The Mechanical Engineering of Collieries"Colliery Guardian" Office, 1882 |
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allow appliances arrangement average balance rope blades bottom cage capstan cast iron centrifugal chimney circumference Clay Cross coal coils colliery Cornish crank crank pin cubic feet cylinder diagram diameter drum effect efficient engine house engineman exhaust feet per minute Figures illustrating Chapter flat ropes flues friction fuel furnace gearing give Guibal headgear pulley heat horizontal horse-power joints Lancashire boiler LENOX AND TILDEN less load machinery Mechanical Engineers mechanical ventilation mining Monkwearmouth output passing Pedestals pillars pipes pit bank placed pressure of steam PUBLIC LIBRARY ASTOR pumping railway revolutions revolutions per minute riveted rods round ropes Schiele Screen Bars screw shown in fig side slack steel strain strength stroke surface TILDEN FOUNDATIONS timber tips tons tubs underground velocity ventilating machine vertical wagons water gauge weight whilst winding engines winding rope Wire Conductors writer wrought iron yards YORK PUBLIC LIBRARY
Popular passages
Page 157 - Every body continues in its state of rest, or of uniform motion in a straight line, except in so far as it may be compelled by impressed forces to change that state.
Page 167 - A cylinder about an inch diameter, and six inches long, exceedingly truly bored, has a solid piston accurately fitted to it, so as to slide easy by the help of some oil; the stem of the piston is guided in the direction of the axis of the cylinder, so that it may not be subject to jam or cause friction in any part of its motion. The bottom of this cylinder has a cock and small pipe joined to it, which, having a conical end, may be inserted...
Page 145 - ... is greatly increased, and the quantity of air delivered is by this means very much augmented in proportion to the quantity of steam employed ; also the great extent of surface contact tends to diminish eddies.
Page 144 - ... the difference in the velocity of the two currents at the point where they come together is much reduced, and in consequence the eddies which previously impaired the efficiency of the steam jet are to a great extent obviated, and a higher useful result is realised.
Page 158 - The general result arrived at by the investigation in this paper* was, that centrifugal action is not an economical mode of applying power for raising water, and that the theoretical limit to the useful effect to be obtained by centrifugal action alone, is 50 per cent, of the power employed, — a loss of 50 per cent, of the power being caused by the absorption of power in the tangential velocity given to the water ; whilst the radial or centrifugal velocity alone is effective in raising the water....
Page 189 - Allowing the last heat however to travel under the bottom of the shell does not promote the circulation of the water, or at all events but slowly ; so that in getting up steam the top of the boiler becomes hotter than the bottom, from which straining ensues. If in addition to this, the feed water when cold be pumped in at or near the bottom of the boiler, the straining at the transverse seams of rivets is intensified. Possibly the Lancashire boiler is...
Page 33 - With a Pair of Direct-Acting Engines.— Assume the piston to travel at an average velocity of 400 ft. per minute, and divide this by twice the length of the stroke, and multiply by the circumference of the drum. This gives the speed of cage in feet per minute. Divide the depth of shaft by this, and the result will be the period of winding. EXAMPLE.— Drum, 31.416 ft.
Page 112 - Ib. of coal per sq. ft. of firegrate per hour. These results were obtained at atmospheric pressure, with the help of a water heater, with good round coal a'nd without making smoke. The boiler described in this paper, having furnaces 2 ft. 9 in. diameter, would evaporate a larger quantity of water per hour. Such a boiler is found in practice to be capable, provided the steam be applied to a fairly economical engine, of developing 200 Ind. HP, and 20 Ind. HP per...
Page 163 - The object of this is to give a uniformly-increasing space beyond the tips of the fan blades, from nothing up to the full area of the discharging aperture.
Page 145 - ... as large as possible, for "the quantity of air delivered per minute by a steam jet depends upon the surface of contact between the air and the steam, irrespective of the steam pressure, up to the limit of exhaustion or compression that the steam jet is capable of producing.