Burkert 8045 - Page 23

23
8045
ENGLISH
CALIBRATION
4.4.3 K-FACTOR
Within this menu the K-factor of the fitting can be entered manually according to the
DN and material of the used fitting (see Type S020/1500/1501 Fitting reference
manual) or a Teach-In procedure can be completed.
The teach-in procedure consists either of a volume measurement or a comparison
measurement with another flow meter.
4.4.3.1 Manual Calculation of the K-Factor
For manual calculation and entry of the K-factor, the following equation can be used to
determine the value. After the value has been determined select TEACH N within the
K-FACTOR option and enter the determined value.
K
8045
= K
fitting
x F
s
x K
w
Where :
K fitting is the specific K-Factor of the fitting
F
s
is the specific cell constant of the sensor. This value is written
on a sticker on the side of the sensor housing or on the cell
cable.
K
w is the temperature correction coefficient. This only needs to be
used if the temperature > 40°C.
4.4.3
The transmitter uses the last K-factor entered or determined.
The correction coefficient depends on the pipe dimensions. Use the correct
coefficient from the values below.
DN15 =+ 0.2 %/°C Kw= 1-(0,2 x (Tw °C- 20 °C)/100)
DN20/25 =+ 0.1 %/°C Kw= 1-(0,1 x (Tw °C- 20 °C)/100)
> DN25 = + 0.05 %/°C Kw= 1-(0,05 x (Tw °C- 20 °C)/100
To assist with the manual determination of the K-Factor a worked example is
displayed below;
K fitting = 1.69 (DN15 in Brass)
F s = 1.01
Temp. of the fluid = 70°C
K w = 1 - (0.2 x (70°C - 20°C) / 100) = 0.9 (§ 6.1 - Temp. Coeff.)
K 8045 = 1.69 x 1.01 x 0.9 = 1.54