The use of laboratory erosion tests for the prediction of wear in pneumatic conveyor bends
This thesis describes a programme of work which has been undertaken with the objective of investigating means of using a laboratory erosion tester to predict the life of a bend in a pneumatic conveyor. Providing a link between a laboratory erosion tester and erosion tests on a pneumatic conveyor would lead to the development of an inexpensive way of predicting the life of a pipe bend operating under any given set of conveying conditions. An extensive literature review was carried out. From this it was concluded that very little work of an experimental corroborative nature had been out to substantiate whether erosion test results from a laboratory tester could be used to predict the life of a pneumatic conveyor bend. Two test facilities were constructed to carry out tests under accurately controlled conditions. The first of these was a laboratory 'rotating disc accelerator' erosion tester, and the second an industrially scaled pneumatic conveying test facility. Both test facilities yielded results that followed previously reported trends but also illustrated some trends that have been unreported in earlier work. It was found that the 'rotating disc accelerator' simulated erosion with minimal interference from inter-particulate collisions. For the pneumatic conveyor test bend used it was found that puncture of the bend wall occurred in the region where secondary particle impacts occurred, rather than in the region of primary impacts as reported in earlier work. Explanations for both these observations are given. An optically based construction for a cylindrical mirror was used to predict the location of the puncture point in the bend, and the intensification of particle impacts in the region of the pipe bend due to the geometry of the bend. When this was combined with an empirical erosion model derived from results obtained from the rotating disc accelerator, an accurate estimate of the life of the bend could be made. Further development of this model is discussed.