Why does the end face of the sliding bearing of the high temperature melt pump wear out?

The high-temperature melt gear pump is relatively stable at the beginning of operation. After a period of time, the high-temperature gear melt pump vibrates. Under the condition that the outlet pressure remains unchanged, the speed of the melt gear pump continues to increase, and the motor current increases accordingly. After a period of time, due to current overload Motor tripped. The disc pump is easy, no jamming. It was found that the wear of the gear end face and the bearing end face exceeded 1mm during the shutdown for maintenance.

The above phenomenon can be concluded that the end face of the gear and the sliding bearing is worn, resulting in an increase in the end face clearance, and the leakage flow rate of the end face clearance is proportional to the third power of the end face clearance value, so that the high-pressure melt flows through the gap between the two ends of the gear to the low-pressure suction chamber or through the gap. The leakage of the bearing cavity increased sharply, resulting in a decrease in the volumetric efficiency of the high-temperature melt gear pump. End clearance leakage is the main internal leakage path of high temperature gear pumps, accounting for about 75% to 80% of the total leakage of gear transmission parts.

Involute helical gears are often used to convey high-viscosity and high-pressure polymer melts to increase the coincidence of gear meshing. When meshing, the material can be continuously and stably extruded to reduce pressure fluctuations. But this form of gear generates axial forces when it works. The axial force acting on the driven helical gear shaft is jointly generated by hydraulic pressure and meshing force, which are equal in magnitude and opposite in direction, so the axial force acting on the driven shaft is zero. The axial force acting on the driving helical gear shaft also comes from the hydraulic pressure and the meshing force, and the directions are the same, so the axial force acting on the driving shaft is the resultant force of the hydraulic pressure and the meshing force, and its magnitude is the same as the suction port and discharge port pressure. proportional to the difference. It is the unbalanced axial force that causes the wear of the gear and the end face of the sliding bearing. At the same time, the drive gear is subjected to the axial force from the cross shaft universal joint, such as the axial force of the universal joint being damaged. The end face wear of all drive gears is consistent with the axial force.

Zhengzhou Batte is a professional melt pump manufacturer, providing various specifications of melt gear pumps for the resin, chemical fiber, rubber and other polymer material industries, and providing various series of melt pump products that can meet all polymer working conditions. The company provides melt pumps with complete specifications: the displacement ranges from 0.1CC to 12000CC, and can also be customized according to user needs. info@battemachinery.com