Pumps and Pumping Machinery, Parte 1E. & F.N. Spon, 1882 - 102 páginas |
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12 inches 24 inches air pump air vessel apparatus barrels BEAM ENGINES bed plate bolts bottom break-down brickwork bucket cast iron centre centrifugal pump coal connecting rods Cornish crank shaft cross head delivery pipes described ditto double double acting Drawing economy exhaust feet 6 inches feet diameter feet stroke fitted fixed flanges fly wheel FORCE PUMPS frame fuel gallons of water gear girders gun-metal high-pressure cylinder horizontal horse-power per hour inch thick inches diameter inches stroke indiarubber kind leather lever lift pumps low-pressure cylinder machinery Messrs motion Number of revolutions patent piston rod piston valve placed plungers Polder pump rods PUMPING ENGINES quantity of water revolutions per minute side slide valve slide-valve piston speed square inch steam chest steam cylinder STEAM DONKEY STEAM PUMP strokes per minute subsidiary piston suction and delivery supply surface condenser tank tubes valve boxes vertical Waterworks wrought iron
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Página 77 - ... and in that way the engine checks itself. So perfect is the action of this gear that when properly adjusted the full load may be thrown suddenly off the engine without any injury resulting. The effect of a sudden loss of load is to reverse the action of the valves, and to throw the steam against the motion of the piston, stopping it before the end of the stroke. Many instances of this have occurred in practice * ' Direct-acting Pumping Engines and Pumps,' by Henry Davey, MIME (Proceeding!
Página 77 - J, and the main valve, G, consequently receives a differential motion compounded of the separate motions given to the two ends of the lever, L. If this lever had a fixed centre of motion at the outer end, M, the steam would be cut off in the engine cylinder at a constant point in each stroke, on the closing of the...
Página 76 - G is actuated by the piston rod through a lever H working on a fixed centre, which reduces the motion to the required extent and reverses its direction. The valve spindle is not coupled direct to this lever, but to an intermediate lever L, which is jointed to the first lever H at one end ; the other end M is jointed to the...
Página 75 - ... high degrees of expansion, is capable of realising the greatest economy of fuel. The chief peculiarity in the invention is the simple manner in which the engine is made perfectly safe in working under all conditions of load, automatically...
Página 97 - ... engines it can only be ascertained by the indicator, as the load upon such engines is variable, and cannot readily be determined : but in the case of engines for pumping water, where the load is constant, the number of strokes performed by the engine represents the duty ; and a mechanism to register the number of strokes made by the engine in a given time, is a sufficient test of the engine's performance. In high pressure engines the actual power is readily ascertained by the indicator, by the...
Página 77 - K, the cut off consequently takes place at the same point in each stroke, so long as the engine continues to work at a uniform speed ; but if the speed of the engine becomes changed in consequence of a variation in the load — if, for instance, the load be reduced, causing the engine to make its stroke quicker, the subsidiary piston has not time to advance so far in its stroke before the cut off takes place, and the cut off is therefore effected sooner, as in Fig.
Página 77 - ... less resistance to encounter, moves off at a higher speed, and sooner overtakes the subsidiary piston, moving at a constant speed under the control of the cataract; the closing of the main valve G-, is consequently accelerated, causing an earlier cut off.
Página 76 - I being actuated by a third lever N, coupled at one end to the intermediate lever L and moving on a fixed centre P at the other end. The motion of the piston in the subsidiary cylinder J is controlled by a cataract cylinder...
Página 77 - Fig. 13, the engine piston having less resistance to encounter moves off at a higher speed, and sooner overtakes the subsidiary piston moving at a constant speed under the control of the cataract ; the closing of the main valve G is consequently accelerated, causing an earlier cut-off. But with a heavy load, as in Fig.
Página 76 - The engine is made to cut off steam by its motion, whilst the uniformly moving subsidiary piston is employed in admitting it. As long as the resistance to the engine is sufficient to prevent its motion becoming relatively equal to that of the subsidiary piston, steam is admitted up to the fixed point of...