| 主权项 |
1. Uni-directional exhalation valve for an exhalation air path of a filtering face mask, comprising a flexible valve element, which is held biased in a housing of the unidirectional valve to close at least one air passage located in a sealing section of the housing with a sealing portion in a sealing manner and to at least partially open the air passage if the valve element is impinged by a sufficient air pressure against the bias, wherein the valve element is designed as a tubular cylinder and that the sealing portion is located on the lateral surface of the cylinder, whereby the sealing portion is located opposite to a support portion located on the lateral surface of the cylinder, the support portion interacting with a support section of the housing, and whereby for causing the bias the distance between the support section and the sealing section of the housing is smaller than the distance between the support portion and the sealing portion in the unbiased state of the valve element, and further wherein at least one opening through which air passing through the air passage can escape is formed in the housing at least essentially perpendicular to the air passage, and further wherein the cross-section of the cylinder is oval, whereby the sealing portion and the support portion are formed by the longer sides of the oval cross-section, respectively, and further wherein the housing comprises a pot-like receptacle with a cylindrical cross-section in which the valve element is coaxially held, the cylindrical cross-section substantially corresponding to the cross-section of the valve element. |
