316 APPLIED SCIENCE 



Where H = the distance from the level of the source of 

 supply to the point of discharge. 



A = area in square feet of surface in contact with 

 the water. 



W = weight of a cubic foot of water, or 62. 5 Ibs. 



EXAMPLE. What is the pull on a pump rod, when the diameter of 

 a bucket is 6 in. and water is raised 20 ft.? 



6 2 X 7854 



P = HAW = 20 X X 62.5 = 245.437 Ibs. 



144 



From the above solution we find that the pull on the pump rod is 

 245.437 Ibs. ; to this must be added the amount of power necessary 

 to overcome friction. 



357. Measurement of Water Cylinder Contents. To find 

 the cubical contents of a water cylinder per stroke, in cubic 

 inches, multiply the area of the piston in square inches by the 

 length of stroke in inches. To find the contents in gallons 

 divide this product by 231, and to find it in cubic feet divide 

 the product by 1728. 



EXAMPLE. What is the capacity per hour of a single-action pump 

 with a water piston 6 in. in diameter and a 10-in. stroke, when the 

 piston makes 60 strokes per minute? 



If the water cylinder is filled at each stroke, the contents are 

 AXL = (6X6X .7854) X 10 = 28.274 X 10 = 282.74 cu. in. 



At 60 strokes per minute there will be 60 X 60 = 3600 strokes per 

 hour. If the piston pumps 282.74 cu. in. per stroke, then for one 

 hour it will pump 



282.74 X 3600 = 1,017,864 cu. in. per hour 

 or 1,017,864 + 1728 = 589 cu. ft. per hour 



or 1,017,864 + 231 = 4406.33 gal. per hour 



To find the H. P. required to pump water to a given height, 

 multiply the weight in pounds of water to be raised per minute 



