The Damping of Vibrations at the Transfer Points of Belt Conveyors Used in the Construction Industry

Abstract

Construction debris removed from demolished buildings or loose building materials are in many cases transported from mining
sites to the places of their processing using belt conveyors. When transporting building materials over longer distances,
transport routes are used, i.e. the required number of belt conveyors arranged one after the other. The grains of the transported
material are projected at an angle through the end drum of one belt conveyor and fall on the working surface of the other belt
conveyor. At the points of material grain impact, the conveyor belt is supported by traditional fixed belt conveyor idlers or by
so-called impact bed conveyors. Traditional belt conveyor idlers, fitted with impact rollers, are usually installed in the places of
the transfer points of belt conveyors arranged one after the other. These can be used mainly for the horizontal, but also the
vertical transport of bulk or piece building materials. The grains of bulk building materials falling on the surface of the
conveyor belt at the transfer points or hoppers damage the covering rubber layer and the supporting frame of the conveyor belt
and generate dynamic forces that are transferred to the load-bearing track of the conveyor belt. This paper presents a belt
conveyor idler of a special design, which consists of placing plastic brackets in structurally modified trestles. Impact rollers can
partially absorb the dynamic forces generated by the high potential energy of the building material grains. The paper presents
the detected forces acting in the places of mechanical attachment provided by experimental measurements carried out on a
laboratory belt conveyor idler attached to the aluminium frame, which simulates the load-bearing carrier track of a conveyor
belt. During experimental measurements done on laboratory equipment made of drawn aluminium profiles, a mechanical shock
occurs between the weight and the rubberized shell of the impact roller. The weight falls in a free fall from a known height on
the casing of the impact roller, thus deriving a dynamic force. This is transferred via the roller axis into the idler and through
its supports to strain gauge force transducers, which are mechanically attached between the frame of the laboratory equipment
and the supports of the belt conveyor idler. From the values of forces obtained when providing repeated measurements under
the same conditions and detected by strain gauge force sensors, values were recorded in the tables presented in the article, and
the mean values of the forces generated by the incident weight on the rubber surface of the impact roller were calculated.