. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . Fio. 8.—Side elevation. Fig. 9.—Section. Balanced centrifugal pump. the spindle bearing from sand and grit, the packing is placed at P, inside tlio main bearingB, which acts also as a gland for compressing the packing. This arrangement is nowemployed in all the various modifications of centrifugal pumps from the authors designs, and in working permits no leak ofeither air or water, and the pack-ing seldom needs rene
. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . Fio. 8.—Side elevation. Fig. 9.—Section. Balanced centrifugal pump. the spindle bearing from sand and grit, the packing is placed at P, inside tlio main bearingB, which acts also as a gland for compressing the packing. This arrangement is nowemployed in all the various modifications of centrifugal pumps from the authors designs, and in working permits no leak ofeither air or water, and the pack-ing seldom needs renewal. Thepumps are characterized by greatsteadiness of i-unning, and anabsence of the i)ulsation or jarcommon with free or open vanes,or with shrouded wheels. Suchjar is often caused by an obtuseor imperfectly formed throat-piece at 7, especially withshrouded wheels, the radialflow being interrupted at Fig. 10.—Bulkhead pumps. Bnll-head Pumps.—\w Fig. 10 is shown a plan of a pair of centrifugal pumps arrangedfor driving the water through a bulkhead against a head varying from nothing to 10 ft. Thepumps are submerged to a sufficient depth to require no charging, and consequently no valvesare necessary. The area of the two discharge nozzles is 150 sq. in. each, and the (juantity ofwater delivered is 500,000 to gallons anhour. This arrangement is the least expensive thatcan be adopted for land drainage or irrigation ; itwas suggested by a Dutch engineer who had erectedsimilar Works in Java, and has been found in every•way satisfactory. The embankment is cut through,and a strong timber bulkhead. A, is erected acrossthe gap. The pumps, P P, are placed immediatelybehind the bulkhead, with their discharge nozzlesprojecting through it. Flap valves opening out-ward are hung over the discharge nozzles at B, toprevent back-flow through the pumps when notworking ; in dry seasons t
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Keywords: ., bookcentury1800, bookdecade189, booksubjectmechanicalengineering
