| 摘要 |
The insides of the cover (1) walls (12,13) and the outsides of the pipes (4) in each chamber (6) form two channels (14,15). In the chambers (6) are at least two push dampers (20,22). The push dampers (20,22) are fitted in pairs on rotary shafts (24,25) so that they can be reversibly turned in one direction to a position in which the adjacent channels (14,15) are simultaneously closed by each of the pairs of push dampers. |
