Method and device for changing the cross section of stream

摘要

The method involves varying the positioning of at least one choke element (18) protruding at least partially into the air disposal line depending on the breathing expiration pressure to vary the effective flow cross-section so that the cross-section is reduced for increasing expiration breathing pressure and increased for reducing expiration pressure. Independent claims are also included for the following: an arrangement for varying the flow cross-section of an air outlet of a breathing apparatus.