724 



HYDRAULICS AND ITS APPLICATIONS 



ART. 194. THE HYDRAULIC INTENSIFIER. 



Where the main pressure supply is of less intensity than is required to 

 work the hydraulic machinery an intensifier is used. In its simplest 

 form, this consists of a ram of area a, carrying a piston of larger area A 

 (Fig. 347). Water from the pressure mains, at pressure p, is admitted 



behind the piston and com- 

 presses the water in the ram 

 cylinder to an increased pres- 



Pressure Water 

 Outlet 



sure P where P = p . 

 a 



EXAMPLE. 



p = 40 Ibs. per square inch, 

 Piston diameter = 48 inches. 

 Ram diameter 8 inches. 



.'. P = 40X 36 = 1,440 Ibs. 

 per square inch. 



This neglects the friction of 

 the packings, and also the 

 weight of the ram and piston. 

 Including these we have 



p A (ir + F) = P a 



A w 4- F .. 



. . P = p - Ibs. 



a a 



per square inch. Where w = 

 weight of ram and piston in 

 Ibs. F = f rictional resistance 

 in Ibs. 



If on the down stroke communication be made between the under side 

 of the piston and the upper side of the ram, the pressure p' below the 

 piston becomes 



w F 



fro/n Supply Mains 



FIG. 347. Hydraulic Pressure Intensifier. 



P = 



A -a 



Ibs. per square inch. 



Various modifications of this type of intensifier are in use, one of tl 

 being illustrated in Fig. 348. Here low pressure water is admitted ] 

 above the hollow ram A, while the intensified water is led away throuj 

 the small stationary ram of area a. 



