STANDARD MAINTENANCE PROCEDURE
ID FAN
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Standard Maintenance Procedure for ID Fan
1. SUMMARY OF THE OBJECTIVE
This document is created to provide the information to job execution team for carrying out maintenance
with best quality and safety
2. Recommended Safety PPEs
S.N. Name Function
01 Safety Element Head Protection
02 Safety Shoes Foot Protection
03 Safety Goggles Eye protection
Protection from
04 Nose Mask
dust
05 Hand Gloves Hand Protection
06 Safety Belt Fall Protection
07 Ear plug Hearing Protection
08 Other specific PPEs If Required
3. FIELD CHECKS FOR SAFE MAINTENANCE
Work Permit No. :- Checks
SR. Checks Reason Yes No
NO s
1 Adequate Illumination Inadequate illumination causes accident
2 Proper Ventilation Easy breathing & relief from early fatigue
3 Any slippery agent on floor To avoid any accident/ incident
4 Cross checked LOTO & tag To avoid any un safe act
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4. STANDARD BEARING CLEARANCE CHART
Taper bore Straight bore
Bore Bearing Clearance-MM Bearing Clearance-MM
Diamete
r CN C3 C4 CN C3 C4
D-MM
Over Incl Min Max Min Max Min Max Min Max Min Max Min Max
30 40 0.035 0.050 0.050 0.065 0.065 0.085 0.030 0.045 0.045 0.060 0.060 0.080
40 50 0.045 0.600 0.060 0.080 0.080 0.100 0.035 0.055 0.055 0.075 0.075 0.100
50 65 0.055 0.075 0.075 0.095 0.095 0.120 0.040 0.065 0.065 0.090 0.090 0.120
65 80 0.070 0.095 0.095 0.120 0.120 0.150 0.050 0.080 0.080 0.110 0.110 0.150
80 100 0.080 0.110 0.110 0.140 0.140 0.180 0.060 0.100 0.100 0.135 0.135 0.180
100 120 0.100 0.135 0.135 0.170 0.170 0.220 0.075 0.120 0.120 0.160 0.160 0.210
5. BELOW TROUBLE SHOOTING GUIDE LINE CAN HELP WHEN YOU SUSPECT A PROBLEM
Problem Cause Area to check Solution
Mounting of Fan Inadequate mass or Stiffen/ increase weight
stiffness of supporting
structural
Misalignment during Shaft, coupling between Correct alignment
installation shaft and drive, belt pulley, shaft got
bent
Impeller Unbalance Material build-up, Install vibration monitor to check the
during operation corrosion, wear trend; Clean the impeller periodically;
Take preventive option for corrosion
and wear; In-suit
VIBRATION balancing of impeller
Looseness In the mounting , Between Tighten fastening bolts; Replace
shaft and impeller, coupling/ coupling pulley; Tighten bearing
pulley or bearing adopter sleeve as per tolerance given
in SKF catalogue
Aerodynamics Inlet condition non-uniform, Duct layout to be modified; baffle
Pre-rotation of the air, System plate/straighteners may be used to
effect , pulsation due to fan achieve uniform flow; Selections of
operating at fan to be reviewed
surge zone
Vibration Impeller unbalance during In-suit balancing
operation
Mounting Inadequate mass or stiffness of Stiffen/Increase weight
supporting
Structure
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ID FAN
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Lubrication Wrong type, over Check recommended lubrication,
PREMATURE lubrication quantity and interval
BEARING FAILURE
Environment Contaminants in lubricant , Ambient Change lubricant immediately; Review
temperature high selection of lubricant
Problem Cause Area to check Solution
Alignment Shaft alignment, over Correct alignment; Dismantlethe
tightened bearings bearing refit with specified tolerance
PREMATURE
BEARING FAILURE
Loading Radial and/or Thrust Review bearing selection
Load Over load from belt drive or Review bearing selection
Coupling
Thermal Shock Malfunctioning controls, Check controls and system
sudden operational change
Vibration System pulsation, looseness Check system; check fastening of bolts
PREMATURE
MATERIAL Abrasion/corrosion Excessive dust from System. Ensure fan inlet dust concentration within
FAILURE Fans running with bypassed dust specified limit. Review selection of
arrestor. Water/acid fume impeller material for aggressive condition
ingress in fan
System effect Turbulent inlet condition, System correction required
Non uniform flow, Deviation of
actual system resistance from
predicted one, pre-
rotation or swirl at inlet
Clearances Impeller and inlet Check for deviation from drawing/manual;
PERFORMANCE
correction
DEFICIENCY IN
VOLUME OR Driver Belt slippage Belt tightness to be adjusted
PRESSURE Environmental Problems Problems material build-up in Check and clean periodically. System
casing; inlet or ductwork correction required
blockage
Rotation Incorrect motor connection, Follow the indicated direction of
Improper impeller rotation rotation given on casing of arrow
mark
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ID FAN
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Mechanical interference Touching between impeller Adjust inlet gap taking care of expansion in
and inlet cone due to external hot condition. Check for expansion
forces on casing or provision in casing foot; fixed and
Impeller/Shaft movement or expansion joint wherever provided are in
thermal extension or place; remove duct
distortion load from fan casing by providing flexible
connection piece.
