Securing Constant Air Circulation Without Draughts
Page 33
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A New-type Ventilator for Passengervehicle Interiors' and Goods-vehicle Cabs Which Ensures a Free Circulation of Fresh Air
IT is not a difficult matter _to arrange for the extraction of vitiated air from, say, a driver's cab, but it is another matter to ensure that the air which enters to replace that extracted is clean. What usually happens is that the incoming air finds its way in via floorboards or other imperfect‘ joints, the result being the promotion of uncomfortable air currents and a general disturbance of the dust and dirt within the compartment.
The ideal system is one in which the means for ventilation not only are responsible for extracting the contaminated air, but also ensure that the incoming air is clean and its entry is via a controllable source.
The Colt ventilator, which " is made by W. H. Colt (London), Ltd., Surbiton, Surrey, is claimed to perform this dual function, and although we cannot confirm this from practical experience, we have seen static tests which fully bear out the theory. Considerable work with ventilators embodying the same principle has been carried out by the concern both in the industrial field and in connection with the ventilating of ships at sea. Its application, therefore, to commercialvehicle cabs, van bodies carrying food4tuffs, and passenger vehicles is a natural one.
Whilst the Colt ventilator is claimed to perform the functions mentioned, it is designed so as to exclude the entry of rain or mist into the compartment being ventilated. Another interesting feature is that the air change goes on while a vehicle is stationary and irrespective of the direction of the wind.
The accompanying drawing will make clear how the foregoing results are achieved. The oncoming air strikes a number of V-shaped baffles which direct it on to semicircular baffles guarding the passage into the cab or other compartment. Any moisture which may be carried over with the air finds an exit from a suitably positioned drainhole, as shown. A simple means for regulating the supply is provided by a revolving panel or butterfly, which can be secured by wing nuts. The method of fixing is quite simple, it being necessary only to cut a suitable aperture in the cab or body roof, any variation in the thickness of which isaccommodated by making the lower portion of the ventilator extensible.
When there is any decided curvature in the roof. correctly shaped inserts, made of cork, are used, as the base of the ventilator is flat.
In the case of the driver's compartment of a passenger vehicle, where there may be no suitable place, immediately above the driver, to fit the device, it would probably be introduced on the near side. However, this is a point that can readily be settled following an inspection of the type and class of vehicle.
It will be noted from the drawing that there are no moving parts, so that, when once fitted, it can be forgotten so far as maintenance is concerned.
Like so many other products, the Colt ventilator was produced primarily as a war-time necessity, but its postwar application to road-transport vehicles should form a useful contribution to driver and passenger comfort and to the more hygienic conveyance of foodstuffs in closed van bodies. We should say, too, that such a device would be of great value in the case of ambulance bodies.