Precision extruder melt pumps for the rubber and plastic industry

In the rubber and plastic industry, precision extruder melt pump as a key equipment, mainly used for high temperature and high viscosity polymer melt conveying, pressurization, pressure stabilization and metering, especially in the need for high stability of pressure and flow rate of the precision extrusion system is outstanding. The following from the working principle, structural characteristics, performance advantages, application scenarios and selection of five aspects of the detailed analysis:

First, the working principle

melt pump based on the principle of positive displacement conveying, through the precision meshing of the active gear and the slave gear to form a closed working volume. When the gear rotates, the working volume changes periodically, realizing the inhalation, conveying and discharging of the melt. This process ensures that the melt is conveyed at a constant, precise flow rate, providing stability for the subsequent extrusion process. For example, in pipe production, the melt pump eliminates pressure pulsations caused by fluctuations in extruder parameters, resulting in a significant increase in pipe thickness uniformity.

Second, structural characteristics

Core components

Pump head: consists of pump casing, front and rear side cover, gear shaft, sliding bearing and shaft seal. The pump casing adopts the whole casting process to ensure the structural strength and sealing; the gear shaft adopts straight tooth or helical tooth design to improve transmission efficiency and reduce noise.

Sealing system: the shaft seal adopts spiral external design, effectively preventing the melt leakage and guaranteeing the safety and hygiene of the equipment.

Heating system: Heating by electric heating rod or thermal medium, precise control of the melt temperature to prevent solidification.

Drive and control

The drive system includes motor, reducer, universal coupling, supports frequency conversion speed regulation, and can flexibly adjust the flow rate.

The control system monitors the pressure, temperature and other parameters in real time to realize the whole online feedback control.

Third, the performance advantages

Stable output pressure

melt pump can eliminate material output instability and pressure pulsation caused by fluctuations in extruder parameters to ensure the dimensional accuracy of extruded products. For example, in film production, pressure stability can be improved to reduce film thickness deviation by more than 50%.

Improved product quality

Minimizes extrudate dimensional tolerances, reducing scrap and reject rates. Optimize gear design for low shear stress under high pressure to protect the physical properties of the rubber melt and avoid shear damage.

Enhance production efficiency

Reduce the pressure requirement on the screw, the screw can be extruded at high speed and high efficiency, and at the same time, adjust the back pressure of the extruder to reduce the melt residence time and stabilize the plasticizing process.

Data show that the combination of coaxial twin-screw pelletizer and melt pump improves mixing quality and production significantly and reduces unit energy consumption by 25%-50%.

Extend equipment life

Reduces pressure inside the extruder screw barrel, reduces screw and barrel wear, and reduces gearbox thrust bearing load.

Wear-resistant bearings and dynamic lubrication technology improve the load capacity and impurity tolerance, ensuring stable operation for a long time.

Fifth, Application Scenarios

Pipe and Sheet Production

Melt pump ensures stable melt pressure for uniform pipe/sheet thickness, especially for products requiring high precision, such as medical plastic catheters and optical fiber sheaths.

Film and Sheet Extrusion

Precise control of extrusion pressure optimizes film surface quality, reduces defects such as crystal spots and streaks, and improves optical properties.

Chemical Fiber Spinning

Stabilizes melt transport, improves fiber strength and uniformity for the production of man-made fibers, industrial filaments and more.

Mixing and Pelletizing

Used in tandem with twin-screw extruder to improve mixing quality, granule consistency is significantly improved and energy consumption is reduced.

Sixth, Suggestions for selection

Temperature and pressure range

Select the working temperature according to the material characteristics: ordinary series (≤400℃) or high temperature series (≤510℃).

The outlet pressure should cover the process demand, such as pipe production needs ≥30MPa, chemical fiber spinning needs ≥50MPa.

Flow rate and viscosity matching

Flow rate needs to be matched with the extruder capacity, to avoid overloading or idling of the pump body.

The viscosity range should be adapted to the material characteristics, e.g. rubber melt viscosity up to 40,000 Pa-s.

Material and seal form

The pump body and gears are made of tool steel, high-speed steel or coated to resist corrosion and wear.

The sealing form is screw seal, packing seal or mechanical seal according to the process requirements.

Precision extruder melt pumps realize precise control of melt pressure and flow rate through the principle of positive displacement conveying, which significantly improves the productivity, product quality and equipment life in the rubber and plastic industry. In the high-precision extrusion scenarios of pipes, films, chemical fibers, etc., melt pumps have become indispensable core equipment. When selecting the type, it is necessary to comprehensively consider the temperature, pressure, flow, viscosity and other parameters, and select a technically reliable manufacturer to maximize the return on investment.

Email: sale@meltpump.com

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