Four reasons for large flow pump vibration and noise
Vibration of the large flow pump will cause cavitation, bearing damage, overloaded operation of the motor, and easy to mix with the gas. The four reasons for the noise and noise of the large flow pump vibration:
1. Electrical aspects
The motor is the main equipment of the unit. The internal magnetic imbalance of the motor and the imbalance of other electrical systems often cause vibration and noise. For example, during the operation of an asynchronous motor, the radial alternating magnetic pulling force between the stator and rotor due to the harmonic flux interaction of the stator and rotor, or the large synchronous motor during operation, the magnetic center of the stator and rotor are inconsistent or the air gap is different in all directions Exceeding the allowable deviation value, etc., may cause the motor to periodically vibrate and emit noise.
2. Mechanical aspects
The unbalanced quality of the rotating parts of the motor and the pump, rough manufacturing, poor installation quality, the asymmetry of the unit axis, the swing exceeds the allowable value, the mechanical strength and rigidity of the parts are poor, the bearings and seals wear and damage, and the critical speed of the pump appears The resonance caused by the natural frequency always produces strong vibration and noise.
3. Water power
Pump inlet flow rate and pressure distribution are uneven, pressure pulsation of pump inlet and outlet working fluid, liquid bypass, bias flow and off flow, non-fixed working conditions and pump cavitation caused by various reasons are common causes of pump unit vibration s reason. The sudden change of pressure in the water pipeline and the effect of water hammer caused by dynamic transition processes such as pump startup and shutdown, valve opening and closing, changing working conditions, and emergency shutdown of the accident also often cause vibration in the pump room and the unit.
4. Hydraulic and other aspects
Incorrect design of the inlet flow channel of the unit or unmatched with the unit, improper pump submersion depth, and unreasonable sequence of unit start and stop, etc., will deteriorate the water inlet conditions, produce vortexes, induce cavitation or increase the vibration of the unit and pump room. Units that use a vacuum-interrupted siphon to break the flow, if the air is difficult to carry in the hump section, the siphon time is too long; the unit that shoots the door and the flow is unreasonable is designed to be unreasonable. Reasons such as uneven settlement of the foundation of the pump and motor or poor rigidity of the foundation will also cause the unit to vibrate.
When the large flow pump is used, if the pump vibration and noise are abnormal, it should be stopped immediately for inspection.
1. Is the pump foundation reliable
When vibration occurs, first check whether the anchor bolts of the centrifugal pump are tight. If not tightened, it will cause centrifugal pump vibration. It is also necessary to consider whether the strength of the foundation is sufficient. Sometimes, due to design reasons, the soft foundation can also cause vibration.
2. Align the coupling
Many centrifugal pumps are driven by couplings, and there are many types of couplings. The alignment of the conventional three-jaw coupling directly affects the normal operation and service life of the coupling, shaft, bearing, mechanical seal, etc.
3. Find a center
Misalignment of the center is also a common cause of vibration, and the center must be adjusted within the specified range strictly according to the standard.
4. Bearing inspection.
Is there any problem with the bearing installation or is it damaged?
5. Rotor center position adjustment.
The rotor of the pump should be concentric with the stator, otherwise friction and vibration will occur when the pump is running.
6. Shaft bending and rotor measurement
If the cause of vibration cannot be found outside, the pump can only be disassembled. Measure and correct the bending of the shaft first. After no problem, install the rotor small. Measure the overall sway and scoop deviation. If it exceeds the standard, it must be corrected.
7. Dynamic and static balance detection.
After dismantling the centrifugal pump, in order to avoid vibration when the pump is turned on, the impeller should also be tested for static balance.
The impact of external conditions on the pump.
