| 摘要 |
PURPOSE:To maintain the pressure differential between the indoor and the outdoor so as to perform a stable and pleasant ventilation by disposing a sensing element which changes its electrical conductivity characteristics in accordance with the pressure differential between the indoor and the outdoor, and operating a feed air fan which changes its speed in accordance with the output signal from a micro computer. CONSTITUTION:When an air purge fan 2 is operated, a pressure differential is generated between the indoor 10 of a house 1 and the outdoor 9. Then, a pressure differential is generated between an indoor side sensing opening 6 and the outdoor side sensing opening 8, which causes electrical conductivity characteristics of a sensing element 7 to similarly change, and the change of ON time of it is inputted to a micro computer. When the ON time becomes greater than a certain limit, an operation command is issued from the micro computer to start the electrical supply, and the speed of a feed air fan 15 is progressively increased and maintained within an allowable range for a certain continuity time. When the ON time begins decreasing, the continuity time is reduced to progessively reduce the speed of the feed air fan 4, and a certain continuity time is maintained with the fan speed in an allowable range. When the ON time becomes lower than a certain limit, the feed air fan 4 is stopped.
|
