CLIAMS: We Claim:
1. A method for replacing slew bearing of ladle turret without removal of arm assembly and shifting of Turret Table of Ladle turret comprising:
(i) providing support below Ladle turret;
(ii) lifting and lowering of main beam structure for lifting ladle turret structure involving hydraulic jack ;
(iii) maintaining said main beam structure is in lifted position for lifting and lowering of bearing involving said hydraulic jack ;
(iv) inserting the insert rods into the bearing inner race and outer race holes for aligning of bearing holes with bottom and top flange holes of Ladle turret;
(v) placing steel balls between roller assembly and bearing bottom surface for aligning bearing with bottom flange holes of top structure for Ladle turret;
(vi) pulling of bearing out using roller assembly ;
(vii) removing the old bearing ;
(viii) Placing the new bearing on rollers and positioning and again lifting the bearing by jacks;
(ix) Removing the roller rod and insert the insert rod in bearing outer holes.
(x) Supporting the bearing with support and jack and remove the rollers;
(xi) Lifting the bearing by jacks.
(xii) Removing insert rod and fixing the outer nut-bolt;
(xiii) Removing support and jacks and insert the insert rod in bearing inner holes and bottom flange ;
(xiv) Lowering the bearing by lowering the main support beams by removing packing stools step by step;
(xv) During last lowering stroke, inserting rollers with steel balls, between stool column and main support beam whereby the bearing is perfectly concentric with the turret axis;
(xvi) Removing rollers and lowering the bearing by lowering main beams.
(xvii) Removing insert rods and remove all supporting structure , assemble the bearing covers.

2. A method for replacing slew bearing of ladle turret as claimed in claim 1 comprising providing tie rod for maintaining stability of arms of Ladle turret during lifting and lowering process.

3. A method for replacing slew bearing of ladle turret as claimed in anyone of claims 1 or 2 wherein said support means used comprises stool means for step by step lifting and lowering of support structure of ladle turret.

4. A method for replacing slew bearing of ladle turret as claimed in anyone of claims 1 to 3 wherein said support means used comprises stool column and jack columns for lifting and lowering of support structure of Ladle turret.

5. A method for replacing slew bearing of ladle turret as claimed in anyone of claims 1 to 4 comprising:
(i) Providing base plate, stool columns and jack columns;
(ii) Placing the support structure beam assembly involving hydraulic jacks & inserting packing stools;
(iii) Fixing tie rod for arm stability during whole lifting process;
(iv) Locating column stools for additional stability during entire process of lifting & lowering;
(v) Removing inside bolt and nut and insert the insert rod at bearing inside to flange.
(vi) Step by step lifting of bearing employing hydraulic jacks ;
(vii) Supporting the bearing by inserting packing stools and jack ;
(viii) Removing insert rod and outer bolt from top flange;
(ix) Placing four roller with roller rod in a position so as to align with bearing inside holes.
(x) Resting the bearing on the rollers ;
(xi) Pulling out the bearing on a bearing replacement L-structure placing four jacks to lift the bearing and then rotating and replacing rollers at 90 so as to pull the bearing at the location where crane access exists;
(xii) Removing the old bearing;
(xiii) Inserting steel balls in the slots on top plate of roller for fine positional adjustment of bearing for original position;
(xiv) Placing the new bearing on rollers and pushing in position and again lifting the bearing by jacks, relocating the rollers and pushing the bearing at original position;
(xv) Removing the roller rod and insert the insert rod in bearing outer holes;
(xvi) Supporting the bearing with packing stools and jack , followed by removing the rollers and lifting the bearing by jacks;
(xvii) Removing insert rod and fix the outer nut-bolt ;
(xviii) Removing support stools and jacks and inserting the insert rod in bearing inner holes and bottom flange ;
(xix) Lowering the bearing by lowering the main support beams and removing packing stools step by step;

(xx) During last lowering stroke, inserting rollers with steel balls, between stool column and main support beam thereby ensuring that the bearing is perfectly concentric with the turret axis;

(xxi) Removing rollers and lowering the bearing by lowering main beams ;
(xxii) Removing insert rods and removing all supporting structure ; and finally
(xxiii) Assembling the bearing covers.

