Patent ID: 8251099

Claim:
A check valve, comprising: a first hose connector housing; a second hose connector housing; and a diaphragm disk positioned between the hose connector housings, the diaphragm disk being made of a flexible material, the diaphragm disk being configured to be lifted from an annular valve seat surrounding an inlet space connected with an entry channel during a first period when a pressure at the entry channel is greater than a pressure at an exit channel, and pressed onto the valve seat during a second period when the pressure at the entry channel is lower than the pressure at the exit channel, wherein the diaphragm disk has an annular bead at an outer circumferential area, the annular bead being received in opposed annular grooves of the hose connector housings, the diaphragm disk located radially outwardly of the valve seat being provided with openings leading to an exit space; a wall of the second hose connector housing opposite to the openings has recesses connected to the exit channel, the wall of the second hose connector housing opposite to the openings has a curvature directed away from the diaphragm disk in the direction of the exit channel, the curvature being configured to cause the wall of the second hose connector the diaphragm disk to contact during the first period when the pressure at the entry channel is greater than the pressure at the exit channel, the exit channel has an entry opening in the wall, a diameter of the entry opening being smaller than that of the exit channel, the exit channel is tapering conically toward the entry opening in a transition section, and the recesses are provided in the transition section and are connected with the exit space, said recesses being dimensioned such that a cross-sectional flow differential between the entry opening and the exit channel is substantially compensated.