COST OF WATER 



IS9 



When Y represents horse power required 



g represents gallons of water per minute 

 h represents height of elevation, measured from the 

 surface of water in well to the highest point to which the water 

 is raised. 



f represents the friction head in the water pipes. 

 Example : 



Determine the theoretical horse power required to pump 

 12,000 gallons of water per hour through a 4-inch pipe 200 feet 

 long, the water being raised 100 feet. 

 Answer: 



The friction head 1 is 1.22 X 2.3 = 2.8 for a pipe 100 feet long. 

 For a pipe 200 feet long f= 2.8X 2 = 5.6 



IS*. X 8.35 X (IOQ+ 5-6) 



Y = ~ 5-34 ** * 



33,000 



As the efficiency of small pumps usually ranges from 60 to 45 

 the theoretical horse power should be doubled when applying 

 it to practical work. For large pumps a higher efficiency is 

 obtained. 



The following table gives the friction loss in pounds pressure 

 per square inch for each 100 feet of length in different size clean 

 iron pipes discharging given quantities of water per minute. 

 This friction loss is greatly increased by bends or irregularities 

 in the pipe. 



To find " friction head" in feet multiply figures by 2.3 



i Table VII. 



