Dynamic Exhaust Device (Side Exhaust)

Dynamic exhaust device is mainly used for devolatilization during the extrusion process and is one of the core technologies for improving the quality of products in the field of plastic extrusion.

Components

Its structure is similar to that of side feeding, mainly composed of eight parts: motor, reduction gearbox, elastic pin coupling, vacuum exhaust pipeline, cast copper heater, water cooling barrel, screw, support base, and caster. A set of vacuum exhaust pipeline is installed in the middle of the barrel. Valves, pressure meter and vacuum chamber (with a visible window) are installed above the vacuum exhaust pipe, and they are connected to the vacuum pump below. The single-section barrel is cooled by water and connected to the side opening barrel of the extruder.

Working principle

Through the synergistic effect of pressure control, mechanical shearing and airflow management, gases, moisture and volatile substances in the materials can be efficiently discharged. During operation, the side exhaust screw presses the material back into the barrel (to prevent the material from escaping from the barrel during vacuuming), while the vacuum system extracts volatile gases through the upper pipelines.

Applications

1. Recycling materials: When recycling EPDM, desulfurization is required to destroy its reticular structure. After desulfurization, sulfur dioxide (an acidic gas with strong pollution) will be produced, and it needs to be vacuumed in sections before handling.
2. Reaction extrusion: When processing maleic anhydride grafting, a low-VOC process can be adopted, that is, dynamic exhaust is carried out after injecting the entrainer (water/alcohol/acetone) into the extruder barrel. By removing reaction by-products and low-molecular-weight volatile substances in real time, the grafting rate and product stability can be improved.
3. Engineering plastic: In the extrusion of engineering plastics such as PET and PA, dynamic venting can remove unreacted monomers (such as formaldehyde and caprolactam), enhancing the safety and aging resistance of the products.