The rotary kiln forms the very heart of pyro-metallurgical processes, objectively determining the actual status of the kiln timeously triggers the relevant proactive corrective or preventive maintenance interventions.
Ultimately this contributes towards maximising the vessel’s overall effectiveness. Dickinson Group in alliance with Fives FCB, a member of the Fives Group offers a revolutionary comprehensive rotary kiln inspection program that has been streamlined to determine the complete status of a rotary kiln within 5 days (for a 3 pier Kiln).
The core parts of the inspection are done while the vessel is in operation, there are however some additional options that require relatively short stoppages (see step 8). This article will give a brief step by step overview of this rotary kiln inspection program.
Pre-Job Briefing and Discussions with the Maintenance Team of The Plant
Kiln floating uphill and downhill sequence?
Refractory lining chart / history?
Last mechanical failures (major issues)?
Shell sections replacement history? (Drawing or file?)
Load at each pier (general drawing or file?)
Last inspection reports and operations performed on the rotary kiln?
Shell thickness measurement report?
Kiln Axis Control
Measurement of the relative position of the tyres : slope, elevation view and top view of the axial deviation
Rollers Axis And Hydraulic Thrust Position Control
Roller bearings support slopes and axis distance
Rollers axis slopes (+ distance and parallelism if shaft ends are accessible)
Hydraulic thrust position control
Rollers And Tyres Diameters Measurements
Measurement of 3 diameters on each rollers and tyres (shape: conicity or concaveness)
Step 3 results + Average diameters provide the rollers operating angles and the position of the thrust under tyre.
Tyres and Girth-Gear Run-Out + Shaft Bending
Tyres wobbling
Girth-Gear wobbling and excentricity (if possible in operation)
Shaft bending measurement (variation of loads?)
Kiln Shell Deformation Control
Shell profile analysis (roundness and excentricity) + location of existing welds
Focus on area of Tyres and Girth Gear + step 5 results provide impact of shell deformation on wobbling & excentricity
Specific focus on kiln feed and discharge end areas
Comprehensive Mechanical Inspection
Axial position of tyres, rollers, pinion, Girth Gear (kiln in downhill)
Contact pattern between rollers and tyres
Relative movement of the shell inside the tyre (clearance)
Visual inspection (rollers, tyres, blocking systems)
Temperatures and global vibrations measurements
Visual control of bearings lubrication
Rollers skewing control (bearings thrusts position when kiln is in downhill)
Hydraulic thrust pressure control (downhill and uphill)
Girth-gear inspection in operation (teeth temperature, contact pattern)
Inlet and Outel seal visual inspection
Possible adjustment range of rollers supports
Adjustment range of inlet and outlet seals (if possible)
Debriefing On Site
Option 1: Girth-Gear inspection (short stoppage required: 0.5 day)
Option 2: Main transmission alignment control (short stoppage required: 0.5 day)
Option 3: Assistance for kiln axis and rollers adjustment (to be defined)
Option 4: Assistance for Kiln shell thickness measurement (to be defined)