6. A method for replacing slew bearing of ladle turret as claimed in claim 5 comprising pulling out the replacing bearing on the bearing replacement L-structure, placing four jacks to lift the bearing and rotating and replacing rollers at 900 so as to pull the bearing at the location where the crane access exists.

7. A method for replacing slew bearing of ladle turret as claimed in claim 5 comprising placing new bearing on rollers and positioning the same and again lifting the bearing by jacks , relocating the rollers at 900 and pushing the bearing in original position.

Dated this the 21st day of January, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)
,TagSPECI:FIELD OF THE INVENTION

The present invention relates to a method for replacement of slew bearing of ladle turret used in steel plants. More particularly, the present invention is directed to a safe and faster method for easy replacement of slew bearing of ladle turret in a simplified procedure with less man hours, without usage of external cranes and without undertaking major dismantling of turret structure. The method according to the invention thus would favour easy replacement of slew bearing of ladle turret which is subjected to rapid wear and tear due to rotational motion under heavy load reducing downtime and manpower involvement thus favouring cost effective maintenance of this vital equipment in steel plants.

BACKGROUND OF THE INVENTION

It is well known in the continuous casting operation in large steel plants, the ladle turret serves for sequence casting. It transports the teeming ladles from the depositing position into the casting position and vice versa. One very important part of a continuous casting plant is the ladle turret. It holds the pouring ladles, which weigh up to 300 t. By means of the ladle turret, the pouring ladles are alternately slewed into pouring and charging position. This function ensures the uninterrupted operation of the continuous casting plant. While one ladle is emptied, a full ladle is provided on the other side.

The applicants continuous casting plant is having Ladle turret which has two arms at 1800 for holding ladle of 250T each. A Slew bearing which allows rotation of the turret. To perform this function, there is one rotating arm on each side of the turret. The arm with the ladle will stop over the tundish after rotating 1800. Then open the slide gate in the ladle to pour the liquid steel into the tundish. When the pouring of this ladle is about to be finished, the other ladle full of the liquid steel can be put on the other arm of the turret. As long as 1800 rotary movement takes place, the liquid steel in the second ladle can be rapidly and continuously supplied for pouring. The ladle change time is only about a minute. The turret is convenient for pouring with remote controlling. But the turret needs a big one-off investment cost and high requirements for repair and maintenance.

This type ladle turret does not have ladle lifting device. It has cover lifting and rotary device for lowering. There is a weighting device on turret. The pouring operator can know the level from the display data. The ladle turret usually have different parts/structures like foundation, drive device, hydraulic cylinder for lifting, rotating support, slew bearing, rotating rack, bracket, forks arm, ladle stand, parallel rod, rotary joint, weighing device, ladder landing platform, fender, lubrication system, anchored parts, ladle cover manipulator, etc. The slew bearing in the ladle turret, in spite of being subjected to high forces and considerable tilting moments, reach service lives of a few years when they need to be replaced.

The existing procedure for slew bearing replacement of ladle turret involve following activities before removing the bearing which takes a lot of time and manpower:
(i) first dismantling various parts like arm assembly, Ladle holder , links etc from Turret structure. This activities require about 2 days.
(ii) Next, removing the dismantled parts from turret location to the convenient free space. This activities require about 4 days.
Moreover, crane is essentially required for dismantling and removing of the parts as mentioned above. Thus, in conventional practice for slew bearing replacement, the total dismantling and replacement work takes about 2/3 weeks time for normal work to resume after such replacement. This in turn adversely affect the caster productivity.

There has been thus a need in the art to provide a safe and simple method for slew bearing replacement of ladle turret which would be faster requiring no involvement of external crane, no requirement of complete dismantling of super structure and no need for additional manpower, thus favouring reduced downtime of plant and enhanced productivity in continuous casting plant.

