| 摘要 |
The invention relates to an impactor (20) comprising one or more successive stages (4; 3; 2; 1), each stage (4; 3; 2; 1) comprising at least a nozzle part (24a; 23a; 22a; 21a), a collection substrate (24b; 23b; 22b; 21b) arranged behind said nozzle part in the direction of a gas flow (21), and a collecting film (24c; 23c; 22c; 21c) arranged on top of said collection substrate in the flow direction, onto which collecting film (24c; 23c; 22c; 21c) are deposited, in a size selective manner, aerosol particles contained in the gas flow (21) passing through the impactor (20). According to the invention, the surface of said nozzle part (24a; 23a; 22a; 21a) facing the next collection substrate (24b; 23b; 22b; 21b) in the flow direction comprises one or more protruding squeeze means (24d; 23d; 22d; 21d; 24e; 23e; 22e; 21e) to keep the collecting film (24c; 23c; 22c; 21c) in its place on the collection substrate (24b; 23b; 22b; 21b). |
