The main function of the wear-resistant melt pump for conveying plastic melt is to pressurize and stabilize the high-temperature plastic melt from the extruder and to keep the melt flow accurately and steadily fed to the extruder head. Wear-resistant melt pump can be high temperature 350 ℃, pressure up to 35MPA or higher under the conditions of continuous work. Its main features are simple and compact structure, reliable work, longer life expectancy.
Wear-resistant melt pump is the pump body, front and rear cover, two intermeshing gears, bearings and seals and other components. The space formed by the two-toothed toothed gallery, the pump body and the side cover forms the pump's feed, delivery and discharge area. Gear is the core part of the melt pump, and its structure varied: According to the meshing mode can be divided into internal and external meshing; according to the curve of the tooth gallery can be divided into involute gear, circular arc gear, cycloidal gear; According to the tooth can be divided into spur gears, helical gears and herringbone teeth, but the most common in the transport of plastic melt involute spur or helical gear pump.
As the wear-resistant melt pump is continuous operation under high temperature and pressure conditions, and the plastic melt conveying generally has a high viscosity, and some also have some corrosive, therefore, require wear-resistant melt pump material resistant to Warm, wear-resistant, corrosion-resistant, to have sufficient strength and dimensional stability. Usually the pump is mainly made of alloy tool steel, gear and shaft into one, so that work under high torque conditions more reliable. Melt pump lubrication and sealing problems more complicated, in order to avoid contamination of plastic melt, it can not use the general lubricants or grease lubrication, but through the transport of plastic melt lubrication. Therefore, the pump bearing and seal structure must be adapted to the specific properties of the plastic melt. Small and medium-sized pumps generally use electric heating heating insulation, large pumps are used jacketed pump fluid insulation.
