Suction and exhaust device

An air supply and exhaust apparatus for blowing out air that has a specified blast pressure and that is introduced into an upper region in a specified supply air space from a supply air duct (5), as air curtain flow, to an outer circumference of a specified local region through a lower air outlet (3) that has a circumferential opening, while sucking air in the specified local region encircled by the air curtain flow, in a direction opposite to a direction in which the air is blown out, through a suction port (2a) located inside the air outlet (3) into an upper region of a suction duct (2) that is bored through a center part of the supply air space to extend outdoors, and exhausting the sucked air, characterized in that:

• the supply air space is divided by a partition plate (41) into two upper and lower chambers, i.e., an upper first supply air space (4c) introducing air from the supply air duct (5) and a second supply air space (4d) extending toward the air outlet (3);
• and
• the first and second supply air spaces (4c, 4d) are communicated with each other through annular straightening passages (40R, 50R) of small passage diameters extending vertically on an outer circumference of the suction duct (2).