The Design and Some Construction Details of Two Laboratory Vacuum Furnaces for Casting Metals,

The designs of two laboratory furnaces for vacuum casting metals are described in detail. The first furnace employs a tungsten or molybdenum resistance winding. The furnace is constructed in two parts, an upper brass cylindrical can containing the heating coil, resting on a similar lower can in which the mold is placed. Bottom pouring techniques are employed in both furnaces. The second furnace uses high frequency induction heating, but may be adapted for resistance heating. It consists of an open-end silica tube resting on a brass cylindrical can. The induction coil fits around the silica tube and the crucible stands inside the tube. The mold is accommodated by the brass can. In both furnaces temperatures in the neighborhood of 1500 degrees Celsius at pressures of 0.001 to 0.00001 mm Hg have been obtained. The design of a vacuum gate valve, compression gland are also given.