Quality Control of the Joints of Fabric Rubber Conveyor Belts with the Aid of a Thermovisor

Abstract

A method of direct quality control of the vulcanised joints of fabric rubber conveyor belts with the use of a TESTO 875-1 high-resolution thermovisor (Germany) has been approved. The method is based on the different thermal conductivity of materials inside and outside the zone of defects. This leads to a difference between the temperature inside the zone of a defect and the temperature outside this zone in the solid mass of the belt during heating (or cooling). This difference is recorded by temperature gauges and very graphically by the thermovisor. Fabric rubber belts of 500 mm thickness, made from fabric TK-200 with artificial defects mirroring those most often encountered during joining and service – blisters, microporosity, damaged joints, incomplete coating with adhesive – were tested. Heating was carried out between the plates of the vulcanisation press used for joining, from a temperature of +10°C for most of the defects, or from −10°C for the defect associated with incomplete coating with adhesive, to a temperature of +70°C. In the case of the most common defect –blisters – tests were also conducted in a cooling regime (from +90 to +70°C). The difference in temperatures between the zone of defects and the solid mass of the belt ranged from 15 to 4°C. In future, it is proposed that the state of the joints be monitored for the entire length of their service, especially on heavy-duty and critical conveyors.