OBJECTS OF THE INVENTION

The basic object of the present invention is thus directed to providing a method for replacement of slew bearing of ladle turret in a safe and reliable manner, in less time with less manpower and needing no external crane.

A further object of the present invention is directed to providing a method for replacement of slew bearing in ladle turret wherein hydraulic jacks and inserting packing stools are used to lift the turret superstructure for creating space for replacing the bearing.

A still further object of the present invention is directed to providing a method for replacement of slew bearing in ladle turret wherein simple fixtures and gadgets produced in-house from readily available materials are used to facilitate disassembling and removal of old bearing as well as insertion and assembly of new bearing with desired precision in positioning/alignment in a user friendly manner.

A still further object of the present invention is directed to providing a method for replacement of slew bearing in ladle turret wherein there is no need to dismantle the top structure thus reducing the time for dismantling and again assembling of said parts after replacement work is over.

A still further object of the present invention is directed to providing a method for replacement of slew bearing in ladle turret wherein stability of top structure is provided during replacement work using support beam structure, stool columns and tie rods.

A still further object of the present invention is directed to providing a method for replacement of slew bearing in ladle turret wherein precise positioning and aligning of the bearing is carried out by providing insert rods, steel balls and roller assembly.

A still further object of the present invention is directed to providing a method for replacement of slew bearing in ladle turret wherein quick, easy and safe removal and insertion of bearing is done with pulling of bearing out/pushing in using roller assembly over temporary structure.

SUMMARY OF THE INVENTION

The basic aspect of the present invention is directed to a method for replacing slew bearing of ladle turret without removal of arm assembly and shifting of Turret Table of Ladle turret comprising:
(i) providing support below Ladle turret;
(ii) lifting and lowering of main beam structure for lifting ladle turret structure involving hydraulic jack ;
(iii) maintaining said main beam structure is in lifted position for lifting and lowering of bearing involving said hydraulic jack ;
(iv) inserting the insert rods into the bearing inner race and outer race holes for aligning of bearing holes with bottom and top flange holes of Ladle turret;.
(v) placing steel balls between roller assembly and bearing bottom surface for aligning bearing with bottom flange holes of top structure for Ladle turret;
(vi) pulling of bearing out using roller assembly ;
(vii) removing the old bearing ;
(viii) Placing the new bearing on rollers and positioning and again lifting the bearing by jacks;
(ix) Remove the roller rod and insert the insert rod in bearing outer holes.
(x) Support the bearing with support and jack and remove the rollers;
(xi) .Lifting the bearing by jacks.
(xii) Removing insert rod and fixing the outer nut-bolt;
(xiii) Removing support and jacks and insert the insert rod in bearing inner holes and bottom flange ;
(xiv) Lower the bearing by lowering the main support beams by removing packing stools step by step;

(xv) During last lowering stroke, inserting rollers with steel balls, between stool column and main support beam whereby the bearing is perfectly concentric with the turret axis;

(xvi) Removing rollers and lowering the bearing by lowering main beams .
(xvii) Removing insert rods and remove all supporting structure, assemble the bearing covers.

A further aspect of the present invention is directed to said method for replacing slew bearing of ladle turret comprising providing tie rod for maintaining stability of arms of Ladle turret during lifting and lowering process.

A still further aspect of the present invention is directed to said method for replacing slew bearing of ladle turret wherein said support means used comprises stool means for step by step lifting and lowering of support structure of ladle turret.

