Excessive current may be caused by the following reasons: The outlet pressure is too high. The outlet line should be checked for blockage and proper outlet valve opening; excessive melt viscosity; poor shaft seal assembly; shaft or bearing wear; and motor failure.
No flow may be caused by the following reasons: Rotor rotates in opposite direction. The direction of rotation of the rotor is very important to the lobe pump, the direction of rotation is reversed the inlet of the pump becomes the outlet, the outlet becomes the inlet, when the outlet naturally will not have media outflow. Check the direction of rotation, according to the sign on the pump to correct the wrong direction; suction or discharge side pipeline valve closed. Check whether the suction or discharge side pipeline valve is closed, if it is closed, open the valve; there is no medium or low pressure at the import. Although there is a strong self-priming function, but there is a certain limit, too low liquid level, but also will not be able to absorb the liquid resulting in no flow of the pump; safety valve is not closed tightly; viscosity is too high, the pump can not bite material.
Suddenly stopping the pump may be caused by the following reasons: power failure; motor overload protection; damaged coupling; high outlet pressure and interlock reaction; abnormal bite in the pump; shaft and bearing sticking jam.
Insufficient pump flow may be caused by the following reasons: low inlet pressure. Check the inlet pipeline to make the pressure reach the specified requirement, otherwise cavitation may occur; the inlet pipeline is clogged; the rotor is severely worn and there is leakage; safety valve problem. The safety valve should be checked for poor sealing; the speed is too low; the viscosity is too low. The working range of this pump needs to be checked, and the model should be reselected if necessary.
There is abnormal vibration noise, which may be caused by the following reasons: large eccentric coupling or poor lubrication; gas in the pump; motor failure; abnormal reducer; poor installation at the shaft seal; shaft deformation or wear.