ATOX Mill maintenance , Replacement of roller bearing and seals.ppt

This document is about maintenance of atox mills

1. Technical Center
Replacement of
Roller Bearings
and Seals
Raja Iftikhar Hussain
Senior Mechanical Expert
Maintenance &Technology (IPMEA)

2. Date 2
Atox Repair
a.Dismantle the roller with roller journal
b.Plug up the sealing air and lubrication holes in the center
yoke and the journal.
c.Place the roller with the roller shaft vertically with the
flange against the ground.

3. Atox Repair
. Dismantle the sealing air ring (48), bearing cover (57) and
retainer ring (47).
The covers are equipped with threaded holes for
dismantling screws.
Date 3

4. Atox Repair
Install the hydraulic nut for removing the tapered sleeve (46).
Connect the rest of hydraulic equipment – see instruction for the
tool. Release the tapered sleeve by slowly increasing pressure,
the pressure of 800 bar is typically necessary.
Date 4

5. Atox Repair
With caution, hook up the roller hub in a crane. Lift
cautiously, providing for the hub moving horisontally, off the
journal. The journal must stand firmly but is not to be fixed to
the floor.
g. Dismantle the sealing air ring (53) and cover (54).
Date 5

6. Atox Repair
. Dismantle the spherical roller bearing (45), the distance ring
(44) and the cylindrical roller bearing (43).
The roller hub is provided with channels for hydraulic
dismantling of the outer races of the bearings.
j. Dismantle the sealing air ring (53) and cover (54).
k. Dismantle the distance ring (44) and the inner race of the
roller bearing (43) from the journal.
By using local fabricated tool, two number of 200tons hydraulic
jacks and Oil pumps, spherical roller bearing can be removed.
Date 6

7. Removal of Distance Ring & Cyl. Roller bearing
By using local fabricated tool, one number of 200 tons hydraulic
jacks and Oil pumps, cylindrical roller bearing and distance ring
were removed.
Date 7

8. Removal of Distance Ring from Journal
Ring can be removed by using over head crane and studs
Date 8

9. Removal of Inner race of Cyl. Roller bearing
By heating and using local fabricated tool inner race can be
removed.
Date 9

10. Removal of Rotary shaft seals
Both side rotary shaft seals and distance ring b/w seals can be
removed.
Date 10

11. Atox Repair
Assembly of bearings, roller shaft and hub
a.Preparation of hub
Clean the hub internals.
Heat the hub to a temperature 120C higher then ambient
temperature or that of the bearings
If the heating is not possible following alternative can be
applied:
Date 11

12. New Cylindrical Roller bearing installation
The cylindrical roller bearing (43) and spherical roller bearing (45) can
be cooled in a mixture of dry ice and alcohol to a little less then -50C
(the temperature of hub is app. 20C). When applying cooling rust-
inhibiting oil must be applied thoroughly to the bearings before
mounting (condensation moist)
Hub can be lifted by Mobile crane and placed over cylinderical bearing and
bolts of bottom cover were tightened.
Date 12

13. Atox Repair
Mount the bearing (43) and the cover (54). The cover is to just
touch the outer bearing race.
Position the hub (39) for inserting the distance ring (44) and
roller bearing (45) in the hub. The outer race of (43) and
bearing (45) must touch the distance ring (44). If the bearings
have channels for lube or dismounting take it into
consideration.
Wait until the temperature is equilized and then remove the
cover (54).
Date 13

14. New Spherical Roller bearing installation
Checked the clearance of bearing before mounting.
Bearing cooled down to -35°C using dry ice.
Checked the inner taper dia of bearing and installed using
overhead crane
Date 14

15. New Rotary Shaft seals installation
Installation of Inner rotary seal.
Installation of distance ring b/w seals.
Making sure the that lubrication hole remain open
Date 15

16. Atox Repair
Smear the outer steel ring of shaft seals (61) with special
grease, Klüber NOSOL UTA 4 (anti-fretting) or a similar and
place the seals in the cover (54).
Don`t forget the distance ring between the seals.
Mount the inner sealing air ring (53) on the bearing cover (54)
and refit the cover.
Date 16

17. Atox Repair
b. Preparation of roller shaft
Clean the sealing air and oil channels using clean and dry
compressed air.
Place the roller shaft in vertical position standing on it´s
flange.
Apply a corrosion inhibitant grease, f.eks. NeverSeez, where
the bearings and rings are to be fitted.
Mount sealing air ring (52) on the roller shaft
Date 17

18. Atox Repair
Mount the wear ring (42) on the roller shaft. The ring is to be
preheated to the temperature 120C higher then the ambient
one.
Mount the inner race of bearing (43) and distance ring (44) on
the roller shaft. The inner race is to be preheated to 50C –
100C for shrink fit.
Grub screw (35) prevents turning of the distance ring.
Date 18

19. Bottom Bearing cover installation
Installation of Bottom cover.
Provide four supports 165mm height.
Lifting the hub by mobile crane for installation on journal.
Date 19

20. Atox Repair
c. Mounting of hub on roller shaft
Mounting is done by cautiously lowering the hub with
inserted bearings and ring down onto the roller shaft.
Grease must be applied between the 2 seals the in cover (54).
Use only Klüberlub BE41-1501 (high temperature thick
grease).
The hub with the bearings must slide smoothly down the
roller shaft until the roller bearing (45) lands on the recess on
the shaft.
Date 20

21. Atox Repair
Check that the rolle shaft is centered in the spherical roller
bearing.
Apply a thin layer of special grease, Klüber Altemp Q NB 50 to
the tapered sleeve (46), internally and externally.
Insert the sleeve so that the parts lie true against one another.
Date 21

22. Atox Repair
Screw the hydraulic nut (70) on to the tapered sleeve collar,
full thread of the nut must be active, the piston of the nut
must face away from the bearing (45).
Mount the retainer plate (71) on the wear ring (55) Oil
channels in the nut and sleeve must flush. Tighten the screws
untill the retainer plate touches the nut.
Date 22

23. Atox Repair
Place the roller/roller shaft assembly horizontally. Apply
hydraulic pressure (72). While increasing the pressure keep
checking the clearance in the bearing (45) by means of a
feeler gauges and turn the roller shaft from time to time. The
final clearance should be 50 – 100 μm.
Release the pressure and check that the clearance stays
within limits.
Fit the retainer ring (47). If som parts have been replaced the
ring may need machining.
Date 23

24. Atox Repair
d. Mounting of outermost covers
Grease Klüber NOSOL UTA 4 or similar must be applied to the
outer steel rings of the shaft seals (69) and then the seals are
mounted in the bearing cover (57). See assambly drawing for
details.
Do not forget the distance ring between the seals.
Mount the sealing air ring (48) on the bearing cover (57)
Grease must be applied between the 2 seals the in cover (57).
Use only Klüberlub BE41-1501 (high temperature thick
grease).
Date 24

25. Atox Repair
Lower the entire cover (57/ very carefully down over the
vertically positioned roller shaft.
Tighten all screws to specified torque levels.
If the roller is to be spare part the interior must be protected:
For short time with lubrication system oil, for long with
conservation oil.
Date 25

26. Thanks
Date 26