Continental Conveyor launch new roller range
The use of plastic rollers is common in European over-ground mining sectors. This is primarily due to the perception of roller weight and general ease of handling, although this is generally the case in relatively low-capacity throughput applications.
To bring this product to a wider market, Continental Conveyor have combined the best available materials with their proven production methods. To help select a suitable cost-effective tube material, Continental Conveyor sought the help of experts and also developed their own in-house comparative accelerated wear test equipment.
The results of the tests indicated which compound of plastic tube has a greater resistance to abrasion. The material selected for the shell of the roller has been developed from a polypropylene plastic base and uses a mineral filler to create an alloy that has enhanced wear characteristics. In the comparative accelerated wear test, the material lasted at least four times longer than high-density polyethylene (HDPE) materials.
In comparison with HDPE, the polypropylene mix gives improved abrasion- and wear-resistance characteristics, increased inherent strength, and improved environment stress-crack resistance. The material is also tolerant to changes in temperature due to its thermal properties.
The plastic tube is extruded with internal splines for added rigidity and to provide an inherent rotational lock between bearing housings and the roller body.
As the service life of an idler roller is directly proportionate to the quality of its seals, Continental Conveyor use sealed bearings from reputable suppliers and protected by high-performance labyrinth seals to give two levels of protection. The labyrinth seal has been specifically developed to provide maximum bearing protection commensurate with low-friction characteristics. All bearings are 25mm diameter 6205 2RS1 sealed units pre-lubricated with Renolit MP3 grease.
Deflection of the roller shafts due to the load on the idler rollers causes misalignment of the bearings, and bending beyond the manufacturers maximum recommendations significantly reduces the bearing life. Continental Conveyor therefore prefer to carry out calculations prior to the selection of the shaft diameters to ensure that the slope angle at the bearings does not exceed the manufacturers maximum recommendations.
The rollers are available in two versions — plastic varitrough and fixed garland. The plastic varitrough structure includes flexible carrying idler sets whose troughing angle varies in relation to the weight of material on the conveyor belt. The variable troughing characteristics ensure that an empty belt is always in contact with the centre roller for effective belt tracking and provides the maximum carrying capacity at a deep trough angle when loaded. The fixed garland version is the same as the varitrough but is not fitted with springs and does not flex.
Continental Conveyor Ltd, Team Valley Trading Estate, Gateshead, Tyne & Wear NE11 0LP; tel: (0191) 487 8888; fax: (0191) 482 1903; email: sales@continental-conveyor.co.uk; website: www.continental-conveyor.co.uk
