| 摘要 |
PURPOSE:To cope with the reversal of airflow immediately and prevent the reverse flow of air surely by a method wherein a movable reverse flow preventing plate is arranged at least one of the inlet and outlet ports of air wind tunnel for the ventilating fan, which serves both for suction and exhaust of air, to operate it in conjuction with the operation of the ventilating fan. CONSTITUTION:In case of suction of air, air flows from outdoor side 4 into indoor side 3 and the air, trying to flow reversely to the outdoor side 4, is precluded by the suction air reverse flow preventing plate 12 while the air is induced into the indoor side 3 smoothly without being disturbed since the exhaust air reverse flow preventing plate 16 is arranged in parallel to the wind tunnel 5. In case of exhaust of air, a fan motor 8 turns into reverse rotation and the air is flowed by the rotation of the fan 7 from the indoor side 3 to the outdoor side 4, simultaneously, a geared motor is operated to turn the exhaust air reverse flow preventing plate 16 and stop it at a position 16' whereat the plate 16 intersects orthogonally to the wind turnnel 5. In this case, the suction air reverse flow preventing plate 12 moves to the position 12' whereat the plate 12 is in parallel to the wind tunnel 5.
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