What does a melt pump do in recycled plastic extrusion? When processing recycled PE, PP and other materials, a melt pump mainly provides melt pressurization and metered conveying. It helps reduce upstream output fluctuations and delivers a more uniform flow to the pelletizing die.
Recycled materials from different sources can vary in particle size after shredding, bulk density and melt flow characteristics. During production, changes in feeding, processing temperature and filtration resistance can all affect output. If strand thickness or pellet size varies, check not only the pelletizer but also whether the material supply to the die is stable.
A pelletizing melt pump uses rotating gears to continuously convey melt toward the outlet through the spaces between the gear teeth and the pump housing. With sufficient inlet feeding and a suitable temperature, adjusting the pump speed helps stabilize the flow rate. The pelletizing melt pump also takes over part of the extruder’s pressure-building load, helping coordinate screw plasticization with downstream melt delivery.
To remove contaminants from recycled materials, a screen changer suited to the operating conditions can be installed upstream of the pump. It captures hard particles and helps reduce wear caused by contaminants entering the pump. The screen changer handles filtration, while the melt pump provides pressurization and metered conveying. Together, they support downstream processing. During operation, monitor the pressure differential across the filter and replace screens promptly to prevent clogging from restricting the pump’s inlet supply.
Selecting a melt pump for recycled plastic extrusion requires consideration of material composition, processing temperature, throughput and differential pressure to determine the appropriate displacement, construction materials and drive. Tianjin Ruicheng Pump Industry provides melt pumps, screen changers and control systems based on actual operating conditions, helping users match equipment to their production line requirements.
