THE COST OF PUMPING.
From a paper recently read by Charles Hawksley and Henry Davey, Technical Engineering makes the following extracts: For public water supply, the drainage of mines and land, and certain other purposes, the power required is generally considerable and continuous, and it is to those applications that we propose to direct attention. In such operations the cost of fuel per pump horsepower is the most important item. The best waterworks and mining engines of today give 1 P. HP. with 12 lbs. to 20 lbs. of steam, depending on the nature of the engine and its application. The mechanical efficiency of the steam engine and pump combined varies from eighty to eighty-six per cent. The steam consumption is 10.5 lbs. to 16 lbs. per indicated horsepower-hour, being as low as that of any high-speed or other steam engine used to produce electrict current. The comparison, then, of the steam pumping engine with electric pumping plant, as regards fuel, becomes reduced to a question of the comparative mechanical efficiencies of the two systems, expressed in terms of pump horsepower. Thus:
Per Cent.
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