| 摘要 |
PURPOSE:To make it possible to secure certain cleanliness in a clean room, by providing a check damper for air within a discharge duct to restrain the speed of dusts contained in outdoor air coming into a clean room through the discharge duct when the clean room is not operating. CONSTITUTION:A nonreturnable member 9A and a check damper 9 are secured to a rotary spindle 9-1 and said spindle 9-1 is mounted rotatably on a duct 7, while the check damper 9 hangs vertically by its self-weight. Three pieces of check dampers 9 close the outlet opening of the duct 7. when a discharge fan 8 is operating, the check dampers 9 are kept at a 'open' state, whereas said fan 8 is stopped, said dampers come to a 'close' state, so that penetration of dusts through the discharge duct 7 from the outdoors is remarkably prevented compared with conventional ducts. |
