Advantages:
Improve Product Quality: It can minimize the dimensional tolerances of extruded products, making the dimensions of plastic products more precise and their shapes more regular, thereby enhancing the stability and consistency of product quality. Whether it's films, pipes, sheets or profiles and other products, the use of melt pumps can effectively reduce defective and waste products caused by dimensional deviations and improve the overall quality of products.
Stabilize the Extrusion Process: It can effectively reduce the instability of material output and pressure pulsation caused by changes in extruder parameters. No matter how the inlet pressure of the pump changes, the fluctuations in its outlet pressure and flow rate can be controlled within a very small range. This helps maintain a stable melt flow throughout the extrusion process, ensuring the stability of product quality. It is especially suitable for production processes with high requirements for the stability of melt pressure and flow rate, such as the production of ultra-thin films.
Increase Production Efficiency: It reduces the pressure requirements on the screw, enabling the screw to extrude materials at high speed and with high efficiency. Meanwhile, it can adjust the back pressure of the extruder, reduce the residence time of the melt in the barrel, stabilize the plasticizing process, lower the melting temperature, and then increase the output of products. For example, when a co-rotating twin-screw pelletizing extruder is combined with a melt pump, the mixing quality and output are significantly improved compared to a single twin-screw pelletizing unit.
Reduce Unit Energy Consumption: Since the polymer melt pump is installed on the extruder and the decompression function of the extruder is transferred to the gear pump to complete, the extruder can operate under low pressure and low temperature conditions, and the leakage flow is greatly reduced, thus reducing the energy consumption for processing each kilogram of materials. Generally speaking, when a co-rotating twin-screw pelletizing extruder is combined with a melt pump, the energy consumption for processing each kilogram of materials can be reduced by about 25%.
Extend Equipment Lifespan: After using the melt pump, the pressure inside the extruder barrel is reduced, which can greatly reduce the wear between the screw and the barrel, as well as the load on the thrust bearings of the gearbox, and extend the service life of the extruder and related equipment. In addition, it can also solve the problem of material venting and overflow that may occur in the extruder during the production process.
Facilitate Detection and Control: The melt pump has linear extrusion characteristics, and its conveying capacity has a basically linear relationship with the rotational speed. After the pump's rotational speed is changed, the flow rate can be accurately known. By collecting information such as the pressure and temperature at the inlet and outlet of the melt pump, the whole extrusion process can be monitored online and controlled with feedback, which is convenient for better realizing the automation control and optimization of the production process, improving production efficiency and the stability of product quality.
Strong Applicability: It can be used for the processing of various polymers, including various thermoplastic resins, thermoplastic elastomers and other polymers, and can meet the needs of different plastic processing processes.
Optimize the Production Process: By adding a melt pump and extrusion heads for pipes, sheets, films, etc. to the original single-screw or co-rotating twin-screw pelletizing extruder, the pelletizing process can be omitted and products can be directly extruded, simplifying the production process of extruded products, shortening the production cycle and achieving energy conservation.
Disadvantages:
Requirements for Materials: Its application is limited when processing plastics containing fillers or special modifiers, and there are strict requirements for the dispersion degree of each component, its compatibility with plastics and its abrasiveness. Materials containing large particles, abrasive fillers or reinforcing agents cannot be processed by an extruder equipped with a melt pump, because these filler particles are prone to form plugs that cannot pass through the tooth gaps of the meshing gears of the melt pump, and the blockage of the plugs and the abrasive wear of the teeth will quickly damage the melt pump. In addition, when fine and dispersed mineral fillers have poor compatibility with plastics and cannot be sheared in the high-speed shear zone, they may also gradually form plugs and then damage the melt pump.
Complex Structure and High Cost: Compared with some simple conveying equipment, the structure of the melt pump is relatively complex and the manufacturing cost is relatively high. Its interior contains multiple components such as the pump casing, gears, bearings, end plates and seals, and the manufacturing process has high requirements, resulting in a relatively expensive equipment price. Moreover, in terms of installation, maintenance and repair, a higher technical level and more time and energy are required, increasing the comprehensive use cost of the equipment.
Large Volume: In some occasions with strict restrictions on equipment installation space, the relatively large volume of the melt pump may bring inconvenience. For example, in some small plastic processing workshops or production lines with a compact equipment layout, installing a melt pump may face the problem of insufficient space.
