Siemens SIPROCESS GA700 Compact Operating Instructions page 75

Calculation of leakage rate
A gas path is considered sufficiently tight for normal heated modules when the leakage rate QL
from a gas line (containment system = CS) is less than 10
• Calculation of the leakage rate QL: QL = V Δp / t
The max. permissible leakage rate Q
The leakage test is performed with air or N
introduced during operation, which has half the viscosity of N
leakage rate of Q
• Determination of the test conditions
Monitoring of the max. permissible leakage loss is carried out according to the pressure drop
method. Here, the absolute pressure p of the gas (air or N
is observed, which - if leakage is present - drops by Δp within a specified time interval t. The
amount of duck drop is a measure of the tightness of the CS.
Considering the leakage losses to be determined at the respective device type, a max.
permissible pressure drop Δp
It is calculated as follows: Δp
• Other
If the test volume V
test value Δp
k = V / V
Device variant
Normal heated mod‐
ule, MG path piped,
VG path tubed
Normal heated mod‐
ule, MG path tubed,
VG path tubed
Normal heated mod‐
ule, MG path tubed,
VG path tubed, with‐
out / with VG pressure
switch
Normal heated mod‐
ule, MG path piped,
VG path tubed, with‐
out / with VG pressure
switch
High-temperature
module, MG path pi‐
ped, RG path piped,
without / with RG
pressure switch
Field module, with‐
out / with RG pressure
switch
SIPROCESS GA700 rack and wall mounted devices
Compact Operating Instructions, 06/2023, A5E35134047-AB
= 5∙10 hPa l / s is applied to metal piped analyzer modules.
-4
L
deviates from the V assumed in the calculation of the test values, the
new
must be multiplied by a correction factor k, which is calculated as follows:
max
new
Test pressure p / hPa Gas path volume V
rel. ml
100 8
100 10
500 7 / 8
2000 6 / 7
2000 6,5 / 7,5
2000 15
always refers to the max. pressure occurring in the CS.
L
. In metal piped analyzer modules, H
2
results.
max
= t Q
max
/ Max. permissible leak‐
0
age rate QL/(hPa ∙ l / s)
10 -3
10
-3
10
-3
5 ∙10
5 ∙ 10
ּ
10
-4
5.4 Checking gas paths for leaks
-3 hPa l / s.
. Therefore, a max. permissible
2
) enclosed in the CS with volume V
2
/ V
L
Max. perm. pressure
drop Δp
37
30
42 / 37
25 / 21
-4
23 / 20
-4
2
Commissioning
can also be
2
/ hPa
max
75