The combination of two high-performance melt filters offers operators the ability to continuously process even heavily contaminated plastic melts at high throughputs with fine filtration. The goal is to elevate the quality of recyclates to a level comparable to virgin material—while simultaneously optimizing plant efficiency.

Limitations of Melt Filtration in Recycling

Post-consumer recycling streams (PCR) from films, bottles, pipes, or from the automotive and construction industries are often contaminated with various material types and stubborn impurities. In addition to paper, wood, or metals, gels, rubber, and other highly viscous components pose particular challenges. Conventional filtration solutions quickly reach their limits when high viscosity, high throughput, and fine filtration are combined. Frequent filter changes, high labor requirements, and pressure fluctuations lead to increased production costs, waste, and downcycling.

Another barrier to high-quality recyclates is the limited service life of filters. Many systems operate under constant pressure for only a few days or weeks before a filter change is required. At low throughput rates, existing solutions are often uneconomical, and the processing of certain input streams is restricted.

Dual Filtration for Consistent Quality and High Cost-Efficiency

MAAG’s new dual-stage melt filtration system combines the disc filter (BRF) with the rotating drum filter (ERF), both of which clean continuously and provide a large open screen area at all times. In the first stage, the BRF removes coarse and medium-sized particles from the melt stream. The ERF, as the second stage, handles fine filtration. This division reduces the load on the second filter stage, resulting in significantly longer service life.

The system enables continuous operation over months without screen changes, maintaining constant pressure and minimal melt loss: approximately 0.5% with the BRF and around 0.3% with the ERF. It is the only system on the market where both stages can be individually adjusted via a single control unit to match the contamination level of the melt, ensuring optimal quality and throughput with minimal melt loss. Depending on the configuration, throughput can reach up to 10 tons per hour. A robust recycling pump ensures a consistent melt flow and expands the process window.

The dual-stage filtration system is suitable for a wide range of applications, including LDPE film recycling, HDPE bottles and pipes, PP from the automotive sector, PVC, and polystyrene from the construction industry. Operators benefit from higher recyclate quality, a stable process, and low operating costs.