856 



HYDRAULIC MACHINERY, FOR MINES 



This engine has one main cylinder A, resting on strong cast-iron bearers u B, fixed 

 across the shaft. The piston-rod c is a continuation of the pump-rod s, and works 

 through the cylinder bottom D. In front of the cylinder A is a smaller one E, with 

 differential diameters for the admission and emission of water, and right and left aro 

 sluice valves not shown for regulating the speed of the engine. Connected with the 

 second cylinder is a small 3-inch auxiliary cylinder F, provided with inlet and outlet 

 regulating cocks. 



In starting this engine the sluice-valves and regulating cocks are opened, the water 

 then flows from the pressure-column o, into the main cylinder A, through the nozzle 



cylinder E, and acts under the piston 

 A, until the upstroke is completed. 

 The piston i has a counter piston K, 

 of larger diameter, and when re- 

 lieved from pressure on its upper 

 surface, the water acting between 

 them forces it i\p wards, in which 

 case the pressure is cut off from the 

 main piston, and the water contained 

 in the cylinder A is free to escape 

 under the piston i, through the hole? 

 L. "With the emission of water from 

 the main cylinder through M, the 

 downstroke is effected. The down- 

 ward displacement of the pistons i 

 and K is performed by the auxiliary 

 cylinder F, and pistons N, o ; the 

 pressure-column is continually acting 

 between these pistons, and by their 

 alternate displacement by the fall- 

 ball P, and canti-arbor Q. The water 

 is either admitted or prevented from 

 operating on the upper surface of 

 the piston K. The water from the 

 top of piston K escapes through 

 the aperture R. The motion of the 

 canti-arbor Q is effected by tappets 

 fixed on the pump-rod s. 



The largest cylinder erected wag 

 35 inches diameter, stroke 10 feet, 

 pressure-column 227 feet high. Its 

 average speed was 80 feet, and maxi- 

 mum speed 140 feet per minute. The 

 pressure of water under the piston 

 was 98 Ibs. per square inch, giving 

 a total weight on its area of about 

 40 tons. The machine required no 

 personal attendance, the motion 

 being certain and continuous, as 

 long as the working parts remained 

 in order ; consequently, the cost 

 of maintaining it was of the most trifling character. 



In 1803, Trevithick erected an engine at the Alport mines, which worked con- 

 tinuously for a period of 47 years, or until 1850, when the mines ceased working. 

 The water from the pressure-columns acted on alternate sides of the main piston, by 

 means of two piston valves, displaced by a heavy tumbling beam, and tilted by a pro- 

 jection from the pump-rod. The construction and action of this machine will be best 

 understood by the accompanying illustration, fig. 1188. 



A, main cylinder ; B and c, valve pistons ; D, chain wheel, upon the axis of which 

 is fixed a lever not shown, in connection with a tumbling beam ; E, aperture through 

 which water enters from pressure-column ; F, pipe in communication with main 

 cylinder A ; and G, pipe for discharging the water admitted both above and under the 

 main piston H. The position of the valve-pistons in the woodcut shows that tho 

 pressure-column is supposed to be flowing through the holes i, upon tho piston H, 

 producing a down-stroke, and that tho water which had been introduced under this 

 piston in order to make the up-stroke is leaving through tho pipe F, holes K, and outlet 

 pipe o. 

 Accumulator and Pumping Engines. Tho applications of pressure derived from 



