Justification of the air distribution system of a down-the-hole hammer with an efficient operating cycle

Abstract

One method for conserving energy in the mining industry and ensuring the required pressure of compressed air in underground mining networks is to decrease the specific energy carrier consumption, particularly in the case of down-the-hole hammers. The objective of this study is to substantiate the air distribution system of an air hammer, aimed at reducing the specific consumption of compressed air. We propose a system consisting of two chambers with a constant supply of compressed air, two controllable chambers, two elastic valves on the hammer, and a valve for cutting off the supply of compressed air to the forward stroke chamber, which is controlled by the hammer’s position. This proposed configuration was employed to create two different designs for the air hammer. The operational cycle of the designed device has been numerically examined using SimulationX software and validated through experimental testing on a laboratory bench. Our calculations reveal that the suggested air distribution system, featuring controlled inlet to the backward stroke chamber, successfully achieves the stated objective. In comparison to the standard M29T hammer with nearly identical dimensions, striking power, and compressed air consumption for cleaning the borehole, the designed hammer exhibits a 53% reduction in specific energy consumption, and its electrical power usage for compressed air supply is halved. These design specifications align with both experimental results and data derived from the existing literature, confirming the accuracy of our calculation.

Keywords

• energy consumption
• down-the-hole hammer
• air distribution system
• specific consumption
• percussion power
• bottomhole purging
• numerical simulation
• operating cycle parameters
• bench experiments