The invention relates to a supply device (1, 51, 81, 101) for supplying breathable air to a breathable air region (2, 52, 82) which is at least partially open to the surroundings. Said supply device comprises means for generating a flow of air (3, 53, 83) for supplying breathable air to the breathable air region (2, 52, 82). Said supply device (1, 51, 81, 101) also comprises means for generating at least one shielding air flow (4, 5, 54, 84) which shields the breathable air flow (2, 52, 82) at least partially with respect to the surroundings.