FISCHER PRO-LINE DE90 Operating Manual page 75

FISCHER Mess- und Regeltechnik GmbH
BA_EN_DE90
Linear approximation of the characteristic curve
Field tests have shown that the curvature of the filter characteristic curve is of-
ten very small. In these cases, a linear approximation is completely sufficient.
[Pa] Δp
Q
min
300
250
200
150
100
50
1 2 3 4 5
Fig. 106: Approximated linear filter characteristic curve
∆p correction value
The
linear characteristic curve so that the deviation from the real filter characteristic
curve is minimized over the entire operating range.
[%] [Pa] Δp
300
250
200
Operating point
150
100
100%
50
0%
1 2
Fig. 107: Correction value Linear filter characteristic curve
The measurement errors resulting from the characteristic curve shift are much
smaller than shown in the graph, since the curvature of the real characteristic
curve is significantly smaller. This superelevation was chosen for reasons of
presentation.
Displ.range C3 start
With the parameters
end
the display characteristic curve can be spread appropriately. Since the
limit curve for the contaminated filter is now fixed, the degree of contamination
of the filter can be determined dynamically for any operating point.
Q
max
Δp
max (soiled)
Δp
max (clean)
6 7 8 9 10 [1000 m
parameter can be used to set an offset for the
Q Q
min max
Δp
max (soiled)
Offset
3 4 5 6 7 8 9 10 [1000 m
Volume flow
filter characteristic curve
soiled filter
filter characteristic curve
clean filter
Q
3
/h]
filter characteristic curve
soiled filter
Corrected filter characteristic
curve soiled filter
soiled filter
cleanfilter
Display range
Q
3
/h]
Displ.range C3
and
Operation | 5
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