| 摘要 |
A hollow air brick 2 comprising a front face with airflow openings; a vane (30, Fig. 4) pivotally mounted behind the front face that rotates between a first open position permitting ventilation and a second closed position inhibiting ventilation; and a temperature sensitive mechanism (20, Fig. 3) adapted to rotate the vane to its second position when the temperature is below a threshold value. The temperature sensitive mechanism may be a bimetallic coil having one end fixed inside the air brick and the other end connected to a projection at one end of the vanes pivoting axis. Alternatively the temperature sensitive mechanism may either be a snap acting bimetallic disc that triggers the rotation of the vane or a switch. The threshold temperature may be the freezing point of water. |
