BMG’s highly efficient belt fastener system – the Super-Screw – which was originally used as a temporary alternative to conventional hot and cold splicing, has proved to be totally reliable as a permanent splice for conveyor belt repairs.
“This high strength splicing system is a flexible rubber splice using self tapping screws that enable Super-Screw to be installed regardless of the configuration of the conveyor belt and irrespective of access and weather conditions,” says Donovan Scott, divisional manager, bulk materials handling, BMG.
“The current trend in the mining industry is to avoid the use of hazardous substances where ever possible. Trichloroethylene, a hazardous solvent used in conventional hot and cold splicing procedures, can now be replaced by using the Super-Screw system as a safe splicing alternative.
“BMG, in conjunction with the SABS, has used various belt classes and widths to test the Super-Screw in different applications over the last three years. Further tension tests are currently being conducted through the CSIR on various splice types and on wider belts (500 mm). We expect to achieve even better results, which will published in the next six months.
“Field tests indicate that the Super-Screw is the quickest method to repair a conveyor belt in any emergency situation, significantly reducing downtime. The mechanical joining technique is easy to complete, without the need for a skilled operator and heavy, costly equipment. This system, with a high tensile strength, has proved to be a suitable alternative to conventional splicing methods. In some cases, the Super-Screw exceeded the tensile rating of hot and cold splice samples of the same class rating.
“Trials, using the same belt width of 600mm, also demonstrate that a conventional hot splice takes seven hours, a cold splice takes over eight hours (including curing) and the Super Screw takes less than one hour.”
This leak proof system can be used for reliably joining a belt, repairing a longitudinal rip, or a puncture in a belt. The Super-Screw splice is compatible with small pulley diameters, suitable for pipe conveyors and is conveyor scraper and V-plough friendly. This flexible splicing system can also be used inserting new belting into old conveyor belt systems.
The screws are self-drilling and self-tapping, spreading the carcass threads without cutting them. No pre-drilling is required.
Super-Screw, which can withstand service tensions to 2 000 kN/m, is available in various grades of rubber, to suit exact requirements.
The rubber material, containing tensile fabric used for the splices, is manufactured in rolls up to 25 m in lengths and in various strength ratings, from Class 315 to Class 2 000 conveyor belting. This system is also available in a ready to install option, with maximum pre-cut lengths of 3 m and pre-installed assembly spacers.
These materials are abrasion, heat, fire or oil resistant and heat retardant, up to 200 °C. The non-magnetic system has metallic inserts made of stainless steel, with stainless steel screws.
Steel screws are screwed into an embedded nut inside the material, forming a sandwich effect of the top and bottom cover that clamps onto the belt carcass.
The surface of the splice is level with the two ends of the original belt, making the splice surface as even and as thick as the belt itself. It is fitted at the bias like regular splices to ensure optimal strength and flexibility around the pulleys.
In selecting the correct Super-Screw fastener for each application, factors to be considered include the belt tension and strength of the belt, as well as the final belt thickness required. Each rubber cover type has important features for specific applications, including heat and abrasion resistance, as well as adherence to food grade specifications.
In addition, ambient conditions have to be considered before a cold splice can take place – if the humidity levels are too high, the adhesive may not be effective. An advantage of the Super-Screw, is it is effective in all weather conditions.
With training from BMG, an in-house maintenance team can quickly and efficiently install the Super-Screw system, using a simple tool like an electrical or battery powered screw driver.
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