| 摘要 |
PROBLEM TO BE SOLVED: To provide a ceiling structure for clean room which can fix the quantity of the air discharged into an attic space of a clean room. SOLUTION: In this ceiling structure for clean room, a holding frame 40 having a U-shaped cross section is arranged so as to surround the opening of a ceiling frame 36 and a closing plate 42 is put on the opening so as to close the opening. The closing plate 42 is held in a vertically movable state and, at the same time, is urged in the direction in which the plate 42 closes the opening by means of coil springs 50. The plate 42 ascends when the differential pressure between the clean room 12 and the attic space 24 of the clean room becomes a fixed value or higher. When the plate 42 ascends, a flow passage having a U-shaped cross section is formed between the edge section 42A of the plate 42 and the holding frame 40 and the air in the clean room 12 is discharged into the attic space 24 through the flow passage. When the differential pressure becomes higher, the gap 44A between the edge section 42A and frame 40 becomes narrower and a fixed quantity of air is always discharged into the attic space 24. |
