Disposable filter unit

A disposable filter unit comprising a filter fixing member having a socket-type recess and a feed member having a front side sealingly inserted into said socket-type recess, a feed channel in said feed member and a filter element in communication with said feed channel and having at least substantially the same diameter as the socket-type recess, said filter element fixed between a ground of the socket-type recess and the front side of the feed member wherein the filter fixing member includes an outlet pipe with an outlet channel therein, said outlet pipe extending through the filter fixing member and said outlet channel communicating with the feed channel through the socket-type recess, wherein an outer peripheral edge of the feed member facing the filter fixing member and an inner edge of a side wall of the socket-type recess respectively define a pair of knife-type cutting edges together forming a cutting tool device, wherein the filter element is cut to size from a sheet-type filter material by said cutting tool device during the assembly of the feed member into the socket-type recess, said filter member thereby having a peripheral edge in contact with at least one cutting edge, and wherein an axially outer portion of the feed member is in contact with the filter member after assembly.