The invention discloses an air vent valve for venting a filter, having a cavity with an inlet and an outlet and a sealing element in the interior of the cavity for sealing the inlet in a first position and for sealing the outlet in a second position. The sealing element is freely movable between the first position and the second position, and a flow is created between the inlet and the outlet when the sealing element is in an intermediate position between the first position and the second position.