Bearings Inadequate lubrication, pitted Replace bearing ;Correct alignment
bearing worn balls, races, seal
failure,
alignment improper
Noise
Airborne High velocities Install silencer
Foreign material in fan casing Build-up on fan impeller, casing Check and clean periodically. System
correction required
Drive Belts too loose and Adjust belt tension
squealing
Too much grease in Consult manual for lubrication
bearings amount and interval
Overheated
Bearing Poor alignment Correct
Bent shaft Replace
Shaft and Hole tolerance chart
Over Dia
3 6 10 18 30 40 50 65 80 100 120 140 160 180 200 225 250 280
from
Up to Incl.-
6 10 18 30 40 50 65 80 100 120 140 160 180 200 225 250 280 315
MM
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Shaft - h7 - - - -
-0.025 -0.03 -0.035 -0.04 -0.046 -0.052
0.01 0.02 0.02 0.02
0.01 0.02 0.02 0.02 0.025 0.03 0.035 0.04 0.046 0.052
Hole H7
0 0 0 0 0 0 0 0 0 0
Bearing installation
S.N. Activities
1 Remove the old bearing with the help of bearing puller
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Check shaft OD in bearing siting area with respect to bearing ID and make it require tolerance as per
2
chart
3 Check the levelling of rotor with master level and align using shim at plumber block base
4 Check top and bottom plumber block half contact with bearing outer race by blue matching.
5 Check the plumber block and maintain recommended interference.
Straight bearings above 50mm ID should be heated to
6 100°C for is ZZ category, 120°C forother bearings. No heating is required for taper bore bearing.
NOTE: Temperature above 120°C not allowed.
7 Bearing lock-nut tightness to be ensured as per clearance chart. Ensure proper surface of lock nut.
8 Install oil seal/ Dust seal/Gauge glass/ Grease nipple with proper care.
Coupling installation and alignment
Sr.No Activities
Check shaft OD at coupling sitting area with respect to coupling OD
1
Check coupling bore and key way and make it require tolerance
2
Heat the coupling maximum upto 140 degree celcius and fixed the coupling without hammering.
3
Before alignment ensure drive and driven should not have any push or pull force by piping/cable.
4
Check the soft foot error and correct it require
5
Fix the two dial for axial and one for radial.Fix alignment clamps on Prime mover also ensured clamp is rigid enough.Dial guage
should move freely in full range of its scale.
6
Do Radial and axial alignment with in limit with minimum number of shims. Take the TIR and make correction by the shim as
per calculations
7
Take final reading & ensure all bolt in proper tightening condition
8
Remove the alignment clamp dial Fix the coupling & lubricant
9
Maintenance Management
Systems Equipment Name:
Primary Air Fans
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Types: M1- Checks, M2- Minor, M3- Major
Maintenance
S.N. Maintenance Activités Yes No N/A Remarks
A M1,M2,M3- Common Checks
1 Is foundation block sufficiently massive?
2 Check for any mechanical “looseness”.
3 Check the motor and base tightness
4 Check static oil level or view glass, where fitted.
5 If grease lubricated, make sure not over packed.
6 Is the scoop cooling turned on (where fitted)?
7 Check oil mist venting from oil mist system, if applicable.
8 Check coupling bolts & spider or grit
9 Check the lubrication of coupling if applicable
10 Is the coupling guard securing?
11 Check the inlet and outlet damper link healthiness.
12 Check the cleanness of all grease nipple for damper line/BRG.
13 Check and applied the grease for all links and its bearings
14 Check freeness of rotor. Without mechanical sounds.
15 Is “Fan” start motor to check rotation correct?
16 If variable speed drive is used, please ensure minimum speed
is above first critical speed.
17 Where fitted, is grease visible from end seal? Does the grease
look old or new?
18 Check oil ring (where fitted) for proper working.
19 Check the healthiness of bellows.
20 Is “Fan” start motor to check rotation correct?
S.N. Maintenance Activités Checks Tools Yes No
B M2-Minor
1 Note down fan running Hrs
2 Check base bolts tightness Properly Tightened Spanner
3 Check coupling bolts & grid Bolts tightness & grid condition Spanner
4 Check both DE &NDE bearing Bearing clearance &lock Feeler gauge
5 Change the grease/Oil Adequate grease or oil Grease gun
6 Check oil leakage No any leakage Cloth
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7 Check & clean the inlet Properly cleaned Cloth, Hand blower
8 Lubricate dampers link and Adequate grease or oil Grease gun
9 Check the Suction slincer Abnormality, cleaning Visual Check
10 Check free rotation of Fan No metal rubbing sound Manual
11 Check the shaft Alignment Reading with in limit Dial gauge
12 Coupling guard condition Properly fitted Spanner
13 Check vibration before & Reading noted and studied Vibration meter
14 Check motor drawing current Reading noted and studied Electrical team
C M3- Major
1 Clean fan internals Clean Rotor and casing Cloth and wire brush
2 Fan internal inspection Abnormality & unwanted solid Visual Check
3 Impeller condition Pitting/erosion Visual Check
4 Check the cone & impeller Cone Clearance Inside caliper
5 Check the coupling Bolt tightness/grid condition Spanner
6 Bearing Inspection Clearance, interference Feeler gauge, lead wire
7 Re-fitment of bearing Replaced if any abnormality ‘C’ Spanner,
8 Lubricate of bearing, Oil/ grease applied Grease Gun
9 Seals and gasket inspection Replaced- if require Gasket, seal plate
10 Check rotor free movement No rubbing sound Manually
11 Check dampers condition Open and close DCS/Manually
12 Check Alignment Set with in limit& recorded Dial gauge
13 Check motor drawing current Current will be normal Electrical team
14 Check vibration Record Before and after Vibration meter
Prepared by Reviewed by Approved by
Mechanical HOD(OEGI) Mechanical HOD(GNAL) Plant head(GNAL)
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