| 摘要 |
Air is allowed to pass in or out through the valve with even pressure. The valve (1) has a wall part (3) which is connected to a wall and provided with a hole, and a part formed as a cover (5) which is fitted over the hole in the wall part. - The wall part incorporates a part (8) extending outwards and shaped so that it encloses the hole. A collar-shaped part (16) is fitted on the extending part to form a collar on it. |