Yet another aspect of the present invention is directed to said method for replacing slew bearing of ladle turret wherein said support means used comprises stool column and jack columns for lifting and lowering of support structure of Ladle turret.
A still further aspect of the present invention is directed to said method for replacing slew bearing of ladle turret comprising:
(i) Providing base plate, stool columns and jack columns;
(ii) Placing the support structure beam assembly involving hydraulic jacks & inserting packing stools;
(iii) Fixing tie rod for arm stability during whole lifting process;
(iv) Locating column stools for additional stability during entire process of lifting & lowering;
(v) Removing inside bolt and nut and insert the insert rod at bearing inside to flange.
(vi) Step by step lifting of bearing employing hydraulic jacks ;
(vii) Supporting the bearing by inserting packing stools and jack ;
(viii) Removing insert rod and outer bolt from top flange;
(ix) Placing four roller with roller rod in a position so as to align with bearing inside holes.
(x) Resting the bearing on the rollers ;
(xi) Pulling out the bearing on a bearing replacement L-structure placing four jacks to lift the bearing and then rotating and replacing rollers at 90 so as to pull the bearing at the location where crane access exists;
(xii) Removing the old bearing;
(xiii) Inserting steel balls in the slots on top plate of roller for fine positional adjustment of bearing for original position;
(xiv) Placing the new bearing on rollers and pushing in position and again lifting the bearing by jacks, relocating the rollers and pushing the bearing at original position;
(xv) Removing the roller rod and insert the insert rod in bearing outer holes;
(xvi) Supporting the bearing with packing stools and jack , followed by removing the rollers and lifting the bearing by jacks;
(xvii) Removing insert rod and fix the outer nut-bolt ;
(xviii) Removing support stools and jacks and inserting the insert rod in bearing inner holes and bottom flange ;
(xix) Lowering the bearing by lowering the main support beams and removing packing stools step by step;
(xx) During last lowering stroke, inserting rollers with steel balls, between stool column and main support beam thereby ensuring that the bearing is perfectly concentric with the turret axis;

(xxi) Removing rollers and lowering the bearing by lowering main beams ;
(xxii) Removing insert rods and removing all supporting structure ; and finally
(xxiii) Assembling the bearing covers.

A further aspect of the present invention is directed to said method for replacing slew bearing of ladle turret comprising pulling out the replacing bearing on the bearing replacement L-structure, placing four jacks to lift the bearing and rotating and replacing rollers at 900 so as to pull the bearing at the location where the crane access exists.

A still further aspect of the present invention is directed to said method for replacing slew bearing of ladle turret comprising placing new bearing on rollers and positioning the same and again lifting the bearing by jacks , relocating the rollers at 900 and pushing the bearing in original position.

The objects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying non limiting illustrative drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1:is the schematic isometric view showing the ladle turret top structure supported with support beam structure, stool columns, jack columns and hydraulic jacks for lifting of the top structure.

Figure 2: is the schematic isometric view showing the ladle turret top structure with assembly of Tie rod fixing for arm stability during whole lifting and lowering process.

Figure 3:is the schematic isometric view of the beam structure assembly for supporting and lifting of the ladle top structure alongwith temporary L-structure assembly for supporting and removal of the old slew bearing.

Figure 4:is the schematic view of different stages for step by step procedure for dismantling and removal of the old slew bearing from ladle turret involving hydraulic jack, packing stool, inserting rod and roller assembly.

Figure 5:is the schematic view of different stages for step by step procedure for inserting in position and assembly of new slew bearing in ladle turret involving hydraulic jack, packing stool, inserting rod and roller assembly.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention relates to a method of replacement of slew bearing for Ladle Turret in continuous casting plat involving a simplified procedure using easy to use kit with less man hours, in less time , without dismantling the top structure of the turret and without usage of external cranes. More specifically, the present invention implemented a step by step procedure for removing the damaged slew bearing and inserting and assembling a new slew bearing carried out by utilizing the hydraulic jacks for creating required gap between the top structure and the undercarriage. Importantly also, in the above methodology the top structure along with the arms and links of turret, is kept fixed by providing required stability using support beam structure, stool columns and tie rods. Moreover, customized tools and fixtures are designed and configured to suit the need for positioning, aligning, sliding out/in of the bearing during the replacement work enabling the entire work to be carried out at minimum time with less manpower in safe and reliable manner without the need for any external crane. The exact methodology and steps involved are now described in details with the help of accompanying drawings as under:

