Author: Charles Pratt, Operations Manager
For decade’s rubber has been skirting the transfer points of conveyors worldwide. (SBR) Styrene- Butadiene Rubber’s high wear resistance, combined with low cost, has made it a logical choice to date. With safety now being the driving force behind innovation and the risk of silicosis apparent, the demand for highly abrasive resistant skirting material is rapidly multiplying. Along with a reduction in employee complacency relating to working environments, higher belt speeds and skills shortage influencing the dramatic change. Today a strain of the high-performance plastic polyurethane is now the most economical way of skirting rubber conveyor belts. This paper analyses the Co-efficient of friction, wear resistance and tensile strength comparing SBR rubber, Natural Rubber, and Polyurethane.
Above production rates and maintenance costs, the health and safety of company employees is now the number one priority. In many bulk materials handling plants, reducing the dust from conveyor transfer points subsequently reduces the risk of an employee’s exposure to Silica dust. The litigation costs rivaling that of asbestosis costing billions of dollars.
Silicosis is a disabling, no reversible and sometimes fatal lung disease caused by inhalation of silica dust. Silica is the second most common mineral in the earth’s crust and is a major component of sand, rock, and mineral ores. Overexposure to silica dust can cause scar tissue to form in the lungs, which reduces the lungs’ ability to extract oxygen from the air we breathe.
Changing out or adjusting skirting on conveyors is a costly job for many bulk material plants across the globe. This is an issue affecting many aspects of business. Today administration time required for simple jobs like changing or adjusting skirting is extreme. Also a major problem for many plants is belt tracking which is often caused by material escaping from worn skirts.
With ever increasing production rates there is a greater requirement for plants to run 24 hours a day 7 days a week. In particular the power generation industry requires long run times between short scheduled maintenance windows. In many cases SBR rubber is not lasting the distance resulting in spillage, airborne dust, tracking issues, premature failure of idlers, belt damage etc.
There are many high wear resistant materials plants have available to combat wear such as ceramics, heat-treated or hardened steels. However, these materials can be unforgiving when used in skirting applications if run close to or contacting the conveyor belt surface.
The misunderstanding within the industry in distinguishing the difference between polyurethanes and polyethylene’s and witnessing plants use materials such as old conveyor belt, Ultra high molecular weight polyethylene (UHMWPE), natural rubber etc, to skirt their transfer points prompted us to research the most economical and belt friendly skirting material available. Ruling out materials that were hard and or abrasive we chose 4 materials to analyse.
- SBR Rubber 60 DURO SHORE A (most commonly used)
- Natural Rubber 60 DURO SHORE A
- Linatex Natural Rubber 60 DURO SHORE A
- Argonics Polyurethan 69 DURO SHORE A