| 摘要 |
<p>A gas filter comprises a zig-zag folded sheet of gas-permeable material as the filter element, the ends of the troughs formed between the folds being sealed. The seal is formed by a band of non-stretching material which is fitted up against the ends of the ridges and troughs and glued to the filter sheet. Prefd. band material is a metal, esp. Al.</p> |
