Application, structure, working principle, and classification of melt pumps

1、 Melt pump extruder application

The melt pump is mainly used for the transportation, pressurization, and metering of high-temperature and high viscosity polymer melts. It has the characteristics of compact structure, reliable operation, low energy consumption, high volumetric efficiency, and small shear effect on the melt. Melt pumps are usually used together with extruders in plastic processing. They can further homogenize the melt, stabilize the flow rate at high temperatures and pressures, ensure no pulsation in material output, have high volumetric efficiency, and have a small shear effect on the melt, thereby improving product quality and accuracy, and reducing costs. It can be used for plastic melt granulation and mixing, as well as for extruding sheets, pipes, films, and profiles.

melt pump extruder

2、 Melt pump structure

A complete melt pump consists of several parts, including a melt pump, motor, reducer, coupling, control and safety device. The melt pump mainly consists of a pump casing, driving gear, driven gear, sliding bearings, front and rear end plates, packing seals, etc. The melt pump utilizes melt self-lubrication, with lubrication grooves on the sliding bearings. It operates at high temperatures and pressures and has good wear resistance. It can work continuously under conditions of 350 ℃, pressure 35Mp or higher.

pump melt gear pump for plastic extruder

3、 Working principle and classification of polymer melt pumps

The melt pump is a positive displacement conveying device, and the flow rate is strictly proportional to the pump speed. Mainly composed of pump casing, driving gear, driven gear, sliding bearings, front and rear end plates, packing seals, etc. The feeding area, conveying area, and discharge area of the pump are composed of the tooth profile of two gears, the pump body, and the side cover plate. During operation, the melt is transported by the change in working volume caused by the mutual meshing of the main and driven gears.

melt gear pump for plastic extrusion

The working volume is composed of the pump body, gear teeth, and bearings with side plate function (i.e. the feeding area). When the gear rotates in the specified direction, the melt enters the grooves of the two gears in the feeding area. As the gear rotates, the melt is brought into the feeding area from both sides. The re meshing of the gears causes the melt in the grooves to be squeezed out of the discharge area and pressed into the outlet pipeline. As long as the pump shaft rotates, the gear will press the melt towards the outlet side, so the pump outlet can reach a high pressure, and there are no high requirements for inlet flow and pressure. The melt gear pump for plastic extrusion belongs to the involute external meshing gear pump (most commonly used in plastic melt transportation), which can be divided into straight teeth, helical teeth, herringbone teeth, etc. according to the tooth direction.

Email: info@battemachinery.com

WhatsApp: +86 158 38331071