What Do We Need To Know About Centrifugal Pumps? (4)

Jun 21, 2025

1. What are the reasons for the heating of the bearing box?

The pump shaft and motor shaft are not concentric.
Excessive or insufficient lubricating oil (grease) can cause deterioration of the oil (grease).
The oil ring breaks or jumps out of its fixed position.
Axial thrust increases.
Insufficient or interrupted cooling water.
Bearing wear.
The flow rate is too small, causing the pump to approach an empty state.
Pump vibration caused by weak foundation, unbalanced rotor, loose bolts, and other reasons.

2. Why do pumps need to be antifreeze in winter?

Water undergoes volume expansion below zero degrees. If the water remaining in the pump body is not cleaned, the force generated by the volume expansion at low temperatures will cause the pump body to swell and crack, resulting in unnecessary damage. There are several methods for preventing freezing, including:
Drain the stored water from the idle pump.
Maintain a steady flow of cooling water.
Insulate the pump or heat it with steam or hot water.
The standby pump maintains flow at the inlet and outlet.

3. What should be done after the pump freezes?

After the pump freezes, it must not be blown directly with steam to prevent rupture due to uneven thermal expansion of the pump body.
After the pump freezes, pour cold water first, and then wait for the turning machine to move. You can pour it with steam or hot water.

4. Why does the pump body need to be cooled?

The flow friction generated between the liquid and the pump body during the operation of the pump, as well as the friction between the rotating and fixed parts such as the ball and inner and outer rings of the bearing, the shaft sleeve and the packing, will generate heat due to friction. At the same time, the high temperature of the medium will be conducted to the pump, causing the pump body to heat up. The purpose of cooling is to reduce the temperature of the pump body, pump seat, bearing box, and shaft seal, and prevent these parts from deforming, aging, and being damaged due to temperature rise.

5. Under what circumstances does the motor need to stop urgently?

When endangering personal safety.
When the motor emits smoke or has a foul odor, or catches fire.
When there is significant vibration or axial movement.
When the body or bearings heat up to the limit.
The motor speed is slow and accompanied by abnormal sound.