Pumping World News Blog

Determining the Capacity of a Pump

Posted by Elizabeth Kaiser on Wed, Aug 22, 2012 @ 08:08 AM

Whether you are flood irrigating, flooding a duck pond, or just determining your pump capacity, it is good to know the measure of your pumping performance.  Below is a table of estimated performance for Crisafulli pumps.

Number of Acres Covered in Twelve Hours Pumping

GPM cu ft/sec. cu ft/sec. 1"
deep
2"
deep
3"
deep
4"
deep
6"
deep
8"
deep
10"
deep
12"
deep
20 .05 2.68 .53 .27 .18 .13 .09 .66 .05 .04
60 .11 6.68 1.33 .66 .44 .33 .22 .17 .13 .11
100 .22 13.4 2.65 1.33 .88 .66 .44 .33 .27 .22
160 .34 20.1 3.98 1.99 1.33 1.0 .66 .50 .40 .33
220 .50 30.1 5.97 2.99 1.99 1.5 .99 .75 .60 .50
300 .67 40.0 7.96 3.98 2.67 2.0 1.33 1.0 .80 .66
400 .90 53.4 10.6 5.31 3.54 1.78 1.77 1.33 1.1 .08
700 1.6 93.5 18.6 9.28 6.18 3.1 3.1 2.32 1.9 1.5
900 2.0 120.4 23.9 11.95 7.96 6.0 4.0 3.0 2.4 2.0
1200 2.7 160.5 31.8 16.0 10.6 8.0 5.3 4.0 3.2 2.7
3000 6.7 400.5 79.5 39.75 26.5 20.0 13.3 10.0 8.0 6.6
10000 22.3 1337.0 265.0 132.5 88.3 66.3 44.2 33.2 26.5 22.1

BY HORIZONTAL OPEN DISCHARGE METHOD
12274 DETERMINING THE CAPAC


To estimate the pumping capacity of any given unit, construct an L-shaped measuring instrument similar to the one shown in the sketch.  The shorter side should be 4" long.  The longer side may be any convenient length marked in inches.  With the water flowing from the horizontal open discharge, place the long side of the L along the top of the discharge pipe, allowing the shorter side to hang downward as shown in the drawing.  Slide the L along the pipe until the 4" length barely touches the flow of water.  Note the distance travelled ("X") by the flow of water before it drops 4".  Presume, for example, that the distance travelled is 15" and the inside diameter of the pipe is 3".  Consulting the table below, locate 15" in the fisrt column (Horizontal Distance X(inches()).  Then move horizontally to the column labeled 3 (pipe diameter used).  Thus, for our hypothetical unit the pumping capacity is approximately 183 gallons per minute.

First Column = Horizontal Distance X (inches)
First Row = Nominal Pipe Diameter (inches)
Last Column = Average Velocity

  1 1.25 1.5 2 2.5 3 4 5 6  8 10 12  
4 6 10 13 22 31 49 84            2.1
5 7 12 16 28 39 61 104 163         2.6
6 9 15 20 33 47 73 125 195 285       3.0
7 10 17 23 39 55 85 146 228 334 580     3.7
8 11 20 27 44 63 &98 166 260 380 665 1060    4.2
9 13  22  30  50  70  110  187  293  430  750  1190 1660  4.7
10  14  25 33  56  78  122 208 326  476  830  1330 1850  5.3
11 16  27  36  61  86 134  229  360 525  915 1460  2200 5.8
12  17 29  40  66  94  146  250 390  570  1000  1600  2220  6.2
13 19  32  43 72  102 158  270 425 620  1080  1730 2400  6.9
14  20  34  47  77  109 170  292  456  670 1160  1860 2590  7.4
15 21 36  50 83  117 183 312  490  710  1250 2000  2780  7.9
16 23  39  53  88  125  196 334  520  760 1330 2120 2960  8.4
17   42  57  93 133 207 355  550  810 1410  2260  3140  9.1
18     60  99 144  220 375  590 860 1500  2390 3330  9.7
19        110  148  232 395 620  910  1580 2520 3500 10.4
20         156  244 415 350  950 1660 2660  3700 10.6
21            256 435 685 1000  1750 2800    11.4
22              460  720 1050 1830 2920   11.8
23               750 1100 1910  3060   12.4
24                 1140  2000 3200   13.0

 

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