Unigas G225X, Manual Of Installation - Use - Maintenance

Page: 10 / 112

PART I: SPECIFICATIONS
10
To get the input in kcal/h, multiply value in kW by 860.
Data are referred to standard conditions: atmospheric pressure at 1013mbar, ambient temperature at 15° C
NOTE: The performance curve is a diagram that represents the burner performance in the type approval phase or in the laboratory tests, but does not
represent the regulation range of the machine. On this diagram the maximum output point is usually reached by adjsuting the combustion head to its
“MAX” position (see paragraph “Adjusting the combustion head”); the minimum output point is reached setting the combustion head to its “MIN” position.
During the first ignition, the combustion head is set in order to find a compromise between the burner output and the generator specifications, that is why
the minimum output may be different from the Performance curve minimum
Pressure in the Network / gas flow rate curves
Performance Curves
Combustion head gas pressure curves
Combustion head gas pressure depends on gas flow and combustion chamber backpressure. When backpressure is subtracted, it
depends only on gas flow, provided combustion is properly adjusted, flue gases residual O2 percentage complies with “Recommended
combustion values” table and CO in the standard limits). During this stage, the combustion head, the gas butterfly valve and the
Gas
p
ressure in the networkr
[mbar]
G225X M-
Power [kW] Power [kW]
Gas
pressure in the networkr
[mb
ar]
G270X M- G325X M-
Power [kW] Power [kW]
ATTENTION: the gas rate value is quoted on the x-axis, the related network pressure is quoted on the y-axis
(pressure value in the combustion chamber is not included). To know the minimum pressure at the gas train inlet,
necessary to get the requested gas rate, add the pressure value in the combustion chamber to the value read on
the y-axis.
The values in the diagrams refer to natural gas with a calorific value of 8125 kcal/Stm
3
(15°C, 1013 mbar) and a density of
0.714 kg/Stm
3
.
The values in the diagrams refer to GPL with a calorific value of 22300 kcal/Stm
3
(15°C, 1013 mbar) and a density of 2.14 kg/
Stm
3
. When the calorific value and the density change, the pressure values should be adjusted accordingly.
Where:
Natural gas pressure shown in diagram
Real gas pressure
Natural gas flow rate shown in diagram
Real gas flow rate
Natural gas density shown in diagram
Real gas density