| 摘要 |
A ventilation device having fans and filters, which, even if the filters clog, minimizes occurrence of overloaded operation of the fans and maintains reduction in the amount of ventilation as minimum as possible. The ventilation device (1) has the fans (4, 5), the filters (6, 7) for capturing dust etc. contained in an air flow generated by the fans (4, 5), and a control section (8) for increasing a target speed (ns) of the fans (4, 5) at a predetermined frequency by using a time input value (ts) for causing an informing section (9) to issue a filter sign. |
