| 摘要 |
The coffee filter is reusable and uses metal filters that are perforated for at least part of their height and held in a plastics ring (6). The perforations (7) at the top are at least twice as large as those lower down (8). The perforations are longitudinal slots arranged along the lines of greatest slope. The perforations at the top have a width of at least 200 microns. The perforations can gradually decrease in size from this towards the base of the filter. |
