Spray device in which the water spray from a water chamber (8) is supplied to the spray head (16) by cylindrical tubes (12) inducing a head loss. The water from the tubes (12) is guided by tubes (13) into a V-shaped water outlet channel (18) forming a continuous slot (19). Water ejection means (7) are mounted on either side of the slot and in the air conduits (3, 4); said water ejection means (7) are formed by vanes (21) in which the flow of spray water is guided perpendicularly to the surface of the item to be treated. Said vanes, which are segment-shaped, are placed end to end along the length of the slot and form converging conduits for the air, ending in rectangular slot openings. A second embodiment is given for a vertical-jet spray.