Influence of pressure fluctuation on normal operation of screen changer

Streamlining the polymer flow through the screen changer will also affect the stability of the process. For sensitive materials or those with unique flow characteristics, CFD (Computational Fluid Dynamics) simulation software can be used to optimize the flow path of screen changer and greatly reduce the retention time of materials. The inventory of polymers along the flow path, sleeve length, steps and transitions, as well as between the tip of the screw and the mesh stack, will be critical for establishing a good flow, while greatly reducing polymer degradation points and thermal stratification.

The exhaust circulation on the continuous screen changer will affect the stability of the pressure. When changing the screen, most bolt type screen changers will have up to 50% of the effective filtering area removed from the process. Although this will cause the head pressure to rise, the flow rate and die pressure will generally remain relatively stable. This problem is caused by reintroducing clean filter material mesh. The air outlet processed in the bolt makes a small part of the polymer melt fill the filter bag in advance and remove the air from it. The slight drop of die head pressure caused by this can be minimized by the operator's skill or more accurate PLC control. Constant voltage screen changer, such as rotary wheel design products, is usually not affected by these problems. The auxiliary equipment that can greatly help overcome the pressure fluctuation is the high-temperature and high-pressure melt pump produced by Barthes, which can keep the head pressure stable when the upstream pressure fluctuation occurs. info@battemachinery.com