Blast furnaces were first built and employed in the creation of iron in China in the first century AD. It is believed that the very first of these evolved from earlier furnaces which were used in the melting of bronze in the 4th and 5th centuries BC, and the same basic structure of those first blast furnaces is still used today! Of course, throughout the many centuries since then, innumerable changes, improvements, and innovations have continued to be made in blast furnace equipment and technological processes. As blast furnaces got larger and larger to turn out mass quantities of iron, specifically for the production of steel during the American Industrial Revolution, finding the most efficient and effective way to introduce such large amounts of charge material at the top of the shaft became an important issue. The three main systems that are used today, and that I would like to explore here, are the single-bell type systems, double-bell systems, and most recently, different variations of bell-less systems. Continue reading →