Backflow-preventing filter module

A backflow-preventing filter module adapted to be connected to a lid, the lid having a lid body that has an inlet and an outlet, an inlet groove that is in fluid communication with the inlet for connection with a raw water source, a positioning groove that is in fluid communication with and disposed downstream of the inlet groove, and an outlet groove that is disposed downstream of the positioning groove and that interconnects the positioning groove and the outlet for outlet of filtered water therethrough, said backflow-preventing filter module comprising:

• a filter unit including
• a filter cartridge that has
• a connector adapted to be connected to the lid body, and having an internal space that is adapted to be in fluid communication with the outlet groove,
• a filtering member adapted for filtering and purifying water, and defining a filtering space that is in fluid communication with said internal space of said connector, and
• an annular groove formed in said connector, and
• a filter shell that encloses said filter cartridge and that defines an accommodating space accommodating said filter cartridge, said filter shell including a shell body and an connecting head that is disposed at a top of said shell body and that is adapted to be inserted fixedly into the positioning groove, said connecting head having an inner surrounding wall that defines an annular slot surrounding an axis, said annular slot having a lower opening that is in fluid communication with said accommodating space, and an upper opening that is disposed at a top of said connecting head and that is adapted to be in fluid communication with the inlet groove;
• and
• a backflow-prevention valve sleeved on said connector and having
• a fixing portion that is disposed in said annular groove, and
• an abutting portion that extends outwardly from said fixing portion towards said accommodating space, and that is movable between an open position and a closed position;
• wherein, when said abutting portion is in the open position, a distal end of said abutting portion opposite to said fixing portion is pushed by water, which flows from the inlet groove, to be away from said inner surrounding wall, so that said annular slot is not blocked;
• and
• wherein, when said abutting portion is in the closed position, said abutting portion is expanded to abut said distal end thereof against said inner surrounding wall, thereby blocking said annular slot.