A ventilator has incorporated in a main body thereof an air blower having a ventilation casing provided with a fan intake opening facing an intake opening of the main body of the ventilator, the inner side of the main body being opened to form the intake opening thereof. A cylindrical soundproof unit including an inner ventilation passage having a larger ventilation area than a fan intake space and formed of a laminated plate which is formed of a plurality of air layers arranged in a direction intersecting the rotation axis of the air blower from the inner ventilation passage, is disposed in a space between the fan intake opening and the intake opening of the main body. The soundproof unit makes it possible to decrease noise generated by the air blower while the ventilation resistance is hardly increased.

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Air ventilators: Air ventilation is the process of supplying fresh air to an enclosed space and removing from it the air, contaminated by odors, gases, or smoke. Ventilation may be produced by any combination of natural or mechanical supply and exhaust. Such systems may include partial treatment such as heating, humidity control, filtering or purification, and, in some cases, evaporative cooling. More complete treatment of the air is generally called air conditioning. Mechanical supply ventilation may be of the central type consisting of a central fan system with distributing ducts serving a large space or a number of spaces. Outside air is needed in controlled quantities to remove odors and to replace the air, exhausted from the various building spaces and equipment. Natural ventilation may be provided by wind force, convection, or a combination of both. Exhaust ventilation is required to remove odors, fumes, dust, and heat from an enclosed occupied space and to maintain hygiene.