VGD
Series
Double
Valves
Technical
Instructions
Document
Number
CC1N7631us
November
08,
2017
Siemens
AG
Building
Technologies
Division
Page
9
Gas
flow
charts
100 2 3 4 5 7 1000 2 3 4 5 7 10000 2 3 4 5 7 100000 2 3
7 100 2 3 4 5 7 1000 2 3 4 5 7 10000 2 3 4 5 7 100000 2
7 100 2 3 4 5 7 1000 2 3 4 5 7 10000 2 3 4 5 7 100000 2
100 2 3 4 5 7 1000 2 3 4 5 7 10000 2 3 4 5 7 100000 2 3
3 4 5 7 10 2 3 4 5 7 100 2 3 4 5 7 1000 2 3 4 5 7
cf/h Natural gas 0.64
1
cf/h Propane gas 1.52
2
cf/h Butane gas 2.00
3
cf/h Air 1.00
4
m3/h Air 1.00
4
Sp. Gr.
1,000
700
500
400
300
200
100
70
50
40
30
20
10
7
5
4
3
2
1
0,7
0,5
0,4
0,3
0,2
1,000
700
500
400
300
200
100
70
50
40
30
20
10
7
5
4
3
2
1
0,7
0,5
0,4
´´W.C. mbar
P
re
s
s
u
re
dr
op
p
7631t0
6us
/121
5
VGD20...
VGD40...
Figure
3.
Sizing
double
valves
Assumptions:
1)
Pressure
downstream
of
valve
is
atmospheric
2)
Maximum
gas
temperature
of
140
°F
3)
Valve
in
fully
open
position
NOTE:
Pressure
drop
is
total
drop
across
both
valves
when
using
a
SKPx5.xxxU
actuator,
with
or
without
an
AGA66.
CAUTION:
Do
not
oversize
valves
equipped
with
regulating
actuators
SKP2x.xxxU,
SKP5x.xxxU
or
SKP7x.xxxU.
Oversizing
may
limit
turndown
and
could
cause
oscillations.
