CHAPTER XX. 



The Hydraulic Transmission of Energy Accumulators Intensifiers Friction of Leather 

 Collars for Rams Water Meters. 



ART. 192. THE HYDRAULIC TRANSMISSION OF ENERGY. 



SINCE water is virtually incompressible, if one end of an enclosed column 

 be exposed to the pressure of a moving ram the energy of this will be directly 

 transferred to the other end, the only loss of energy being due to pipe 

 friction. With water of a given pressure intensity, the energy trans- 

 mitted varies directly as the volume of water flowing per second, and 

 hence as the velocity of flow, while with a given velocity the energy varies 

 directly as the pressure. 



It follows, that as the loss due to friction increases as the square of 

 the velocity, the proportional effect of this will diminish as the working 

 pressure increases, and for high efficiency of transmission the working 

 pressure is of necessity high. 



In many instances the use ,of water under considerable pressure as 

 a medium for the transmission of energy from a central power station 

 to a private consumer offers decided advantages over other methods of 

 power transmission, and this is particularly the case where the power 

 is required to operate machinery in which the action is either 



(a) Comparatively slow, but in which a considerable force is required, 

 and particularly where the motion is to be regulated with great precision ; 



(b) Largely continuous in one direction and in which frequent reversals 

 of motion are not necessary ; or 



(c) Very intermittent, a large force being required at intervals and for 

 a comparatively short time. 



It is thus well adapted for the operation of presses, flanging and riveting 

 machinery, lifts, hoists, cranes and testing machines. 



The state of high efficiency to which the transmission and utilization 

 of energy in this form have attained is largely due to Lord Armstrong, 

 who was probably the first to develop the use of high pressure energy, 

 and who evolved the many details necessary to make the system a 

 practical success. 



In many large towns, of which London, Manchester and Glasgow are 





