Directional Control for Ventilation
Page 67
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FOR some years the Punkah Louvre has been employed for ventilating the cabins of passenger ships. It consists of a nozzle arranged in a ball, so that by moving the ball in its socket the direction of the air stream issuing from the louvre may be controlled. Many modern ships are equipped with Punkah Louvre ventilation in place of the electric fans that were hitherto employed; fans frequently go wrong and, as normally applied, they stir up the atmosphere instead of introducing fresh air. Without some sort of directional control, the introduction of fresh air into cabins, which are generally small, is apt to cause annoyance to the occupants. The Punkah Louvre overcomes this difficulty, and on ships it is used in conjunction with quite an extensive system of air ducts, these conveying fresh air to each of the many cabins.
It will he seen that the Punkah Louvre has possibilities in connection with the ventilation of public-service vehicles, and for this reason Thermotank, Ltd., 150, Helen Street, Govan, Glasgow, is now turning its attention closely to this problem.
In addition to exhausting foul air from the closed saloons of buses and motor coaches, it is generally found necessary to introduce a positive supply of fresh air, and many methods of meeting this requirement are available. The advantage which the Punkah Louvre has over many such methods lies in the directional control of the air stream to
suit the wishes of the passengers. It is possible to incorporate in its design a scientific diffuser, although for air streams in the horizontal plane this would probably not be required. The Punkah Louvres may be fitted in the front bulkheads or in the roof.
An interesting development of the system is seen in the Thermo-Reg Louvre. This incorporates a device for delivering the air from either or both of two duets connected to it, so that, if one duct be receiving a supply of cold air and the other a supply of air through a radiator, the passenger is able to control not only the volume and direction of the air admitted, but also its temperature. This is done in a simple way, by rotating the Louvre.