7
Then: H = 33.5'* - NPSHR - H
f
- H
v
- H
s
H = 33.5' - 10' - 1.45' - 2.195' - 1.64 = 18.215'
H = 18.215' = Minimum inlet pressure
* 1 Bar = 14.5 PSI x 2.31 ft. of head = 33.5'
TABLE II – Vapor Pressure of Water
Temperature in °F
(°C)
Vapor Pressure in
PSIA (kPa)
Absolute Pressure in
Feet (m) of Water
32 (0)
0.089 (.61)
0.205 (.062)
40 (4.4)
0.122 (.84)
0.281 (.086)
60 (15.6)
0.256 (1.77)
0.592 (.180)
80 (26.7)
0.507 (3.50)
1.172 (.358)
100 (37.8)
0.95 (6.55)
2.195 (.669)
120 (48.9)
1.695 (11.69)
3.914 (1.193)
140 (60.0)
2.892 (19.94)
6.681 (2.036)
160 (71.1)
4.745 (32.72)
10.961 (3.341)
180 (82.2)
7.515 (51.84)
17.36 (5.291)
200 (93.3)
11.529 (79.49)
26.632 (8.117)
210 (98.9)
14.125 (97.39)
32.629 (9.945)
212 (100)
14.698 (101.34)
33.952 (10.349)
220 (104.4)
17.188 (118.51)
39.704 (12.102)
230 (110.0)
20.78 (143.28)
48.002 (14.631)
240 (115.6)
24.97 (172.17)
57.681 (17.581)
248 (120.0)
28.79 (188.51)
66.505 (20.271)
5
10
15
20
30
25
60
0
0
80
100 120
140
160 180
200
220
NPSHR in Feet
Flow in GPM
PVM 32
Figure 7. Net Positive Suction Head Requirement (NPSHR).
F
F
D
F
D
DB
F
D
D
D
D
D
DB
DB
F
D
D
D
D
D
D
DB
DB
F
D
D
D
D
D
D
D
DB
DB
F
D
D
D
D
D
D
D
D
DB
DB
F
D
D
DB
F
D
D
D
DB
F
D
D
D
D
DB
F
D
D
D
D
D
DB
1
2
3
4
5
6
7
8
9
10
11
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
1
2
3
4
5
6
1
2
3
4
1
2
Type DB and D Stages
Type DB and D Bowl
Type F Stage
Type F Bowl (note
slots for straps)
Collet (D, DB, F)
Locknut (D, DB, F)
Bearing (DB only)
Impeller
Figure 8. Stack assembly order.