Filter system comprising a filter element and secondary element for closing a central tube

A filter system for filtering a fluid, the filter system comprising:

• a filter housing comprising a housing top part and a housing bottom part, wherein the housing top part and the housing bottom part extend along a housing axis of the filter housing;
• an outlet socket, arranged at the housing bottom part, configured to discharge the fluid after filtration;
• wherein the outlet socket comprises an outlet opening through the housing bottom part that is arranged concentrically relative to the housing axis;
• a central tube arranged concentrically to the housing axis in the filter housing and connected in flow communication with the outlet socket in at least one operating state, wherein the central tube, over at least a portion of an axial length of the central tube, comprises a radially open region;
• a secondary element arranged within the central tube so as to be slidable along the housing axis between at least a first operating position and a second operating position, wherein the secondary element is tubular;
• a filter element configured to be arranged in the filter housing and to separate fluid-tightly a raw fluid side from a clean fluid side, wherein the filter element comprises a filter bellows arranged about a longitudinal axis of the filter element, wherein the filter bellows comprises a first end plate at a first end face of the filter bellows and further comprises a second end plate at a second end face of the filter bellows, wherein the first and second end plates each comprise a central opening configured to receive the central tube in an interior of the filter element;
• and
• wherein the secondary element in the first operating position is arranged within the central tube at a first distance from the housing top part along the housing axis and opens a fluid path through the radially open region of the central tube and in the second operating position is arranged within the central tube at a second distance from the housing top part along the housing axis that is greater than the first distance and closes the fluid path through the radially open region of the central tube.

A filter system for filtering a fluid, the filter system comprising:

• a filter housing comprising a housing top part and a housing bottom part, wherein the housing top part and the housing bottom part extend along a housing axis of the filter housing;
• an outlet socket, arranged at the housing bottom part, configured to discharge the fluid after filtration;
• a central tube arranged concentrically to the housing axis in the filter housing and connected in flow communication with the outlet socket in at least one operating state, wherein the central tube, over at least a portion of an axial length of the central tube, comprises a radially open region;
• a secondary element arranged within the central tube so as to be slidable along the housing axis between at least a first operating position and a second operating position, wherein the secondary element is tubular;
• a filter element configured to be arranged in the filter housing and to separate fluid-tightly a raw fluid side from a clean fluid side, wherein the filter element comprises a filter bellows arranged about a longitudinal axis of the filter element, wherein the filter bellows comprises a first end plate at a first end face of the filter bellows and further comprises a second end plate at a second end face of the filter bellows, wherein the first and second end plates each comprise a central opening configured to receive the central tube in an interior of the filter element;
• and
• wherein the secondary element in the first operating position is arranged within the central tube at a first distance from the housing top part along the housing axis and opens a fluid path through the radially open region of the central tube and in the second operating position is arranged within the central tube at a second distance from the housing top part along the housing axis that is greater than the first distance and closes the fluid path through the radially open region of the central tube;
• and
• wherein the secondary element comprises a first sealing element and a second sealing element, wherein the first sealing element and the second sealing element are disposed at a radial outer side of the secondary element, wherein, with the secondary element at the first operating position, the first sealing element and the second sealing element are between the radial outer side of the secondary element and the central tube, and wherein, with the secondary element at the second operating position, the first sealing element is between the radial outer side of the secondary element and the central tube and the second sealing element is between the radial outer side of the secondary element and the housing bottom part.