| 摘要 |
<p>It comprises a bottom 1 and a lid 2 each having a groove 4 along the edge of their opening, this opening being covered by a stretched membrane 5. The edge of the membrane 6 is held by wedging in the groove 4 by means of a thread or retaining ring 7. It furthermore comprises means 8-12 making it possible to hold the lid 2 on the bottom 1 in the closed position. <IMAGE></p> |
