An investigation of particle degradation by impact within a centrifugal accelerator type degradation tester

Abstract

There are several testing devices that are used throughout the world for quantifying particle degradation by impact against a solid surface. Some devices use pressurized air to accelerate particles so that they impinge upon a target, some use a vacuum system or mechanical devices to accelerate the particles. Others attempt to drop particles from a height to achieve the required velocity. All previous testers have some disadvantage associated with them, the most common being poor control over particle velocity. Because it is well known that impact velocity is the single most important controlling factor in particle degradation, this is a major disadvantage. The second major disadvantage of most previous work is that it involves only single or small numbers of particles, making it very difficult to scale to bulk. The purpose of this work was to design and construct an improved testing method in a pilot bench-scale unit for assessing degradation by impact. This test facility can control both the velocity of the particles and the angle of impact. Benefits associated with this facility are that the particle velocity is very closely controlled, the tester is portable, and only a small quantity of test material is required for each test.