Referring to accompanying Figure 1 which is the schematic isometric view showing the ladle turret top structure supported with support beam structure, stool columns, jack columns and hydraulic jacks for lifting of the top structure for desired slew bearing replacement. AT first the base plates are placed in position and stool columns (6) and jack columns(7) are positioned on the base plates. Next, the support structure beam assembly(5) is placed over stool columns (6) and jack columns(7) using hydraulic jacks(8) and inserting packing stools(11), to support the turret top structure for lifting to desired height to create gap for removal of damaged bearing. Importantly, Tie rod(10) is fixed between arm assembly(1) and turret structure(4) for arm stability during whole lifting process. Accompanying Figure 2 is the schematic isometric view showing the ladle turret top structure with assembly of Tie rod(10) fixing for arm stability during whole lifting and lowering process. Also, column stools(9) are placed at specified position on support structure beam assembly(5)for additional stability of (1,2,4) during entire process of lifting & lowering.
Accompanying Figure 3 is the schematic isometric view of the support structure beam assembly (5) placed over stool columns (6) and jack columns(7) for supporting and lifting of the ladle top structure and the temporary L-structure(12) assembly for supporting and removal of the old slew bearing placed at a level lower than the support structure beam assembly (5).

Accompanying Figure 4 is the schematic view of different stages shown as 4.1 to 4.7 in figure 4, for step by step procedure for dismantling and removal of the old slew bearing from ladle turret involving hydraulic jack, packing stool, inserting rod and roller assembly. The procedure involves hydraulic jacks for lifting and lowering of main beam structure(5) for lifting ladle turret structure and also involve use of hydraulic jack for lifting and lowering of bearing when main beam structure is in lifted position.

First, for lifting the ladle turret top structure supported on support structure beam assembly (5) using hydraulic jacks (8) for creating required gap between foundation and turret top structure after all bolts and nut (17) on inside of bearing inner race are unfastened and removed. In the next step, insert-rods (18) are inserted at bearing inside holes to bottom flange holes to arrest any angular shift. Next, by employing 4 hydraulic jacks (19), the turret top structure with bearing is lifted step by step by about 460 mm, and the bearing is supported at this elevated position by inserting packing stools (11) and jack(19). In the next step, the insert rods (18) are removed and bearing outer bolts (14) fastened with top flange(15) are unfastened and removed. In the next step, four roller assembly (20) with roller rod (21) are placed in a position so as to align with bearing inside holes. The roller assembly (20) is provided with a fixed plate having slots for inserting guide pin and steel balls for easy removal and inserting/positioning of the bearing during replacement. The jacks(19) are now gradually lowered in synchronization to lower and rest the bearing on the four rollers(20) placed inside channels of the L-structure (12). The damaged slew bearing to be removed is now pulled out on rollers(20) through the channels on the "bearing replacement L-structure"(12). Place four jacks to lift the bearing. Then rotate and replace rollers at 900 and then rest the bearing again on the rollers replaced at 900 so as to pull the bearing on cross channels on the L-structure to the location where crane access exists. Now, the old/damaged bearing(13) is now easily removed with the help of crane promptly without any detention of the crane.

Accompanying Figure 5 is the schematic view of different stages as illustrated through 5.1 to 5.8 in figure 5 for step by step procedure for inserting the new bearing in position and assembly of new slew bearing in ladle turret involving hydraulic jack, packing stool, inserting rod and roller assembly.

