To drain the water accumulated in a water purifier by setting a drain valve disc in the hose connected to the water discharge part taking out the water purified by the purifying filter material in an outer cylinder.
When tap water is allowed to flow in a water purifier, the interior of the water purifier is held to a pressurized state by water pressure and both of an air intake valve 20 and a residual water drain valve 30 are cut off so as to be isolated from the communication with the outside. Therefore, tap water is treated according to the regular route in the water purifier to be supplied. When the supply of tap water to the water purifier is cut off, water pressure is not applied to the interior of the water purifier and, therefore, both of the air intake valve 20 and the residual water drain valve 30 are opened to communicate with the outside. Herein, the whole of the water in the water purifier flows out of the residual water drain valve 30 and, since no water remains in the water purifier, the propagation of bacteria or the like in the water purifier is not generated.
INOUE KANJI
NEGISHI KOICHI
