Hydraulic press

An improved invention on the principle of the Standing Press (q.v.). It is used by printers for pressing their printed work, the pressure being given by means of water instead of the lever-bar, which works the screw. The pumps and tank are fixed at the side of the press, and as they are worked, the piston is forced upwards. Some hydraulics have only one pump; but most of them have two. One pump is used at first, till the piston is raised high enough to cause a pressure, and when this becomes tight the other is applied, which increases the pressure still more. A long haudle is then placed in the first pump, which gives greater power still; and when placed on the second pump, two or three persons give their united strength till the required pressure is attained. The sheets are generally allowed to remain in the press all night; but sometimes it is necessary to fill the press twice a-day. To release the sheets, it is only necessary to turn a tap, which lets the water escape hack into the tank, and the piston is lowered in proportion as the water rims out. Its descent can be impeded instantly by fastening the tap again.