An exhalation-valve structure (22) for a respiratory device for providing artificial respiration to a patient is flowable in the expiratory flow direction (E), extends along a first flow path trajectory (K1) and An upstream respiratory gas flow path (54) connected to or connectable with a portion of the exhalation tubing coming from-a respiratory gas absorption source (54) extending along a second flow path trajectory (K2) and U) connected to or connectable to a downstream respiratory gas flow path (58), and-with respect to the downstream respiratory gas flow path (58) at a given first in the upstream respiratory gas flow path (54). When the respiratory gas overpressure of No. 1 occurs, the expiratory respiratory gas flow from the upstream respiratory gas flow path (54) to the downstream respiratory gas flow path (58) is permitted, and the upstream respiratory gas flow path ( 54) to the upstream respiratory gas flow channel (54) when a given second respiratory gas overpressure occurs in the downstream respiratory gas flow channel (58). ), a valve element (64) and a valve seat (66) provided between the upstream respiratory gas flow channel (54) and the downstream respiratory gas flow channel (58) so as to block the gas flow to And a valve assembly (63) comprising. It is contemplated in accordance with the present invention that the exhalation valve structure (22) is in fluid dynamic communication with the upstream respiratory gas flow path (54) from the upstream respiratory gas flow path (54) to the downstream respiratory gas flow path (54). It comprises a bypass chamber (74) which extends into the region of the flow channel (58) and is formed there to connect the gas pressure sensor (80).患者に人工呼吸を施す呼吸装置のための呼気弁構造体（２２）は、呼気流方向（Ｅ）に貫流可能であり、‐第１の流路軌跡（Ｋ１）に沿って延伸しかつ、患者から来ている呼気配管の一部分と接続されているか又は接続可能な上流側呼吸ガス流路（５４）と、‐第２の流路軌跡（Ｋ２）に沿って延伸しかつ、呼吸ガス吸収源（Ｕ）と接続されているか又は接続可能な下流側呼吸ガス流路（５８）と、‐下流側呼吸ガス流路（５８）に対して上流側呼吸ガス流路（５４）内で所与の第１の呼吸ガス過圧が起こった場合に、上流側呼吸ガス流路（５４）から下流側呼吸ガス流路（５８）への呼気性の呼吸ガス流を許可し、上流側呼吸ガ
