Wear rings can be defined as a device used to seal the
pressure leakage of the liquid between the inlet of the
impeller and the pump casing. Wear rings are typically
found on pumps with closed impellers. A similar device that
serves the same function called a wear plate can be found
on some pumps with a semi-open impeller.
The typical reason for using a wear ring is to decrease the
amount of leakage loss around the impeller. Due to more
work available to push the pumped liquid out the discharge
there is a slight improvement in pump efficiency.
And also as name indicates 'WEAR' which is a ring can
sacrifice its size by taking friction generated between
stationary and rotating elements.
The replacement of rings is easier & cheaper than replacing
Hope this is clear.
Ans.- 1. cost factor.
2. keep safe of our casing and impeller.
3. Mainten the clearance beetwin impeller and casing.
guys we can mainten the clearenc without wearing
but think, you wich one esey reples the wearing
or, impeller and casing.
SAUDI KAYAN (KSA)
A clearance between the pump casing and impeller is
required for free rotation of the impeller,if the clarance
is more between them,there is some possibility of water
leakage from the high discharge to suction side which
ultimately reduce the efficiency of the pump performance
and the leakage water will cause corrosion.In order to
avoid these problem a wear ring is incorporated in the pump.
In total the purpose of wear ring is to prolong the
life of the pump casing and impeller
To reduce pump maintenance and costly repairs of impeller
and casing a replaceable wear rings are installed in the
centrifugal pumps,which allows a small running clearance
between pump impeller and casing.
there is a small clearence maintained between impeller nd the casing, so that impeller can rotate freely.Now there is a small amount of liquid leaking from discharge side to suction side causing erosion of the parts near clearence,causing this clearence to increase. so casing wear rings are provided to minimize these clearence nd take up the erosive action of leakage fluid on itself rather than letting the impeller or casing to be eroded. Now as casing wear rings are cheap they can b replaced by new one if it has worn out enough.