Improvement of Down-the-Hole Air Hammer Efficiency by Optimizing Shapes of Colliding Parts

Abstract

Design development of down-the-hole (DTH) air hammers is discussed with the aim of increasing efficiency of rock drilling. The problem is solved by making hammering piston with curvilinear frees surfaces which are in no contact with the hammer body. This ensures generation of rock-breaking impact at the minimum energy input. New designs of hammering pistons are developed for DTH air hammer models PP110EN and PP110NK designed at the Institute of Mining, Siberian Branch Russian Academy of Sciences. Experiments prove that selection of rational shape of hammering pistons allows improving performance of DTH air hammers by 15% at the average.