Sartorius SE2-F - Air Density Determination Procedures

91
Air Density Determination
Equations for Air Density Determination
The balance uses the equation below to calculate the air density for steel and aluminum
based on the reference weights supplied:
m
A
· W
ST
–m
ST
· W
AL
Rho
A
= –––––––––––––––––––––––––––––––––
m
A
· W
ST
m
ST
· W
AL
–––––––––– – –––––––––––
Rho
AL
Rho
ST
where:
Rho
A
= air density [kg/m
3
]
Rho
AL
= density of aluminum [kg/m
3
] Rho
ST
= density of steel [kg/m
3
]
m
A
= mass of aluminum m
ST
= mass of steel
W
AL
= weight value of aluminum W
ST
= weight value of steel
The mass of aluminum is calculated according to the following equation:
m
AL
=M
AL
· (1 – 1.2 / 8000) / (1 – 1.2 / Rho
AL
)
where:
m
AL
= mass of aluminum (specification)
M
AL
= conventional mass value of aluminum
Rho
AL
= density of aluminum [kg/m
3
]
The mass of steel is calculated according to the following equation:
m
ST
=M
ST
· (1 – 1.2 / 8000) / (1 – 1.2 / Rho
ST
)
where:
m
ST
= mass of steel (specification)
M
ST
= conventional mass value of steel
Rho
ST
= density of steel [kg/m
3
]
You can obtain the air density value in one of two ways:
1. Numeric Entry of the Air Density
● Turn on the balance and select the “Application parameters” as described for
Air Buoyancy Correction
● Start application for “Air buoyancy correction”: press
Start
● Start “Air density determination”: press the RhoA soft key
● Use the numeric keys to enter the air density (1.0 – 1.4 kg/m
3
): 1 . 2 ... 0
● Save value for air density: press the
RhoA soft key
● Exit the application for determining the air density: press the
oo soft key
2. Weighing and Saving the Reference Weights for Steel and Aluminum
● See the example on the following pages