Noise Level in Pumps

Various  contributing factors that will produce noises when the pumps are in operation, such as the following

Mechanical Failures
a)Misaligned Pumpsets such as
     - coupling misalignment
     - Pipework misalignment at suction / discharge
    - uneven concrete base

b )Bearing Problems
c) pump Problems, damaged by foreign material such as welding fluxes,bolts
    or metals entering the pump
d) Isolators or Vibration Mounting Pad Not installed
e) Flexible Bellows not installed


Hydraulic Failures

a) Caviatation , NPSH avialable lower than required by the pump
   
b) Insufficient flow reaching the pump , this is most common as most installer fail
   to determine the flow capacity of the pipe , ideal pipe diameter should be 80 mm
    for 450 Lpm or 27 m3/hr ( quick calculation , pipe velocity can be found in earlier posting)
A very recent case , customer upgraded pump capacity from  200 lpm  to 450 lpm
Previous suction line and tank outlet was 50 mm
However for this new installation, the tank outlet  and suction line remained  50mm
Discharge product goes close to the outlet of the tank , creating air pockets which get into
the pump causing Noises

Othe Factors
a) Pump & Driver Size
b) Operating Pressure
c) Pump operating speed

For Cavitation cases , the following could be done or rectified
a) Reduce flowrate by reducing speed of pump
b) enlarge suction line
c) increase product level in the tank
d) avoid air pockets going the tank bottom and into the suction line


Sound Level complying to manufacturer should be acceptable