Page 34 - Know and Understand Centrifugal Pumps

NPSH, Net Positive Suction Head

Properties of water II - Vapor Pressure
~~~ ~~ ~~~_______
Specific Vapor Vapor
Temp. 'F Temp. "C Gravity 60 OF Density Pres. psi Pressure*
Feet Abs.
32 0 1.002 62.42 0.0885 0.204
40 4.4 1.001 62.42 0.1 21 7 0.281
45 7.2 1.001 62.40 0.1475 0.34
50 10 1.001 62.38 0.1 781 0.41 1
55 12.8 1 .ooo 62.36 0.21 41 0.494
60 15.6 1 .ooo 62.34 0.2563 0.591
65 18.3 0.999 62.31 0.3056 0.706
70 21.1 0.999 62.27 0.6331 0.839
75 23.9 0.998 62.24 0.4298 0.994
80 26.7 0.998 62.19 0.5069 1.172
85 29.4 0.997 62.1 6 0.5959 1.379
90 32.2 0.996 62.11 0.6982 1.617
95 35.0 0.995 62.06 0.81 53 1.890
100 37.8 0.994 62.00 0.9492 2.203
110 43.3 0.992 61.84 1.275 2.965
120 48.9 0.990 61.73 1.692 3.943
130 54.4 0.987 61.54 2.223 5.196
140 60.0 0.985 61.39 2.889 6.766
150 65.6 0.982 61.20 3.71 8 8.735
160 71.1 0.979 61.01 4.741 11.172
170 76.7 0.975 60.79 5.992 14.178
180 82.2 0.972 60.57 7.510 17.825
190 87.8 0.968 60.35 9.339 22.257
200 93.3 0.964 60.13 11.526 27.584
21 2 100.0 0.959 59.81 14.696 35.353
220 104.4 0.956 59.63 17.186 41.343
240 11 5.6 0.948 59.10 24.97 60.77
2 60 126.7 0.939 58.51 35.43 87.05
280 137.8 0.929 58.00 49.20 122.18
300 148.9 0.919 57.31 67.01 168.22
320 160.0 0.909 56.66 89.66 227.55
340 171.1 0.898 55.96 11 8.01 303.1 7
3 60 182.2 0.886 55.22 153.04 398.49
380 193.3 0.874 54.47 195.77 51 6.75

4. The Hf, friction head, can be calculated, approximated, or
measured. The friction head can be calculated with the friction
tables for pipe and fittings. You can consult the Hazen Williams
formula, or the Darcy Weisbach formula mentioned in Chapter 8 of
this book. The friction head can be measured with gauges using the

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