Lamtec BT300 BurnerTronic, Руководство пользователя

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4 Design and Functions
4.5 Leakage Test for Main Gas Valves
4.5.1 Calculation Example
With BT300 the gas pressure monitor is also applicable to the monitoring of minimal gas pres-
sure. Therefore the minimal gas pressure of the burner must be set.
The valve leakage test time t3 (P 311) would be set by BT300. The time t2 for BT300 is fixed
to 2s. The time t3 (P 311) must be set in a way that the maximum allowable leakage rate Q
Leck
can be securely detected. The maximum leakage rate stated in EN1643 and ISO23551-4 is
0.1% of the nominal volumetric flow of the gases or a minimum of 50l/h.
Example 1
Burner capacity =1000 KW
Fuel = natural gas H, calorific value = 10 kW/m
3
Nominal volumetric flow of the gases = 100 m
3
/h
Leakage rate max. = 0,1 m
3
/h or 100l/h
Example 2
Burner capacity =1000 KW
Fuel = propane, calorific value = 25,9 kW/m
3
Nominal volumetric flow of propane = 38,6 m
3
/h
Leakage rate max. = 50 l/h (not 38,6 l/h)
Calculation
Fig. 4-27 Principle scheme
The test volume V
test
must be calculated with tube diameter and valve volume. The value vol-
umes are provided by the valve manufacturer. If valve 1 and valve 2 are be used as a double
valve, the test volume would be provided by the valve manufacturer.
The leakage test V
Leak
is calculated according to the Boyle-Mariotte principle.