| 摘要 |
<p>The louvre is a sheet metal box over an opening in the wall. It has a front (1) and three sides (2, 34) and is open at the back and top. A tube (6) behind the centre of the front takes the fixing screw holding the louvre to the wall. At the back of the tube a plate (8) from the centre to one side closes part of the open back. The box is bigger than the wall opening and its centre is offset from the opening. Air enters the back of the box and leaves through the open top. The box can be rotated about its centre to vary the direction of discharge and in one position the backplate (8) closes the wall opening.</p> |
