Patent ID: 8920650

Claim:
A filter device comprising: a filter housing cover defining a receiving chamber, an annular filter element arranged within the receiving chamber, the filter housing cover having a base with a threaded opening, a housing having a threaded dome arranged centrally in the housing and to which the threaded opening of the filter housing cover is screwed, and at least one incline disposed peripherally along the dome and extending obliquely in an axial direction, at least one intermediate piece arranged between the filter housing cover and the housing when the filter housing cover is screwed to the housing, a housing-side inlet duct in communication with an untreated side of the annular filter element, and a housing-side outlet duct in communication with a clean side of the annular filter element, a housing-side drainage duct arranged in the housing and through which the receiving chamber can be drained during the removal of the filter housing cover, a closure device arranged in the intermediate piece so as to be rotatable about a filter axis and which has a closure element configured to close the drainage duct, the closure device having at least one rib facing the dome configured to cooperate with the at least one incline, wherein the closure device is arranged in alignment to the drainage duct and by the screwing on of the filter housing cover is capable to adjust the closure element into a position closing off the drainage duct and on unscrewing of the filter housing cover is rotated and moved axially away from the housing so that the closure element opens the drainage duct.