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Series
KNAR/F, KNARP/F, KNAR-D/F, KNARP-D/F,
KNAR-S/F, KNARP-S/F
1.4
Actuating torques
Test medium:
water 68 °F (20 °C)
Higher actuating torques may occur with other media.
DN
≤ 45
85
[inch]
[in-lbs] [in-lbs] [in-lbs] [in-lbs]
½"
71
71
¾"
71
71
1"
106
106
1½"
177
177
2"
221
221
3"
531
531
4"
708
708
6"
1770
2213
8""
1770
2213
1 in-lbs = 0.112 Nm
The actuating torque of the actuator must be at least
as high as the actuating torque of the valve, about
20% higher being better however.
With highly viscous media and/or solids in the medium
it may be necessary to consider other safety
allowances in dimensioning the actuator. This is
particularly true for non-Newtonian fluids such as high
polymer substances, suspensions, pastes, lubricants,
resins, lacquers etc.
Admissible factors of safety lie in the range of 20 -
50% of the actuating torque.
In order to avoid damage to the valve, it is imperative
to observe the max. admissible actuating torque!
1.5
Cavitation coefficient z for
75% duty (Cv/Cv
There are at least 3 different V-control ball/stem units
for each nominal size
DN
z1
z2
½"
0.65
0.60
¾"
0.65
0.60
1"
0.65
0.60
1½"
2"
3"
4"
6"
8"
9520-032-en
Revision 15
TM 9549
Edition 11/2018
Δp in psi
max. adm.
145
235
[in-lbs]
71
89
620
71
89
620
106
106
620
177
221
1990
221
266
1990
575
708
4425
797
1505
4425
3098
--
19470
3098
--
19913
=0,75)
100
z3
z4
z5
0.60
0.60
0.58
0.43
0.60
0.60
0.58
0.43
0.60
0.60
0.58
0.43
0.53
0.50
0.35
0.47
0.39
0.32
0.31
0.29
0.22
0.27
0.24
0.16
0.15
0.13
0.08
0.15
0.13
0.08
ASME
∆��
��
=
��
��
− ��
1
��
X
= Differential pressure ratio
F
Δp = Differential pressure input/outlet
p
= Absolute pressure at inlet
1
p
= Vapour pressure at operating temp.
v
X
≤ z
F
X
≤ 1,4 x z :
F
X
> 1,4 x z :
F
1.6
Flow values Cv in %
Opening
[%]
10
20
30
40
50
60
70
80
90
100
1.7
Flow rates
There are 3-6 different V-control ball/stem units per
nominal size
DN
[inch]
½"
0.93 1.86
¾"
0.93 1.86
1"
0.93 1.86
z6
1½"
2"
3"
4"
6"
8"/6"
8"
:
non-critical conditions
tolerable cavitation
inadmissible cavitation
Cv
[%]
5.5
7.6
Characteristics
10.5
equal percentage
14.5
rangeability 25:1
20.0
27.6
Best control range
20-90% of angle of
38.1
opening
52.5
72.5
100.0
Cv
[USgpm]
4.66
9.32
16.3
4.66
9.32
16.3
4.66
9.32
16.3
18.64
29.12
18.64
29.12
46.6
46.6
93.2
139.8
69.9
116.5
186.4
186.4
291.25
186.4
291.25
Page 5
23.3
23.3
23.3
46.6
69.9
186.4
291.25
466
466
1165
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