Melt Filtration Systems
Piston Screen Changers
Introduction
Piston Screen Changers are designed for continuous melt filtration in demanding polymer extrusion applications. Utilizing a precision piston mechanism, they enable screen replacement with minimal pressure fluctuation while maintaining reliable sealing under high-temperature and high-pressure operating conditions.
The series includes single-piston, double-piston, double filter drum, and four-position backflush configurations, providing filtration solutions for standard extrusion, high-capacity production, recycled materials, and continuous processing.
Overview
Piston Screen Changers are installed between the extruder and downstream equipment to remove contaminants from molten polymers before pelletizing, extrusion, or molding.
Compared with conventional slide plate designs, piston technology offers improved sealing performance, higher pressure resistance, and more stable melt flow during screen replacement. Different piston configurations are available to satisfy various production requirements, from economical continuous operation to high-capacity filtration and automatic backflush systems for recycled materials.
Single-Piston Screen Changer
Key Features
- Single-piston continuous screen changing design for uninterrupted production.
- Double working stations ensure continuous melt flow during screen replacement.
- High-strength alloy steel construction with heat-treated components.
- Excellent sealing performance under high temperature and high pressure.
- Stable melt pressure with minimal flow fluctuation.
- Compact structure for easy installation and maintenance.
- Suitable for standard extrusion and compounding applications.
Double-Piston Continuous Screen Changer
Key Features
- Dual-piston design enables continuous filtration without production interruption.
- Two independent filtration chambers minimize pressure fluctuation during screen change.
- Stable melt flow for high-quality extrusion processes.
- Integrated venting design improves operational stability.
- Suitable for high-output continuous production lines.
- Reliable sealing under demanding operating conditions.
Double Filter Drum Continuous Screen Changer
Key Features
- Cylindrical filter drum design provides a filtration area 5–6 times larger than conventional double-piston systems.
- Higher throughput with lower energy consumption.
- Ideal for high-capacity recycling and compounding applications.
- Continuous operation without melt flow interruption.
- Low pressure fluctuation ensures consistent product quality.
- Excellent performance when processing materials with higher contamination levels.
Double-Piston Four-Position Backflush Screen Changer
Key Features
- Four independent filtration stations with automatic online backflushing.
- Continuous production without stopping the extrusion line.
- Automatic backflush extends screen service life and reduces consumable costs.
- Large filtration area with minimal pressure fluctuation.
- Reusable filter screens reduce operating costs.
- PLC automatic control for reliable unattended operation.
- Designed for demanding recycling and filtration applications.
Technical Specifications
| Model | Product Type | Filter Size / Filter Area | Capacity | Heating Power | Max. Pressure |
|---|---|---|---|---|---|
| DHZ-100 ~ DHZ-740 | Single-Piston Screen Changer | Ø70 – 350 × 250 mm | 50–3000 kg/h | 2.6–15 kW | ≤15–50 MPa |
| DHZ-2-100 ~ DHZ-2-600 | Double-Piston Continuous Screen Changer | Ø70 – 230 × 310 mm | 50–2400 kg/h | 2.5–20 kW | ≤20–35 MPa |
| DHZ-600 ~ DHZ-5700 | Double Filter Drum Continuous Screen Changer | 298 × 100 – 722 × 390 mm | 300–8000 kg/h | 5.5–38 kW | ≤15–25 MPa |
| DHX-4-134 / DHX-4-170 | Double-Piston Four-Position Backflush Screen Changer | Ø134 / Ø170 mm | ≤800 / ≤1500 kg/h | 16 / 25 kW | ≤20–25 MPa |
Key Technologies
- Precision piston switching mechanism for stable melt flow
- High-pressure sealing technology for demanding extrusion conditions
- Continuous screen changing with minimal pressure fluctuation
- Double-piston configurations for increased filtration capacity
- Filter drum design for extended operating cycles
- Four-position backflush technology for online screen cleaning and reuse
- PLC automatic control for reliable continuous operation
- Optimized melt flow channels to reduce melt residence time and pressure loss
The four-position backflush model is designed with four independent filtration stations, allowing filtered melt to reverse-clean the screens and discharge contaminants through a dedicated channel, enabling automatic screen reuse and reducing operating costs.
Note
The Piston Screen Changer series includes four configurations for different production requirements:
- Single-Piston Screen Changer – An economical solution for continuous production with stable sealing performance and compact structure.
- Double-Piston Continuous Screen Changer – Designed for uninterrupted screen changing with improved production continuity and higher throughput.
- Double Filter Drum Continuous Screen Changer – Features an enlarged filtration area and extended operating cycles, making it suitable for higher-output extrusion lines.
- Double-Piston Four-Position Backflush Screen Changer – Incorporates four independent filtration stations with automatic online backflushing, reusable filter screens, and PLC control, making it particularly suitable for recycling applications and materials containing higher levels of contaminants.
For standard production lines with moderate filtration requirements, Slide Plate Screen Changers provide a cost-effective solution. For fully automatic continuous filtration of highly contaminated recycled materials, Belt Screen Changers or Meshless Self-Cleaning Filters may offer even greater automation and longer uninterrupted production cycles.
Applications
Piston Screen Changers are suitable for continuous filtration in a wide range of thermoplastic extrusion processes, including:
- Plastic Recycling
- Polymer Compounding
- Masterbatch Production
- Pelletizing
- Pipe Extrusion
- Sheet & Board Extrusion
- Film Extrusion
- Profile Extrusion
- Engineering Plastics Processing
Applicable polymers include:PE / PP / PS / ABS / PET / PA / PC / EVA / TPU / Other thermoplastic materials
Interested in This Product?
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