Patent ID: 8662104

Claim:
A respiration system for a patient, the respiration system comprising: a breathing tube bidirectionally conveying a flow of fluid to a patient, said breathing tube having diametrically opposite first and second ends, said first end of said breathing tube being adapted to be in contact with the patient; a slot valve arranged at said second end of said breathing tube, said slot valve opening in a first direction of flow toward the patient when a pressure in said first direction of flow is above a first pressure threshold, said slot valve closing in said first direction of flow when said pressure in said first direction of flow is below said first pressure threshold, said slot valve opening in a second direction of flow away from the patient when a pressure in said second direction of flow is above a second pressure threshold, said slot valve closing in said second direction of flow when said pressure in said second direction of flow is below said second pressure threshold, said second pressure threshold being higher than said first pressure threshold, said slot valve including a membrane defining a plurality of slots which intersect each other and extend completely through said membrane, said slots forming a plurality of lamellae that are pivotal about pivot lines, said lamellae contact each other to close said valve, a material thickness of said lamellae asymmetrically varying as a function of a radial position of the membrane, said material thickness varying asymmetrically to vary a value of said first and second pressure thresholds.