ACCU'MULA'TORS. Apparatus for equal izing pressure or for the accumulation of energy for intermittent use. The storage battery' and the Leyden jar are electrical atecumulalors. (See SW/RACE BATTERY CONDENSER.) Hydraulic ac cumulators are extensively used in connection with hydraulic machinery for operating cranes, punching and riveting machines, presses, etc. The simplest way of storing up water for pres sure purposes is to erect a tank at a sufficient height to give the required pressure by the weight or head of the water column alone. This arrangement is generally adopted for hydraulic elevators in warehouses and lofty buildings. (See EhEvvrous.) Where very high pressures are required, however, it becomes impracticable to adopt a tank or water tower, since the elevation required to give the necessary pressure would be impracticable to obtain, 700 pounds pressure, for instance, requiring a tank I1110 feet high. In such eases accumulators are employed, and they generally assume the form of a vertical cylinder resting on a firm base and having a pillager working through a stuffing-box at the top. This plunger has at its upper end a yoke which carries by means of suspension rids a heavy weight of east iron or other heavy mate rial. A power pump forces water into the cyl
inder at a pressure suffieient to lift the weighted plunger to the top of the cylinder, where the plunger strikes a stop which prevents its rising further and prevents the further escape of water from the pump. In this position the cylinder is tilled with a column of water, which supports the weighted plunger on its top. As water is drawn from the cylinder to supply the crane. press. riveter. or other machinery, the weighted plunger descends, always keeping a pressure on the top of the Water col lllll n equal to the tour hived weight of the plunger and its load. As soon as the plunger descends the pump resumes work and raises it again. Ity this vombination of operations the water pressure is always kept constant for supplying the hydraulic machinery. Soinetime, steam or air pressure acting oar the top of the plunger is substituted for the more common suspended weights. Hydraulic accumu lators are built to give pressures ranging from fire pounds to ten tons per square inch.