Patent ID: 7297282

Claim:
A drain mechanism of a fluid filter comprising: a cap engaged with a case and having a drain hole; a drain member detachably mounted to said cap from an outer side thereof and closing said drain hole; a valve member provided in an inner side of said cap and closing said drain hole; and an elastic means for energizing said valve member in a direction of closing said drain hole; wherein a closure of said drain hole achieved by said valve member is cancelled by displacing said valve member against the energizing force of said elastic means by means of a tubular draining jig having an axial end inserted to said drain hole, in a state in which said drain member is detached from said cap, a plurality of slits notched from the axial end of said draining jig and an engaging portion having an outward bulged shape are provided in the axial end of said draining jig, an engaged portion which said engaging portion is allowed to be engaged with and disengaged from with an elastic deformation generated by said slits is provided in an inner side of said cap, wherein said engaged portion does not move with said valve member, and a seal member attached to a bottom portion of said cap so as to surround said drain hole, wherein said drain member has a flange portion which is in contact with said seal member in a state in which said drain member is mounted to said cap.