1 Introduction
Rexline Engineering had successfully completed the conversion of a rubber lining tub to a ceramic lining on a screw conveyor for Crushing Service International (CSI).The previous lining on the tub wears out quickly than expected so after analyzing the situation, our engineering team decided that a more stiff and rigid liner is needed to withstand the high amount of impact.
The screw tub is used by CSI to transport
REXLINE ENGINEERING with its technical expertise and combined experience of over 75 years in the wear and corrosion application industry successfully implemented its final product which was complimented by CSIengineering team
2 Case Study
The current rubber lining on the screw conveyor tub is used by CSI to transport lithium finefor one of their mining applications. Due to high amount of impact and abrasion, the current rubber lining provides only a service life of 6 weeks.
When approached by CSI, REXLINE ENGINEERING reliability Engineering Department, undertook this project to identify and provide a solution which would extend the maintenance shutdown schedule and replacement costs down.
After conducting intensive study at site on this screw conveyor, REXLINE ENGINEERING proposed using its ceramic lining. This specialized material contains a large percentage of Alumina 92% which is more than enough to withstand the impact.
Furthermore, REXLINE ENGINEERING proposed few design changes in the lining to cater to the delamination issues and inclusion of breather holes to avoid any inclusion of bubbles within the Spool.
Based on final design review and Approval for construction, REXLINE ENGINEERING manufactured these spools to specifications and delivered on schedule for Alcoa Shutdown work in 2018.
3 Technical Specifications
| TECHNICAL DATA SPECIFICATIONS : CERAMICS | |
| Description | 92% CERAMICS |
| Alumina Content | 92% |
| Density (g/ cm3) | 3.61 |
| Rockwell Hardness (HRA) | 85 |
| Vickers Hardness (HV10) | 1200 |
| Fracture Toughness (KIC or Mpa.m) | 3.6 |
| Compressive Strength (Mpa) | 2000 |
| Wear Volume (cm3) | 0.02 |
| TECHNICAL DATA SPECIFICATIONS: RUBBER | |
| Items | Index |
| Elongation | >450% |
| Tensile Strength | >180 |
| Mpa Break Extension | >500% |
| shore Hardness | 55-65 HA |
| Tear Strength | > 70 KN/M |
| Break Permanent Deformation | < 24% |
| Rubber and Ceramic Adhesion Force (Shearing Stress) | > 3.0 Mpa |
| Temperature Resistance | < 100 C |
| Rubber Aging Life | > 8 years |
| Gap Between Tile | 0.8 – 2.0 mm |
| Rubber Edge | 1.5 – 2 .0mm |
3.1 Tiling System
150 x 100 x 6mm REXLINETUFF 92 Alumina Tiles
150 x 50 x 6mm REXLINETUFF 92 Alumina Tiles
3.2 Coating System for Gap Filling
WULFWEAR 1008 is a two-part, ambient temperature curing, epoxy compound containing abrasion resistant fillers designed to provide a long-lasting protective lining to metal or concrete surfaces which are subjected to high wear and tear by solids and/or slurries. The thixotropic texture allows for easy mixing and application. It can be applied by spatula, trowel or by hand (using protective gloves) onto both horizontal and vertical surfaces.
3.3 Tiling Procedure
3.3.1 Surface Preparations:
The Tub was abrasive blasted to class 2.5 finish in accordance with AS 1627 to achieve an angular blast profile for premium adhesion and primed upon when sent for Ceramic workshop after Rubber lining workshop
3.3.2 Mixing Tile Adhesive:
The Megapoxy is mixed according to the manufacturer’s instructions and of a quantity that will suffice for the intended area and also suits the speed of the installer.
It is CRITICAL to ensure that the epoxy is well mixed.Using a hand trowel a bed of epoxy is then spread onto the steel surface covering the intended area to a depth of about 4 to 5mm ensuring complete coverage.The spread epoxy must then be notch troweled using either a 6mm or 10 mm notch.
3.3.3 Process of Tile Application:
- The first tile must then be laid hard up into the upper most left-hand corner of the area where the epoxy has been notched and worked
- Slightly with downward pressure to ensure that the epoxy spreads on underside of the tile face and over the surface of the steel.
- The next tile to be laid must then have a film of epoxy spread along the edge that will butt up to the first tile laid. This tile is then pushed up hard against the first tile squeezing out excess epoxy between the 2 tiles and again working the tile into the epoxy bed.
- Complete the first row from left to right before starting on the second row and repeat.
- Once any tile is laid, besides scrapping/wiping off excess epoxy, the tile should not be touched until the epoxy has fully set. In the planning and laying procedure it should be ensured that the work or laying area progresses away from already or previously laid tiles until the epoxy is fully cured. Under no circumstances must the tiles be leaned on, walked on etc.
4 Project Benefits Review
| PARAMETER | BENEFITS |
| SERVICE LIFE | The ceramic liner is expected to last 30 weeks compared to the previous rubber liner which only lasted for 6 weeks |
| COST | Maintenance cost can be reduced to 144h downtime save |
5 Photos
5.1 Case Study Photos
Figure 1: Screw Feeder Tub Outside View
Figure 2: Old rubber lining inside the tub
Figure 5: Final assembly of the liner
Figure 3: Ceramic lining installation
Figure 4: Ceramic liner