Pressure Balance
GB
CPB 3000
WIKA Operating Instructions Pressure Balance Version 1.1
9
2.3.4 How the cross-sectional surface responds to pressure
.
At higher pressures, the effective cross-sectional surface changes due to the pressure load.
The ratio of the cross-section and prevailing pressure is linear within an initial approximation. It is
represented by the coefficient of expansion caused by pressure distortion (
λ
).
pressure
Nominal
1
pressure
Nominal
⋅
+
=
λ
pressure
True
Example:
Measuring point: 1000 bar
System with distortion coefficient: 10
–7
1/bar:
bar
bar
pressure
True
90
.
999
1000
10
1
1
1000
7
=
⋅
⋅
+
=
−
Without the correction, measurements would all be "off" by 0.01 %.
