: flutuação de PE/PP, afundamento de PET/PVC em linha de lavagem

Numa linha de garrafas PET, o tanque situa-se após o removedor de rótulos. As tampas de PEHD/PP flutuam; o PET, PVC e metais afundam. Numa linha de PEHD/PP rígido ocorre o inverso. Em ambos os casos, o tanque elimina o polímero incorreto antes da lavagem a quente para proteger a extrusora e o permutador de calor.

  • Separa PET/PVC/metal de PE/PP com 98–99% de pureza numa passagem
  • Elimina papel, rótulos e restos de película que flutuam após a pré-lavagem
  • Circuito de água que alimenta o loop de filtragem para 70–85% de reutilização
Recycled PE and PP plastic flakes after sink float separation

Sink Float Separation Tank in Operation

Watch how the paddle agitator, weir skimmer and sinking screw conveyor separate mixed plastic flakes into pure PE/PP floating fraction and PET/PVC sinking fraction in a controlled water bath.

Typical Sink Float Tank Use Cases

A sink float tank earns its place in any plastic washing line where the target and contaminant polymers differ by at least 0.05 g/cm³ and the feed is already wet from pre-wash.

  • PET Bottle-to-Bottle Washing Lines

    Removes HDPE caps, PP rings, paper label fragments and PLA sleeves from PET flakes before hot wash. Critical stage for lines targeting food-grade rPET approval from EFSA, FDA or similar regulators.

  • HDPE Milk/Detergent Jug Recycling

    Separates PP caps, PET tamper bands, metal fines and dirt from HDPE flakes produced from milk, detergent and motor-oil bottles. Prepares HDPE flakes for pipe, crate and packaging compounders.

  • PP Rigid Packaging and Caps Regrind

    Splits PP from residual PET, PVC tamper bands and PS labels coming off food tubs, buckets and cap regrind so compounders receive a single-polymer feedstock.

  • Mixed Post-Consumer Plastic Sorting

    Acts as the first bulk density stage for mixed post-consumer curbside input, routing a clean PE/PP float fraction to pelletizing while high-density material is sent to NIR, electrostatic or manual picking.

  • Agricultural Film and Big-Bag Reclaim

    Paired with a pre-wash, the tank floats LDPE film fragments while soil fines, stones and metal wear particles sink — reducing extruder melt filter changes by 2–3×.

  • WEEE and Automotive Plastic Regrind

    Used as a rough density splitter ahead of electrostatic separation to remove metals, glass fragments and rubber from ABS/PS/HIPS-dominant WEEE and automotive shredder residue feeds.

Reference Configurations

These are sizing references. Actual purity, water reuse and sludge volume depend on feed composition, contamination level and the filtration loop selected — Rumtoo confirms the final specification after reviewing your material data.

ModelThroughputTank VolumePowerKey Features
RT-SF500300–500 kg/h2.5 m³3 kWCompact single-stage tank, 304 stainless, for small PET or HDPE lines
RT-SF1000800–1200 kg/h5 m³5.5 kWPaddle agitator + weir skimmer, bag filter loop, suits standard PET bottle washing lines
RT-SF20001500–2500 kg/h9 m³7.5 kWTwin-tank with brine adjustment, DAF loop, 70–80% water reuse
RT-SF50003500–5000 kg/h18 m³15 kWBottle-to-bottle grade twin-tank, 316L, DAF + screw press, 80–85% water reuse

Typical water make-up with a full reuse loop is 3–5 m³ per ton of clean flake. Energy consumption is 20–35 kWh per ton including agitators, pumps and filtration. Rumtoo sizes the unit after reviewing your feed analysis, contamination level and local water and discharge cost.

Sink Float Tank Checklist Before RFQ

Bring these data points to the RFQ and Rumtoo can size the tank, water-reuse loop and commissioning protocol in the first reply — avoiding weeks of back-and-forth.

  1. Polymer Mix and Density Spread

    List every polymer in the feed with its approximate share — PET, HDPE, PP, PVC, PS, PA, metals — so Rumtoo can confirm the cut-point target and decide whether plain water, salt brine, or a two-stage tank is required.

  2. Feed Flake Size and Shape

    Share the flake size distribution (typical working range is 6–30 mm), shape (flake vs film vs granule) and fines content below 4 mm. Particle size controls paddle speed and retention time.

  3. Contamination Load (Paper, Film, Fines, Sand, Metal)

    Specify the expected contamination per ton — paper label, PE/PP film, paper pulp, sand and metal fines. This determines filtration, sludge press sizing and tank cleaning frequency.

  4. Target Throughput and Shift Pattern

    Provide target kg/h, planned shift hours and scheduled cleaning windows. Rumtoo builds around a realistic effective uptime, not name-plate capacity.

  5. Water Source, Reuse Target and Discharge Limits

    Share local water cost, discharge cost and effluent limits (COD, TSS, pH). The water-reuse loop is sized for the economic break-even between make-up water cost and capex.

  6. Downstream Stages (Hot Wash, Friction, NIR, Electrostatic)

    Describe the full line — what comes before and after the tank. Rumtoo adjusts the cut-point, skimmer angle and discharge method so the tank integrates with existing hot-wash, friction and polishing stages.

Sink Float Tank vs Alternative Separation Methods

A sink float tank is the right answer when the density gap is clear and the feed is already wet. This table shows where it wins and where a hydrocyclone, electrostatic separator or NIR sorter fits better.

Decision CriteriaHydrocycloneNIR Optical SorterElectrostatic SeparatorRumtoo Sink Float Tank
PE/PP vs PET bulk separationGood, but high capexWorks if colors differNeeds pre-dryingProven at 98–99% in one pass
Food-grade bottle-to-bottle rPETWorks as polishing stageWorks upstream of washFinal PVC-ppm stageEssential bulk stage, add electrostatic for <50 ppm
Handles paper, label and film finesPoorNot designed for thisBlocks the fieldRemoves them continuously
Water consumptionVery high, high pressureNoneNone3–5 m³/ton with reuse loop
Energy per ton40–60 kWh + pump pressure10–15 kWh30–50 kWh20–35 kWh including filtration
Capex vs operating costHigh capex, high opexVery high capex, low opexMedium capex, low opexLow-medium capex, low opex

Perguntas Frequentes

Pode separar PET de PVC?

Não por si só, pois as densidades sobrepõem-se (1,35–1,45 g/cm³). O tanque elimina PE/PP, mas para grau alimentar <50 ppm PVC, a Rumtoo adiciona separação eletrostática ou ótica.

É necessária água quente no tanque?

A separação ocorre a 25–40 °C. A Rumtoo costuma recuperar o calor da lavagem a quente posterior via permutador para otimizar a energia.

Pronto para Dimensionar um Tanque de Flutuação para a Sua Linha?

Envie à Rumtoo uma análise do fluxo. Devolveremos um modelo ROI e plano de comissionamento em 24 horas.

Solicitar Proposta de Tanque de Flutuação
Expert response within 24 hours. No obligation quote.