| 摘要 |
<p>After a material to be dried is frozen, it is efficiently freeze-dried in a short time to largely improve production efficiency. Provided are a vertical tube (2) having a freezing face (2a) formed on an inner peripheral surface, a liquid feeder (5) for supplying the liquefied material (47) to be dried onto the freezing face (2a), a freezer (10) located around the vertical tube (2) for cooling the freezing face (2a), a pressure-reducing device (12) for forming a vacuum state inside the vertical tube (2), and an internal heater (41) in the vertical tube (2). The internal heater (41) is located along the center axis of the vertical tube (2) and includes an elongate cylindrical radiating face (43) on its external surface. The liquefied material (47) to be dried supplied from the liquid feeder (5) is sprinkled over the freezing face (2a), and the freezing face (2a) is cooled to freeze the material (47) into a pipe-like form. Then the inside of the vertical tube (2) is pressure-reduced, and the radiant heat is supplied from the internal heater (41) to the material (47) to have the material (47) freeze-dried.</p> |
