The principles of colliery ventilation / [Alan Bagot].

  • Alan Charles Bagot
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: The principles of colliery ventilation / [Alan Bagot]. Source: Wellcome Collection.

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    must balance each other, or if one is lighter than the other the heavier column will descend and push the other up until equilibrium is produced, when the motion of the respective air columns will cease until further alteration takes place in the respective weights of the two columns, and it will be seen that if the difference in weight of the two columns is constant, the motion and the velocity of the whole of the air in the tube will also continue constant, and in one and the same direction. We propose treating of the furnace system first. This system is only an artificial development of the natural laws of ventilation. If air is heated under a constant pressure it expands -^-g of its volume at the temperature of zero of Fahrenheit’s thermometer; and it can easily be understood that if the mean temperature of the upcast shaft is artificially increased, the heated air becomes lighter, bulk for bulk, than that in the downcast shaft; the consequence being that the heavier air column in the downcast shaft overcomes the lighter air column in the upcast, forcing the latter up the shaft before it; and if we were to prolong the upcast shaft to an indefinite length, the top of the heated column of air would stand possibly 60 feet higher than the level of the top of the cold air column. This difference is called the e Head of Air.’ The cool air, taking the place of the heated air, passes over the furnace in its turn, and so a per-
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