Filter unit and valve for a fuel supply system

Disclosed is a valve (49) that is inserted into the conduit connecting a fuel pump to a system of injection valves and is embodied as a pressure-maintaining valve. Said valve (49) is characterized by a flow-through pipe element (50) into which a sleeve (53) is inserted that forms a damping cylinder (55) in a central area thereof. One end of a blocking element (57) is accommodated inside said damping cylinder (55) so as to be slidable in the direction of the axis (58) of the pipe element (50). The opposite end of the blocking element (57) is characterized by a sealing member (67) that is made of an elastomer material and cooperates with a valve seat (66) to which a continuous bore (65) of a transversal wall (63) of the pipe element (50) is assigned. The blocking element (57) rests against said valve seat in a spring-biased manner while being moved in a damped fashion or such that the least possible amount of noise is created as a result of the cooperation thereof with the damping cylinder. The inventive valve (49) is particularly suitable for establishing a reliable sealing function in the area of the valve seat (66) and thus performing a pressure-maintaining function in said conduit of a fuel supply system.