Dozzles
When steel solidifies in a mould, uneven cooling causes a central cavity or 'pipe' to form in the casting. In 1861 Mushet invented the 'Dozzle'; a clay cone or sleeve, heated white hot and inserted into the top of the ingot mould near the end of the pour, and then filled with molten steel. Its purpose was to maintain a reservoir of molten steel, which drained down and filled the pipe as the casting cooled. Mushet claimed this, and other small inventions of his, saved the steelmakers of Sheffield 'many millions of pounds' (in 19th century money), yet he received neither payment nor recognition for these inventions. Dozzles, now called hot tops or feeder heads, are still in use today.
Read more about this topic: Robert Forester Mushet