| 摘要 |
In an exhaust system for fume hoods (6) and other exhaust demanding sites comprising an exhaust source (1) connected to the exhaust sites and an air injection source (2) connected to the room accommodating the exhaust sites, a first damper (3) is inserted between the exhaust source and an exhaust duct (4) to which the exhaust sites are connected. The damper is controlled by a first regulator (14) maintaining the pressure constant in the exhaust duct (4). A second identical damper (25) is inserted between the air injection source (2) and the room (5), and both dampers (3, 25) are controlled in such a manner that their openings are always equal. A third regulating damper (29) is inserted in series with the second damper (25) and is responsive to the difference between the pressure drops over the first and second dampers. |
