Endress+Hauser NXA820 - Page 37

Tankvision Calculations
Endress+Hauser 37
• Mass in temperature and product property independent
• Mass is needed for "Loss Reconciliation" required for every refinery and terminal
• Mass is calculated out of NSV and the reference density (or GOV and observed density)
8.1.13 Net Weight in Air - NWA
L00-NXA82xxx-16-00-00-xx-075
• The flotation of a body is based on the principle discovered by Archimedes on century 3 BC
"Every submerged body in a liquid experience a vertical upper force that is equal to the
weight of the liquid displaced"
• Considering the liquid displaced is air
• The flotation is related to the liquid density where the body is floating because:
Weight = Vol x Dens.
Calculation formula:
L00-NXA82xxx-16-00-00-xx-057
Dens
Air
Air density
Dens
Ref
Product reference density
Dens
Vap
Vapor density
Dens
Brass
Brass density used to calibrate the weight scale
Net weight in Air methods
The Net Standard Weight in Air is in some countries called Mass.
Air density
WAC
NSW in Air
Liquid Mass/
NSW in VacuumAir
Air corr.
calc.
10.
Net Weight in Air
Calculation
WAC =
NWA = WAC Mass´
1 -
1 -
Dens
Air
Dens
Ref
Dens
Vap
Dens
Brass
WAC Methods Calculated AirDen VapDen BrassDen
Weight in vacuum No 0 0 0
OIML R85 Yes 1.2 1.2 8000
Table 56 Yes 1.22 1.22 8100
Table 57 (short
tons)
Yes≈ 1.2194 1.2194 8393.437
Table 57 (long tons) Yes 1.224 1.224 8135.8
Simplified Yes 1.1 0 1
Custom Yes 1.225 1.225 8553