Press: RareBooksClub.com (May 11, 2012)
Author Name:Engineers, North Of England
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1878 Excerpt: ...
that are needed.
This being so, it would appear to be a more important consideration in the mechanism of an anemometer that the friction should continue a constant quantity, under wear and tear, rather than that it should be reduced to a minimum at the risk of more frequent variation.
When dealing with the same air-way, as much information is conveyed by entering the number of revolutions only as by working out the precise quantity of air passing.
Hitherto, in order to test the ventilation, it has been the practice to descend the mine, and at selected places make careful measurements of the air passing, and on returning to the surface enter such observations in the ventilation report book.
At important collieries this is the daily practice, the duty being performed by a fireman, master wasteman, or other official, and necessarily occupying much time.
Indeed, at some large collieries the whole of one person's time is taken up for this purpose, and a serious expense incurred.
The " Ventilation Tell-tale," which is the subject of this paper, is an arrangement by means of which the quantities of air passing in the principal air-ways of coal and other mines, can be accurately measured at any moment in the Colliery Office, on the surface or elsewhere, without making a descent into the mine.
The system is also applicable to the measurement of the ventilation of railway tunnels and sewers.
This is effected as follows:--Having decided upon the point where the measurement of air is to be made in the mine.
A "Robinson" or "Biram" anemometer is fixed permanently and firmly to an inch-round iron bar stretched across the air-way.
The attachment is made with a small collar and screw, so that the instrument may vibrate as little as possible w...
PDF Download And Online Read: Transactions - North of England Institute of Mining and Mechanical Engineers Volume 27
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