Practical sanitation; a handbook for sanitary inspectors and others;with apxon Sanitary law, by Herbert Manley . rocess of cooling, be so increased as to overcome theupward tendency of the warmer, and, therefore, lighter air below VENTILATION AND WARMING. 51 and thus the shaft in question may cease to act as a tendency to down-draught in damp weather in the case of achimney of a fire-place, which for some time has not had a firein it, is a familiar example of the effect of the process justdescribed; and if such may occur, notwithstanding the presenceof a fire to encourage the dr
Practical sanitation; a handbook for sanitary inspectors and others;with apxon Sanitary law, by Herbert Manley . rocess of cooling, be so increased as to overcome theupward tendency of the warmer, and, therefore, lighter air below VENTILATION AND WARMING. 51 and thus the shaft in question may cease to act as a tendency to down-draught in damp weather in the case of achimney of a fire-place, which for some time has not had a firein it, is a familiar example of the effect of the process justdescribed; and if such may occur, notwithstanding the presenceof a fire to encourage the draught, still more must it do so undersimilar circumstances in the case of a ventilating shaft which isnot artificially warmed. 2. The aspirating effect of the wind on the air of an uprightshaft is considerable, irrespective of any apparatus, but it isclaimed for the various extractors (as their name implies),that they assist this natural tendency; experiment, however,does not fully support this claim. 3. No doubt cowls are to a certain extent preventers of down-draught, the result of downward gusts of View from room. View from chimney. Fig. 11. From what has teen said, it will be understood that cowls donot exercise any very wonderful power, but simply aid to acertain extent, the natural upward current that takes placethrough a shaft which communicates with a room, the tempera-ture of which is higher than that outside. The Chimney, which in itself is a powerful extractor, may beutilised as an outlet for air on a level with the ceiling, by tappingit at that point, and introducing a form of ventilator which willallow of the passage of air from the room without permitting areverse current. BoyleS Mica-flap Ventilator, which is represented in theaccompanying sketch (Fig. 11) is designed for this is almost entirely prevented by means of valvesin the shape of thin talc plates suspended on cross-bars behindan iron-grating ; these move backwards by reason of
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectsanitat, bookyear1904
