MA-037 - CB Watch 3 Operating Manual
v7.0 - May 2020
Page 54 of 118
•
The long-term gas mass leak rate = change in gas mass calculated using the long-
term pressure leak rate and the nominal gas mass in each tank, scaled to a year (in
mass unit per year)
•
The long-term gas percentage leak rate = change in gas percentage calculated using
the long-term pressure leak rate and the nominal gas mass in each tank and the gas
density, scaled to a year (in mass unit per year)
Two values need to be entered during setup for:
•
Initial gas pressure = Nominal (fill) gas pressure
•
Initial gas mass = Nominal (fill) gas mass
per tank
(so the total mass divided by 3 if
there are 3x tanks)
These values are available from the CB name plate
Figure 78
–
Typical CB nameplate with gas info
HMI: Settings/Gas monitoring
Figure 79
–
Nominal gas values entry
Since we know the density of the gas at 20
o
C that goes with these 2 nameplate information
and since we also keep in the long-term stack both the pressure at 20
o
C and the density, we
can therefore calculate the “Long term gas density change rate” in g/l/yr
The long-term gas mass leak rate = Long term gas density change rate x Mass of gas in the
tank
The long-term gas % leak rate = Long term gas mass leak rate / Nominal (fill) gas mass
