| 摘要 |
<p>Sheet metal ducts such as used for ventilation plant and the like are prefabricated and assembled on site, instead of being prepared in large dimensions and cut to size on site, by providing sheet metal sections the edges of which are bent so that when two edges are placed against each other they form a T-shaped cross section, and by subsequently attaching the edges to each other by sliding over the length of the edges a strip of which the cross section is that of a hollow T. This construction makes assembly on site easy and speedy and facilitates transport.</p> |
