| 摘要 |
<p>The stopper (1) has an internal thread (11) which screws onto the gas bottle. The outer surface of the stopper is covered with a ring (2) which is loose on the stopper and allowed to turn on the stopper. The inside of the stopper is fitted with a groove to take a sealing washer (1, 2). The outer ring is made from harder and more brittle material than the stopper. The ring protects the stopper from accidental shocks and prevents accidental loosening of the stopper.</p> |