After removing the old bearing from rollers(20) support, steel balls are inserted in the slots on top plate of roller assembly(20). This is required for fine positional adjustment of bearing for original position. Next, the new bearing is placed on balls of roller assemblies with roller rod (21) in position so as to align with bearing inside holes and restrict relative displacement of the bearing with respect to rollers and then the bearing with rollers are pushed to position for placement in relation to turret structure. The bearing is again lifted by jacks at the cross joint of channels of the L-structure. The rollers (20) are relocated at 900 and then the bearing is pushed to its original position for assembly.
Next, the roller rod is removed and the insert rods (18) are inserted in bearing outer holes. The bearing is supported with packing stools (11) and jacks (19) at four locations. The rollers are now removed. The bearing is now lifted by jacks(19) so that the top face of bearing outer ring touches the bottom of the top flange(15) of turret structure. Now, the insert rods (18) are removed and fix the outer nut-bolt (14) on bearing outer holes.
The jacks(19) are lowered and support stools(11) and jacks(19) are removed in the next step. The insert rods (18) are now inserted in bearing inner holes and bottom flange(16). Now the bearing is lowered by lowering the main support beams (5), lowering jack (8) and by removing packing stools(11) step by step. During last lowering stroke, insert rollers with steel balls, between stool column (6) and main support beam (5). This ensures that the bearing is perfectly concentric with the turret axis. Then rollers are removed and the bearing is lowered by lowering main beams (5) so that the bottom face of bearing inner ring touches the top of bottom flange(16). Now insert rods (18) are removed, all inner nut-bolts(17) are fixed to bearing inner holes to complete the assembly of bearing and all supporting structure(5,6,7,8,9) are removed. Finally, the bearing covers are assembled.
It is thus possible by way of the present invention to providing a method for replacement of slew bearing for Ladle Turret in continuous casting plant involving a simplified procedure using easy to use kit with less man hours, in less time, without dismantling the top structure of the turret and without usage of external cranes. It provides a step by step procedure for removing the damaged slew bearing and inserting and assembling a new slew bearing carried out by utilizing the hydraulic jacks for creating required gap between the turret top structure and the bottom support structure. Importantly also, in the above methodology the top structure along with the arms and links of turret, is kept fixed by providing required stability using support beam structure, stool columns and tie rods. Moreover, customized tools and fixtures are designed and configured to suit the need for positioning, aligning, sliding out/in of the bearing during the replacement work enabling the entire work to be carried out at minimum time with less manpower in safe and reliable manner without the need for any external crane.

We Claim:
1. A method for replacing slew bearing of ladle turret without removal of arm assembly and shifting of Turret Table of Ladle turret comprising:
(i) providing support below Ladle turret;
(ii) lifting and lowering of main beam structure for lifting ladle turret structure involving hydraulic jack ;
(iii) maintaining said main beam structure is in lifted position for lifting and lowering of bearing involving said hydraulic jack ;
(iv) inserting the insert rods into the bearing inner race and outer race holes for aligning of bearing holes with bottom and top flange holes of Ladle turret;
(v) placing steel balls between roller assembly and bearing bottom surface for aligning bearing with bottom flange holes of top structure for Ladle turret;
(vi) pulling of bearing out using roller assembly ;
(vii) removing the old bearing ;
(viii) Placing the new bearing on rollers and positioning and again lifting the bearing by jacks;
(ix) Removing the roller rod and insert the insert rod in bearing outer holes.
(x) Supporting the bearing with support and jack and remove the rollers;
(xi) Lifting the bearing by jacks.
(xii) Removing insert rod and fixing the outer nut-bolt;
(xiii) Removing support and jacks and insert the insert rod in bearing inner holes and bottom flange ;
(xiv) Lowering the bearing by lowering the main support beams by removing packing stools step by step;
(xv) During last lowering stroke, inserting rollers with steel balls, between stool column and main support beam whereby the bearing is perfectly concentric with the turret axis;
(xvi) Removing rollers and lowering the bearing by lowering main beams.
(xvii) Removing insert rods and remove all supporting structure , assemble the bearing covers.

2. A method for replacing slew bearing of ladle turret as claimed in claim 1 comprising providing tie rod for maintaining stability of arms of Ladle turret during lifting and lowering process.

