HYDRAULICS. 



161 



For irhat other 

 purposes than 

 raising water 

 is the chain- 

 pump used ? 



■^^^latisan Hy 

 draulic Kam? 



Describe the 

 construction of 

 the Hydraulic 

 Kam. 



This machine i.s not, however, used exclusively for raising 

 water. Its application, in principle, may be seen in any grist- 

 mill, where it conveys the flour discharged from the stones, 

 to an upper part of the building, where it is bolted. Dredg- 

 ing machines for elevating mud from the bottom of rivers, are 

 also constructed on the same principle. 



361. The Hydraulic Ram is a niacliine 

 constructed to raise water by taking advantage 

 of the imijulse, or momentum, of a current of water sud- 

 denly stopped in its course, and made to act in another 

 direction. 



The simplest construction of the hydraulic ram is repre- 

 sented in Fig. 153, and its operation is aa follows: — At the 

 end of a pipe, B, connected with a spring, or reservoir, A, 

 somewhat elevated, from which a supply of water is derived, 

 is a valve, E, of such weight as just to fall when the water is quiet, or still, 

 Fig. 153. within the pipe; this pipe is con» 



nected with an air-chamber, D, 

 from which the main pipe, F, leads ; 



1^J^ this air-chamber is provided with 



I ^^^ a valve opening upward, as shown 



i iflA in the cut. Suppose now, the 



water being still within the tube 

 the valve E to open by its own 

 weight; immediately the stream 

 begins to run, and the water flow- 

 ing through B soon acquires a 

 momentum, or force, sufBcient to 

 raise the valve E up against its seat. The water, being thus .suddenly ar- 

 rested in its passage, would by its momentum burst the pipe, were it not for 

 the other valve in the air-chamber, D, which is pressed upward, and allows 

 the water to escape into the air-chamber, D. The air contained in the 

 chamber D is condensed by the sudden influx of the water, but immediately 

 reacting by means of its elasticity, forces a portion of the water up into the 

 tube F. 



As soon as the water in the pipe B is brought to a state of rest, the valve 

 of the air-chamber closes, and the valve E falls down or opens ; again the 

 6tream commences running, and soon acquires sufRcient force to shut the 

 valve E ; a new portion is then, by the momentum of the stream, urged into 

 the air-chamber and up the pipeF; and by a continuance of this action, 

 water will be continually elevated in the pipe F. 



Fig. 154 represents a more improved construction of the ram, in which by 

 the use of two air-chambers, C and F, the force of the machine is greatly in« 

 creased. A represents tlie main pipe, B the valvo from whence the water 

 escapes, G the pipe m which it is elevated. 



