Lamtec ETAMATIC, Manual

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65
8 Control Mode
8.2.2 Calculation example
An (approximate) formula for calculating the leakage test monitoring facility is summarised be-
low:
That is, for a maximum gas flow rate of 50 m3/h the formula is:
Insert the numerical value in mbar for Δ P.
The formula for a gas rate of flow Q of >50 m3/h is:
The numerical value is to be inserted in m
3
/h or Q and in mbar for.
A. Assuming: ∆ p = 20 mbar, gas flow rate < 50 m
3
/h
B. Assuming: ∆ p = 20 mbar, gas flow rate < 200 m
3
/h;
Definitions: GDW: gas pressure monitor
V1: gas-side safety shut-off device
V2: burner-side safety shut-off device
P
B
barometric air pressure <1000 mbar
P
SU
lower GDW switching point (falling)
P
SO
upper GDW switching point (rising)
DP = P
SO
- P
B
GDW switching difference
PG gas flow pressure (supply pressure before V1)
V
P
volume of gas line tested
V
L
leakage quantity
V
Lmax
maximum admissible leakage quantity (limit value)
t
P
testing time (30 seconds, fixed)
i.e. the gas line you want to test should not
exceed 20,8 dm
3
, for being able to detect
the required leakage quantity.
i.e. the gas line you want to test should not
exceed 83,3 dm, for binge able to detect
the required leakage quantity of 200 dm
3
/h.