HUMIDIFIER

A humidifier having a housing that extends along an axial direction, the housing having a first inlet, a first outlet, a second inlet and a second outlet, and a membrane unit being arranged in the interior of the housing. The first inlet and the first outlet are in flow connection with each other by means of a first flow path, and the second inlet and the second outlet are in flow connection with each other by a second flow path. The membrane unit is cylindrical and has a plurality of hollow fiber membranes arranged side by side. The membrane unit is outwardly surrounded at least in part by a first chamber, and the first chamber is outwardly surrounded at least in part by a second chamber separate from the first chamber. The first chamber and the second chamber are in flow connection with each other via one or more throttle slots.