3. A method for replacing slew bearing of ladle turret as claimed in anyone of claims 1 or 2 wherein said support means used comprises stool means for step by step lifting and lowering of support structure of ladle turret.

4. A method for replacing slew bearing of ladle turret as claimed in anyone of claims 1 to 3 wherein said support means used comprises stool column and jack columns for lifting and lowering of support structure of Ladle turret.

5. A method for replacing slew bearing of ladle turret as claimed in anyone of claims 1 to 4 comprising:
(i) Providing base plate, stool columns and jack columns;
(ii) Placing the support structure beam assembly involving hydraulic jacks & inserting packing stools;
(iii) Fixing tie rod for arm stability during whole lifting process;
(iv) Locating column stools for additional stability during entire process of lifting & lowering;
(v) Removing inside bolt and nut and insert the insert rod at bearing inside to flange.
(vi) Step by step lifting of bearing employing hydraulic jacks ;
(vii) Supporting the bearing by inserting packing stools and jack ;
(viii) Removing insert rod and outer bolt from top flange;
(ix) Placing four roller with roller rod in a position so as to align with bearing inside holes.
(x) Resting the bearing on the rollers ;
(xi) Pulling out the bearing on a bearing replacement L-structure placing four jacks to lift the bearing and then rotating and replacing rollers at 90 so as to pull the bearing at the location where crane access exists;
(xii) Removing the old bearing;
(xiii) Inserting steel balls in the slots on top plate of roller for fine positional adjustment of bearing for original position;
(xiv) Placing the new bearing on rollers and pushing in position and again lifting the bearing by jacks, relocating the rollers and pushing the bearing at original position;
(xv) Removing the roller rod and insert the insert rod in bearing outer holes;
(xvi) Supporting the bearing with packing stools and jack , followed by removing the rollers and lifting the bearing by jacks;
(xvii) Removing insert rod and fix the outer nut-bolt ;
(xviii) Removing support stools and jacks and inserting the insert rod in bearing inner holes and bottom flange ;
(xix) Lowering the bearing by lowering the main support beams and removing packing stools step by step;

(xx) During last lowering stroke, inserting rollers with steel balls, between stool column and main support beam thereby ensuring that the bearing is perfectly concentric with the turret axis;

(xxi) Removing rollers and lowering the bearing by lowering main beams ;
(xxii) Removing insert rods and removing all supporting structure ; and finally
(xxiii) Assembling the bearing covers.

6. A method for replacing slew bearing of ladle turret as claimed in claim 5 comprising pulling out the replacing bearing on the bearing replacement L-structure, placing four jacks to lift the bearing and rotating and replacing rollers at 900 so as to pull the bearing at the location where the crane access exists.

7. A method for replacing slew bearing of ladle turret as claimed in claim 5 comprising placing new bearing on rollers and positioning the same and again lifting the bearing by jacks , relocating the rollers at 900 and pushing the bearing in original position.

Dated this the 21st day of January, 2014
Anjan Sen
Of Anjan Sen & Associates
(Applicants Agent)

ABSTRACT

TITLE: A METHOD FOR REPLACING SLEW BEARING OF LADLE TURRET WITHOUT REMOVAL OF ITS ARM ASSEMBLY AND SHIFTING OF TURRET TABLE.

The present invention relates to a method for replacement of slew bearing of ladle turret used in steel plants in a safe and faster and simplified step by step procedure with less man hours, without usage of external cranes and without undertaking major dismantling of arm assembly/turret top structure. The method favour easy replacement of worn out slew bearing of ladle turret with new one involving temporary structures to support the ladle turret structure, hydraulic jacks for lifting the top structure for creating required gap for bearing replacement, fixing of tie rod for stability, roller assembly to pull or push the bearing from and to the original position, hydraulic jacks for lifting/lowing bearing, and locating rods for precise positioning and matching of holes of bearing with flanges on structure, reducing downtime and manpower involvement thus favouring cost effective maintenance of this vital equipment in steel plants.