. Machinery for metalliferous mines : a practical treatise for mining engineers, metallurgists and managers of mines. INES. the position shown in the illustration, the cylinder (a) will be in com-munication with the atmosphere through the ports (;;;, / and /i). Theresult of this will be that the piston is forced forward, and, immediatelythe piston (c) uncovers the small port (d), a portion of the compressedair passes into the small cylinder (r) behind the valve (e); and actingon a larger area than that which is subject to the constant pressure at/, and the fact that there is no resistance at t
. Machinery for metalliferous mines : a practical treatise for mining engineers, metallurgists and managers of mines. INES. the position shown in the illustration, the cylinder (a) will be in com-munication with the atmosphere through the ports (;;;, / and /i). Theresult of this will be that the piston is forced forward, and, immediatelythe piston (c) uncovers the small port (d), a portion of the compressedair passes into the small cylinder (r) behind the valve (e); and actingon a larger area than that which is subject to the constant pressure at/, and the fact that there is no resistance at the other end of the valve(c) owing to the passage (;/) communicating with the atmosphere, forcesthe valve (c) over to the other end of the valve chest, thereby cuttingoff the communication with the air under pressure, and placing thecylinders (a and a) in communication through the ports {/ and 7/1).Then the air that has acted on the piston {c) now passes into the cylinder{a) where it acts on the piston (4^) of larger area than the piston (c) there-by moving the piston backwards to its original position. When the. Fig. 115.—Section of the Optimus Compound Rock Drill. piston (r) during its backward stroke passes the port (d) the cylinder (r)is placed in communication with the atmosphere through the ports (dand /i) and the constant pressure acting on the piston valve (e) at /moves the said valve over to the position as shown in the illustration,the air again enters the cylinder (a) and the action is repeated. It will be seen that the air used for the forward stroke is againutilised for the backward stroke without in any way impeding the pistonin its forward stroke, and this, as well as the shortness of the port {/>),causes a great saving of motive fluid. The air being instantaneouslyadmitted to the cylinder (d) while the cylinder (a) is in free communica-tion with the outlet, causes the piston to give a very powerful blow,which makes this machine more effective than any other
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyo, bookyear1902
