Patent ID: 9700819
Date: 2017-07-11
CPC Classifications: B01D,F01M

Claim:
1. A liquid filter comprising: a filter housing having a removable screw cover, a raw liquid inlet and a clean liquid outlet, a filter insert situated exchangeably in the filter housing and separating a raw side and a clean side of the liquid filter from one another, the filter housing further having a central discharge duct for emptying the filter housing when the filter insert is removed, a closing pin that is fixed to the housing in an installed state and that has at least one radially sealing seal in a sealing seat in the discharge duct being capable of being axially displaced between a lower, closed position, assumed when the filter insert is installed and the screw cover is closed, and an upper, open position, assumed when the screw cover is removed and the filter insert is removed, and mechanical, releasable coupling elements located on at least one of the screw cover or the filter insert and on the closing pin, the coupling elements on the closing pin and corresponding coupling elements on at least one of the screw cover or the filter insert being configured to enter into an engagement that transmits a torque and a thrust force upon the closing pin through a fastening direction of rotation of the screw cover, the coupling elements on the closing pin and corresponding coupling elements on at least one of the screw cover or the filter insert being configured to enter into an engagement that transmits a torque and a tensile force upon the closing pin through a release direction of rotation of the screw cover, as least as long as the seal is situated in the sealing seat so as to exert a braking moment on the closing pin, and the coupling elements on the closing pin and corresponding coupling elements on at least one of the screw cover or the filter insert being configured to automatically move out of engagement when the seal is moved out of the sealing seat, and as a result, the closing pin is freely capable of rotation about its longitudinal axis.