Mechanical Technology November 2015

⎪ Proactive maintenance, lubrication and contamination management ⎪

Super-screw conveyor belt splicing

“ T his high strength splicing system is a flexible rubber splice using self-tapping screws that en- able Super-Screw to be installed regardless of the configuration of the conveyor belt and irrespec- tive of access and weather conditions,” says Donovan Scott, divisional manager, bulk materials handling, BMG. “The current trend in 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,” he argues. BMG, in conjunction with the SABS, has used various belt classes and widths to test the Super-Screw in different ap- plications 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, and these will be published in the next six months,” he adds. Field tests indicate that the Super-Screw is the quickest method to repair a conveyor belt in an 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 high tensile strength, has proved to be a suitable alternative to conventional splicing methods. In some cases, the Super-Screw exceeds the tensile rating of hot and cold splice samples of the same class rating. “Trials, using the same belt width of 600 mm, also demon- strate that a conventional hot splice takes seven hours, a cold splice takes over eight hours (including curing), while the Super Screw can be applied in less than one hour,” Scott points out. 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 length 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 3.0 m and pre-installed assembly spacers. These materials are abrasion-, heat-, fire- or oil-resistant and heat-retardant at up to 200 °C. The non-magnetic system BMG’s highly efficient belt fastener system – the Super-Screw TM – 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.

Above: BMG’s Super-Screw belt fas- tener system screws onto a conveyor belt for an efficient repair in all conditions. Right: The mechanical joining tech- nique is easy to complete, without the need for a skilled operator and heavy, costly equipment.

has metallic inserts made of stainless steel, with stainless steel screws. The 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 on the bias, like regular splices, to ensure optimal strength and flexibility around the pulleys. In selecting the correct Super-Screw fastener for each ap- plication, 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 ap- plications, 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 similar to an electrical or battery powered screwdriver. q

Mechanical Technology — November 2015

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