Handling of Water Pump with Contaminated Wood Dust

Dear Mr Nadarajah

The present pump that you used is DAB closed Coupled pump for clean water or domestic water application.The solid passage between the impeller plates is small gap ,approx 4 mm
This is why the Pump is getting choked and motor over loaded,a s the water you are pumping
is having high percentage of dust

A right pump with be an open impeller pump , with soild passage of 10 mm or more
and the solid content should not exceed 15% for closed coupled pumps
Pefer Not go for Pressed Metal ,but casted material which are more heavy duty

End Suction pumps with wider impeller vane with is a better option,but the pump need
more spaces and higher is cost ,the motor can be over sized slightly in case the
solid contents gets too high and motor will not be overloaded

Closed Coupled Pumps ,the motors are rated to Water Curve . SG of 1 .0 low viscosity and no solid
and you cannot over size the motor as the pump motor mounting is fixed for certain frame
size

CAVITATION

Cavitation is a hydraulic condition which can exist in any type of pump
It is primarily a situation in which the pump is discharging less liquid than its rated
capacity due to reduction or lack of supply to the pump
Common causes are
a) excessive suction lift
b)Net positive suction head avaialble is insufficient
c)selected operating speed is too high

Pitting,vibration and noises are common troubles stemming from cavitation

Severe cavitation will cause excessive noise and mild cavitation will give a small reduction
in pumping efficiency and moderate wear of the pumps parts

What you can do :-

a) slow down the pump
b) reduce suction lift
c) increase positive head pressure (reduce the suction head losses )
d) use bigger pump if you are not able to accept the
reduction of flow

Before going for the bigger pump . what is the right pump .........calculate
the NPSH avaialable ( NPSH A) , and the NPSHA must be higher than
NPSH required by the pump

Look up earlier postings on NPSH A