How Does a Wire Mesh-Free Melt Filter Work?

A wire mesh-free melt filter (also called a self-cleaning melt filter or continuous screen changer) removes impurities from polymer melt without traditional wire mesh screens. Here’s how it works:

Contaminated melt enters the filter housing and flows through wedge-shaped filter elements. Impurities larger than the filter gap are trapped on the element surface, while clean melt passes through to the outlet. As particles accumulate, filtration speed decreases and differential pressure between inlet and outlet rises. When pressure reaches the preset value, a differential pressure transmitter signals the controller to activate the backwash system—opening the drain valve, rotating the suction mechanism, and discharging trapped contaminants without stopping production. Once cleaning completes, pressure drops and normal filtration resumes automatically.

The filter consists of four main components: a housing, multiple filter elements, a backwashing mechanism, and a differential pressure controller. The housing splits into upper and lower chambers. The upper chamber holds multiple wedge filter elements, providing large filtration area in a compact footprint. The lower chamber houses the reversing suction cup.

During operation, contaminated melt enters from below, passes through separator ports into each filter element lumen, and exits clean from the top outlet. Impurities larger than the element gap remain trapped inside.

The self-cleaning cycle triggers by either differential pressure or preset timer. When impurity buildup on the element surface reaches the set pressure value—or when the timer expires—the electric control box activates the backwash drive.

The suction cup aligns with the target filter element, the drain valve opens, and the system briefly depressurizes. The suction cup descends inside the element, creating a pressure drop below the element diaphragm. This forces a portion of clean filtrate to flow reverse through the element wall—from outside to inside—dislodging trapped particles. Contaminants wash into the suction cup and discharge through the drain valve.

Key advantages of wire mesh-free melt filters:

Continuous operation — no production stops for screen changes

No wire mesh consumption — eliminates mesh replacement costs and material waste

Low backwash water use — minimal clean filtrate consumed per cleaning cycle

Gentle filtration — smooth inner element walls prevent material degradation; melt properties remain unchanged

Full automation — differential pressure and timer controls require no manual intervention

FAQ

Q1: What is a wire mesh-free melt filter?

It is a self-cleaning continuous filter that removes contaminants from polymer melt using wedge-shaped elements instead of disposable wire mesh screens. It backwashes automatically without stopping production.

Q2: How does the self-cleaning mechanism work?

When differential pressure reaches a preset value—or a timer expires—a suction cup aligns with the filter element, clean filtrate flows in reverse, and dislodged particles discharge through a drain valve. The cycle takes seconds and requires no manual intervention.

Q3: What are the advantages over traditional wire mesh filters?

No mesh replacement costs, no production downtime for screen changes, lower operating costs, and continuous automated operation. Melt properties remain unchanged because filtration is gentle and temperature-stable.

Q4: What materials can it filter?

It handles polymer melts including PE, PP, PET, PS, ABS, and PA—especially valuable for recycled plastic pelletizing where contamination levels are high.

Q5: Is backwash water consumption high?

No. The system uses only a small portion of clean filtrate per cycle. Water consumption is minimal compared to the production throughput.