Filter device

A filter device, comprising:

• a filter housing cover defining a receiving chamber;
• an annular filter element arranged within the receiving chamber;
• a housing defining an axis and a dome arranged centrally in the housing to which the filter housing cover is rotatably secured;
• an intermediate piece arranged between the filter housing cover and the housing when the filter housing cover is secured to the housing, wherein the intermediate piece includes a cap having a surrounding wall enclosing an axially open cavity;
• an inlet duct in communication with an untreated side of the annular filter element, and an outlet duct in communication with a clean side of the annular filter element;
• a drainage duct arranged at a bottom of 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 cap of the intermediate piece and rotatable about the axis, wherein the closure device includes a closure element configured to close the drainage duct;
• wherein the closure element of the closure device is arranged in axial alignment to the drainage duct and by rotating the filter housing cover in a first direction relative to the housing the closure element is rotated and axially adjustable into a position closing off the drainage duct, and by rotating the filter housing cover in a second direction opposite the first direction relative to the housing the closure element is rotated and axially displaced away from the housing so that the closure element opens the drainage duct;
• and
• wherein the closure device further includes an annular plate and a lateral wall extending axially therefrom and surrounding a central opening, and wherein the closure device has at least one projection disposed at an axial end of the lateral wall opposite the annular plate, the at least one projection extending radially from the lateral wall away from the axis.

A filter device comprising:

• a filter housing cover defining a receiving chamber, an annular filter element arranged within the receiving chamber;
• a housing defining an axis and a dome arranged centrally in the housing to which the filter housing cover is rotatably secured;
• at least one intermediate piece including a cap arranged between the filter housing cover and the housing when the filter housing cover is secured 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 including a plate arranged in the cap of the at least one intermediate piece, the closure device further including a closure element configured to close the drainage duct;
• wherein the plate of the closure device is structured and arranged to position the closure element in alignment with the drainage duct, and by rotatably securing the filter housing cover on the housing the plate adjusts the closure element into a position closing off the drainage duct, and by rotatably loosening the filter housing cover from the housing the plate of the closure device is moved axially away from the housing so that the closure element opens the drainage duct;
• and
• wherein the cap of the at least one intermediate piece has a surrounding wall enclosing an axially open cavity, and the plate of the closure device is arranged coaxially in the cap;
• and
• wherein the closure device further includes a lateral wall extending in a circumferential direction, the lateral wall including at least one radially projecting incline, and wherein the at least one incline engages the cap at a projection of the cap and through rotatably securing the filter housing cover on the housing the closure element of the closure device is axially displaceable into the position closing off the drainage duct.