The ZB melt pump is made up of pump body, front and back cover plate, two meshing gears, bearings and seals. The space formed by the two gear teeth Gallery, the pump body and the side cover plate forms the feed zone, the conveying area and the discharging area of the pump. The gear is the core part of the melt pump, and its structural form is varied. According to the meshing mode, the gear can be divided into internal and external meshing methods; according to the tooth Gallery curve, it can be divided into involute gear, Garden arc gear, cycloid gear and so on; the tooth direction can be divided into straight gear, helical gear and human tooth, but the most common in the conveying plastic melt is gradually. An outer meshing gear pump with straight or oblique teeth.
Because the melt pump is working continuously under high temperature and high pressure, the plastic melt conveyed generally has high viscosity and some corrosiveness. Therefore, it is required that the material of the melt pump should be resistant to temperature, wear resistance and corrosion resistance, with sufficient strength and dimensional stability. Usually pumps are made of alloy tool steel, and gear and shaft are integrated so that the work is more reliable under high torque conditions. The problem of lubrication and sealing of the melt pump is more complicated. In order to avoid polluting the plastic melt, it can not be lubricated by the ordinary lubricating oil or grease, but self lubrication by the plastic melt conveyed. Therefore, the bearing and sealing structure of the pump must be adapted to the special properties of the plastic melt. Small and medium sized pumps are usually heated by electric heating, while large pumps use jacket pumps for fluid insulation.
