Double-Plunger Screen Changer

Working Process of Double-Plunger Screen Changer

Normal Production

Both plungers participate in filtration simultaneously (or one in use, one on standby). The melt is filtered through the screens on the plungers and discharged continuously.

Screen Changing Operation

• Activate the hydraulic system to drive one plunger to retract slowly from the main body and move to the screen-changing position.
• Quickly remove the old screen, install a new one, and push the plunger back into place. Slow down the operation near the working position to ensure precise resetting.
• After the plunger reheats and restores its filtration capacity, replace the screen of the other plunger in the same manner, maintaining continuous production throughout the process.

Functions of Each Component

Plunger

Installs the screen, alternately undertaking the filtration task to intercept impurities in the melt.

Hydraulic Cylinder

Provides power to drive the plunger to move axially, enabling screen changing.

Guide Rod

Guides the plunger for smooth movement, ensuring precise and offset-free screen changing.

Body (Including Flow Channel)

Forms the melt flow passage, connecting the extruder to downstream equipment and serving as the core carrier for filtration.

Side Plate (with Handle/Warning Label)

Protects internal structures, assists in operations (e.g., opening/closing), and provides safety warnings via labels.

Support Bracket

Stabilizes the entire screen changer, ensuring no shaking during operation.

Advantages

1. Non-Stop Screen Changing
   Enables “one working, one changing” to avoid production interruptions and improve efficiency.
2. Large Filtration Area
   The double-plunger design increases the effective filtration area, adapting to high-output requirements and reducing screen-changing frequency.
3.  High Stability
   A rigid sealing structure minimizes material leakage; the alternating working mode stabilizes melt flow and pressure, ensuring consistent product quality.
4. Wide Applicability
   Suitable for various production scenarios (e.g., plastic pelletizing, pipes, sheets, cast films) and compatible with different materials (e.g., PE, PP).

Besides, for the extrusion production line with underwater pelletizing, to achieve continuous production, we recommend this Double-Plunger Screen Changer.