Bfp de side bearing high temperature why why. Boiler feed pump bearing temperature high root cause analysis. Fish bone diagram.

1. BFP DE Side Bearing Failure Aim towards zero failure-TPP
P a g e | 1
Aim towards
zero Failure
Fishbone diagram and
Why-Why analysis of BFP
DE Side Bearing
Temperature High

2. BFP DE Side Bearing Failure Aim towards zero failure-TPP
P a g e | 2
Contents
BFP DE Side Bearing
 What is DE Side Bearing?
 Fishbone diagram of Bearing temperature high
 Why-Why analysis of Bearing temperature high

3. BFP DE Side Bearing Failure Aim towards zero failure-TPP
P a g e | 3
 What is DE Side Bearing?
DE side bearing is the bearing of the BFP which provide static support to the
shaft space provided in between pump mechanical seal and coupling. In
generally a static bearing (Split type Journal bearing) is provided as DE side
bearing. Which means the bearing will not rotate with shaft, thus no rolling
element is provided with in the split type bearing enclosure i.e. bearing housing.
The Journal bearing partially dipped inside oil bath with in bearing housing and a
oil splash ring is provided for splashing the oil from oil bath in between the
bearing inner face and shaft. A layer of oil film is maintained in between the inner
face and shaft. The oil film resist the metal to metal contact in between the shaft
and inner face. Bearing inner face is coated with white metal or soft babit metal
layer. The purpose of soft metal coating is to sacrifice for the protection of shaft in
case of any oil film failure. The lubrication oil is cooled by external cooling water
pumped by auxiliary water pump with in the jacket provided in side bearing
housing. The oil level cup is provided on bearing housing body for visualizing the
oil level. Also a drain plug is provided on housing bottom for draining lube oil
during maintenance. 2nos Cooling water port inlet and outlet port is provided at
both side of the housing.

4. BFP DE Side Bearing Failure Aim towards zero failure-TPP
P a g e | 4
 Fishbone diagram of Bearing temperature high
Machine
Method
Man
Material
Bearing
housing
damage
Oil
splash
ring
damage
Babbitt
layer
damage
Improper
venting
Base
bolt
looseness
Coupling
miss-alignment
Shaft
worn
out
Pipe
line
damage
Improper
lubrication
Suction
valve
throttling
Low
pump
RPM
Low
ACW
pressure
Low
Deareator
level
Bearing
life
exhausted
Impeller
degradation
Balancing
disk
erosion

5. BFP DE Side Bearing Failure Aim towards zero failure-TPP
P a g e | 5
 Why-Why analysis of Bearing temperature high
Sl.
No.
Reason Why 1 Why 2 Why 3 Why 4 Why 5 Root Cause
Corrective
Action
1
High
Vibration
Bearing
rubbing
with shaft
Breakage
of oil film
Loss of oil
viscosity
Lube oil
over
heating
Insufficient
oil quantity
Low Quantity
of lube oil
Rise lube
oil level
2
Improper oil
cooling
Improper
cooling
Rise
cooling
water
pressure
3
Lube oil
contaminatio
n
Lube oil
contamination
Replace
lube oil
4
High bearing
clearance
Bearing
clearance high
Replace
bearing
5
High
friction
between
bearing &
shaft
Abrasive
scrubbing
Lube oil
contaminati
on
Mixing of
Babbitt
material to
oil
Breakage of
Babbitt layer
Bearing
Babbitt layer
damage
Recoat
Babbitt
layer
6
Eccentric
rotation of
shaft
Off centre
between
motor &
pump
centre line
Axial or
radial
misalignm
ent
Mis-alignment
Re Check
pump
alignment
7
Oscillation
of pump
body
Improper
vibration
dumping
Loose
pump base
Pump
base bolt
looseness
Base bolt
Looseness
Tightened
pump base
bolt
8
Vibration
transfer
from pipe
line
Pipe line
strain
Pipe
Vibration
not
dumped
Improper
pipe support
Support not
proper
Install pipe
support
9
Pump part
rubbing
with each
other
Looseness
in parts
Worn
parts
Parts Damage
Replace
damage
parts
10
Excessive
axial load
on bearing
Improper
rotor axial
thrust
Balancing
pressure is
too high
Clearance
in
balancing
chamber
Balancing
disk worn-
out
Balancing disk
damage
Change
balancing
disk
11
Excessive
radial load
on bearing
Shaft lifted
too much
high during
operation
Rotor high
Radial
thrust
Pump radial lift
disturbed
Contact
OEM
12
Resonance
build up in
impeller
Un
balanced
mass of
impeller
Deposition
of scale
Scale
deposition
Clean
impeller
13
Degradatio
n of
material
Degradation of
impeller
Change
impeller
14
Low lube
oil
cooling
Heat
transfer
from oil not
proper
Low
cooling
water
supply
In sufficient
flow
quantity
Low ACW
pump
pressure
Low ACW
pump
pressure
Rise ACW
pressure
15
Low
circulation
pressure
Flow
restriction
to coolant
Chocking
of cooling
water pipe
line
Impurities in
water
Impurities in
water
Check for
water
impurity
16
Pressure
drop at
scale
band
Scale band
chocking
Scale band
chocking
Clean scale
band
17
Improper
lubricatio
Restriction
to lube oil
Locking of
oil splash
Wear of
splash ring
Wear of
splash ring
Replace
splash ring

6. BFP DE Side Bearing Failure Aim towards zero failure-TPP
P a g e | 6
n circulation ring
18
Change in
lube oil
circulating
profile
Defective
bearing
housing
Damage
Bearing
housing
Replace
housing
19
Loss of oil
viscosity
Change in
oil density
Slurry
formation
Slurry
formation in oil
Replace
lube oil
20
Heat
transfer
from
shaft
Heating of
impeller
Excessive
heating of
water
Formation
of
cavitation
Water
vapour
formation
Pressure
drop at
pump
suction
Low suction
head
Rise
Deareator
level
21
Suction
isolation valve
throttled
Full open
suction
valve
22
Clogged
suction
strainer
Clean
suction
strainer
23
Low pump
rotation
Low pump
rotation
Rise pump
speed as
per Q-H
curve
24
High back
pressure
Resistanc
e to
discharge
Low
discharge
head
Low discharge
head
Rise pump
speed as
per Q-H
curve
25
Formation
of air
pocket
Improper
pipe venting
Or pump
priming
Improper Air
venting
Release air
from
pumping
system
26
High pipe
friction
Pipe rough
internal
surface
Rough internal
surface
Replace
pipe & pipe
fittings