Membrane element for humidifier and humidifier

A humidifier for a fuel cell system, the humidifier comprising:

• a housing comprising:
• an inlet for a first fluid;
• an inlet for a second fluid;
• an outlet for the first fluid;
• and
• an outlet for the second fluid;
• a membrane element comprising:
• a membrane media bellows being zigzag-pleated and comprising a membrane media that is moisture permeable but gas impermeable, the membrane media bellows extending at least partially in a circumferential direction about a longitudinal axis, the membrane media bellows further comprising pleats extending essentially parallel to the longitudinal axis, and the membrane media bellows further comprising inner pleat folds at an inner circumference and outer pleat folds at an outer circumference;
• a support body comprising a hollow body and an outer wall arranged at the inner circumference of the membrane media bellows, the support body further comprising a support body inlet at one end and a support body outlet at an opposing end, the outer wall of the support body comprising fluid-permeable passages arranged circumferentially through the outer wall at each end of the support body;
• and
• a bypass valve integrated into the support body, the bypass valve being for selectively blocking and unblocking a fluid passage through the support body,
• wherein the membrane element is arranged inside the housing, at least parts of the outer circumference of the membrane media bellows being fluidly connected to the inlet for the second fluid and the outlet for the second fluid, the support body inlet being fluidly connected to the inlet for the first fluid, and the support body outlet being fluidly connected to the outlet for the first fluid;
• and
• an actuator connected to the bypass valve and for activating the bypass valve depending on at least one operating parameter of the humidifier.