University of Nevada, Las Vegas

Cornish pump

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The Cornish Pump This fabulous machine had a 36' diameter flywheel with a top walking beam of 34 tons. The main pump rod was of 16" x 16" timber built in 60 foot lengths. Some rods nearly one-half mile long weighed as much as 135,000 lbs. Power was supplied from a 85" diameter steam cylinder. The steam pressed down the piston, raisiing the main pump rod; it descended by it's own weight. It was operated by rods attached to a single beam or pump rod. The single acting condensing steam engine transmitted the motion to pump rods strung down the shaft in series at 200 foot intervals. As the piston was pulled upward, water from the sump was sucked into the piston chamber. At the end of the up stroke, weight of the water closed the chamber valve. On the down stroke, this water forced open a clack valve in the main column line, advancing the water up the colum until the clack valve closed, trapping the water. This procedure continued until the column of water was discharged 200 feet up the shaft. Such was the operation of the series of pumps attached to the one main pump rod. The Cornish Pump of 1850 has gone the way of much early mining history, yet is the father of all pumps, both for age and reputation, having operated continuously for over forty years.



Cornish pump
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