Jafar 4495, Operating Manual

Page: 4 / 11

OPERATING MANUAL 07-2021 4/11
DN
[mm]
ISO
5211
Closing/opening torque value on valve shaft required
for (Nm),
gas media*
P/N 4497
Δ p 1.0 [MPa] 1.6 [MPa]
40 F05 16 24
50 F05 24 35
65 F05 31 43
80 F05 43 70
100 F07 66 94
125 F07 110 156
150 F07 156 219
200 F10 329 368
250 F10 438 506
300 F10 625 781
350 F10 1,313 1,594
400 F14 1,719 2,344
500 F14 3,469 4,000
600 F16 5,000 5,781
700 F25 9,219 11,719
800 F25 11,719 14,063
900 F25 13,281 17,188
1000 F25 15,625 19,531
1200 F30 17,188 22,031
Table 2. Operating torque values for gas media
* Applicable to networks which conduct chemically inert gases (e.g. air without oil). For the remaining gas group,
a separate document is available: “
P/N 4497 Operating Manual for Gas Applications ”.
•
The minimum valve switchover time (to close or open) dependent on the DN size (nominal diameter) is listed
in Table 2:
DN (mm) Switchover time (s)
40-350 10
400-600 16
700-800 40
900-1200 50
Table 3. Minimum valve switchover time
The valve switchover time is the minimum time to close or open the valve connected to a pump which delivers a
medium. The time values listed in Table 2 are calculated with the following formula:
=
∙
∙ ℎ ∙ ( − 1)
∙ √
T –> switchover time (s)
L –> piping length (m)
g –> 9.81(m/s
2
)
h –> nominal pressure in metres of sweet water
column
V –> flow rate (m/s)
k –> shockwave pressure rise factor, calculated in
relation to the nominal pressure (1-1.25)
The listed time values are calculated for: L=500(m), V= 4(m/s), k= 1.25. If the closing time is shorter, it is
mandatory to install water hammer dampers (and standard safety valves are unfit for this application).