THE HYDRAULIC FORGING PRESS 



769 



with pressure water at 600 atmospheres. By using each cylinder 

 separately, or the two in combination, three powers having the ratio 1 : 

 2 : 3 may be obtained, the effective force varying from 1,300 tons with 

 the small ram to 4,040 tons with the two in combination. Two lifting 

 cylinders, using water at 50 atmospheres pressure, exert a constant upward 



Supply at 600 Atmospheres 



Supply ai GQQAtmospheres- 



FIG. 382. Cylinders of 3-power Hydraulic Forging Press for a maximum 

 effort of 4,000 tons. 



force of 70 tons, which has been taken into account in obtaining the 

 above values. 



As, during the working portion of the stroke of a hydraulic press or 

 similar machine, the ram velocity is required to be only very slow, the 

 diameters of the supply pipes may be very small without appreciable loss 

 of head. A ratio of ram diameter to pipe diameter of about 12 to 1 is 

 usually adopted. 



H.A. 



3 D 



