TIGERFLOW CD Series - Page 7

09 10
3. TECHNICAL
3.2. Minimum suction pressure
Figure 3:
Drawing of an open system
with a CD pump
Figure 4:
Pressure according to
temperature
Installation, Operation and Maintenance Manual Installation, Operation and Maintenance Manual
3.3. Maximum Pressures
The maximum suction “H” (Figure 3) can be worked out as follows:
H = P
b · 2.31 - NPSH - Hf - Hv
Where:
P
b = Barometric pressure in psi; Pb can be set to 14.7 psi at sea level; In closed systems, pb
indicates the system pressure in psi.
NPSH = Net Positive Suction Head in feet of head; To be read from the NPSH curve at the
highest flow the pump will be delivering.
H
f = Friction loss in inlet pipe in feet of head at the highest flow the pump will be delivering.
H
v = Vapor pressure in feet of head.To be read from the vapor pressure scale. Hv depends
on theliquid temperature tm.
If “H” value is positive, the pump can operate at a maximum suction of “H” FT (meters).
If “H” value is negative, a minimum supply pressure of “H” FT (meters) column of water must
be guaranteed. The pressure while in operation depends on the value calculated for “H”.
Maximum supply pressure and maximum operating pressure can be seen below. However, the actual supply pressure plus the
maximum pump pressure (without flow) must always be below the values in Maximum operating pressure.
Pumps have been tested at 1.5 the maximum suction pressure.
Table1. Maximum Operating Pressure
300
150 (300)
300
300
150 (300)
300
300
300
300
150 (300)
300
150 (300)
300
300
25
16   
30
30
16   
25   
30
25   
30
16   
25
16   
25
25
CD1,3,5,10,15,20
42-7-2~42-7
CD65
65-1-1~65-3
65-4-2~65-5-2
CD85
85-1-1~85-3-2
85-3-1~85-4-2
CDF65,85
CD32
32-1-1~32-6-2
32-6~32-10-2
CDF32
CD42
42-1-1~42-4-2
42-4~42-6
42-7-2~42-7
CDF42
42-1-1~42-6
Model
Max. Working Pressure
Pumps with pressure inside brackets need to specify especially.
(PSI) (bar)
20
15
12
10
8.0
6.0
5.0
4.0
3.0
2.0
1.0
0.8
0.6
0.4
0.3
0.2
0.1
1.5
120
110
90
100
80
70
60
50
40
30
20
10
0
Hv
(m)
tm
(°C)
130
140
25
35
30
66
49
39
33
26
20
16
13
10
6.6
3.3
2.6
2.0
1.3
0.9
0.7
0.3
4.9
250
230
194
212
176
158
140
122
104
86
68
50
32
Hv
(FT)
tm
(°F)
270
280
82
115
98