Abstract: Nonreturn valve, in particular for medical uses, with a first tube connection housing and a second tube connection housing and, arranged between the two tube connection housings, a diaphragm disc which is made of flexible material and which can be lifted from an annular valve seat when there is an overpressure in an inlet channel and can be pressed onto the valve seat when there is an overpressure in an outlet channel. At its outer peripheral area, the diaphragm disc is provided with an annular bead which is received in mutually opposite annular grooves of the tube connection housings. The diaphragm disc is provided, radially outside the valve seat, with openings leading to an outlet chamber, and the wall of the second tube connection housing lying opposite the openings is provided with recesses which communicate with the outlet channel, are separated from each other by supporting surfaces for the diaphragm disc and are connected to the outlet channel by narrow deep grooves.

Abstract: A check valve in particular for medical applications has a first hose connecting casing and a second hose connecting casing and a membrane disk configured between the two hose connecting casings. The membrane disk is made of a resilient material and cooperates with an annular valve seat. The membrane disk is fitted radially outside the valves seat with apertures leading to a discharge space. The wall of the second hose connecting casing is opposite the apertures and fitted with a surface curved away from the membrane toward the discharge channel. The discharge channel is fitted with an intake mouth in the wall, and conically tapers within a transition segment toward the intake mouth. Recesses communicating with the discharge space are fitted into the transition segment and are dimensioned in a way to substantially compensate the different flow cross-sections between the intake mouth and the discharge channel.

Abstract: One-way valve, especially low-pressure check valve, for use in the medical technology, having a housing consisting of an inlet half and an outlet half and having an inlet channel and an outlet channel with a diaphragm being positioned in a pressure space which is contacting an annular valve seat under pre-tension which is opening into the outlet channel. The pressure space is consisting of two pressure chambers. In the direction of flow before the closing mechanism formed by the valve seat and the diaphragm a second valve mechanism is provided which is opening in the same sense with the first closing mechanism at an over-pressure in the entry channel and which is closing at an over-pressure in the exit channel.

Abstract: A check valve, especially for the medical technique having a first hose connector housing (1) and a second hose connector housing (2) and further a flexible diaphragm disk (3) positioned between the two joined hose connector housings (1, 2). At an overpressure in an entry space (6) the diaphragm disk (3) can be lifted from a lip-shaped sealing ring (13), whereby a flow cross-sectional area is created, and wherein the diaphragm disk (3) at an overpressure in an exit space (7) safely and in minimal times can be pressed onto a sealing seat to close the valve. The circular diaphragm disk (3) is produced from liquid silicone, silicone rubber or natural rubber and the thickness (3c) of the diaphragm cross-section (3a) is uniform.