Optimalizace distribuční křivky zrnitosti materiálu těženého sacím bagrem

Abstract

In this dissertation I present the optimization of the particle size distribution of aggregate extracted by a plain suction dredger. The main objective of the optimization was to reduce the number of fine particles (i.e. aggregate fraction in size smaller than 0,063 mm), which can negatively affect the technological properties of concrete. According to the European technical standard EN 12620, the maximum amount of fine particles of aggregate intended for concrete is only 3 %. These fine particles are usually reduced at the end of the separation process by hydrocyclones, as no device has yet been developed to allow this directly in the extraction process.

In this dissertation I come up with an innovative idea on how to reduce the number of fine particles at the beginning of the extraction process, by installing a new mechanical device (hydroreducer) on the discharging pipeline of a plain suction dredger. The hydroreducer is designed as a box that uses the energy of the mining pump of the plain suction dredger to reduce fine particles directly at the area of extraction. The hydroreducer achieved the most significant fine particle reduction for material with an initial fine particle content of 4.80 % of these fine particles, with a reduction to 3.89 %. The amount of fine particles was thus reduced by 19.2% thanks to the optimization.