The role of high-temperature melt pumps for extrusion process

With the increasingly fierce competition in the market, the requirements to continuously improve product quality and reduce product costs, so the melt pump will be widely used in a variety of extrusion process. What is its role?

Increase extrusion output

After a few years of extruder operation, there will be greater wear between the screw and the material barrel in the extruder, thus increasing the extrusion gap. At this point, the remelt volume increases as the pressure in the head increases during production. As a result, production will decrease compared to a new screw. At this point in time, this problem can be ameliorated with the installation of a SEACOR Melt Gear Pump. Table 1 shows measured data of a refrigerator profile produced by a company. It is made of ABS and 8% TiO2. and the initial high output that can be achieved with a new extrusion line is 450 kg/h. Due to screw wear the output after 8 years has dropped to 380 kg/h. After the installation of a SEACOR Melt Gear Pump the relevant parameters have improved considerably.

Energy savings

In general, melt pumps help with the task of pressure generation, which allows the extruder to "focus" on feeding, melting, mixing, etc. As shown in Figure 2, when the gear pump is not in use, a high pressure is generated in the extruder head. When a melt gear pump is installed, the pressure is higher at the back of the pump rather than at the front of the pump, thus reducing the pressure inside the extruder. The extruder does not need to generate high pressures, so the shear strength of the corresponding melt decreases, the temperature profile becomes flatter and the temperature rise is reduced. Taking into account the torque of the extruder, this reduces energy consumption.

Reduced raw material consumption

In batch production, it is often necessary to start and stop. In general, it usually takes a long time, i.e. a long discharge cycle, for the melt pressure and related parameters to reach a normal and stable value after each start-up. If the extruder is equipped with a melt pump, the melt parameters can be quickly stabilized, thus reducing the discharge time accordingly, thus saving raw materials. Similarly, when masterbatches are used in production, the products often need to change color, and the installation of melt gear pumps significantly reduces the discharge of waste materials.

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