Analysis of a pipe conveyor's idler housing failure due to a missing roller in terms of contact forces

Abstract A missing roller in a hexagonal idler housing of the hose conveyor represents a failure that is often underestimated and overlooked. However, its consequences can often be serious and are manifested mainly on the conveyor belt or within the individual components of the hose conveyor. This type of failure is often identified late so there is no relevant method for its early identification. In most cases, this damage is registered by visual identification, which, however, is not easy to be performed on long transport routes. For this reason, it is therefore appropriate to identify such a type of failure by measuring force ratios. However, detailed research is needed to implement this approach. The paper presents research based on a series of experimental measurements to identify the interdependencies between a missing roller and subsequent changes in force ratios in the existence of such failures. A necessary condition for proper operation of pipe conveyors is the contact forces that arise between the guide rollers and the conveyor. The analysis of measurement results confirmed a strong dependence between the force ratios and a missing roller, which creates a precondition to identify existence of such a kind of failure in a hose conveyor. The observed differences in the magnitude of pressing forces are not constant and directly depend on the position in which the rollers are missing. The largest change in contact force was up to 407 N in a specific position compared to correct, error-free state. The results of measurements made allow to formulate exact dependencies and define mutual relations of force ratios between individual roller positions.