Dual-column hydraulic screen changer
The dual-column hydraulic screen changer is a device used in the extrusion production processes of plastics, chemical fibers, and other materials to enable non-stop screen replacement. Below is a detailed introduction:
Structural Composition
The dual-column hydraulic screen changer primarily consists of the screen changer body and the power system. The screen changer body includes key components such as the sealing assembly, perforated plate, filter screen, and switching device. The power system is typically hydraulically driven, using hydraulic fluid to activate cylinders that move the screen changer's slide plate or screen columns to perform screen changes.
Working Principle
The dual-column hydraulic screen changer employs a dual-column, dual-flow-channel design. During normal operation, both screens function simultaneously. Material flows from the periphery toward the interior of the plunger, undergoing filtration at the screen's outer perimeter. When screen replacement is required, the hydraulic system controls one screen column to retract from the main body for screen change while the other column continues operation, ensuring uninterrupted material flow. The column with the replaced screen is first slowly advanced to the material feed and venting position. After material feeding and venting, it is retracted back to the working position. The process then alternates to the other screen column, enabling screen replacement without stopping production.
Features and Advantages
High Production Continuity: Dual-column alternating operation enables dynamic switching between “working position” and “screen-changing position.” Screen replacement occurs without shutdown, eliminating material interruptions and speed reductions associated with traditional single-screen changes. Production efficiency increases by over 50%.
Minimal Pressure Fluctuations: Hydraulic systems precisely control column movement during screen changes, maintaining melt pressure within ±5% fluctuations. This preserves extrusion stability, particularly benefiting materials sensitive to process parameters.
High Filtration Efficiency: Featuring a large-area filtration design with curved or elliptical mesh screens, the filtration area exceeds traditional single-screen changers by over 30%. This enables efficient filtration of high-viscosity, highly-filled melts with superior impurity retention.
Broad Process Adaptability: Suitable for conventional plastics like PE, PP, PVC, as well as specialty materials such as fluoroplastics. Compatible with highly filled, high-temperature, and high-pressure conditions. By replacing screens with different mesh sizes, it meets diverse filtration needs from coarse to fine filtration.
Application Fields
The dual-column hydraulic screen changer is widely used in chemical fiber production, blown film, cast film, and cast sheet manufacturing, as well as in the production of pipes, sheets, wires, and fibers. It is also employed in pelletizing lines and recycling applications. It meets the high-temperature, high-pressure, and high-extrusion production demands of any polymer material and can be integrated with extruders of various standards.
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