700 



HYDKAULICS AND ITS APPLICATIONS 



base of the column, due to the external water pressure, becomes sufficiently 

 great to force the mixture above the supply level and out of the top of the 



c. 



FIG. 340. Air Lift Pumps. 



pipe. This excess pressure increases with the depth of submersion of the 

 pipe, and the latter must therefore be regulated to suit the height to 

 which water is to be lifted. 



