| 摘要 |
A drop tube type granular crystal producing device (1) for manufacturing generally spherical crystal bodies by solidifying the granular molten liquid of inorganic material while allowing the liquid to free-fall in a drop tube, comprising a molten liquid forming device (2), a drop tube (3), a gas flow forming mechanism (4) for forming the gas flow of cooling gas inside the dro p tube (3), and a recovery mechanism (5) for recovering the crystal bodies (25 a) from the lower end part of the drop tube (3), the drop tube (3) further comprising an inlet tube (30), a cooling tube (31), and a solidifying tube (32), wherein the cooling tube (31) is formed so that a cross sectional area is reduced toward a bottom side to make generally equal the flow velocity of the cooling gas to the free-fall speed of the granular molten liquid and the solidifying tube (32) is connected to the bottom end of the cooling tube (31 ) and the cross sectional area thereof is increased discontinuously from the bottom end of the cooling tube (31), whereby, since the cooling gas is decelerated suddenly near the upper end of the solidifying tube (32) to increase a gas pressure, crystal nuclei are generated in the molten liquid i n overcooled state, and the liquid is crystallized at a stroke. |
