The melt gear pump consists of pump housing, front and rear cover, gear shaft, sliding bearing and shaft seal. The melt gear pump is a positive displacement pump, and the working volume changes caused by the meshing of the main and driven gears are used to transport the melt. The working volume is composed of pump body, gear tooth groove and bearing with side board function. When the gear rotates, the melt into the suction chamber two gear tooth, with gear running, the melt from either side into the discharge chamber, the gear meshing, again make tooth melt out of the discharge chamber and pressure to the export pipeline. As long as the pump shaft turns, the gear will be pressed to the outlet side of the melt, so the pump outlet can be very high pressure, and the flow rate is basically independent of the discharge pressure.
The gears of high viscosity gear pump are common with straight teeth, helical teeth, helical teeth, helical teeth, and involute and arc types. Generally, the small gear pump adopts involute spur gear, and the high temperature gear pump often adopts the gear shift gear, and the melt pump with high viscosity and high pressure polymer melt is used with involute helical gear. The gear and shaft are made into one, and its rigidity and reliability are higher than that of gear pump which is made separately by gear and shaft. The gear of foreign low-pressure gear pump is usually square, that is, the tooth width of the gear is equal to the diameter of the top circle. The high viscosity gear pump used in high pressure occasions is less than the diameter of the top circle of the tooth, which is to reduce the radial compression area of the gear and reduce the load of the gears and bearings.