O
PERATION
M
ANUAL
VKL
10
/100
V
ERSION
V005-06-2020
14
5.3. The Calibration Certificate
For manufacturing reasons it is not possible to exactly trim the dilution factor to its
theoretical value of 10. Therefore, every single stage is calibrated and the data values are
recorded in a calibration certificate.
You will find the calibration certificate for the delivered dilution stage on the appendix of
this manual. Essentially, it consists of a table and a diagram.
The inlet flow rate V
an
, the clean air flow rate V
r
, and the dilution factor W as a function of
the pre-pressure P, are recorded in the table. The diagram shows the dilution factor (circles)
and the inlet flow rate (dots) as a function of the pre-pressure. The left ordinate gives the
dilution factor while the right ordinate gives the inlet flow rate. As already mentioned in
section 4.1. the dilution system is a self-sucking system. In using table and diagram, the
sample flow rate can now be adjusted to the desired value via the pre-pressure.
Important!
The pre-pressure not only determines the inlet flow rate, but influences also the isokinetic
conditions when sampling the outlet flow out of the mixing chamber. See also point 4.2.
"Selecting appropriate Outlet Nozzles" of this manual.