| 摘要 |
A respiratory filter unit comprising a housing (1) in the form of two shells (2, 3) having circular rims (4, 5) which can interlock and form a seal and around which one shell can be rotated with respect to the other. Each shell has a gas port (9, 10) to enable gas to flow (12) through the housing and the longitudinal axes of the gas ports are inclined to the planes of the circular rims of the respective shells so that rotation of the shells varies the angle between the gas ports. The unit also includes means for locating a filter element (8) within the housing across the path of gas flow. |
