1. Technical Field
This invention relates to devices for insufflating gas into a mass of molten metal wherein the device is positioned in the refractory lining of the bottom or wall of the vessel and gas is introduced into the vessel therethrough.
2. Description of the Prior Art
Prior structures have generally employed permeable plugs or solid plugs and spaced jackets thereabout positioned in apertured refractory pocket blocks. Usually frusto-conical apertures in the conventional pocket blocks received the frusto-conical plugs or solid frusto-conical plug and jacket combinations and all of the prior art devices have a relatively short life due to the erosion of the pocket block and the plugs or their equivalents incorporated therein.
Typical prior art devices may be seen in U.S. Pat. Nos. 4,396,179 to LaBate, 4,483,520 to LaBate, 4,538,795 to LaBate, 4,632,367 to LaBate, 4,687,184 to LaBate, et al., and 4,725,047 to LaBate.
The present invention comprises an improvement with respect to the devices disclosed in my above-mentioned U.S. Patents, all of which use conventionally formed pocket blocks.
The present invention discloses a stirring block for introducing gas into a mass of molten metal in a vessel wherein the actual block has a substantially greater density than pocket blocks heretofore known in the art, the greater density being achieved by pressure ramming of multiple layers of refractory material or alternately high pressure formation of pressed units of refractory material with the passageways in a block being formed during the ramming or pressing stages of formation so as to extend through the stirring block in the direction of the grain structure whereby the working or exposed surface of the stirring block presents an unusually dense surface having very great erosion resistance such as heretofore unknown in the art.