| 摘要 |
Apparatus for detachably locking a gas filter in operative position in a wall opening, wherein the upper end of the bag has a circumferential thickened portion which is retained, in a converging section of a socket mounted in the opening, by means of a locking cylinder which fits closely within the socket and within the upper end of the bag and is readily insertable and removable by means of a foldable handle thereon. |
