17
n
Model MDH-(F) 400,401,422,423,425
Thickness of mouth ring
New
Replace
inches (mm)
0.315 (8)
0.236 (6)
n
Wear limits of impeller thrust and spindle
Pumps whose model identification codes have D or E at the end are designed to have contact between the
impeller thrust tip and the spindle face in the event of an abnormal operating condition (cavitation, dry opera-
tion, etc.). If the surfaces are worn out beyond the wear limit "A", the pump is subject to serious damage. The
condition of the surfaces in contact must be checked if an abnormal operation such as dry running or cavitation
lasts a total of over 3 hours.
The step between the surfaces of the mouth
ring and the impeller upon shipment is 0.078
in. (2mm). Replace the mouth ring when this
step is reduced to 0 in.
Fig. 8
IM P E L L E R
M O U T H R IN G
U P O N S H IP M E N T
S T E P 0 .0 7 8 in (2 m m )
IM P E L L E R
C O N IC A L
T H R U S T
B E A R IN G
S P IN D LE
B E A R IN G
M A G N E T
C A P S U L E
R E A R
C A S IN G
(N O R M A L
O P E R AT IO N )
(D R Y
R U N N IN G )
A
B
B
